A ginsenoside G-Rg3 PEGylated Long-Circulating liposome for hyperglycemia and insulin resistance therapy in Streptozotocin-Induced type 2 diabetes mice

Ginsenoside (GS), one of the main active components in ginseng, can enhance insulin sensitivity, improve the function of islet β cells, and reduce cell apoptosis in the treatment of diabetes. However, the drawbacks of high lipid solubility, poor water solubility, and low oral availability in Ginsenoside Rg3 (G-Rg3) seriously limit further application of GS. In this work, a G-Rg3 PEGylated long-circulating liposome (PEG-L-Rg3) is designed and developed to improve symptoms in type 2 diabetic mice. The as-prepared PEG-L-Rg3 with a spherical structure shows a particle size of ∼ 140.5 ± 1.4 nm, the zeta potential of -0.10 ± 0.05 mV, and a high encapsulation rate of 99.8 %. Notably, in vivo experimental results demonstrate that PEG-L-Rg3 exhibits efficient ability to improve body weight and food intake in streptozotocin-induced type 2 diabetic mice. Moreover, PEG-L-Rg3 also enhances fasting insulin (FINS) and insulin sensitivity index (ISI). In addition, the glucose tolerance of mice is significantly improved after the treatment of PEG-L-Rg3, indicating that PEG-L-Rg3 can be a potential drug for the treatment of type 2 diabetes, which provides a new way for the treatment of type 2 diabetes using ginsenosides.

Ji-Ni-De-Xie ameliorates type 2 diabetes mellitus by modulating the bile acids metabolism and FXR/FGF15 signaling pathway

Introduction: Ji-Ni-De-Xie (JNDX) is a traditional herbal preparation in China. It is widely used to treat type 2 diabetes mellitus (T2DM) in traditional Tibetan medicine system. However, its antidiabetic mechanisms have not been elucidated. The aim of this study is to elucidate the underlying mechanism of JNDX on bile acids (BAs) metabolism and FXR/FGF15 signaling pathway in T2DM rats. Methods: High-performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-QQQ-MS) and UPLC-Q-Exactive Orbitrap MS technology were used to identify the constituents in JNDX. High-fat diet (HFD) combined with streptozotocin (45 mg∙kg-1) (STZ) was used to establish a T2DM rat model, and the levels of fasting blood-glucose (FBG), glycosylated serum protein (GSP), homeostasis model assessment of insulin resistance (HOMA-IR), LPS, TNF-α, IL-1β, IL-6, TG, TC, LDL-C, HDL-C, and insulin sensitivity index (ISI) were measured to evaluate the anti-diabetic activity of JNDX. In addition, metagenomic analysis was performed to detect changes in gut microbiota. The metabolic profile of BAs was analyzed by HPLC-QQQ-MS. Moreover, the protein and mRNA expressions of FXR and FGF15 in the colon and the protein expressions of FGF15 and CYP7A1 in the liver of T2DM rats were measured by western blot and RT-qPCR. Results: A total of 12 constituents were identified by HPLC-QQQ-MS in JNDX. Furthermore, 45 chemical components in serum were identified from JNDX via UPLC-Q-Exactive Orbitrap MS technology, including 22 prototype components and 23 metabolites. Using a T2DM rat model, we found that JNDX (0.083, 0.165 and 0.33 g/kg) reduced the levels of FBG, GSP, HOMA-IR, LPS, TNF-α, IL-1β, IL-6, TG, TC, and LDL-C, and increased ISI and HDL-C levels in T2DM rats. Metagenomic results demonstrated that JNDX treatment effectively improved gut microbiota dysbiosis, including altering some bacteria (e.g., Streptococcus and Bacteroides) associated with BAs metabolism. Additionally, JNDX improved BAs disorder in T2DM rats, especially significantly increasing cholic acid (CA) levels and decreasing ursodeoxycholic acid (UDCA) levels. Moreover, the protein and mRNA expressions of FXR and FGF15 of T2DM rats were significantly increased, while the expression of CYP7A1 protein in the liver was markedly inhibited by JNDX. Discussion: JNDX can effectively improve insulin resistance, hyperglycemia, hyperlipidemia, and inflammation in T2DM rats. The mechanism is related to its regulation of BAs metabolism and activation of FXR/FGF15 signaling pathway.

Modified Citrus Pectin (MCP) Confers a Renoprotective Effect on Early-Stage Nephropathy in Type-2 Diabetic Mice

Diabetic nephropathy (DN) is a significant global health concern with a high morbidity rate. Accumulating evidence reveals that Galectin-3 (Gal-3), a β-galactoside-binding lectin, is a biomarker in kidney diseases. Our study aimed to assess the advantageous impacts of modified citrus pectin (MCP) as an alternative therapeutic strategy for the initial and ongoing progression of DN in mice with type 2 diabetes mellitus (T2DM). The animal model has been split into four groups: control group, T2DM group (mice received intraperitoneal injections of nicotinamide (NA) and streptozotocin (STZ), T2DM+MCP group (mice received 100 mg/kg/day MCP following T2DM induction), and MCP group (mice received 100 mg/kg/day). After 4 weeks, kidney weight, blood glucose level, serum kidney function tests, histopathological structure alterations, oxidative stress, inflammation, apoptosis, and fibrosis parameters were determined in renal tissues. Our findings demonstrated that MCP treatment reduced blood glucose levels, renal histological damage, and restored kidney weight and kidney function tests. Additionally, MCP reduced malondialdehyde level and restored glutathione level, and catalase activity. MCP demonstrated a notable reduction in inflammatory and apoptosis mediators TNF-α, iNOS, TGF-βRII and caspase-3. Overall, MCP could alleviate renal injury in an experimental model of DN by suppressing renal oxidative stress, inflammation, fibrosis, and apoptosis mediators.

Analysis of immunohistomorphological changes in the colonic mucosa in a high-saturated fat and high-cholesterol fed streptozotocin/nicotinamide diabetic rat model

The mucosal surface of gastrointestinal tract is lined with epithelial cells that establish an effective barrier between the lumen and internal environment through intercellular junctions, preventing the passage of potentially harmful substances. The "intestinal barrier function" consist of a defensive system that prevent the passage of antigens, toxins, and microbial products, while maintains the correct development of the epithelial barrier, the immune system and the acquisition of tolerance toward dietary antigens and intestinal microbiota. Intestinal morphology changes subsequent to nutritional variations, stress, aging or diseases, which can also affect the composition of the microbiota, altering the homeostasis of the intestine. A growing body of evidence suggests that alterations in intestinal barrier function favor the development of exaggerated immune responses, leading to metabolic endotoxemia, which seems to be the origin of many chronic metabolic diseases such as type 2 diabetes mellitus (T2DM). Although the mechanisms are still unknown, the interaction between dietary patterns, gut microbiota, intestinal mucosa, and metabolic inflammation seems to be a key factor for the development of T2DM, among other diseases. This chapter details the different techniques that allow evaluating the morphological and molecular alterations that lead of the intestinal barrier dysfunction in a T2DM experimental model. To induce both diabetic metabolic disturbances and gut barrier disruption, Wistar rats were fed a high-saturated fat and high-cholesterol diet and received a single dose of streptozotocin/nicotinamide. This animal model may contribute to clarify the understanding of the role of intestinal barrier dysfunction on the late-stage T2DM etiology.

A fetal rat model of ventricular noncompaction caused by intrauterine hyperglycemia

BACKGROUND

This study aims to develop a fetal rat model of ventricular noncompaction (NVM) using streptozotocin (STZ)-induced gestational hyperglycemia and compare it with a retinoic acid (RA) model.

METHODS

Female SD rats were categorized into STZ, RA, and normal control (NC) groups. The STZ group was given a high-fat diet pre-pregnancy and 35 mg/kg of 2% STZ postpregnancy. The RA group received a 90 mg/kg dose of RA on day 13 postpregnancy. Embryonic myocardial morphology was analyzed through HE staining, and embryonic cardiomyocyte ultrastructures were studied using electron microscopy. Diagnoses of NVM were based on a ratio of noncompact myocardium (N) to compact myocardium (C) >1.4, accompanied by thick myocardial trabeculae and a thin myocardial compaction layer. Kruskal-Wallis test determined N/C ratio differences among groups.

RESULTS

Both STZ and RA groups displayed significant NVM characteristics. The left ventricular (LV) N/C in the STZ, RA, and NC groups were 1.983 (1.423-3.527), 1.640 (1.197-2.895), and 0.927 (0.806-1.087), respectively, with a statistically significant difference (P<0.001). The right ventricular (RV) N/C in the STZ, RA, and NC groups were 2.097 (1.364-3.081), 1.897 (1.337-2.662), and 0.869 (0.732-1.022), respectively, with a significant difference (P<0.001). Electron microscopy highlighted marked endoplasmic reticulum swelling in embryonic cardiomyocytes from both STZ and RA groups.

