Streptozotocin as a tool for induction of rat models of diabetes: a practical guide

Comparative evaluation of the antidiabetic potential of three varieties of Ipomoea batatas L

Sweet potato (Ipomoea batatas L.) is a nutrient-dense tuber often used in traditional diabetic treatment. This research compares the antidiabetic potential of three sweet potato varieties: orange-fleshed (OFSP), purple-peel white-fleshed (PPWSP), and white-peel white-fleshed (WPWSP), utilising in vitro and in vivo techniques. Sweet potatoes (OFSP, PPWSP, and WPWSP) boiled at 100°C for 20 minutes were incorporated into formulated diets and administered to streptozotocin-induced diabetic rats for 14 days. Aqueous extracts of the diets were tested in vitro for antioxidants and phytochemicals. Glycaemic control parameters, lipid profiles, oxidative stress indicators, and pancreatic histology were investigated. Gene expression analysis was performed on critical diabetes-related pathways. OFSP showed significant strong anti-diabetic benefits, including better glycemic control, weight maintenance, lower HOMA-IR scores, and lowered α-amylase and α-glucosidase activity. OFSP-fed rats had higher insulin, glycogen, and hexokinase activity than those given PPWSP and WPWSP. OFSP decreased mRNA expression of DPP-4 while increasing GLP-1 expression. OFSP also improved lipid profiles, increasing HDLc while decreasing LDLc and triglycerides more than other varieties. Histopathological examination revealed restorative effects in pancreatic beta cells. OFSP demonstrated more pronounced antidiabetic effects compared to PPWSP and WPWSP, particularly in terms of glycemic control, insulin regulation, and lipid profile improvement. These findings suggest that OFSP may offer significant potential for diabetes management. However, further clinical studies are needed to validate these results and explore the practical dietary applications of OFSP in diabetes control.

Exploring the efficacy of plant-based nutraceuticals in managing diabetic neuropathy

Diabetes-induced peripheral neuropathy is one of the most common complications in patients with diabetes. Plant-derived natural products have been tested in animal models as agents to treat this complex condition. Therefore, this study aimed to examine the therapeutic potential of plant-based nutraceuticals used for managing diabetic neuropathy in rat models using a systematic literature review approach. The literature review was performed in November 2023 on two databases, PubMed and Scopus. Nerve conduction velocity and pain-related behaviors were considered primary outcome measures. For meta-analysis, a random effect model was selected with a mean difference at 95% confidence intervals to estimate the effect of plant-based nutraceuticals on the primary outcome measures. Eighteen studies were included in the meta-analysis, with results indicating that plant extracts or isolated compounds significantly increased nerve conduction velocity and thermal and mechanical paw withdrawal latencies. Different mechanisms of action to reduce neuropathy symptoms have been proposed in these studies including a reduction in inflammatory cytokines and oxidative stress markers. This study suggests that plant-based therapies are effective in the management of diabetes-induced peripheral neuropathy. However, more studies are required with a standard experimental design and reporting.

Revitalizing Pleurotus eryngii polysaccharides: gamma irradiation boosts antidiabetic and antioxidant potential

Polysaccharides derived from Pleurotus eryngii possess various bioactive properties, including antioxidant, antidiabetic, anti-inflammatory, and immunomodulatory effects. In this study, polysaccharides were extracted from P. eryngii fruiting bodies and exposed to gamma irradiation at doses of 50 and 100 kGy, with a dose rate of 5 kGy/h. The surface morphology of the polysaccharide irradiated at 100 kGy exhibited numerous pores and a smaller flake structure compared to those irradiated at 50 kGy and the non-irradiated sample. 1H and 13C NMR spectra of all samples indicated that both irradiated and non-irradiated polysaccharides exhibited α- and β-configurations, with signals corresponding to C1-C5 clearly observed. HPLC analysis of the polysaccharides revealed that glucose (75.23%), galactose (4.96%), glucuronic acid (1.38%), ribose (0.94%), rhamnose (2.35%), and mannose (3.87%) are the main components. All polysaccharides demonstrated antioxidant activity, which increased with concentration. Both non-irradiated and irradiated polysaccharides exhibited antidiabetic effects, significantly reducing blood glucose levels, and restoring insulin level with superiority of irradiated polysaccharides. Additionally, they significantly elevated body weight, slightly reduced MDA levels, and markedly enhanced catalase activity in treated rats compared to diabetic controls. The antidiabetic effects of the polysaccharides were further confirmed by histopathological examination of the pancreas and liver sections from polysaccharide-treated diabetic rats. This suggests that irradiation, by reducing the molecular weight of polysaccharides, enhances their bioavailability and efficacy in modulating glucose metabolism.

Combinational effect of metformin and mature coconut water on streptozotocin model of diabetes

Diabetes mellitus (DM) is a persistent metabolic disease typified by hyperglycemia, caused by insufficient or ineffective insulin. This study examined the therapeutic effects of metformin combined with coconut water. In this study, twenty male Wistar rats (150-220 g) were divided into four groups: normal control, diabetic control, diabetic treated with metformin, and diabetic treated with metformin plus coconut water. Diabetes was induced using nicotinamide and streptozotocin (STZ), followed by a 21-day oral treatment regimen. Body weight, fasting blood glucose levels, feed, and water intake were measured weekly. A molecular docking study was employed to assess the degree of affinity that compounds of coconut water have for important metabolic proteins. Combination therapies of metformin and coconut water significantly reduced the glucose levels in the blood when compared to the diabetic controls. Molecular docking revealed strong binding affinities between coconut water constituents, particularly chlorogenic acid, and key metabolic proteins, suggesting potential therapeutic effects. The study demonstrates that coconut water, in combination with metformin, effectively ameliorates hyperglycemia and enhances antioxidant enzyme activities in diabetic rats induced with STZ. These results imply that coconut water could serve as a beneficial adjunct treatment for managing DM.

Graphical abstract

Unveiling the bladder's early response to acute glucosuria: first evidence from an animal study

PURPOSE

While chronic damage to the lower urinary tract in diabetic patients is well-known, the specific effects of acute glucosuria on the bladder remain unclear. This study, being the first of its kind in the available literature, aims to exclusively investigate the early effects of acute glucosuria on bladder function and morphology, independent of the broader impacts of diabetes.

METHODS

Wistar Albino rats were divided into four groups: CONTROL, Empagliflozin (EMPA), Diabetes Mellitus + Empagliflozin (DM + EMPA), and DM. Acute glucosuria was induced using empagliflozin in the EMPA and DM + EMPA groups. The effects on bladder function were assessed through contraction protocols using potassium chloride (KCl), cumulative acetylcholine (ACh) applications and electrical field stimulation studies (EFS). The bladder tissues were also examined histopathologically to evaluate morphological changes.

RESULTS

In the organ bath studies, a significant increase in the response to KCl was observed in the diabetic group receiving empagliflozin compared to others (p < 0.001). When examining the contraction responses to ACh, it was found that the diabetic group receiving empagliflozin exhibited significantly higher contraction responses (p < 0.001). In the EFS, no significant difference was found between the groups. The histopathological examinations revealed a significant muscularis propria hypertrophy in the groups receiving empagliflozin compared to the control group (p < 0.001).

CONCLUSIONS

In our study, we found that short-term treatment defined as 15 days with empagliflozin increased the receptor-independent contractile capacity of the bladders in diabetic rats and enhanced their contraction responses to ACh. However, there was no significant difference observed in the EFS studies. Histopathological analysis revealed the development of detrusor hypertrophy in rats receiving empagliflozin treatment.

Leiurus quinquestratus venom promotes β islets regeneration and restores glucose level in streptozotocin induced type 2 diabetes mellitus in rats

Diabetes mellitus type 2 (T2-DM) is one of the most prevalent chronic metabolic diseases, marked by insulin resistance and a relative lack of insulin production. T2-DM can be treated using various methods; however, these treatments are risky for several vital organs. Subsequently, novel T2-DM replacement therapies should be discovered. The goal of this study was to see how efficient Leiurus quinquestratus venom (LQV) was as a diabetic medicine for the treatment of T2-DM in rats. The median lethal dose (LD50) of LQV has been determined. Then, forty male Sprague Dawley rats were divided into four groups (n = 10) as follows, with group 1 (Gp1) separated as a negative control. Gp2, Gp3, and Gp4 were fed a high-fat diet (HFD) for 12 weeks before receiving an intraperitoneal (i.p) injection of streptozotocin (STZ) as 30 mg/kg b.wt. Gp3 received metformin (Met) as 150 mg/kg b.wt i.p. LQV as 1/40 LD50 was given i.p. to Gp4. Treatments with Met or LQV were once every day for eight weeks. Hematological, biochemical, histopathological, and immunohistochemical studies were determined, along with the percentages of changes in total body weight. Results: LD50 of LQV was 0.3 mg/kg b.wt. Met or LQV treatment reduced hyperglycemia and C-peptide levels and lessened the hepato-renal biomarkers disorders in T2-DM rats. Intriguingly, histological analysis revealed that LQV treatment outperformed Met in improving and restoring β-cells in pancreatic tissues of T2-DM mice. In conclusion, this study demonstrated a new and promising method for treating T2-DM with LQV. Further investigation is required to isolate the bioactive elements from LQV to treat T2-DM.

