Puerarin enhances superoxide dismutase activity and inhibits RAGE and VEGF expression in retinas of STZ–induced early diabetic rats

Exploring the protective effects of Qiju Granule in a rat model of dry age-related macular degeneration

AIM

The aim of this study was to evaluate the potential protective effect of Qiju Granule in a rat model of age-related macular degeneration (AMD) and investigate the underlying mechanisms involved.

METHODS

Rats were injected intravenously with 40 mg/kg of sodium iodate (SI) to induce a dry AMD model. The rats in the treatment group received three different doses of Qiju Granule once a day via gavage, while the rats in the control group were given an equal volume of physiological saline. On day 14 and day 28 following the intervention, various methods were employed to evaluate retinal function and structure, including electroretinography (ERG), optical coherence tomography (OCT), and histological examination. The expression of glial fibrillary acidic protein (GFAP), basic fibroblast growth factor (bFGF), brain-derived neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF) was assessed via immunofluorescence. Beyond immunofluorescence, the mRNA levels of bFGF, BDNF, and CNTF were quantitatively determined using real-time polymerase chain reaction (qRT-PCR).

RESULTS

Rats treated with Qiju Granule exhibited significant improvements in both retinal function and structure compared to the model group. The most noteworthy effects were observed at a high dose of Qiju Granule. Furthermore, the expression levels of bFGF, BDNF, and CNTF were significantly unregulated in the treated groups compared to the model group.

CONCLUSIONS

Qiju Granule demonstrated a protective effect on the retina in the SI-induced rat model of AMD. The protective mechanism may be attributed to the upregulation of retinal neurotrophic factors expression.

Protective effects of puerarin on metabolic diseases: Emphasis on the therapeutical effects and the underlying molecular mechanisms

Metabolic diseases (MetD) such as diabetes mellitus, obesity, and hyperlipidemia have become global health challenges. As a naturally occurring plant component, puerarin has been verified to possess a wide range of pharmacological effects including lowering blood glucose, improving insulin resistance, and regulating lipid metabolism, which has attracted extensive attention in recent years, and its potential in the treatment of MetD has been highly acclaimed. In addition, puerarin has exhibited antioxidant, anti-inflammatory, and cardiovascular protective effects, which are of great significance in the prevention and treatment of MetD. This article comprehensively summarizes the research progress of puerarin in the treatment of MetD and explores its pharmacological mechanisms, clinical applications, and future perspectives. More importantly, this review provided a list of the involved molecular mechanims in treating MetD of puerarin. Taking into account these conclusions, it may provide a strong foundation for the optimized use of puerarin in the treatment of patients suffering from MetD.

Puerarin: A review of its mechanisms of action and clinical studies in ophthalmology

BACKGROUND

Pueraria is the common name of the dried root of either Pueraria montana var. lobata (Willd.) Maesen & S.M.Almeida ex Sanjappa & Predeep (syn. Pueraria lobata (Willd.) Ohwi) or Pueraria montana var. thomsonii (Benth.) M.R.Almeida (syn. Pueraria thomsonii Benth.). Puerarin is a C-glucoside of the isoflavone daidzein extracted from Pueraria. It has been widely investigated to explore its therapeutic role in eye diseases and the molecular mechanisms.

PURPOSE

To collect the available literature from 2000 to 2022 on puerarin in the treatment of ocular diseases and suggest the future required directions to improve its medicinal value.

METHOD

The content of this review was obtained from databases such as Web of Science, PubMed, Google Scholar, China National Knowledge Infrastructure (CNKI), and the Wanfang Database.

RESULTS

The search yielded 428 articles, of which 159 articles were included after excluding duplicate articles and articles related to puerarin but less relevant to the topic of the review. In eleven articles, the bioavailability of puerarin was discussed. Despite puerarin possesses diverse biological activities, its bioavailability on its own is poor. There are 95 articles in which the therapeutic mechanisms of puerarin in ocular diseases was reported. Of these, 54 articles discussed the various signalling pathways related to occular diseases affected by puerarin. The other 41 articles discussed specific biological activities of puerarin. It plays a therapeutic role in ophthalmopathy via regulating nuclear factor kappa-B (NF-ĸB), mitogen-activated protein kinases (MAPKs), PI3K/AKT, JAK/STAT, protein kinase C (PKC) and other related pathways, affecting the expression of tumour necrosis factor α (TNF-α), interleukin-1β (IL-1β), intercellular adhesion molecule-1 (ICAM-1), monocyte chemoattractant protein-1 (MCP-1), superoxide dismutase (SOD), B-cell lymphoma-2 (Bcl-2) and other cytokines resulting in anti-inflammatory, antioxidant and anti-apoptotic effects. The clinical applications of puerarin in ophthalmology were discussed in 25 articles. Eleven articles discussed the toxicity of puerarin. The literature suggests that puerarin has a good curative effect and can be used safely in clinical practice.