CONCLUSION

Our model underscores the pivotal role of an adverse intrauterine developmental environment in the onset of NVM. This insight holds significant implications for future studies exploring the pathogenesis of NVM.

Fabrication of gelatin coated polycaprolactone nanofiber scaffolds co-loaded with luliconazole and naringenin for treatment of Candida infected diabetic wounds

The current study focuses on the development of gelatin-coated polycaprolactone (PCL) nanofibers co-loaded with luliconazole and naringenin for accelerated healing of infected diabetic wounds. Inherently, PCL nanofibers have excellent biocompatibility and biodegradation profiles but lack bioadhesion characteristics, which limits their use as dressing materials. So, coating them with a biocompatible and hydrophilic material like gelatin can improve bioadhesion. The preparation of nanofibers was done with the electrospinning technique. The solid state characterization and in-vitro performance assessment of nanofibers indicate the formation of uniformly interconnected nanofibers of 200-400 nm in diameter with smooth surface topography, excellent drug entrapment, and a surface pH of 5.6-6.8. The antifungal study showed that the nanofiber matrix exhibits excellent biofilm inhibition activity against several strains of Candida. Further, in-vivo assessment of nanofiber performance on C. albicans infected wounds in diabetic rats indicated accelerated wound healing efficacy in comparison to gauge-treated groups. Additionally, a higher blood flow and rapid re-epithelialization of wound tissue in the treatment group corroborated with the results obtained in the wound closure study. Overall, the developed dual-drug-loaded electrospun nanofiber mats have good compatibility, surface properties, and excellent wound healing potential, which can provide an extra edge in the management of complex diabetic wounds.

Formulation and characterization of polyvinyl alcohol/chitosan composite nanofiber co-loaded with silver nanoparticle & luliconazole encapsulated poly lactic-co-glycolic acid nanoparticle for treatment of diabetic foot ulcer

Chronic wounds are prone to fungal infections, possess a significant challenge, and result in substantial mortality. Diabetic wounds infected with Candida strains are extremely common. It can create biofilm at the wound site, which can lead to antibiotic resistance. As a result, developing innovative dressing materials that combat fungal infections while also providing wound healing is a viable strategy to treat infected wounds and address the issue of antibiotic resistance. Present work proposed anti-infective dressing material for the treatment of fungal strains Candida-infected diabetic foot ulcer (DFU). The nanofiber was fabricated using polyvinyl Alcohol/chitosan as hydrogel base and co-loaded with silver nanoparticles (AgNP) and luliconazole-nanoparticles (LZNP) nanoparticles, prepared using PLGA. Fabricated nanofibers had pH close to target area and exhibited hydrophilic surface suitable for adhesion to wound area. The nanofibers showed strong antifungal and antibiofilm properties against different strains of Candida; mainly C. albicans, C. auris, C. krusei, C. parapsilosis and C. tropicalis. Nanofibers exhibited excellent water retention potential and water vapour transmission rate. The nanofibers had sufficient payload capacity towards AgNP and LZNP, and provided controlled release of payload, which was also confirmed by in-vivo imaging. In-vitro studies confirmed the biocompatibility and enhanced proliferation of Human keratinocytes cells (HaCaT). In-vivo studies showed accelerated wound closure by providing ant-infective action, supporting cellular proliferation and improving blood flow, all collectively contributing in expedited wound healing.

The effect of Iranian snake, Naja naja oxiana venom on the blood glucose concentration and some biochemical parameters of experimental diabetic rats

Diabetes is a chronic disease resulting from impaired insulin production and function; leading to hyperglycaemia and long-term complications. The treatment for Type I diabetes treatment involves insulin injections while Type II diabetes treatments include drugs such as metformin and sulfonylureas, along with lifestyle changes. These medicines can be expensive and may have adverse effects. Therefore, the search for new therapeutic agents continues. Venoms from various animals yield numerous pharmacologically active compounds. In this study, we investigated the effects of the venom from an Iranian snake, Naja naja oxiana, on blood glucose concentration and certain serum biochemical parameters in male rats with induced diabetes. Diabetes was induced in male rats using either a single injection of streptozotocin (STZ) alone (55 mg/kg i. p.) or STZ (65 mg/kg i. p.) preceded by nicotinamide (230/kg i. p.) administered 15 min earlier. The diabetic rats produced by either method received a single injection of either vehicle or venom (0.2 or 0.4 mg/kg i. p.). In the STZ rats, this was done 13 days after diabetes induction, while in the STZ-nicotinamide rats, venom was injected 3 days after diabetes induction. The venom from Naja naja oxiana significantly reduced blood glucose levels in male rats with diabetes induced by either method. Additionally, the venom decreased serum cholesterol and triglycerides concentrations. However, the venom had no effect on the blood glucose levels of healthy male rats. Pretreatment with the venom did not prevent the induction of diabetes by STZ. These findings suggest that Naja naja oxiana venom exhibits an anti-diabetic effect and could be a potential candidate for effectively controlling diabetes.

Ketogenic diet preserves muscle mass and strength in a mouse model of type 2 diabetes

Diabetes is often associated with reduced muscle mass and function. The ketogenic diet (KD) may improve muscle mass and function via the induction of nutritional ketosis. To test whether the KD is able to preserve muscle mass and strength in a mouse model of type 2 diabetes (T2DM), C57BL/6J mice were assigned to lean control, diabetes control, and KD groups. The mice were fed a standard diet (10% kcal from fat) or a high-fat diet (HFD) (60% kcal from fat). The diabetic condition was induced by a single injection of streptozotocin (STZ; 100 mg/kg) and nicotinamide (NAM; 120 mg/kg) into HFD-fed mice. After 8-week HFD feeding, the KD (90% kcal from fat) was fed to the KD group for the following 6 weeks. After the 14-week experimental period, an oral glucose tolerance test and grip strength test were conducted. Type 2 diabetic condition induced by HFD feeding and STZ/NAM injection resulted in reduced muscle mass and grip strength, and smaller muscle fiber areas. The KD nutritional intervention improved these effects. Additionally, the KD altered the gene expression of nucleotide-binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome- and endoplasmic reticulum (ER) stress-related markers in the muscles of diabetic mice. Collectively, KD improved muscle mass and function with alterations in NLRP3 inflammasome and ER stress.

Animal models for induction of diabetes and its complications

Objectives

Animal models are widely used to develop newer drugs for treatment of diabetes and its complications. We conducted a systematic review to find various animal models to induce diabetes and also the suitable methods in various diabetic complications. With an emphasis on the animal models of diabetes induction, this review provides a basic overview of diabetes and its various types. It focused on the use of rats and mice for chemical, spontaneous, surgical, genetic, viral, and hormonal induction approaches.

Methods

All observations and research conducted on Diabetes and its complications published up to 18 May 2023 in PubMed, Web of Science, Scopus and Conchrane Library databases were included. Main outcome measures were reporting the induction of diabetes in experimental animals, the various animal models for diabetic complications including diabetic nephropathy, diabetic retinopathy, diabetic neuropathy and diabetic osteopathy. The quality of reporting of included articles and risk of bias were assessed.

Results

We reached various articles and found that rats and mice are the most frequently used animals for inducing diabetes. Chemical induction is the most commonly used followed by spontaneous and surgical methods. With slight modification various breeds and species are developed to study and induce specific complications on eyes, kidneys, neurons and bones.

Conclusions

Our review suggested that rats and mice are the most suitable animals. Furthermore, chemical induction is the method frequently used by experimenters. Moreover, high quality studies are required to find the suitable methods for diabetic complications.

Acute and sub-chronic toxicity of Liberin, an anti-diabetic polyherbal formulation in rats

BACKGROUND

The polyherbal formulation (PHF) liberin, is known to exert anti-hyperglycemic effects in type 2 diabetes mellitus. Hence, it is important to study the safety profile of PHF in the current study through acute and chronic toxicity evaluation.

OBJECTIVES

This research aims to assess the acute and sub-chronic toxicity of PHF in rats.

MATERIALS AND METHODS

PHF was administered once orally (1000 mg/kg body weight), and the rats (male and female) were monitored for toxicity signs for a 14-day period. For a 28-day chronic toxicity study, rats were daily administered with PHF dose of 500 mg/kg and 1000 mg/kg body weight. Rats were followed up for mortality, weight changes, and other morbidities. Further haematological, biochemical, and histopathological changes were assessed.

RESULTS

No death related to treatment or toxicity signs were recorded in the acute single-dose administration group. The results showed that the PHF was tolerated well up to a dose of 1000 mg/kg body weight. Even at the high dose of 1000 mg/kg body weight, sub-chronic tests did not show any significant difference between the dosed and normal groups. No significant changes were seen in the histopathological analysis of the liver, spleen, and kidney as well as haematological and biochemical parameters in acute, sub-chronic and satellite groups following the administration of PHF.