Dapagliflozin Ameliorate Type-2 Diabetes Associated Neuropathy via Regulation of IGF-1R Signaling

Dapagliflozin, an approved SGLT2 inhibitor, has been shown to have extra-glycemic effects like cardio-reno protection. However, the neuroprotective effects of SGLT2 inhibitors against diabetic neuropathy (DN) have not been explored. The current study aimed to determine the neuroprotective potential of Dapagliflozin against STZ-NAD-induced DN in Wistar rats via IGF-1 signaling. DN was induced by STZ-NAD in male Wistar rats. After 60 days of induction, behavioural tests were conducted to access DN, and treatment with Dapagliflozin (0.75 mg/kg & 1.50 mg/kg) was initiated for 30 days. At the end of the study, the brain and sciatic nerve were isolated and expression analysis of IGF-1R signaling molecules was carried out using western blotting, qRTPCR, and immunohistochemistry. Structural changes in the brain and sciatic nerve were ascertained by histopathology. The results showed that treatment with Dapagliflozin improved behavioural parameters in STZ-NAD-induced DN rats. The decreased expression levels of IGF1R signaling pathway molecules and increased expression of p-AKT were found to increase and decrease in the brain and sciatic nerve, respectively after the treatment. Histological studies demonstrated the restoration of normal architecture of the brain and sciatic nerve after treatment with dapagliflozin. The altered expression of IGF-1R signaling molecules established the neuroprotective potential of dapagliflozin against DN.

PLGA/HA sustained-release system loaded with liraglutide for the treatment of diabetic periodontitis through inhibition of necroptosis

Diabetes and periodontitis exhibit a bidirectional relationship, posing significant challenges for the treatment of periodontitis in patients with diabetes. Our previous studies showed that the hypoglycemic agent liraglutide (LIRA), together with glycemic control, had favorable therapeutic effects on diabetic periodontitis (DP), achieving a "two birds with one stone" effect. Therefore, exploration of the topical application of LIRA for treating DP is warranted. In this study, nanoparticles were loaded with LIRA using poly (lactic-co-glycolic acid) (PLGA), and their morphology, particle size, encapsulation efficiency, drug loading, and drug release profiles were characterized. These nanoparticles were further encapsulated with hyaluronic acid (HA) to form a LIRA@PLGA/HA sustained-release system. The cytotoxicity of LIRA@PLGA/HA was analyzed using CCK-8 assays, and its anti-inflammatory and osteogenic effects on periodontitis in diabetic rats were evaluated by histology, ELISA, and micro-CT analysis, while its influence on necroptosis-related factors was assessed using qRT-PCR and Western blotting. The results indicated that LIRA@PLGA (30000 Da) exhibited an encapsulation efficiency of 86.2 %, a drug loading capacity of 4.3 %, and a cumulative release of LIRA reaching approximately 60 % after 8 days, thereby meting the requirement for sustained release. Following 24 h of stimulation with various concentrations (0-20 mg/ml) of LIRA@PLGA/HA, the viability of human periodontal ligament cells (HPDLCs) remained above 85 %. Topical application for four weeks significantly inhibited the expression of the inflammatory factors TNF-α and IL-1β in gingival crevicular fluid and serum, reduced inflammatory cell infiltration in periodontal tissues, and attenuated alveolar bone resorption while improving alveolar bone microstructure, showing therapeutic effects similar to the commercial drug PERIOCLINE® (PERIO). Furthermore, LIRA@PLGA/HA reduced the expression of necroptosis-related factors RIPK1, RIPK3, and MLKL. In conclusion, these results suggest that topical application of LIRA@PLGA/HA is effective for the treatment of DP through inhibition of necroptosis, representing a promising treatment strategy.

Curcumin Analog J7 Attenuates Liver Fibrosis and Metabolic Dysregulation in a Rat Model of Type 2 Diabetes via Modulation of TGF-β/Smad and NF-κB/BCL-2/BAX Pathways

Objective

To evaluate the therapeutic potential of the curcumin analog J7 in protecting the liver and regulating glucose and lipid metabolism in rats with type 2 diabetes.

Methods

Bioinformatics methods were used to identify signaling pathways linked to diabetic liver disease. Diabetic rats were treated with curcumin, low-dose J7, or high-dose J7, and liver function and fibrosis were assessed through biochemical analyses, histopathology, immunohistochemistry, and ELISA.

Results

J7 administration significantly improved lisver function, reduced fibrosis, and regulated metabolic profiles in diabetic rats. J7 downregulated TGF-β1, NF-κB p65, and BAX, while upregulating BCL-2, showing superior effects to traditional curcumin in reducing TGF-β1 and inhibiting α-SMA expression.

Conclusion

J7 demonstrates potential as a therapeutic agent for managing liver complications in type 2 diabetes, effectively attenuating liver fibrosis and regulating metabolism through the modulation of key signaling pathways and proteins.

Metabolomic analyses of multiple biologic matrices reveal metabolic heterogeneity in diabetic complications

AIMS

Type 2 diabetes mellitus (T2DM) arises from a complex interplay of genetic and environmental factors. Patients with T2DM are susceptible to hyperglycemia-related complications that can impair organ function, underscoring the need to explore the metabolic profiles of affected organs.

METHODS

In this study, a comprehensive metabolomic analysis was conducted on the serum, kidney, and heart tissues from a rat model of diabetic complications (DC). Pattern recognition and multivariate statistical analyses were applied to identify the potential biomarkers of DC, and metabolic network analysis served to understand the specific metabolic pathways associated with DC.

RESULTS

Fourteen significantly altered metabolites were identified in serum, 20 in the kidney, and 14 in the heart. The corresponding metabolic pathways included mineral absorption, mTOR signaling pathway, taurine and hypotaurine metabolism, glycine, serine and threonine metabolism, ABC transporters, glucagon signaling pathway, protein degradation and uptake, galactose metabolism, purine metabolism, nicotinic acid and nicotinamide metabolism, and glycolysis and gluconeogenesis. Differential metabolite network analysis revealed instinct metabolic patterns among the serum, kidney, and heart. Notably, the serum's metabolic correlation patterns were found to be somewhat similar to those observed in the kidney, whereas the heart exhibited less pronounced metabolite correlations compared to the other two biological matrices.

CONCLUSIONS

These findings provide insights into the mechanism underlying the development of diabetic complications. The integration of metabolomics and biological network analyses into diabetes research can potentially revolutionize the field by revealing novel biomarkers for early detection and personalized treatment of diabetes and its associated complications.

Long-term nitrate administration modulates sialin gene expression in the main tissues of male Wistar rats with type 2 diabetes

The increased sialin gene expression in the main tissues of diabetic rats is associated with decreased nitrate and nitrite levels, suggesting a counterregulatory response for reduced nitric oxide (NO) bioavailability. In this study, we hypothesized that long-term nitrate administration (6 months) would decrease sialin gene expression in rats with type 2 diabetes (T2D). Rats were assigned to two groups (n=10): T2D and T2D+nitrate, receiving nitrate in their drinking water at a concentration of 100 mg/L over 6 months. Samples from the main tissues were collected and used to measure the gene expression of sialin, as well as nitrate and nitrite levels. Nitrate-treated T2D rats had higher nitrate levels in the soleus muscle (SM) (163 %), stomach (83 %), lung (271 %), pancreas (90 %), aorta (61 %), adrenal gland (88 %), brain (145 %), liver (95 %), and heart (87 %). Nitrite levels were also higher in SM (136 %), lung (108 %), pancreas (86 %), kidney (88 %), aorta (33 %), brain (221 %), epididymal adipose tissue (eAT) (52 %), and heart (93 %), of nitrate treated T2D rats (all P<0.05). Nitrate decreased sialin gene expression in the SM (0.21-fold, P<0.001), stomach (0.37-fold, P=0.002), liver (0.21-fold, P<0.001), and eAT (0.47-fold, P=0.016) but it increased it in the intestine (1.99-fold, P<0.001), pancreas (2.01-fold, P=0.006), and the kidney (2.45-fold, P<0.001) of diabetic rats, with no effects in the lung, aorta, adrenal gland, brain, and heart. Nitrate administration restores the compensatory increase in sialin gene expression in tissues of T2D rats. However, this compensatory mechanism is not generalizable to all tissues.