CONCLUSION

This review has illustrated the diverse applications of puerarin acting on ocular diseases and suggested that puerarin can be used for treating diabetic retinopathy, retinal vascular occlusion, glaucoma and other ocular diseases in the clinic. Some ocular diseases are the result of the combined action of multiple factors, and the effect of puerarin on different factors needs to be further studied to improve a more complete mechanism of action of puerarin. In addition, it is necessary to increase the number of subjects in clinical trials and conduct clinical trials for other ocular diseases. The information presented here will guide future research studies.

Downregulated HDAC3 or up-regulated microRNA-296-5p alleviates diabetic retinopathy in a mouse model

Objective

It has been demonstrated the efficacy of histone deacetylase 3 (HDAC3) in diabetes. Nevertheless, the function of HDAC3 in diabetic retinopathy (DR) remained largely obscure. Here, we investigated the HDAC3 effects in DR mice through the microRNA (miR)-296-5p/G protein subunit alpha i2 (GNAI2) axis.

Methods

The mice diabetes model was established. HDAC3, GNAI2 and miR-296-5p levels in retina tissues of DR mice were evaluated. The weight, blood glucose, Evans blue leakage in DR mice, apoptosis of retinal ganglion cells, vascular endothelial growth factor (VEGF) and malondialdehyde (MDA) contents and superoxide dismutase (SOD) activity in DR mice were detected after miR-296-5p elevation or HDAC3 depletion. The relations among HDAC3, miR-296-5p and GNAI2 were validated.

Results

HDAC3 and GNAI2 expressed at a high level while miR-296-5p expressed at a low level in retina tissues of DR mice. Restoring miR-296-5p or depleting HDAC3 reduced Evans blue leakage in DR mice, attenuated apoptosis of retinal ganglion cells, reduced VEGF and MDA, and enhanced SOD activity in serum and retinal tissues of DR mice. HDAC3 repressed miR-296-5p expression by binding to its promoter region, thereby enhancing GNAI2 expression.

Conclusion

Depleting HDAC3 or restoring miR-296-5p suppresses apoptosis of retinal ganglion cells of DR mice via down-regulating GNAI2.

Effects of "Bacuri" Seed Butter (Platonia insignis Mart.), a Brazilian Amazon Fruit, on Oxidative Stress and Diabetes Mellitus-Related Parameters in STZ-Diabetic Rats

This study aimed to investigate the effects of oral administration of Platonia insignis Mart. ("bacuri") seed butter (BSB) on oxidative stress and diabetes mellitus-related parameters in streptozotocin-induced (STZ) diabetic rats. Diabetes mellitus was induced in female Wistar rats (180-250 g) by the intraperitoneal administration of STZ (45 mg/kg, b.w). BSB (25, 50, and 100 mg/kg) was administered to animals for four weeks. The effect on weight gain, food intake, blood glucose, glycated hemoglobin, hepatic transaminases, plasma and liver TBARS and MPO activity, erythrocyte SOD activity, non-protein sulfhydryl groups (SH-NP), and histopathology of the liver tissue was investigated. BSB at the dose of 100 mg/kg had a positive effect on the reduction in glycated hemoglobin percentage and increased albumin concentration, as well as decreased ALT and AST levels and increased SH-NP liver levels in treated animals compared to normal control rats. Moreover, BSB had no effects on weight gain, food intake, and fasting glucose. Thus, the BSB presented marked properties in improvement of hepatic antioxidant defenses, which demonstrates BSB as a potential hepatoprotective agent in metabolic disorders.

Research progress on exosomes/microRNAs in the treatment of diabetic retinopathy

Diabetic retinopathy (DR) is the leakage and obstruction of retinal microvessels caused by chronic progressive diabetes that leads to a series of fundus lesions. If not treated or controlled, it will affect vision and even cause blindness. DR is caused by a variety of factors, and its pathogenesis is complex. Pericyte-related diseases are considered to be an important factor for DR in many pathogeneses, which can lead to DR development through direct or indirect mechanisms, but the specific mechanism remains unclear. Exosomes are small vesicles of 40-100 nm. Most cells can produce exosomes. They mediate intercellular communication by transporting microRNAs (miRNAs), proteins, mRNAs, DNA, or lipids to target cells. In humans, intermittent hypoxia has been reported to alter circulating excretory carriers, increase endothelial cell permeability, and promote dysfunction in vivo. Therefore, we believe that the changes in circulating exocrine secretion caused by hypoxia in DR may be involved in its progress. This article examines the possible roles of miRNAs, proteins, and DNA in DR occurrence and development and discusses their possible mechanisms and therapy. This may help to provide basic proof for the use of exocrine hormones to cure DR.