CONCLUSION

The results confirmed that there was no adverse effect of this PHF at the maximum dose of 1000 mg/kg body weight in Wistar rats. Further, no adverse delayed effects related to PHF were observed in the satellite group. Therefore, this PHF appears safe for therapeutic purposes in the Ayurvedic medicinal system.

Diabetic retinopathy: a comprehensive update on in vivo, in vitro and ex vivo experimental models

Diabetic retinopathy (DR), one of the leading causes of visual impairment and blindness worldwide, is one of the major microvascular complications in diabetes mellitus (DM). Globally, DR prevalence among DM patients is 25%, and 6% have vision-threatening problems among them. With the higher incidence of DM globally, more DR cases are expected to be seen in the future. In order to comprehend the pathophysiological mechanism of DR in humans and discover potential novel substances for the treatment of DR, investigations are typically conducted using various experimental models. Among the experimental models, in vivo models have contributed significantly to understanding DR pathogenesis. There are several types of in vivo models for DR research, which include chemical-induced, surgical-induced, diet-induced, and genetic models. Similarly, for the in vitro models, there are several cell types that are utilised in DR research, such as retinal endothelial cells, Müller cells, and glial cells. With the advancement of DR research, it is essential to have a comprehensive update on the various experimental models utilised to mimic DR environment. This review provides the update on the in vitro, in vivo, and ex vivo models used in DR research, focusing on their features, advantages, and limitations.

Targeting β Cells with Cathelicidin Nanomedicines Improves Insulin Function and Pancreas Regeneration in Type 1 Diabetic Rats

Type 1 diabetes (T1D) is an incurable condition with an increasing incidence worldwide, in which the hallmark is the autoimmune destruction of pancreatic insulin-producing β cells. Cathelicidin-based peptides have been shown to improve β cell function and neogenesis and may thus be relevant while developing T1D therapeutics. In this work, a cathelicidin-derived peptide, LLKKK18, was loaded in poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), surface-functionalized with exenatide toward a GLP-1 receptor, aiming the β cell-targeted delivery of the peptide. The NPs present a mean size of around 100 nm and showed long-term stability, narrow size distribution, and negative ζ-potential (-10 mV). The LLKKK18 association efficiency and loading were 62 and 2.9%, respectively, presenting slow and sustained in vitro release under simulated physiologic fluids. Glucose-stimulated insulin release in the INS-1E cell line was observed in the presence of the peptide. In addition, NPs showed a strong association with β cells from isolated rat islets. After administration to diabetic rats, NPs induced a significant reduction of the hyperglycemic state, an improvement in the pancreatic insulin content, and glucose tolerance. Also remarkable, a considerable increase in the β cell mass in the pancreas was observed. Overall, this novel and versatile nanomedicine showed glucoregulatory ability and can pave the way for the development of a new generation of therapeutic approaches for T1D treatment.

Neuroprotective effects of terpenoids against streptozotocin-nicotinamide-induced diabetic rats: An in silico, in vitro and in vivo study

The present study focused to determine the neuroprotective effects of terpenoids in streptozotocin & nicotinamide-induced type-2 diabetes in rats. The in silico studies were carried out for 68 terpenoids using AutoDock 4.2. The in vitro cholinestrerase, α-amylase enzyme inhibitory assays were perfomed using standard procedures. For in vivo neuroprotective studies, male wistar rats were separated into five groups and each group comprised of six animals. Treatment groups were received low dose and high dose α-Bisabolol 100 and 200 mg/kg respectively, and the standard groups received rivastigmine 2 mg/kg, p.o. and metformin group 100 mg/kg, p.o. for 30 consecutive days. Administration of streptozotocin (45 mg/kg, i.p.) and nicotinamide (110 mg/kg, i.p.)-induced the type 2 diabetes in all groups except the control. The behavioural assessments such as Morris water maze, and open field test were performed and biochemical parameters such as acetylcholinesterase levels and enzymatic antioxidants and reduced glutathione level were estimated from brain homogenates. Treatment of diabetic rats with α-Bisabolol was lowered blood glucose level, improved spatial recognition memory in behavioural assessments in a concentration dependent manner. It can be concluded that α-Bisabolol could act as a potential drug candidate in the management of diabetic Alzheimer's disease.

Orange Peel Extract and Physical Exercise Synergistically Ameliorate Type 2 Diabetes Mellitus-Induced Dysmetabolism by Upregulating GLUT4 Concentration in Male Wistar Rats

Diabetes mellitus (DM) is a chronic disease and one of the oldest known disorders. It is characterized by dysglycemia, dyslipidemia, insulin resistance (IR), and pancreatic cell dysfunction. Although different drugs, metformin (MET), glipizide, glimepiride, etc., have been introduced to treat type 2 DM (T2DM), these drugs are not without side effects. Scientists are now seeking natural treatments such as lifestyle modification and organic products known with limited side effects. Thirty-six male Wistar rats were randomized into six groups (n = 6 per group): control, DM untreated rats, DM+orange peel extract (OPE), DM+exercise (EX), DM+OPE +EX, and DM+MET. The administration was once daily through the oral route and lasted for 28 days. EX and OPE synergistically ameliorated the diabetic-induced increase in fasting blood sugar, homeostatic model assessment for insulin resistance (HOMA IR), total cholesterol (TC) and triglyceride (TG), TC/high-density lipoprotein (HDL), TG/HDL, triglyceride glucose (TyG) index, and hepatic lactate dehydrogenase, alanine transaminase, malondialdehyde, c-reactive protein, and tumour necrosis factor α when compared with the diabetic untreated group. Also, EX+OPE blunted DM-induced decrease in serum insulin, homeostasis model assessment of β-cell function (HOMA-B), homeostasis model assessment of insulin sensitivity (HOMA S), quantitative insulin-sensitivity check index (QUICK 1), HDL, total antioxidant capacity, superoxide dismutase, and hepatic glycogen. Furthermore, EX+OPE ameliorated the observed DM-induced decrease in glucose transporter type 4 (GLUT 4), expression. This study showed that OPE and EX synergistically ameliorate T2DM-induced dysglycaemia, dyslipidaemia, and down-regulation of GLUT4 expression.

Modulatory role of Coriandrum sativum (coriander) extract against diabetic complications on the gonads of female rats and their offspring

It is well known that diabetes is associated with impairment of ovarian and testicular structure and function. Coriander (Coriandrum sativum L.) is identified as one of the oldest herbal plants valued for its nutritional and medicinal properties. This work is mainly designed to evaluate the possible modulatory role of dry coriander fruit extract against gonadal impairments associated with diabetes in female rats and their pups. Twenty-four pregnant rats were divided into four groups (n = 6): group I served as control, group II was administered daily with coriander fruit extract (250 mg/kg b.wt), group III was injected interaperitoneally with a single dose of streptozotocin (STZ) (80 mg/kg b.wt), and group IV was injected with single dose of STZ and post administered coriander extract. The experiment was conducted from the 4th day of gestation till the end of weaning. At the end of the experiment, the mothers' rats and their offspring were weighed, sacrificed, the ovaries from mothers as well as ovaries and testes from offspring were immediately excised, and processed for histological, immunohistochemical and evaluation of apoptosis and transforming growth factorβ (TGF-β). Also, blood samples were collected and analyzed to estimate the levels of sex hormones as well as antioxidants.In STZ induced diabetes in mother's rats and their offspring, the ovarian sections revealed severe histopathological signs included several atretic follicles, dilated and congested blood capillaries. Additionally, the testicular sections of offspring appeared with destructive seminiferous tubules. Immunohistochemically, the ovarian sections displayed weak to negative expression for calretinin marker however the testicular sections showed strong expression for Bax protein (apoptotic marker) and weak to negative expression for Ki67 protein (proliferative marker). Also, the mean % values of positively expressed cells for TGF-β and annexin-v markers (late and early apoptosis indicator) were significantly elevated in the ovarian and testicular tissues of STZ-induced group of mother's rats and their pups if compared with control. Further results revealed that the levels of insulin, FSH, LH, estrogen, SOD and CAT were significantly decreased if compared with control however the levels of MDA and NO were significantly elevated. Administration of coriander fruit extract to diabetic rats successfully alleviated most of the altered histological, immunohistochemical, biochemical, and apoptotic changes induced by diabetes. Coriandrum sativum fruit extract has a powerful ameliorative role against STZ-induced diabetic gonadal dysfunctions in female rats and their offspring.