Facilitation of diabetic wound healing by far upstream element binding protein 1 through augmentation of dermal fibroblast activity

AIMS

Diabetes mellitus (DM) often leads to wound healing complications, partly attributed to the accumulation of advanced glycosylation end products (AGEs) that impair fibroblast function. Far Upstream Element Binding Protein 1 (FUBP1) regulates cell proliferation, migration, and collagen synthesis. However, the impact of FUBP1 on diabetic wound healing remains unknown. This study is designed to explore the function and mechanisms of FUBP1 in diabetic wound healing.

METHODS

Eighteen Sprague-Dawley rats (weighing 220-240 g) were randomly assigned to three groups (n = 6): a control group (NC) of healthy rats, a model group (DM) of untreated diabetic rats, and a treatment group (DM + FUBP1) of diabetic rats accepting FUBP1 treatment. A 10 mm diameter circular full-thickness skin defect was created on the back of each rat. On days 1 and 7, rats in the treatment group received local injections of 5 µg FUBP1 protein at the wound site, whereas the control group and model group were administered saline. Wound healing was documented on days 0, 3, 7, 10, and 14, with tissue samples from the wound areas collected on day 14 for histological analysis, including H&E staining, Masson's trichrome staining, and immunohistochemistry. Western blot analysis was utilized to assess the expression of GSK-3β, Wnt3a, and β-catenin. In vitro, the effects of various concentrations of AGEs on cell viability and FUBP1 expression were examined in human dermal fibroblasts (HDF). Cells were genetically modified to overexpress FUBP1 using lentiviral vectors and were cultured for 48 h in media with or without AGEs. The impacts on fibroblast proliferation, migration, and Wnt/β-catenin signaling were evaluated using CCK-8, scratch assays, and Western blot analysis.

RESULTS

Animal investigation revealed that from day 7 onwards, the wound healing rate of the treatment group was higher than that of the model group but lower than the control group. On day 14, the wound healing rates were as follows: control group (0.97 ± 0.01), model group (0.84 ± 0.03), and treatment group (0.93 ± 0.01). These differences were statistically significant. Histological analysis indicates that FUBP1 promotes granulation tissue formation, re-epithelialization, and collagen deposition in treatment group. Additionally, FUBP1 protein expression decreased in dermal fibroblasts when exposed to AGEs. Overexpression of FUBP1 significantly enhanced fibroblast proliferation and migration, activating the Wnt/β-catenin pathway and mitigating the inhibitory effects of AGEs.

CONCLUSIONS

Our results suggest that FUBP1 can be a promising therapeutic target for diabetic wound healing, potentially counteracting the detrimental effects of AGEs on dermal fibroblasts through the Wnt/β-catenin pathway.

Effect of cubebin against streptozotocin-induced diabetic nephropathy rats via inhibition TNF-α/NF-κB/TGF-β: in vivo and in silico study

Cubebin, a dibenzyl butyrolactone lignan belonging to several distinct families, including Aristolochiaceae, Myristicaceae, Piperaceae, and Rutaceae, and possesses several pharmacological activities, including analgesic, anti-inflammatory, antioxidant, and vasodilatory. The current study aimed to evaluate the effect of cubebin on streptozotocin (STZ)-evoked diabetic nephropathy (DN). DN is a well-identified complication of diabetes mellitus (DM) characterized by renal hypertrophy that progressively declines kidney function. Wistar rats were randomly divided into groups- normal, STZ control (65 mg/kg/body weight), and STZ + cubebin (10 and 20 mg/kg). Biochemical parameters such as glucose levels, kidney parameters, lipid profile, oxidative stress, endogenous antioxidant markers, inflammatory cytokines and histopathology were performed. Molecular docking [(PDB ID: TNF-α (7JRA), NF-κB (1SVC), TGF-β1 (3TZM)] and dynamic simulation (MDS) were also performed with the selected target. STZ-induced DN was changes in these parameters. In contrast, DN + cubebin at 10 and 20 mg/kg doses improved the biochemical parameters and histological changes. Furthermore, molecular docking and simulation studies showed a binding affinity with negative binding energy with TNF-α (7jra, - 11.342 kcal/mol), TGF-β1 (3tzm, - 9.162 kcal/mol) and NF-κB (1svc, - 6.665 kcal/mol). The results of MDS provided insight into the mechanisms that associate proteins TNF-α, NF-κB, and TGF-β1 in conformational dynamics upon binding to cubebin. In conclusion, these findings exhibit a potential effect of cubebin in STZ-evoked DN rats.

A Comparative Study of Nanoconjugates of a Synthetic and a Natural Drug Against T2DM-Induced Cognitive Dysfunction

Type II Diabetes Mellitus (T2DM) is one of the risk factors for the development of dementia leading to cognitive dysfunctions. The present study evaluates the efficacy of a synthetic drug (Vildagliptin, VLD) and a natural glycosidic compound (Hesperidin, HSP) against T2DM-induced cognitive dysfunction in rats. The drugs were conjugated with metal nanoparticles like gold (Au) and selenium (Se) to enhance their efficacy. The synthesis of the monometallic and bimetallic nanoparticles of VLD and HSP was established via the turkevich method and characterised by different spectroscopical techniques like UV (Ultraviolet)-visible, FTIR (Fourier Transform Infrared Spectroscopy), zeta potential, particle size, HR-TEM (High Resolution Transmission Electron Microscopy), SAED (Selected Area Electron Diffraction) and SEM-EDX (Scanning Electron Microscopy with Energy Dispersive X-ray Analysis). Both Streptozotocin (STZ) of 65 mg/kg (Group I-X) and Alloxan (ALX) of 150 mg/kg (Group I-X) were injected into 120 Wistar rats to induce cognitive dysfunction. After the induction, the BGL levels were evaluated and rats with BGL > 250 mg/dl were used in the study. Then the test drug and nanoformulations were administered for 21 days. Neurobehavioral assessment, antioxidant studies, and estimation of AChE (acetylcholinesterase) and nitrite levels were done. The VLD and HSP with its nanoconjugates significantly attenuated the effect of STZ and ALX by improving the memory and learning function in Y-maze, radial arm maze (RAM), and elevated plus maze (EPM), increased antioxidant levels of SOD (superoxide dismutase), CAT (catalase), and GSH (glutathione); decreased lipid peroxidation and reduced the AChE and nitrite levels in the rat brain. The bimetallic nanoconjugates of both VLD and HSP were more effective than the monometallic forms of VLD and HSP. However, VLD and its nanoconjugates exhibited better neuroprotective activity than HSP and its nanoconjugates in STZ and ALX animal models. VLD and its nanoformulations were more effective against long-term memory than HSP and its nanoconjugates. Both VLD and HSP may be a potential lead for cognitive and neurodegenerative diseases.

Effect of cinnamon oil (Cinnamomum burmannii) on the histological kidney of male diabetic rats (Rattus norvegicus)

Background

Chronic systemic disease known as diabetes mellitus is defined by elevated blood glucose levels and problems with fat, carbohydrate, and protein metabolism. In Indonesia, the cinnamon species found include Cinnamomum burmannii, which also has hypoglycemic activity. The primary antioxidant chemicals found in C. burmannii bark extract are polyphenols, which include tannins and flavonoids.

Aim

The antidiabetic activity of cinnamon essential oil (C. burmannii) against streptozotocin (STZ) was examined in this study.

Methods

STZ (45 mg/kg BW) was administered intraperitoneally as a single dose. Twenty male rats were employed in this investigation. The rats were divided into five groups: treatment 1 (P1) was administered with STZ and provided with 100 mg/kg BW; treatment 2 (P2) was administered with STZ and provided with 200 mg/kg BW; and treatment 3 (P3) was administered with STZ and provided with 400 mg/kg BW. The negative control group (K-) was not treated with STZ and was treated with 1% Tween 80. For 14 days, the medication was administered daily.