Horsetail (Equisetum hyemale) Extract Accelerates Wound Healing in Diabetic Rats by Modulating IL-10 and MCP-1 Release and Collagen Synthesis

Traditionally, Equisetum hyemale has been used for wound healing. However, its mechanism of action remains to be elucidated. For this purpose, a 40% ethanolic extract of E. hyemale was prepared. Phytochemical screening revealed the presence of minerals, sterols, phenolic acids, flavonols, a lignan, and a phenylpropenoid. The extract reduced the viability of RAW 264.7 cells and skin fibroblasts at all times evaluated. On the third day of treatment, this reduction was 30–40% and 15–40%, respectively. In contrast, the extract increased the proliferation of skin fibroblasts only after 48 h. In addition, the extract increased IL-10 release and inhibited MCP-1 release. However, the extract did not affect both TGF-β1 and TNF-α released by RAW 264.7 cells. The higher release of IL-10 could be related to the up-/downregulation of inflammatory pathways mediated by the extract components associated with their bioactivity. The extract inhibited the growth of Staphylococcus aureus and Escherichia coli. Topical application of the extract accelerated wound healing in diabetic rats by increasing fibroblast collagen synthesis. These results suggest that E. hyemale extract has great potential for use in the treatment of wounds thanks to its phytochemical composition that modulates cytokine secretion, collagen synthesis, and bacterial growth.

Altered sialin mRNA gene expression in type 2 diabetic male Wistar rats: implications for nitric oxide deficiency

Nitrate therapy has been suggested to boost nitric oxide (NO) levels in type 2 diabetes (T2D); however, little is known about nitrate transport across the membranes. This study aimed to assess changes in the mRNA expression of sialin, as a nitrate transporter, in the main tissues of rats with T2D. Rats were divided into two groups (n = 6/group): Control and T2D. A high-fat diet combined with a low dose of streptozotocin (STZ, 30 mg/kg) was used to induce T2D. At month 6, samples from the main tissues of rats were used to measure the mRNA expression of sialin and levels of NO metabolites. Rats with T2D had lower nitrate levels in the soleus muscle (66%), lung (48%), kidney (43%), aorta (30%), adrenal gland (58%), epididymal adipose tissue (eAT) (61%), and heart (37%) and had lower nitrite levels in the pancreas (47%), kidney (42%), aorta (33%), liver (28%), eAT (34%), and heart (32%). The order of sialin gene expression in control rats was: soleus muscle > kidney > pancreas > lung > liver > adrenal gland > brain > eAT > intestine > stomach > aorta > heart. Compared to controls, rats with T2D had higher sialin mRNA expressions in the stomach (2.1), eAT (2.0), adrenal gland (1.7), liver (8.9), and soleus muscle (3.4), and lower sialin expression in the intestine (0.56), pancreas (0.42), and kidney (0.44), all P values < 0.05. These findings indicate altered sialin mRNA expression in the main tissues of male T2D rats and may have implications for future NO-based treatment of T2D.

Invitro impact of a combination of red and infrared LEDs, infrared laser and magnetic field on biomarkers of oxidative stress and hemolysis of erythrocytes sampled from healthy individuals and diabetes patients

AIMS

Low-intensity infrared laser irradiation with output emissions of the laser and LED for in vitro irradiation of plasma and erythrocyte samples collected from healthy individuals and diabetes mellitus (DM) patients was used in the current study.

METHODS

The generated emission was in the range 0.85-0.89 nm with pulse duration near 130 ns and repetition rates of pulses 50, 150, 600, and 1500 Hz, average power 0, 50, or 100 mW, in the range of 1-9 min for different 30 variants of irradiation. The levels of 2-thiobarbituric-acid reactive substances (TBARS), aldehydic and ketonic derivatives of oxidatively modified proteins (OMP), total antioxidant capacity (TAC), acid-induced resistance of erythrocytes, and activities of the main antioxidant enzymes were assessed in erythrocyte and plasma samples after irradiation.

RESULTS

The low-intensity infrared laser irradiation and low-intensity light emitted by a red LED decreased the lipid peroxidation levels in the erythrocytes of both healthy individuals and DM patients. A statistically significant decrease in TBARS and OMP levels and an increase in the TAC level were observed at the irradiation energy of 34.39 and 68.79 J/cm² for samples collected from both healthy individuals and DM patients. The effects of the irradiation were accompanied by a statistically significant decrease in catalase activity of both healthy individuals and DM patients.

CONCLUSIONS

In many variants of the laser irradiation and low-intensity light emitted by a red LED used in our study, a decrease in the percent of hemolyzed erythrocytes was observed, suggesting that laser therapy protocols should take into account fluencies, frequencies, and wavelengths of the laser before the beginning of treatment, especially in DM patients.

Rodent models for diabetes

Diabetes mellitus (DM) is associated with many health complications and is potentially a morbid condition. As prevalence increases at an alarming rate around the world, research into new antidiabetic compounds with different mechanisms is the top priority. Therefore, the preclinical experimental induction of DM is imperative for advancing knowledge, understanding pathogenesis, and developing new drugs. Efforts have been made to examine recent literature on the various induction methods of Type I and Type II DM. The review summarizes the different in vivo models of DM induced by chemical, surgical, and genetic (immunological) manipulations and the use of pathogens such as viruses. For good preclinical assessment, the animal model must exhibit face, predictive, and construct validity. Among all reported models, chemically induced DM with streptozotocin was found to be the most preferred model. However, the purpose of the research and the outcomes to be achieved should be taken into account. This review was aimed at bringing together models, benefits, limitations, species, and strains. It will help the researcher to understand the pathophysiology of DM and to choose appropriate animal models.

The effect of dapagliflozin on myocardial ischemia-reperfusion injury in diabetic rats

The incidence of ischemic heart disease is 2-3 times higher in diabetic patients. However, the effect of dapagliflozin on ischemia-reperfusion myocardial injury in diabetic rats has not been studied. We examined the effects of dapagliflozin on myocardial IR injury in streptozotocin-nicotinamide-induced diabetic rats. Rats were divided into four groups (n = 7 in each group): control, control-dapagliflozin, diabetes, and diabetes-dapagliflozin. Dapagliflozin (1.5 mg/kg/day) was administered concomitantly in drinking water for 2 months. The hearts were perfused in a Langendorff's apparatus at 2 months and assessed before (baseline) and after myocardial IR for the following parameters: left ventricular developed pressure (LVDP), minimum and maximum rates of pressure change in the left ventricle (±dP/dt), endothelial nitric oxide (NO) synthase (eNOS) and inducible NO synthase (iNOS) mRNA expressions, creatine kinase MB (CK-MB) and troponin imyocardial enzyme extravasation, and lactate dehydrogenase. The recovery of LVDP and ±dP/dt in diabetic rats was lower than that in controls but near normal after dapagliflozin treatment. Diabetic rats had decreased eNOS expression and increased iNOS expression at baseline and after IR, whereas dapagliflozin normalized these parameters after IR. Compared with controls, cardiac NOx levels were initially lower in diabetic patients but higher after IR. Baseline MDA levels were higher in diabetic rats after IR, whereas cardiac NOx levels decreased after treatment with dapagliflozin. Dapagliflozin protects the diabetic rat heart from ischemia-reperfusion myocardial injury by regulating the expression of eNOS and iNOS and inhibiting cardiac lipid peroxidation.

Efficacy of Polydeoxyribonucleotide in Promoting the Healing of Diabetic Wounds in a Murine Model of Streptozotocin-Induced Diabetes: A Pilot Experiment

We assessed the efficacy of polydeoxyribonucleotide (PDRN) in accelerating the healing of diabetic wounds in a murine model of streptozotocin (STZ)-induced diabetes. After the creation of diabetic wounds, the mice of the PDRN SC, PDRN IP and PBS groups received a subcutaneous, an intra-peritoneal injection of PDRN and a subcutaneous injection of PBS, respectively. After euthanasia, time-dependent changes in the wound diameter and histologic scores were measured and vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1) and collagen types I and III were assessed for their expression levels. The PDRN SC and the PDRN IP groups showed a significantly smaller diameter of diabetic wounds, significantly higher histologic scores, a significantly greater expression of VEGF, a significantly lower expression of TGF-β1 and a significantly greater expression of collagen types I and III as compared with the PBS group (p < 0.05 or 0.0001). In conclusion, PDRN might be effective in promoting the healing of diabetic wounds in a murine model of STZ-induced diabetes.

Ageratina adenophora (Spreng.) King & H. Rob. Standardized leaf extract as an antidiabetic agent for type 2 diabetes: An in vitro and in vivo evaluation

Type 2 diabetes has become one of the major health concerns of the 21st century, marked by hyperglycemia or glycosuria, and is associated with the development of several secondary health complications. Due to the fact that chemically synthesized drugs lead to several inevitable side effects, new antidiabetic medications from plants have gained substantial attention. Thus, the current study aims to evaluate the antidiabetic capacity of the Ageratina adenophora hydroalcoholic (AAHY) extract in streptozotocin-nicotinamide (STZ-NA)-induced diabetic Wistar albino rats. The rats were segregated randomly into five groups with six rats each. Group I was normal control, and the other four groups were STZ-NA-induced. Group II was designated diabetic control, and group III, IV, and V received metformin (150 mg/kg b.w.) and AAHY extract (200 and 400 mg/kg b.w.) for 28 days. Fasting blood glucose, serum biochemicals, liver and kidney antioxidant parameters, and pancreatic histopathology were observed after the experimental design. The study concludes that the AAHY extract has a significant blood glucose lowering capacity on normoglycemic (87.01 ± 0.54 to 57.21 ± 0.31), diabetic (324 ± 2.94 to 93 ± 2.04), and oral glucose-loaded (117.75 ± 3.35 to 92.75 ± 2.09) Wistar albino rats. The in vitro studies show that the AAHY extract has α-glucosidase and α-amylase inhibitory activities which can restore the altered blood glucose level, glycated hemoglobin, body weight, and serum enzymes such as serum glutamic pyruvic transaminase, serum glutamic oxaloacetic transaminase, serum alkaline phosphatase, total protein, urea, and creatinine levels close to the normal range in the treated STZ-NA-induced diabetic rats. The evaluation of these serum biochemicals is crucial for monitoring the diabetic condition. The AAHY extract has significantly enhanced tissue antioxidant parameters, such as superoxide dismutase, glutathione, and lipid peroxidation, close to normal levels. The presence of high-quantity chlorogenic (6.47% w/w) and caffeic (3.28% w/w) acids as some of the major phytoconstituents may contribute to the improvement of insulin resistance and oxidative stress. The study provides scientific support for the utilization of A. adenophora to treat type 2 diabetes in the STZ-NA-induced diabetic rat model. Although the preventive role of the AAHY extract in treating Wistar albino rat models against type 2 diabetes mellitus is undeniable, further elaborative research is required for efficacy and safety assessment in human beings.

Therapeutic Efficacy of Natural Product 'C-Phycocyanin' in Alleviating Streptozotocin-Induced Diabetes via the Inhibition of Glycation Reaction in Rats

Diabetes is a long-term metabolic disorder characterized by persistently elevated blood sugar levels. Chronic hyperglycemia enhances glucose-protein interactions, leading to the formation of advanced glycation end products (AGEs), which form irreversible cross-links with a wide variety of macromolecules, and accumulate rapidly in the body tissues. Thus, the objective of this study was to assess the therapeutic properties of C-phycocyanin (C-PC) obtained from Plectonema species against oxidative stress, glycation, and type 2 diabetes mellitus (T2DM) in a streptozotocin (STZ)-induced diabetic Wistar rat. Forty-five days of C-PC administration decreased levels of triglycerides (TGs), blood glucose, glycosylated hemoglobin, (HbA1c), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), liver and kidney function indices, and raised body weight in diabetic rats. C-PC suppressed biochemical glycation markers, as well as serum carboxymethyllysine (CML) and fluorescent AGEs. Additionally, C-PC maintained the redox state by lowering lipid peroxidation and protein-bound carbonyl content (CC), enhancing the activity of high-density lipoprotein cholesterol (HDL-C) and renal antioxidant enzymes, and preserving retinal and renal histopathological characteristics. Thus, we infer that C-PC possesses antidiabetic and antiglycation effects in diabetic rats. C-PC may also act as an antidiabetic and antiglycation agent in vivo that may reduce the risk of secondary diabetic complications.

Palm Oil Derived Tocotrienol-Rich Fraction Attenuates Vascular Dementia in Type 2 Diabetic Rats

Vascular dementia (VaD) is a serious global health issue and type 2 diabetes mellitus (T2DM) patients are at higher risk. Palm oil tocotrienol-rich fraction (TRF) exhibits neuroprotective properties; however, its effect on VaD is not reported. Hence, we evaluated TRF effectiveness in T2DM-induced VaD rats. Rats were given a single dose of streptozotocin (STZ) and nicotinamide (NA) to develop T2DM. Seven days later, diabetic rats were given TRF doses of 30, 60, and 120 mg/kg orally for 21 days. The Morris water maze (MWM) test was performed for memory assessment. Biochemical parameters such as blood glucose, plasma homocysteine (HCY) level, acetylcholinesterase (AChE) activity, reduced glutathione (GSH), superoxide dismutase (SOD) level, and histopathological changes in brain hippocampus and immunohistochemistry for platelet-derived growth factor-C (PDGF-C) expression were evaluated. VaD rats had significantly reduced memory, higher plasma HCY, increased AChE activity, and decreased GSH and SOD levels. However, treatment with TRF significantly attenuated the biochemical parameters and prevented memory loss. Moreover, histopathological changes were attenuated and there was increased PDGF-C expression in the hippocampus of VaD rats treated with TRF, indicating neuroprotective action. In conclusion, this research paves the way for future studies and benefits in understanding the potential effects of TRF in VaD rats.

In Vitro and In Vivo Evaluation of the Antidiabetic Activity of Solidago virgaurea Extracts

Background

Solidago virgaurea (Asteraceae) has been used for more than 700 years for treating cystitis, chronic nephritis, urolithiasis, rheumatism, and inflammatory diseases. However, the antidiabetic activity of Solidago virgaurea has been rarely studied.

Methods

Three extracts of Solidago virgaurea were prepared, and their antidiabetic potentials were evaluated by various cell-free, cell-based, and in vivo studies.

Results

We found that the Solidago virgaurea contained multiple bioactive phytochemicals based on the GC-MS analysis. The Solidago virgaurea extracts effectively inhibited the functions of the carbohydrate digestive enzyme (α-glucosidase) and protein tyrosine phosphatase 1B (PTP1B), as well as decreased the amount of advanced glycation end products (AGEs). In the L6 myotubes, the Solidago virgaurea methanolic extract remarkably enhanced the glucose uptake via the upregulation of glucose transporter type 4 (GLUT4). The extract also significantly downregulated the expression of PTP1B. In the streptozotocin-nicotinamide induced diabetic mice, the daily intraperitoneal injection of 100 mg/kg Solidago virgaurea methanolic extract for 24 days, substantially lowered the postprandial blood glucose level with no obvious toxicity. The extract's anti-hyperglycemic effect was comparable to that of the glibenclamide treatment.

Conclusion

Our findings suggested that the Solidago virgaurea extract might have great potential in the prevention and treatment of diabetes.

R, T. K. P, Naik MR, S. J. A novel family of small molecule HIF-1 alpha stabilizers for the treatment of diabetic wounds; an integrated in silico, in vitro, and in vivo strategy

Hypoxia-inducible factor-1 alpha (HIF-1α) is a crucial regulator of wound healing, which includes epithelialization, angiogenesis, granulation, tissue development, and wound contraction. Even though diabetic wounds are hypoxic, HIF-1α levels are decreased during healing. Diabetic wound healing necessitates the modulation of hypoxia-induced responses by VHL-HIF-1α protein-protein inhibition. Our proposed hypothesis is to increase HIF-1α levels by inhibiting VHL and HIF-1α interactions by novel small bioactive molecules, accelerating diabetic wound healing. A three features (two aromatic rings and one hydrogen bond acceptor) pharmacophore hypothesis was generated from the existing HIF-1α modulators. Virtual screening was done based on the generated pharmacophore, and a library consisting of the top 20 out of 3728 compounds was selected using ZINCPharmer. Of the top 20 molecules, the pyrazole moiety was identified as the top "HIT". Five analogues of pyrazole were designed, and Scifinder ascertained the novelty. The designed compounds were synthesized and characterized by IR, Mass, and NMR. Preliminarily, we have carried out a scratch wound assay using 3T3L1 cell lines. All the synthesized compounds showed significant wound healing activity. Further, to validate the in vitro assay, the compound CI, which showed effective in vitro results was used for in vivo study. Using the diabetes mouse model, comprising streptozotocin-induced (STZ) diabetic mice and scratch wound assay, we demonstrated that inhibiting the VHL and HIF-1α connection is a promising strategy for treating diabetic ulcers. Molecules CI and CP were found to have substantial in silico, in vitro, and in vivo outcomes.

Therapeutic significance of thymoquinone-loaded chitosan nanoparticles on streptozotocin/nicotinamide-induced diabetic rats: In vitro and in vivo functional analysis

To overcome the low bioavailability of lipophilic free thymoquinone (TQ), this study aims to evaluate a novel oral formula of TQ-loaded chitosan nanoparticles (TQ-CsNPs) for the effective treatment of diabetes. The XRD, FTIR, FESEM, HRTEM, and dynamic light scattering were all conducted on the prepared formula. The release pattern of TQ, cytotoxicity against MRC-5 cell line (human lung fibroblast cells), and antidiabetic activity on streptozotocin/nicotinamide (STZ/NA) rat model of diabetes were investigated. The results confirmed the formation of TQ-CsNPs with an entrapment efficiency of 75.7 ± 6.52 %, a mean Zetasizer distribution of 84.25 nm, and an average particle size of about 50 nm. After 24 h, the percentage of free TQ-cumulative release was approximately 35.8 %, whereas TQ-CsNPs showed a sustained release pattern of 78.5 %. The investigated formula was not toxic to normal lung cells, and more efficient in ameliorating the altered glycemia, dyslipidemia, inflammation, and oxidative stress induced by STZ/NA than free TQ, blank CsNPs, and metformin-HCl (as a reference drug). Additionally, TQ-CsNPs restored the normal pancreatic islets' configuration and morphometry, suggesting a potent insulinotropic action. In conclusion, the antidiabetic efficacy of TQ was improved by engaging TQ with CsNPs as an excellent nanoplatform to enhance the oral bioavailability of TQ.