Results

The essential oil of cinnamon may lessen glomerulosclerosis, tubular necrosis, tubular degeneration, and glomerular necrosis. The kidney P3 treatment (400 mg/kg BW) produced negligible effects.

Conclusion

It is possible to create cinnamon essential oil as an herbal antidiabetic medication by lowering the degree of kidney cell damage.

In Silico and In Vivo Evaluation of Novel 2-Aminobenzothiazole Derivative Compounds as Antidiabetic Agents

Currently, there are several drugs used for the treatment of type 2 diabetes (T2D); however, all of them have adverse effects. Benzothiazoles have a broad spectrum of biological activities such as antidiabetic. This study aimed to evaluate in silico and in vivo two series of 2-aminobenzothiazole derivatives linked to isothioureas (3a-w) or guanidines (4a-z) for the treatment of T2D. The ADMET properties were determined in silico, from which it was possible to select nine compounds (two isothioureas and seven guanidines), and, with molecular docking, it was shown that compounds methyl (E)-N'-(benzo[d]thiazol-2-yl)-N-methylcarbamimidothioate (3b) and 2-(benzo[d]thiazol-2-yl)-1,3-di-tert-butylguanidine (4y) showed a high affinity for PPARγ (ΔG = -7.8 and -8.4 kcal/mol, respectively). In vivo, the LD50 value was estimated in rats based on OECD Guideline 425, being >1750 mg/kg for both compounds. The pharmacological effect of 3b and 4y was evaluated in the T2D rat model, showing that after oral administration in an equimolar ratio to pioglitazone (15 mg/kg) for 4 weeks, both compounds were able to reduce blood glucose levels (<200 mg/dL) and improve the lipid profile. Therefore, 3b and 4y could be used in the future as antidiabetic agents.

Effect of Combined Treatment with Levofloxacin and Metformin on Diabetes-the Diabetes Related Behavioral and Biochemical Alterations

Objectives

The current experiment was conducted to investigate the combined effect of levofloxacin (LVX) and metformin treatment on blood glucose levels, malondialdehyde (MDA),nitrite levels, and anxiety in streptozotocin (STZ)+ nicotine adenine dinucleotide (NAD)-induced diabetic rats.

Materials and Methods

In this study, Wistar rats have been used. After receiving a single dose of STZ + NAD (45 mg/kg, i.p.+ 50 mg/kg, i.p.), the rats developed diabetes. Glucose levels in diabetic rats exceeded 200 mg/dL (verified on the third day). Saline was administered to non-diabetic rats (controls). Thediabetic rats were administered metformin (50 mg/kg, p.o.), LVX (30 mg/kg, i.p.), or metformin + LVX for 14 days. Blood samples were obtained after the 14th day of therapy, and the rats were given behavioral parameters to determine locomotor activity and anxiety level. Blood plasma samples were separately collected for the determination of nitrite and MDA levels.

Results

It was observed that the combined treatment of metformin and LVX significantly increased glucose levels in the blood of diabetic rats compared with diabetic control (p < 0.05) and diabetic rats treated with metformin alone (p < 0.001) at days 3 and 7. Further, combined treatment of metformin and LVX significantly reduced time spent at the center of the open field test (p < 0.001), significantly reduced time spent and entry made in the light chamber of the light-dark test (p < 0.001), significantly increased time spent in the open arm and reduced the time spent in the closed arm of the Elevated plus maze (p < 0.001) compared with alone metformin-treated diabetic rats. Further, combined treatment with metformin and LVX significantly increased the nitrite level, (p < 0.001) but reduced the MDA level in plasma compared with metformin alone-treated diabetic rats (p <0.001).

Conclusion

The present study suggests that combined treatments with levofloxacin and metformin may modulate glucose levels and anxiety-related activity.

Gambogic Acid Mitigates Nephropathy by Inhibiting Oxidative Stress and Inflammation in Diabetic Rats

Diabetic nephropathy is a leading cause of end-stage renal disease globally, with limited treatment options to prevent its progression. Gambogic acid (GA), a xanthone isolated from Garcinia hanburyi, has shown notable anti-oxidative, anti-inflammatory, and anti-proliferative properties. This study aimed to assess GA's renoprotective effects in a model of diabetic nephropathy mediated by low dose streptozotocin (STZ) combined with a high-fat diet, focusing on its potential to reduce oxidative stress and inflammation. Control-treated vehicle and STZ/high-fat diet-mediated diabetic rats were administered either the vehicle or 3 or 6 mg/kg of GA to assess its effects on renal inflammation, fibrosis, and oxidative stress. Renal histological changes were assessed, and markers for inflammation and oxidative stress, including I-κBα, p-p38/MAPK, and p-p65NF-κB pathways, were measured to explore the mechanisms of GA. Diabetic rats showed significant renal dysfunction, structural damage, and increased inflammation and fibrosis. Treatment with GA markedly improved renal structure and function. GA also reduced oxidative stress, increased I-κBα expression, and inhibited key signaling pathways, specifically p-p38/MAPK and p-p65NF-κB, involved in cellular inflammation. GA exhibits promising renoprotective effects in diabetic nephropathy by reducing oxidative stress and inflammation, supporting its potential as a natural therapeutic agent for diabetic renal disease.

Streptozotocin-induced morphological changes in rat lungs

Streptozotocin (STZ) is a commonly used compound for the induction of type 2 diabetes (T2D) in animal models, but its effects on non-pancreatic tissues like the lungs are not well understood. This study aimed to examine the histopathological impact of STZ on the lungs using male Sprague-Dawley rats. The rats were divided into two groups: a control group on a normal diet and an STZ-treated group receiving a high-fat diet and 10% sucrose water for 8 weeks, followed by an STZ injection (30 mg/kg body weight). All rats were terminated 9 days after STZ administration, and lung samples were collected for light microscopy, transmission electron microscopy (TEM), and confocal laser scanning microscopy. Light microscopy revealed thickening of alveolar septa, narrowing of alveoli, and inflammatory infiltrates in the STZ group. TEM showed mitochondrial damage in type 2 pneumocytes, including membrane fragmentation, cristae loss, and formation of mitochondrial-derived vesicles. Confocal microscopy revealed significantly higher expression of myeloperoxidase, neutrophil elastase, and citrullinated histone 3 in the STZ group compared to controls. These findings suggest that STZ induces considerable lung damage, emphasizing the need to consider lung toxicity in studies involving STZ.

Therapeutic Potential of N-acetylcysteine and Glycine in Reducing Pulmonary Injury in Diabetic Rats

INTRODUCTION

Diabetes mellitus is associated with systemic complications, including the development of pulmonary injury, characterized mainly by excessive accumulation of extracellular matrix components and inflammatory cell infiltration in lung tissue. This process is driven by oxidative stress and chronic inflammation, both caused and exacerbated by hyperglycemia. N-acetylcysteine (NAC) and glycine, known for their antioxidant and anti-inflammatory effects, offer potential therapeutic benefits in mitigating diabetes-induced lung injury.

OBJECTIVE

The study aimed to investigate the effects of supplementation by either NAC or glycine or their combination on reducing lung injury in rats with type 1 diabetes Materials and methods: The study used 30 adult Wistar albino rats (10 weeks old, weighing between 180 g and 380 g). Six of them were used as controls, while 24 adult rats (10 weeks old, 180-380 g) with type 1 diabetes, induced through a single intraperitoneal injection of streptozotocin (STZ) at a dose of 55 mg/kg, were randomly assigned to four experimental groups: control (CTL), diabetic (Db), NAC treatment (diabetic+NAC), glycine treatment (diabetic+glycine), and combined NAC and glycine treatment (diabetic+NAC+glycine). NAC (100 mg/kg) and glycine (250 mg/kg) were administered orally for 12 weeks. At the end of the study, lung tissues were collected for histopathological examination. Qualitative, semi-quantitative, and stereological histological analysis was used to analyze structural changes in the lung tissue. Semi-quantitative scoring was carried out to evaluate the extent of inflammation, while stereological analysis was performed to determine the volume density of alveolar spaces and septal connective tissue. The semi-quantitative scoring included scores ranging from 0 (absent), 1 (minimal), 2 (mild), 3 (moderate), to 4 (severe).