The Nicotinamide/Streptozotocin Rodent Model of Type 2 Diabetes: Renal Pathophysiology and Redox Imbalance Features

Diabetic nephropathy (DN) is a common complication of diabetes mellitus. While there has been a great advance in our understanding of the pathogenesis of DN, no effective managements of this chronic kidney disease are currently available. Therefore, continuing to elucidate the underlying biochemical and molecular mechanisms of DN remains a constant need. In this regard, animal models of diabetes are indispensable tools. This review article highlights a widely used rodent model of non-obese type 2 diabetes induced by nicotinamide (NA) and streptozotocin (STZ). The mechanism underlying diabetes induction by combining the two chemicals involves blunting the toxic effect of STZ by NA so that only a percentage of β cells are destroyed and the remaining viable β cells can still respond to glucose stimulation. This NA-STZ animal model, as a platform for the testing of numerous antidiabetic and renoprotective materials, is also discussed. In comparison with other type 2 diabetic animal models, such as high-fat-diet/STZ models and genetically engineered rodent models, the NA-STZ model is non-obese and is less time-consuming and less expensive to create. Given that this unique model mimics certain pathological features of human DN, this model should continue to find its applications in the field of diabetes research.

Development of Fermented Shrimp Shell Product with Hypoglycemic and Hypolipidemic Effects on Diabetic Rats

In 2020, approximately 9.3 billion tons of crustaceans were consumed, and 45–48% of shrimp shell (SS) by-products were discarded as waste. In this study, the SS of Litopenaeus vannamei was fermented by Lactobacillus plantarum LV33204, Stenotrophomonas maltophilia LV2122 (strong proteolytic activity), and Aeromonas dhakensis LV1111 (chitin-degrading activity), and the optimal fermentation conditions of liquid-fermented SS was established. Contents of total peptide, astaxanthin, and total phenolic content of the fermented SS were significantly higher than that of unfermented SS. In the presence of fermented SS, glucose uptake and insulin resistance of TNF-α-stimulated FL83B hepatocytes were markedly improved. Furthermore, daily oral supplement of fermented SS to streptozotocin (STZ)/nicotinamide (NA)-induced diabetic rats for 7 weeks significantly reduced plasma glucose and insulin resistance. Meanwhile, ingestion of fermented SS might enhance hepatic catabolism of glucose by increasing hexokinase and glucose-6-phosphate dehydrogenase activity and decreasing glucose-6-phosphatase activity. In addition, the fermented SS downregulated plasma total cholesterol (TG), triglycerides (TCs), low-density lipoprotein cholesterol (LDL-C), liver TG, and TC and lipid peroxidation levels in diabetic rats. In conclusion, a biorefinery process for waste SS was established through mixed strain fermentation. The in vitro and in vivo data reveal that the fermented SS is a promising functional food for the management of diabetic hyperglycemia and hyperlipidemia.

Ameliorative Processes of Beta-Carotene in Streptozotocin-Induced Diabetic Vascular Dementia in Rats

Beta-carotene (BC) is a precursor of vitamin A and an excellent antioxidant. It protects the vascular system. Vascular dementia (VaD) is one of the aging disorders causing memory dysfunction. The available medicines for the management of VaD are limited. The present study aimed to evaluate the ameliorative effect of BC in streptozotocin (STZ)-induced diabetic VaD in rats. Diabetic VaD was induced through the administration of nicotinamide (NA, 50 mg/kg; i.p.) and STZ (50 mg/kg; i.p.). The test compound BC (50 and 100 mg/kg; p.o.) and reference compound donepezil (1 mg/kg; p.o.) were administered for 15 consecutive days. Cognitive changes were assessed by transfer latency (TL) using the elevated plus maze (EPM) test. The changes in acetylcholinesterase (AChE) activity were estimated in the septohippocampal system of rat brains. The administration of STZ caused significant changes in cognitive functions (increased TL) as compared to the normal group. BC ameliorated the anxiety-related cognitive behavior and neurotransmitter (elevated AChE) changes provoked by diabetic VaD. Therefore, BC could be a potential therapeutic candidate in the management of VaD.

The Attenuating Effect of Beta-Carotene on Streptozotocin Induced Diabetic Vascular Dementia Symptoms in Rats

This study investigated the ameliorative effects of beta-carotene (BC) on diabetes-associated vascular dementia and its action against biomolecule oxidation. The diabetic vascular dementia (VaD) was induced by administration of nicotinamide (NA; 50 mg/kg; i.p.) and streptozotocin (STZ; 50 mg/kg; i.p.). The test compound, BC (50 and 100 mg/kg; p.o.), and the reference compound, donepezil (DP) (1 mg/kg; p.o.), were administered for 15 consecutive days. Changes in learning and memory were assessed by escape latency time (ELT) and times spent in target quadrant (TSTQ) in the Morris water maze (MWM) test. The changes in neurotransmitter, i.e., acetylcholinesterase (AChE) and oxidative stress markers, i.e., thiobarbituric acid reactive substance (TBARS) and reduced glutathione (GSH), were estimated in hippocampal tissue of the rat brain. The administration of STZ caused significant deterioration of cognitive function (decreased ELT and raised the TSTQ) as compared to the normal group. Treatment with BC and DP diminished the increased AChE activity, TBARS level and decreased GSH level caused by STZ. Thus, BC ameliorates the diabetic vascular complications in VaD due to its potential anticholinergic, antioxidative and free radical scavenging actions.

Type 2 Diabetes Mellitus: Pathogenic Features and Experimental Models in Rodents

Type 2 diabetes mellitus (T2DM) is the most common endocrine disorder (90%) in the world; it has numerous clinical, immunological, and genetic differences from type 1 diabetes mellitus. The pathogenesis of T2DM is complex and not fully clear. To date, animal models remain the main tool by which to study the pathophysiology and therapy of T2DM. Rodents are considered the best choice among animal models, because they are characterized by a small size, short induction period, easy diabetes induction, and economic efficiency. This review summarizes data on experimental models of T2DM that are currently used, evaluates their advantages and disadvantages vis-a-vis research, and describes in detail the factors that should be taken into account when using these models. Selection of a suitable model for tackling a particular issue is not always trivial; it affects study results and their interpretation.

Therapeutic Effects of Modified Tempeh on Glycemic Control and Gut Microbiota Diversity in Diabetic Rats

Background:

The role of the gut microbiota in improving glycemic control in diabetic patients is gaining attention. Tempeh is a fermented soy food from Indonesia that has antidiabetic and antidysbiotic effects. Interestingly, modification of tempeh processing by adding lactic acid bacteria has been reported to enhance the antidiabetic effect of tempeh.

Aim:

To evaluate the effects of modified tempeh on serum glucose, insulin, and gut microbiota diversity of diabetic rats.

Methods:

Modified tempeh was developed by adding lactic acid bacteria from fermented cassava during tempeh processing. Diabetes was induced by injection of streptozotocin nicotinamide. Normal tempeh or modified tempeh was added to the diet and replaced 15% or 30% of casein. Serum glucose and insulin were analyzed before and after 30 days of intervention. At the end of the experiment, the appendix was sampled for gut microbiota analysis.

Result:

Modified tempeh has a significantly higher number of lactic acid bacteria (9.99±0.09 versus 7.74±0.07 log CFU, p < 0.001) compared to normal tempeh. There was a significant difference (p < 0.01) in serum glucose and insulin after treatment. Both tempeh supplements increased the diversity of the gut microbiota. Gut microbiota diversity has a strong negative correlation with delta glucose (r=-0.63, p < 0.001) and delta insulin resistance index (r=-0.54, p=0.003).

Conclusion:

Modified tempeh has potential therapeutic antidiabetic activity, possibly through increased diversity of the gut microbiota.