RESULTS

Qualitative histological analysis revealed pronounced inflammation and fibrosis in the lungs of untreated diabetic rats, characterized by thickened alveolar septa and immune cell infiltration. Both treatments with NAC and glycine individually reduced inflammation and fibrosis compared to untreated diabetic rats. The greatest improvement was observed in the NAC+glycine group, where the alveolar structure appeared almost normal, with minimal inflammation. Semiquantitative analysis showed statistically significant differences in peribronchial and peribrochiolar infiltrates between the diabetic group (2.16±0.47) and the control group (0.33±0.21, p=0.026). The combination of NAC and glycine significantly reduced peribronchial and peribronchiolar infiltrates (0.33±0.33, p=0.026) compared to the diabetic group. Similarly, septal inflammatory infiltrates were significantly lower in the NAC+glycine group (1±0.36) compared to diabetic rats (3.33±0.33, p=0.004). Total airway inflammatory infiltration was also significantly reduced in the NAC+glycine group (1.33±0.33, p=0.002) compared to the diabetic group (5.5±0.5).

CONCLUSION

As the combination of NAC and glycine demonstrated protective effects against lung inflammation and fibrosis in diabetic rats, a synergistic effect of NAC and glycine in mitigating pulmonary complications associated with type 1 diabetes may be suggested. These findings warrant further exploration of the combination for managing diabetic lung disease and potentially other fibrotic conditions.

Effect of Buddleja cordata Leaf Extract on Diabetic Nephropathy in Rats

One of complications of diabetes mellitus is diabetic nephropathy. In Mexico, in traditional medicine, Buddleja cordata Humb. Bonpl. & Kunth, ("tepozán blanco") is a shrub plant used for the treatment of rheumatic diseases, postpartum bath, stomachache, skin burns, diarrhea in children, sores, and cancer. Objectives: We examined the effect of methanol extract of leaves of B. cordata on the expression of pro-inflammatory cytokines and its antioxidant effects in diabetic nephropathy. Methods: We used the streptozotocin-induced diabetes mellitus model in rats; these were treated with methanol extract from leaves of B. cordata at 50 and 100 mg/kg (orally) for 4 weeks. Kidney weight/total body weight ratio and proteins/DNA, proteinuria and creatinine clearance, Western blot of nuclear factor κΒ (NFkB) p65 (cytoplasm and nucleus), peroxisome proliferator activated receptor gamma (PPARγ), and activities of glutathione peroxidase, superoxide dismutase, and catalase were determined.

The effects of ecdysterone and enalapril on nitric oxide synthesis and the markers of oxidative stress in streptozotocin-induced diabetes in rats: a comparative study

Cardiovascular functions in diabetes greatly depend on constitutive NOS (cNOS) activity. A comparative study of the effects of a steroid hormone ecdysterone and enalapril, an ACE inhibitor widely used to treat cardiac disorders on cNOS, inducible NOS (iNOS), xanthine oxidoreductase (XOR) activity, RNS, ROS, and lipid peroxidation in heart tissue in experimental diabetes was conducted. The rat model of diabetes was established by streptozotocin injection. NOS activity, NO2-, NO3-, uric acid, nitrosothiols, hydroperoxide, superoxide, and diene conjugate formation were studied spectrophotomerically. In diabetes, cNOS downregulation correlated with a dramatic fall of NO2- production and ~4.5-fold elevation of nitrosothiols, which agreed with a steep rise of iNOS activity, while NO3- remained close to control. Dramatic activation of XOR was observed, which correlated with the elevation of both superoxide production and nitrate reductase activity and resulted in strong lipid peroxidation. Ecdysterone and enalapril differently affected RNS metabolism. Ecdysterone moderately restored cNOS but strongly suppressed iNOS, which resulted in the reduction of NO3-, but full restoration of NO2- production. Enalapril better restored cNOS but less effectively suppressed iNOS, which promoted NO3- formation. Both drugs similarly inhibited XOR, which equally alleviated oxidative stress and lipid peroxidation. The synergistic action of iNOS and XOR was a plausible explanation for strong lipid peroxidation, abolished by the inhibition of iNOS and XOR by ecdysterone or enalapril. Complementary effects of ecdysterone and enalapril on cNOS, iNOS, and RNS are a promising basis for their combined use in the treatment of cardiovascular disorders caused by cNOS dysfunction in diabetes.

Linalool exerts antioxidant activity in a rat model of diabetes by increasing catalase activity without antihyperglycemic effect

Diabetes mellitus (DM) is a prevalent metabolic disorder often accompanied by oxidative stress, which contributes to various diabetic complications. Investigating the antioxidant activity of linalool (LIN) is crucial as it may offer a natural therapeutic approach to mitigate oxidative damage in DM. The aim of the present study was to investigate the antioxidant activity of LIN in a DM rat model. A total of 40 male Wistar albino rats (age, 8 weeks; weight, 250-300 g) were used. CONTROL and DM groups were administered physiological saline solution by oral gavage for 21 days. In rats in the DM + LIN and LIN groups, 100 mg/kg LIN was administered intragastrically after streptozotocin injection (n=10 per group). In the first (48 h after STZ injection), second (1 week later), third (2 weeks later), and fourth (3 weeks later) blood glucose measurements, a statistically significant increase was found in the blood glucose values of the DM and DM + LIN groups compared with those of the CONTROL group. During the 21-day experimental period, there was no reduction in blood glucose levels of the DM + LIN group. Consequently, no discernible anti-hyperglycemic effect of LIN was observed. Catalase enzyme activity, superoxide dismutase (SOD) enzyme activity, malondialdehyde (MDA) levels and glutathione (GSH) levels were measured spectrophotometrically. All assays were conducted according to the protocols provided in the respective kits. The results were analyzed to assess the oxidative status and antioxidant capacity in the experimental groups. Catalase (CAT) activity was decreased in the DM group compared with that in the CONTROL group in both the serum and liver. However, LIN administration restored CAT activity in the DM + LIN group to the level of the CONTROL group. In the liver, the DM + LIN-treated group showed a notable reduction in malondialdehyde (MDA) levels compared with those in the DM group. In conclusion, the present results suggest that the antioxidant properties of LIN may have a regulatory effect on the oxidative status in diabetes-affected systems, potentially offering therapeutic benefits in managing oxidative stress associated with diabetes.

Mechanism of streptozotocin to induce cardiac fibrosis through TNFa and Bcl2 pathways in in silico and in vivo study

Background

Cardiac fibrosis is often associated with various heart-related problems such as heart failure, atrial arrhythmia, and sudden cardiac death, making it a leading cause of death globally. Diabetes-associated fibrosis, on the other hand, is influenced by activated cardiac fibroblasts and potentially involves fibrosis-inducing activity of macrophages, cardiomyocytes, and vascular cells. Streptozotocin (STZ) is a known diabetogenic agent, but inadequate preclinical data in animal models hinders its clinical success.

Aim

This study aims to provide practical guidelines for STZ utilization in inducing diabetes-associated cardiac fibrosis.

Methods

The research was conducted in vivo using white rats (Rattus norvegicus) of the Wistar strain, induced with STZ at doses of 30 mg/KgBW and 50 mg/KgBW per injection. Observations were carried out in the 4th and 8th weeks, consisting of the measurement of blood sugar levels and the examination of heart muscle cell fibrosis. Subsequently, in silico validation of STZ's affinity with inflammatory receptors causing diabetes pathology, such as TNFα and Bcl2, was performed.

Results

The study results indicated that the administration of STZ led to an increase in random blood sugar levels and extensive fibrosis of heart muscle cells in mice. The optimal dose for the diabetes model experimented in this study was 50 mg/KgBW for 8 weeks. In silico tests revealed an affinity for TNFα (PDB ID 2AZ5) and Bcl2 (PDB ID 6QGH).

Conclusion

Consequently, it can be concluded that administering STZ to mice at a dose of 50 mg/KgBW for 8 weeks is an effective inducer of a diabetes-associated cardiac fibrosis model.

Neuroprotective Effects of Bexarotene and Icariin in a Diabetic Rat Model

Objective Type 2 diabetes mellitus (T2DM), a chronic metabolic disorder affecting over 400 million people globally, is increasingly recognized for its detrimental impact on the central nervous system. T2DM is linked to neurodegenerative diseases like Alzheimer's and vascular dementia. This study investigates the neuroprotective effects of bexarotene and icariin in a T2DM rat model, focusing on brain-derived neurotrophic factor (BDNF), glial fibrillary acidic protein (GFAP), and neurofilament-light chain (NfL) levels. Methods Before the study, rats underwent fasting blood glucose tests, lipid profile assessments, and general health evaluations, followed by a high-fat diet for two weeks and a single streptozotocin dose (35 mg/kg). Rats with fasting blood glucose levels ≥250 mg/dl were classified as diabetes mellitus (DM) and continued on the high-fat diet throughout the experiment. Forty-seven male Wistar Albino rats were divided into six groups: a healthy control group, a DM control group, a DM group treated with bexarotene, a DM group treated with icariin, and two DM groups treated with combinations of low and high doses of bexarotene and icariin. After the 45-day treatment, blood samples were collected under thiopental sodium anesthesia, with HbA1c (glycosylated hemoglobin) and hematological parameters analyzed within eight hours, and serum stored at -80°C for further analysis. The animals were then euthanized, and brain tissues were harvested, frozen, and stored at -80°C until further examination. Brain tissues were analyzed for BDNF, GFAP, and NfL levels using ELISA (enzyme-linked immunosorbent assay). For comparing multiple groups, the Kruskal-Wallis test was applied to nonparametric data, and one-way ANOVA was used for parametric data, followed by Bonferroni's post hoc test for pairwise comparisons. Statistical significance was determined with two-tailed tests at p < 0.05. Results Significant changes in GFAP levels were observed across groups (p < 0.001). The DM control group showed the highest GFAP levels, while treatment groups exhibited reductions. The DM control group also showed the highest BDNF levels, while treatment groups exhibited reductions. The DM control group showed the lowest NfL levels, while treatment groups exhibited increments. Conclusion This study highlights the neuroprotective potential of bexarotene and icariin in a diabetic rat model, evidenced by significant changes in GFAP levels. The lack of significant changes in BDNF and NfL suggests that longer study durations may be necessary to observe these effects. Future research should include extended study periods, larger sample sizes, varied dosages, and comprehensive behavioral assessments to better understand the therapeutic potential of these agents.

Effects of Sevoflurane and Fullerenol C60 on the Heart and Lung in Lower-Extremity Ischemia-Reperfusion Injury in Streptozotocin-Induced Diabetes Mice

Background and Objectives: Lower-extremity ischemia-reperfusion injury can induce distant organ ischemia, and patients with diabetes are particularly susceptible to ischemia-reperfusion injury. Sevoflurane, a widely used halogenated inhalation anesthetic, and fullerenol C60, a potent antioxidant, were investigated for their effects on heart and lung tissues in lower-extremity ischemia-reperfusion injury in streptozotocin (STZ)-induced diabetic mice. Materials and Methods: A total of 41 mice were divided into six groups: control (n = 6), diabetes-control (n = 7), diabetes-ischemia (n = 7), diabetes-ischemia-fullerenol C60 (n = 7), diabetes-ischemia-sevoflurane (n = 7), and diabetes-ischemia-fullerenol C60-sevoflurane (n = 7). Diabetes was induced in mice using a single intraperitoneal dose of 55 mg/kg STZ in all groups except for the control group. Mice in the control and diabetes-control groups underwent midline laparotomy and were sacrificed after 120 min. The DIR group underwent 120 min of lower-extremity ischemia followed by 120 min of reperfusion. In the DIR-F group, mice received 100 μg/kg fullerenol C60 intraperitoneally 30 min before IR. In the DIR-S group, sevoflurane and oxygen were administered during the IR procedure. In the DIR-FS group, fullerenol C60 and sevoflurane were administered. Biochemical and histological evaluations were performed on collected heart and lung tissues. Results: Histological examination of heart tissues showed significantly higher necrosis, polymorphonuclear leukocyte infiltration, edema, and total damage scores in the DIR group compared to controls. These effects were attenuated in fullerenol-treated groups. Lung tissue examination revealed more alveolar wall edema, hemorrhage, vascular congestion, polymorphonuclear leukocyte infiltration, and higher total damage scores in the DIR group compared to controls, with reduced injury parameters in the fullerenol-treated groups. Biochemical analyses indicated significantly higher total oxidative stress, oxidative stress index, and paraoxonase-1 levels in the DIR group compared to the control and diabetic groups. These levels were lower in the fullerenol-treated groups. Conclusions: Distant organ damage in the lung and heart tissues due to lower-extremity ischemia-reperfusion injury can be significantly reduced by fullerenol C60.

The potential of Myrmecodia pendans in preventing complications of diabetes mellitus as an antidiabetic and antihyperlipidemic agent

Background

Hyperglycemia in diabetes mellitus (DM) can lead to dyslipidemia, which is a risk factor for macrovascular complications such as heart disease and stroke. Aside from administering antidiabetic medications, DM treatment can also be achieved through the use of natural components, such as Myrmecodia pendans, commonly known as the ant nest plant (ANP).

Aim

This study aimed to investigate the impact of administering the ANP on the lipid profile of Wistar rats.

Methods

A group of 20 rats was divided into two categories: 6 rats served as healthy controls (H), while the remaining 14 rats were subjected to a high-lipid diet and streptozotocin to generate a model of type 2 diabetes mellitus (T2DM). The diabetic rats were divided into two groups: the DM group consisted of rats that did not receive any treatment, while the ANP group was administered the herb orally.

Results

The results revealed significant variations in triglyceride, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) levels among the three groups (p < 0.05). The post hoc test revealed disparities in triglyceride and LDL between those in the DM group and the ANP group (p < 0.05).

Conclusion

Myrmecodia pendans demonstrated the ability to decrease triglyceride and LDL, while increasing HDL levels in rats with T2DM.

Effects of empagliflozin on gonadal functions of hyperglycemic male wistar rats

Empagliflozin (EMPA) showed antiapoptotic, oxidative and anti-inflammatory potential effect. EMPA attenuates the inflammation and oxidative stress biomarkers in patients with heart failure while significantly decreases the malondialdehyde (a lipid peroxidation marker) levels in the plasma of diabetic patients. The present study examined the effects of moderate hyperglycemia on reproductive function. Sixty male Wister rats ‎ were divided and randomly allocated into four groups of 15 animals each‎‎. Diabetes was induced by a single intraperitoneal injection of a prepared solution containing STZ diluted in 0.1 M sodium citrate buffer (pH 4.5) at a dosage of 40 mg/kg body weight in selected in groups II and III for seven days before starting the treatment with EMPA. The current study revealed that EMPA for eight weeks prevented testicular high glucose-induced oxidative stress markers such as penile nitric oxide (NO), glutathione peroxidase (GPX) and total anti-oxidant capacity (TAC) in STZ-induced hyperglycemia in a rat model. In addition, EMPA ameliorated the high levels of endogenous Interleukin-6 (IL-6) present in gonads in response to an acute inflammatory found in the hyperglycemic STZ-induced rats. The present study further suggested the protective effects of EMPA and how it has a beneficial role and can effectively attenuate hyperglycemia-induced testicular oxidative damage and inflammatory markers as well as androgen dependent testicular enzymes activity as a protective role against the consequences of hyperglycemia and male sub-infertility.

Functional candesartan loaded lipid nanoparticles for the control of diabetes-associated stroke: In vitro and in vivo studies

Diabetes mellitus is a metabolic disease that raises the odds of developing stroke. Candesartan has been used to prevent stroke due to its inhibitory effects on blood pressure, angiogenesis, oxidative damage, and apoptosis. However, oral candesartan has very limited bioavailability and efficacy due to its weak solubility and slow release. The study aimed to develop a nasal formulation of candesartan-loaded liposomes containing ethanol and propylene glycol (CLEP) to improve candesartan's delivery, release, permeation, and efficacy as a potential diabetes-associated stroke treatment. Using design expert software, different CLEP formulations were prepared and evaluated in vitro to identify the optimum formulation, which. The selected optimum formulation composed of 3.3% phospholipid, 10% ethanol, and 15% propylene glycol significantly increased the release and permeation of candesartan relative to free candesartan by a factor of 1.52 and 1.47, respectively. The optimum formulation significantly reduced the infarction after stroke in rats; decreased flexion, spontaneous motor activity, and time spent in the target quadrant by 70%, 64.71%, and 92.31%, respectively, and enhanced grip strength by a ratio of 2.3. Therefore, nasal administration of the CLEP formulation could be a potential diabetes-associated stroke treatment.

Quercetin prevents kidney against diabetes mellitus (type 1) in rats by inhibiting TGF-β/apelin gene expression

BACKGROUND

One of the main causes of diabetic nephropathy is oxidative stress induced by hyperglycemia. Apelin inhibits insulin secretion. Besides, renal expression of TGF-β is increased in diabetes mellitus (DM). The preventive effect of quercetin (Q) against renal functional disorders and tissue damage developed by DM in rats was assessed.