Effects of Ethanol Extract of Propolis on Repair Optic Nerve Damage in a Rat Model for Diabetes Mellitus (Study of MDA, CRP, Caspase-3, and TGF-β Expression and Histopathological Changes on Optic Nerve Damage)

Purpose Hyperglycemia in diabetes increases oxidative stress in the body. It causes optic nerve damage and risk of glaucoma. In this study, we evaluated and analyzed the effect of propolis ethanol extract on repair of optic nerve damage in a rat model for Diabetes Mellitus. Study Design Laboratory experimental using the posttest only control group design was used in this study. Methods A total of 28 male Wistar rat were randomly divided into the following four groups namely control (K1), diabetes mellitus (K2), diabetes mellitus with propolis treatment (100 mg/kg) (P1) and diabetes mellitus with propolis treatment (200 mg/kg) (P2). Statistical analysis used ANOVA and Kruskal Wallis with a significance of p < 0.05. Results The results showed that Gunung Lawu propolis significantly reduced serum glucose levels, malondialdehyde levels and C-reactive protein levels (p<0.01). Furthermore, propolis extract significantly decreased caspase-3 expression and TGF-β expression (p<0.05) in the optic nerve. Propolis can significantly repair optic nerve damage (optic nerve necrosis, thinning of the retinal nerve fiber layer and retinal ganglion cell apoptosis (p < 0.01). Conclusion The final results showed that most of the beneficial effects of propolis were mediated by the reduction of blood glucose levels in diabetic rat.

Amelioration of diabetes and its complications by Manilkara zapota (L) P. Royen fruit peel extract and its fractions in alloxan and STZ-NA induced diabetes in Wistar rats

Purpose

This study aims to evaluate the effects of Manilkara zapota (L) P. Royen fruit peel extract (EMZFP) and its fractions in ameliorating diabetes and its complications in alloxan and STZ-NA induced diabetes in Wistar rats.

Methods

Antidiabetic effects of EMZFP were assessed in alloxan (150 mg kg^-1) induced diabetes in differently grouped rats (n=6). Diabetic rats were treated with EMZFP 150, 300, and 600 mg kg^-1 while, glimepiride (0.09 mg kg^-1) was used as a reference standard. Treated animals were assessed for various biological parameters i.e. blood glucose, serum lipids, nephroprotective markers, cardiovascular risk indices, liver glycogen, neuropathy, body weight, and histopathology of kidneys. However, for evaluating antidiabetic effects of fractions (chloroform, acetone, ethyl acetate, and remaining ethanol fraction) of EMZFP, diabetes was induced by streptozotocin (60 mg kg^-1)-nicotinamide (120 mg kg^-1/ml) in differently grouped male rats (n=6). Diabetic rats were treated with EMZFP fractions 200 mg kg^-1 however; glibenclamide (10 mg kg^-1) was a reference standard and evaluated for blood glucose, serum lipids, cardiovascular risk indices, and diabetic neuropathy.

Results

EMZFP 300 and 600 mg kg^-1/day demonstrated significant antihyperglycemic effects with augmentation in glycogen content, perfection in serum lipid profile, cardiovascular risk indices, body weight enhancement, nephroprotective effects, beneficial in peripheral neuropathy, and histopathological evidence of reversal of glomerulosclerosis. EMZFP-Et and EMZFP-EA fractions depicted a significant improvement in blood glucose, serum lipid profile, cardiovascular risk indices, and peripheral neuropathy.

Conclusion

EMZFP and its Et and EA fractions ameliorated diabetes and its complications by improving glycemic control and associated biochemical alteration.

Highlights

• Manilkara Zapota (L.) P. Royen fruit peel 70% ethanolic extract exert antidiabetic effects• EMZFP significantly ameliorated diabetic biochemical parameters and its complications.• EMZFP-Et and EMZFP-EA fractions exert potential antihyperglycemic, hypolipidemic effects and significantly improved cardiovascular risk indices, and peripheral neuropathy.• Studied MZFP can be used as promising natural herbal source of antidiabetic principles.

Endoplasmic reticulum stress-dependent activation of TRB3-FoxO1 signaling pathway exacerbates hyperglycemic nephrotoxicity: Protection accorded by naringenin

Endoplasmic reticulum (ER) dysfunction contributes greatly to the pathophysiology of hyperglycemic nephrotoxicity. This study unravels the critical role of Tribbles 3 (TRB3)-Forkhead box O1 (FoxO1) signaling pathway during hyperglycemic renal toxicity. It also uncovers the novel role of Naringenin, a flavanone, in regulating ER stress in proximal tubular cells, NRK 52E, and kidneys of streptozotocin/nicotinamide induced experimental diabetic Wistar rats. Results demonstrate that expression of ER stress marker proteins including phosphorylated protein kinase ER like kinase (p-PERK), phosphorylated eukaryotic Initiation Factor 2α (p-eIF2α), X Box Binding Protein 1 spliced (XBP1s), Activating Transcription Factor 4 (ATF4) and C/EBP Homologous Protein (CHOP) were upregulated in diabetic kidneys indicating the activation of ER stress response due to nephrotoxicity. Treatment with Naringenin reduced the expression of TRB3, an ER stress-inducible pseudokinase, both in vitro and in vivo. Gene silencing of TRB3 enhanced Akt and FoxO1 phosphorylation and alleviated FoxO1 mediated apoptosis during hyperglycemic nephrotoxicity. Notably, TRB3 gene silencing effects were comparable to the response with Naringenin treatment. Prevention of nuclear colocalization of ATF4 and CHOP in Naringenin treated cells was evident. Naringenin also reduced insulin resistance, apoptosis and glycogen accumulation along with enhancement of glucose tolerance in diabetic rats. Prevention of ultrastructural aberrations in the ER of hyperglycemic renal cells by Naringenin confirmed its anti-ER stress effects. These findings affirm that activation of TRB3-FoxO1 signaling is critical in the pathogenesis of hyperglycemia-induced renal toxicity and protective effect of Naringenin via modulation of ER stress may be exploited as a novel approach for its management.

The Effect of Strobilanthes crispus on Blood Glucose Levels and Lipid Profile of Streptozotocin-induced Diabetic Rats

BACKGROUND: Diabetes mellitus is a metabolic disease associated with unhealthy eating patterns, a lack of physical activity, obesity, smoking habits, and family history. Strobilanthes crispus (SC) contains antioxidant compounds known to exert a hypoglycemic effect during long-term interventions in non-diabetic samples. AIM: This study sought to determine the effect of administering the extract of SC leaves on the blood glucose levels and blood serum lipid profiles of streptozotocin (STZ)-induced diabetic rats. METHODS: A total of 30 male Rattus norvegicus rats were divided into control and treatment groups. The control groups consisted of negative (normal rats) and positive controls (diabetic rats), whereas the treatment groups consisted of diabetic rats administered with 3.2% and 16.8% SC leaf extract, and glibenclamide as the drug comparison groups. Blood samples were collected from the rats’ retro-orbital vein for the purposes of glucose level and lipid profile measurement before and after the induction of diabetes with STZ as well as 14 days after the intervention. The collected data were analyzed statistically by means of a one-way analysis of variance continued with Duncan’s multiple range test. RESULTS: The results showed the rats to be hyperglycemic experienced changes in their lipid profiles following the induction of diabetes. The administration of 3.2% SC leaf extract for 14 days reduced the rats’ blood glucose levels, while the effect of the 16.8% SC leaf extract was more pronounced in terms of reducing the rats’ blood glucose levels and improving their lipid profiles (reducing the triglyceride, total cholesterol, and low-density lipoprotein cholesterol levels, while increasing the high-density lipoprotein cholesterol levels). CONCLUSIONS: This study found 16.8% SC leaf extract to exert a good hypoglycemic effect and leads to an improvement in the lipid profiles in diabetic rats.

Phytochemical screening and antidiabetic effects of fruit rind of Momordica dioica roxb. on streptozocin induced type 2 diabetic rats

Momordica dioica (M. dioica) is a gourd like blooming plant that is readily available in Bangladesh, requiring biological research to discover its therapeutic values. The goal of our research was to see if the ethanolic extract of this plant had any anti-hyperglycemic properties. Water, glibenclamide and M. dioica extracts were fed to Streptozocin induced type-2 diabetic rat models at a dose of 1.25 g/kg body weight (bw) for 28 days to see what kind of effects they had on serum glucose, insulin, liver glycogen and lipid contents. Except for the control group, all the groups followed a pattern of maintaining the body weight. The oral glucose tolerance test was observed to be improved in extract after 14 days of the experiment. When assessed with the control group, the M. dioica extract showed a significant (p = 0.0015) decrease in postprandial serum glucose level (M±SD, mmol/l, 13.23 ± 1.03 control Vs 11.47 ± 2.21 extract) at 120 min. The treatment of diabetic model rats with extract resulted in a 7% (p < 0.0001) reduction in serum cholesterol levels. While subsequent 28 days of treatment, insulin levels were found to be lowered in all groups (from 246.76 to 200.44 pg/dL; p < 0.0001 for standard and from 309.01 to 204.61 pg/dL; p < 0.0001 for sample). The results revealed that prolonged administration of M. dioica improved the glycemic and lipidemic state of type-2 diabetic rats, implying that more research is needed to identify the active ingredient (s).