METHODS

Forty male Wistar rats were grouped into normal control (NC), normal + quercetin (NQ: quercetin, 50 mg/kg/day by gavage), diabetic control (DC: streptozotocin, 65 mg/kg, i.p.), diabetic + quercetin pretreatment (D + Qpre), and diabetic + quercetin post-treatment (D + Qpost). All samples (24-hour urine, plasma, pancreatic, and renal tissues) were obtained at the terminal of the experiment.

RESULTS

Compared to NC and NQ groups, DM ended in elevated plasma and glucose levels, decreased plasma insulin level, kidney dysfunction, augmented levels of malondialdehyde, decreased level of reduced glutathione, reduced enzymatic activities of superoxide dismutase and catalase, elevated gene expression levels of apelin and TGF-β, also renal and pancreatic histological damages. Quercetin administration diminished entire the changes. However, the measure of improvement in the D + Qpre group was higher than that of the D + Qpost group.

CONCLUSION

Quercetin prevents renal dysfunction induced by DM, which might be related to the diminution of lipid peroxidation, strengthening of antioxidant systems, and prevention of the apelin/ TGF-β signaling pathway.

Identifying the stability of housekeeping genes to be used for the quantitative real-time PCR normalization in retinal tissue of streptozotocin-induced diabetic rats

AIM

To investigate the stability of the seven housekeeping genes: beta-actin (ActB), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), 18s ribosomal unit 5 (18s), cyclophilin A (CycA), hypoxanthine-guanine phosphoribosyl transferase (HPRT), ribosomal protein large P0 (36B4) and terminal uridylyl transferase 1 (U6) in the diabetic retinal tissue of rat model.

METHODS

The expression of these seven genes in rat retinal tissues was determined using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) in two groups; normal control rats and streptozotocin-induced diabetic rats. The stability analysis of gene expression was investigated using geNorm, NormFinder, BestKeeper, and comparative delta-Ct (ΔCt) algorithms.

RESULTS

The 36B4 gene was stably expressed in the retinal tissues of normal control animals; however, it was less stable in diabetic retinas. The 18s gene was expressed consistently in both normal control and diabetic rats' retinal tissue. That this gene was the best reference for data normalisation in RT-qPCR studies that used the retinal tissue of streptozotocin-induced diabetic rats. Furthermore, there was no ideal gene stably expressed for use in all experimental settings.

CONCLUSION

Identifying relevant genes is a need for achieving RT-qPCR validity and reliability and must be appropriately achieved based on a specific experimental setting.

Topical naltrexone increases aquaporin 5 production in the lacrimal gland and restores tear production in diabetic rats

Diabetes mellitus is a prevalent disease that is often accompanied by ocular surface abnormalities including delayed epithelial wound healing and decreased corneal sensitivity. The impact of diabetes on the lacrimal functional unit (LFU) and the structures responsible for maintaining tear homeostasis, is not completely known. It has been shown that the Opioid Growth Factor Receptor (OGFr), and its ligand, Opioid Growth Factor (OGF), is dysregulated in the ocular surface of diabetic rats leading to overproduction of the inhibitory growth peptide OGF. The opioid antagonist naltrexone hydrochloride (NTX) blocks the OGF-OGFr pathway, and complete blockade following systemic or topical treatment with NTX restores the rate of re-epithelialization of corneal epithelial wounds, normalizes corneal sensitivity, and reverses dry eye in diabetic animal models. These effects occur rapidly and within days of initiating treatment. The present study was designed to understand mechanisms related to the fast reversal (<5 days) of dry eye by NTX in type 1 diabetes (T1D) by investigating dysregulation of the LFU. The approach involved examination of the morphology of the LFU before and after NTX treatment. Male and female adult Sprague-Dawley rats were rendered hyperglycemic with streptozotocin, and after 6 weeks rats were considered to be a T1D model. Rats received topical NTX twice daily to one eye for 10 days. During the period of treatment, tear production and corneal sensitivity were recorded. On day 11, animals were euthanized and orbital tissues including conjunctiva, eyelids, and lacrimal glands, were removed and processed for histologic examination including immunohistochemistry. Male and female T1D rats had significantly decreased tear production and corneal insensitivity, significantly decreased number and size of lacrimal gland acini, decreased expression of aquaporin-5 (AQP5) protein and decreased goblet cell size. Thus, 10 days of NTX treatment restored tear production and corneal sensitivity to normal values, increased AQP5 expression, and restored the surface area of goblet cells to normal. NTX had no effect on the number of lacrimal gland acini or the number of conjunctival goblet cells. In summary, blockade of the OGF-OGFr pathway with NTX reversed corneal and lacrimal gland complications and restored some components of tear homeostasis confirming the efficacy of topical NTX as a treatment for ocular defects in diabetes.

Therapeutic potential of orally applied KB-R7943 in streptozotocin-induced neuropathy in rats

Both peripheral neuropathy and depression can be viewed as neurodegeneration's consequences of diabetes, at least in part coexisting with or resulting from sodium-calcium dysbalance. This study aims to assess the therapeutic potential of the orally applied reverse-mode inhibitor of the sodium-calcium exchanger (NCX) KB-R7943 in the streptozotocin (STZ) diabetes model in rats. A pilot pharmacokinetic (PK) study with high-performance liquid chromatography with high-resolution tandem mass spectrometric detection revealed higher drug exposure (AUC), lower volume of distribution (Vd) and clearance (Cl), and faster decline of the plasma concentration (ƛ) in rats with diabetes vs. controls. Brain and heart accumulation and urinary excretion of the unmetabolized KB-R7943 at least 24 h were also demonstrated in all rats. However, heart and hippocampus KB-R7943 penetration (AUCtissue/AUCplasma) was higher in controls vs. diabetic rats. The development of thermal, mechanical, and chemical-induced allodynia was assessed with the Cold plate test (CPT), Randall-Stiletto (R-S) test, and 0.5% formalin test (FT). Amitriptyline 10 mg/kg, KB-R7943 5 mg/kg, or 10 mg/kg p.o once daily was applied from the 28th to the 49th day. The body weight, coat status, CPT, R-S, and FT were evaluated on days (-5), 0, and 42. On day 41, a forced swim test and 24-h spontaneous physical activities were assessed. The chronic treatment effects were calculated as % of the maximum. A dose-depended amelioration of neuropathic and depression-like effects was demonstrated. The oral application of KB-R7943 for potentially treating neurodegenerative consequences of diabetes merits further studies. The brain, heart, and kidneys are essential contributors to the PKs of this drug, and their safety involvement needs to be further characterized.

Nephroprotective effect of cranberry (Vaccinium oxycoccos) in streptozocin-induced diabetic nephropathy in mice

OBJECTIVES

Diabetic nephropathy is a chief reason of mortality particularly in individuals with renal dysfunction. The current research was aimed to assess the nephroprotective portion of Vaccinium oxycoccos toward mice diabetic nephropathy induced by streptozotocin (STZ). V. oxycoccos was purchased and used for hydroalcoholic extraction.

METHODS

Sixty male mice were subjected to STZ-intraperitoneal injection (45 mg/kg). After diabetes induction, mice were divided into five groups of diabetic control (received only STZ), non-diabetic control (received only citrate buffer), two V. oxycoccos treatment (received V. oxycoccos extract (200 and 400 mg/kg) oral daily by gavage), and metformin treatment (received metformin (500 mg/kg) oral daily by gavage). Glucose and weight of mice were checked weekly.

RESULTS

After 28 days, the effect of V. oxycoccos extract on serum and urine parameters were assessed. STZ caused significant decreased in the mice body weight. Mice treated with the V. oxycoccos (400 mg/kg) harbored the lowest weight loss at day 28 (70.2±1.38 g). STZ caused significant increase in the mice FBS. Mice treated with the V. oxycoccos (400 mg/kg) harbored the lowest FBS at day 28 (189.2±1.20 mg/dL). Treatment of mice with V. oxycoccos (400 mg/kg) caused the lowest increase in the levels of cholesterol, HbA1c and triglycerides compared to the diabetic control mice. Compared to the diabetic control group, mice treated with V. oxycoccos (400 mg/kg) had the highest HDL, insulin, SOD, and GSH (p<0.05). The lowest serum BUN, CR, and UR were found in mice treated with V. oxycoccos (400 mg/kg). Anti-inflammatory effects of V. oxycoccos (400 mg/kg) was shown by the lowest TNF-α, IL-6, and TGF-β1 concentration in mice treated with V. oxycoccos (400 mg/kg).