Animal models of diabetic microvascular complications: Relevance to clinical features

Diabetes has become more common in recent years worldwide, and this growth is projected to continue in the future. The primary concern with diabetes is developing various complications, which significantly contribute to the disease's mortality and morbidity. Over time, the condition progresses from the pre-diabetic to the diabetic stage and then to the development of complications. Years and enormous resources are required to evaluate pharmacological interventions to prevent or delay the progression of disease or complications in humans. Appropriate screening models are required to gain a better understanding of both pathogenesis and potential therapeutic agents. Different species of animals are used to evaluate the pharmacological potentials and study the pathogenesis of the disease. Animal models are essential for research because they represent most of the structural, functional, and biochemical characteristics of human diseases. An ideal screening model should mimic the pathogenesis of the disease with identifiable characteristics. A thorough understanding of animal models is required for the experimental design to select an appropriate model. Each animal model has certain advantages and limitations. The present manuscript describes the animal models and their diagnostic characteristics to evaluate microvascular diabetic complications.

Naturally Acquired Lactic Acid Bacteria from Fermented Cassava Improves Nutrient and Anti-dysbiosis Activity of Soy Tempeh

Introduction: Gut microbiota dysbiosis indicated by increased gram-negative bacteria and reduced Firmicutes-producing short chain fatty acids bacteria has been linked with impairment in glucose metabolism. Tempeh is traditional fermented soy food that can stimulate the growth of beneficial bacteria. In Indonesia, some tempeh was produced by adding acidifier that contains lactic acid bacteria. This process may impact the nutrient and anti-dysbiosis activity of tempeh.   Objectives: To evaluate the impact of acidifier on nutrient and gut microbiota profile of diabetic animal model.  Method: Modified tempeh was made by addition of water extract of fermented cassava. Standard and modified tempeh were subjected to proximate analysis and dietary fibre. Diabetic animals were received standard tempeh or modified tempeh diet replacing 15% and 30% of protein in the diet for 4 weeks of intervention. At the end of experiment, caecal content was collected. Short chain fatty acids and microbiota composition were analysed using 16s rDNA next generation sequencing (NGS). Result: There is significant different (p<0.05) on fat, protein, water and dietary fibre content between regular soy tempeh and modified tempeh. There is significant different (p<0.05) on serum glucose and short chain fatty acid composition among group. Diabetic animal has low ratio of Firmicutes/Bacteroidetes. Supplementation of both tempeh increased bacterial diversity, Firmicutes /Bacteroidetes ratio and short chain fatty acids producing bacteria.   Conclusion: Addition of naturally occurred lactic acid bacteria from fermented cassava during tempeh processing improved both nutrient and microbiota composition in the gut of diabetes mellitus.  

Differential expression of gluconeogenic enzymes in early- and late-stage diabetes: the effect of Citrullus colocynthis (L.) Schrad. Seed extract on hyperglycemia and hyperlipidemia in Wistar-Albino rats model

Background

The medicinal plant Citrullus colocynthis (L.) Schrad. (C. colocynthis) may benefit patients at different phases of diabetes by attuning to contrasting situations. Our primary objective was to find the mechanism(s) behind the antidiabetic/anti-hyperlipidemic effects of C.colocynthis seed aqueous extract (CCAE) in two different stages of type 2 diabetes (T2D) in rats.

Methods

Fasting blood sugar (FBS) levels, body weights, and the degree of impaired glucose tolerance (IGT) were measured in healthy nondiabetic control rats (Con), as well as rats with early and late stages of T2D, denoted as ET2D and LT2D, respectively. CCAE was intraperitoneally (IP) injected for 28 days. In the end, the hepatic mRNA expression levels of the following genes were determined by RT-PCR: glucose-6-phosphatase (G6Pase), phosphoenolpyruvate carboxykinase (PEPCK), insulin-dependent sterol regulatory element-binding protein-1c (SREBP-1c), acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), peroxisome proliferator-activated receptor alpha (PPARα), and carnitine palmitoyltransferase I (CPT1). The liver was examined by hematoxylin and eosin (H&E) and Oil-Red O staining. CCAE was partially analyzed by HPLC-DAD.

Results

ET2D and LT2D were characterized by differentially elevated FBS, deteriorated bodyweight, and significant IGT compared to Con. Hepatosteatoses of varying morphologies and higher hepatic expression of G6Pase than PRPCK in ET2D versus the opposite in LT2D further confirmed the divergent nature of metabolic aberrations. At the end of 28 days, the high levels of FBS, alkaline phosphatase (ALP), triglyceride (TG), urea, hepatic protein carbonyl content (PCC), and alanine and aspartate aminotransferases (AST and ALT, respectively) persisted in untreated LT2D. CCAE ameliorated oxidative stress and upregulated PPARα expression in diabetic groups and Con; it downregulated CPT1 expression in the LT2D group. CCAE’s ability to lower FBS and serum and hepatic TG in both ET2D and LT2D indicated its ability to act via different mechanisms. Ferulic acid (Fer A) and rutin hydrate (RH) were detected in CCAE.

Conclusion

CCAE lowered the FBS in ET2D via inhibiting the hepatic G6Pase expression (glycogenolysis). In LT2D, CCAE abated sugar levels by diverting PEPCK activity, preferably towards glyceroneogenesis than gluconeogenesis. The preserved triglyceride/fatty acid (TG/FA) cycle, the upregulated PPARα, and the downregulated CPT1 gene expressions reduced serum and hepatic TG.

Changes in biomarkers of endothelial function in the blood after intracerebral hemorrhage in rats with type 2 diabetes mellitus

Clinical evidence suggests that type 2 diabetes mellitus can increase the risk of intracerebral hemorrhage and provocation of neurodegeneration. This study was aimed at evaluating biomarkers of glycemic control, lipid profile, oxidative modification of proteins, as well as the functional state of endothelium in Wistar rats with type 2 diabetes mellitus complicated by intracerebral hemorrhage. Experimental type 2 diabetes mellitus was induced by intraperitoneal injection of streptozotocin (65 mg/kg) and nicotinamide (230 mg/kg). The intracerebral hemorrhage was induced by microinjection of sterile saline containing 0.2 IU bacterial collagenase into the striatum. Assessed biomarkers included the area under glycemic curve, glycated hemoglobin, total cholesterol, triglyceride, high-density lipoprotein, advanced glycation end products, markers of oxidative modification of proteins – aldehyde- and ketonephenylhydrazones, and markers of endothelial dysfunction – homocysteine, endothelin-1, von Willebrand factor and asymmetric dimethylarginine in blood serum. Both rats with type 2 diabetes mellitus and rats with intracerebral hemorrhage and diabetes had a significant elevated glycemic control as compared to intact animals. But combined pathology was additionally characterized by an impairment of lipid profile (increased triglyceride level and decreased as total cholesterol and high-density lipoprotein) resulting in a rise in the atherogenic index of plasma. A significant increase in the content of the markers of oxidative modification of proteins was observed in both experimental groups. But the rats with intracerebral hemorrhage and diabetes only had higher levels of advanced glycation end products in comparison with intact animals. The highest levels of endothelin-1, as a biomarker of endothelial dysfunction, were observed in animals with intracerebral hemorrhage and diabetes. Homocysteine and von Willebrand factor were elevated in rats with type 2 diabetes mellitus, while acute intracerebral hemorrhage did not potentiate the further growth in its levels. Such effect was not accompanied by a marked increase of asymmetric dimethylarginine level in blood serum, although there was a clear trend. In conclusion, the development of intracerebral hemorrhage in rats with type 2 diabetes mellitus can intensify the manifestations of oxidative stress, worsen lipid profile, and aggravate endothelial dysfunction. In this case, the pathological process may have the character of a “vicious circle”.

Ameliorative effects of Carica papaya extracts against type II diabetes-induced myocardial pathology and dysfunction in albino rats

Diabetes is characterized by hyperglycemia. Secondary complications of diabetes are serious risk factors that might lead to cardiovascular diseases. This study evaluated the effects of methanolic extract of Carica papaya fruit and seed in ameliorating the abnormal structural changes in myocardium and functional impairment induced by diabetes in albino rats. The experimental animals were divided into control (C), induced type II diabetes (D), protected seed extract (PSE), protected fruit extract (PFE), treated seed extract (TSE), and treated fruit extract (TFE). The myocardium of diabetic group exhibited disorganized myocardial fibers. Regard both normal, seed and fruit extract groups, which are of almost similar normal pattern of regular oriented muscle fibers. The diabetic group exhibited increased myocardial lipid peroxidation coincides with depletion of superoxide dismutase and increase of the levels of creatine kinase, troponin-1, nuclear factor Kappa B, caspase 3, tumor necrosis factor-α, and activity of lactic dehydrogenase. The diabetic group showed intense dark brown immune reaction against α-smooth muscle actin and P53. Experimental diabetic group protected with either seed and fruit extract exhibited marked amelioration of the assessed parameters. In conclusion, both seed and fruit extract of Carica papaya are of potential medical importance through managing high glucose level and keep myocardium against diabetes-induced cell death.