CONCLUSIONS

The current study disclosed that treatment with V. oxycoccos resulted in substantial development in the serum and urine parameters and also antioxidant and anti-inflammatory response of STZ-induced diabetic mice.

Myocardial infarct size is reduced by nitrite and nitrate administration: a systematic review and meta-analysis of animal studies

Ischemic heart disease (IHD) is the leading cause of mortality worldwide and can be complicated by myocardial infarction (MI), leading to cardiac failure. Inorganic nitrite and nitrate, which release nitric oxide (NO), can protect the heart against myocardial injury. This animal systematic review and meta-analysis aims to assess whether the administration of nitrite/nitrate decreases myocardial infarct size. We systematically searched PubMed, Scopus, and Web of Science databases until October 2023; 15 eligible animal studies (35 study arms for in-vivo and 10 for in-vitro studies) published between 1989 and 2023 were included. In-vivo studies were conducted on rats, mice, cats, and dogs, and in-vitro studies on rats and mice with an overall exposure of 0.03 to 12713 mg/kg to nitrate/nitrite administrated before, after, or during ischemia mainly by intravenous single bolus or by oral over 270 days. All in-vitro studies used nitrite/nitrate before ischemia, with the concentration ranging between 0.34 to 201 μM. MI was induced by occlusion of the left anterior diagonal or left circumflex arteries in in-vitro studies and by isoproterenol in in-vivo studies. Infarct size was measured by direct staining of the sliced heart sections. In in-vivo studies, nitrite (overall effect size (ES)=-17.0 %, 95 % confidence interval (CI)=-21.3, -12.8, P<0.001) and nitrate (overall ES= -9.6 %, 95 % CI=-15.7, -3.4, P=0.002) reduced myocardial infarct size. In in-vitro studies, nitrite (overall ES=-15.8 %, 95 % CI=-25.5, -6.2, P=0.001) reduced the infarct size. Sensitivity analysis showed that the overall effect of nitrite on myocardial infarct size was unaffected by doses or health conditions in in-vivo and in-vitro studies. In conclusion, our meta-analysis showed that nitrite/nitrate administration can effectively reduce myocardial infarct size. However, these results should be approached with caution because of the limitations of animal studies and the existing high heterogeneity.

Structural changes in testes of Streptozotocin induced diabetic rats and possible protective effect of royal jelly: light and electron microscopic study

Diabetes mellitus (DM) is one of the most common metabolic diseases causing damage in many organs in the body including the testes. Royal Jelly (RJ) is one of the honey bee products that has antioxidant, anti-inflammatory and antidiabetic properties. This study was performed to evaluate the changes in the microscopic structure of the testes in Streptozotocin (STZ)-induced diabetic rats, and the possible protective role of RJ. 60 adult male albino rats were divided into three groups. Group I Control group, Group II STZ group, and Group III STZ+RJ group. Group II received a single dose of STZ (50 mg/kg) by intraperitoneal injection. Group III received a single dose of STZ as in the second group then received RJ orally by intragastric tube in dose of (100 mg/kg/day) for 4 weeks after confirmation of diabetes. Light and electron microscopic studies were performed. Group II revealed marked structural changes affecting seminiferous tubules with sever reduction in germinal epithelium and loss of mature spermatozoa in their lumina. The interstitial tissue revealed degenerated Leydig cells and congested blood vessels. Mallory trichrome stained section of group II revealed marked increase in the amount of collagen fibers. Group III revealed highly preserved testicular architecture almost near to that appeared in the control group except few tubules that were damaged. In conclusion, RJ protected the testicular structure from the damaging effect of diabetic oxidative stress through its antioxidant effect thus preserving male fertility.

Long-term effects of warm water immersion on kidney tissue damage in diabetic rats

Objectives

This study aimed to investigate the effects of Warm Water Immersion (WWI) on inflammation, kidney function, and kidney tissue damage in rats with diabetes mellitus (DM).

Materials and Methods

Forty male rats were divided into four groups: Healthy Control (HC), Diabetic Control (DC), Diabetic Rats treated with WWI (DW), and Healthy Rats treated with WWI (HW). Daily 15-minute WWI sessions at 43 °C were administered for eight weeks. Various parameters including lipids, fasting blood sugar (FBS), HbA1C, insulin, advanced glycation end products (AGEs), HSP70, glomerular filtration rate (GFR), urinary albumin excretion, creatinine, blood urea nitrogen (BUN), oxidative stress, anti-oxidant parameters, and gene expression of RAGE, VEGF, and TGFß1 were assessed. Histological examination of kidney tissue was also conducted.

Results

Significant reductions in FBS, AGEs, glutathione, superoxide dismutase (SOD), and nitric oxide (NO) levels were observed in the DW group compared to DC. Expression of RAGE, VEGF, and TGFß1 genes decreased in DW. Triglycerides, total cholesterol, and LDL cholesterol were lower in DW. Insulin, HDL cholesterol, catalase, total anti-oxidant capacity (TAC), and tissue HSP70 were higher in DW. Histological assessment revealed reduced kidney damage in DW compared to DC.

Conclusion

WWI for eight weeks shows promise in mitigating diabetic nephropathy in rats, suggesting its potential as a non-invasive adjunctive therapy for managing diabetes complications.

Evaluation of the Hypoglycemic Activity of Methanolic Extract of Foeniculum vulgare in Streptozotocin-induced Diabetic Wistar Rats

OBJECTIVE

This study aimed to assess the hypoglycemic effects of methanolic extract of Foeniculum vulgare in male Wistar rats that were diabetic due to streptozotocin.

METHODS

Experimental diabetes was initially induced in male Wistar rats by intravenous injection of streptozotocin (55 mg/kg). Subsequently, the rats received daily oral administration of the methanolic extract of Foeniculum vulgare (250 mg/kg) and the standard drug metformin (300 mg/kg) for 28 days. Furthermore, a tolerance test was carried out.

RESULTS

The study findings suggest that the diabetic rats in the untreated control group showed hyperglycemia and significant weight loss, as well as polydipsia, polyphagia, and polyuria. However, rats treated with methanolic extract of Foeniculum vulgare for 28 days showed a significant reduction in blood glucose levels and a marked improvement in body weight. Additionally, there was a notable decrease in the daily rate of food consumption and water intake and a significant reduction in serum glucose level, triglycerides, total cholesterol, creatinine, urea, AST, and ALT levels compared to the untreated diabetic control group. Histopathological examination revealed that after 28 days of treatment with 250 mg/kg of methanolic extract of the Foeniculum vulgare, the size of the islets of Langerhans in the pancreas tissue was decreased. Moreover, liver tissue demonstrated normalization with a normal central lobular structure, and kidney tissue showed normalization with a normal Bowman's capsule.

CONCLUSION

These findings suggest that the methanolic extract of Foeniculum vulgare can potentially treat diabetes and should be evaluated further for drug development.

Dissolving sodium hydrosulfide in drinking water is not a good source of hydrogen sulfide for animal studies

Hydrogen sulfide (H2S) has many physiological and pathological roles in the human body. Sodium hydrosulfide (NaHS) is widely used as a pharmacological tool for assessing H2S effects in biological experiments. Although H2S loss from NaHS solution is a matter of minutes, some animal studies use NaHS in solution as an H2S-donating compound in drinking water. This study addresses whether 30 μM NaHS in drinking water prepared in rat/mouse water bottles remains stable for at least 12-24 h, as presumed by some authors. NaHS solutions (30 μM) were prepared in drinking water and immediately transferred to rat/mice water bottles. Samples were obtained from the tip of water bottles and from inside of the bottles at 0, 1, 2, 3, 4, 5, 6, 12, and 24 h for sulfide measurement using the methylene blue method. Furthermore, NaHS (30 μM) was administered to male and female rats for two weeks, and serum sulfide concentrations were measured every other day in the first week and at the end of the second week. NaHS solution was unstable in the samples obtained from the tip of water bottles; it declined by 72% and 75% after 12 and 24 h, respectively. In the samples obtained from the inside of the water bottles, the decline in the NaHS was not significant until 2 h; however, it decreased by 47% and 72% after 12 and 24 h, respectively. NaHS administration did not affect serum sulfide levels in male and female rats. In conclusion, NaHS solution prepared in drinking water can not be used for H2S donation as the solution is unstable. This route of administration exposes animals to variable and lower-than-expected amounts of NaHS.

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.