The Benefits of Flavonoids in Diabetic Retinopathy

Diabetic retinopathy (DR), one of the most common complications of diabetes, is the leading cause of legal blindness among adults of working age in developed countries. After 20 years of diabetes, almost all patients suffering from type I diabetes mellitus and about 60% of type II diabetics have DR. Several studies have tried to identify drugs and therapies to treat DR though little attention has been given to flavonoids, one type of polyphenols, which can be found in high levels mainly in fruits and vegetables, but also in other foods such as grains, cocoa, green tea or even in red wine. Flavonoids have anti-inflammatory, antioxidant and antiviral effects. Since it is known that diabetes induces oxidative stress and inflammation in the retina leading to neuronal death in the early stages of the disease, the use of these compounds can prove to be beneficial in the prevention or treatment of DR. In this review, we summarize the molecular and cellular effects of flavonoids in the diabetic retina.

Suppression of Oxygen Radicals Protects Diabetic Endothelium Damage and Tissue Perfusion in a Streptozotocin-Induced Diabetes Rodent Model

BACKGROUND

Oxygen free radicals play a central role in diabetic angiopathy. This study investigated whether suppression of oxygen radicals could decrease endothelial damage and increase peripheral tissue circulation in a diabetic rodent model.

METHODS

Sprague-Dawley rats were treated using streptozotocin to induce diabetes. The experiments were performed 4 weeks after diabetes induction: group 1: control, consisted of normal rats; group 2: diabetes, did not receive treatment; groups III (SOD10) and IV (SOD50): diabetes, received polyethylene glycol-conjugated superoxide dismutase (SOD), an antioxidant, 10 and 50 U/kg per day intraperitoneally for 4 weeks. Each subgroup consisted of 10 rats. Oxygen radicals in blood mononuclear cells were detected by flow cytometry. The blood lipid peroxidation byproduct malondialdehyde was measured. Tissue perfusion of hind limb was examined by laser Doppler. The expressions of oxygen radicals, as demonstrated by 8-hydroxyguanosine (8-OG), and constitutive endothelial nitric oxide synthase in distal femoral vessels were examined by immunohistochemical staining.

RESULTS

Oxygen radicals, as demonstrated by H2O2 with 2',7'-dichlorofluorescin diacetate-conjugated expression, were significantly increased in diabetic rats. However, the SOD treatment groups significantly suppressed the H2O2 reaction. Diabetic-induced high malondialdehyde levels were significantly suppressed in the SOD50 group. The topical tissue blood perfusion was significantly increased as detected by laser Doppler in SOD10 and SOD50 groups, as compared with that in diabetes without treatment group (P < 0.05). The expression of 8-OG was markedly increased in the diabetic endothelium and subintima compared with that in normal vessels. Polyethylene glycol-conjugated SOD significantly suppressed 8-OG expression and protected endothelial nitric oxide synthase expression.

CONCLUSIONS

Suppression of oxygen radicals, particularly with the higher dosage of polyethylene glycol-conjugated SOD at 50 U/kg per day, could have a positive effect to protect against endothelial damage and enhance peripheral perfusion in diabetes.

Puerarin enhance vascular proliferation and halt apoptosis in thiram-induced avian tibial dyschondroplasia by regulating HIF-1α, TIMP-3 and BCL-2 expressions

Tetramethyl thiuram disulfide (thiram) is a dithiocarbamate pesticide used for crop protection and storage. But, it's widespread utilization is associated with deleterious growth plate cartilage disorder in broilers termed as avian tibial dyschondroplasia (TD). TD results in non-mineralized and less vascularized proximal tibial growth plate cartilage causing lameness and poor growth performance. This study investigated the therapeutic potential of puerarin against thiram toxicity in TD affected chickens. One-day-old broiler chickens (n = 240) were alienated into three equal groups i.e. control, TD and puerarin (n = 80) and were offered standard feed. Additionally, TD and puerarin groups were offered thiram at 50 mg/kg of feed from 4 to 7 days for TD induction followed by puerarin therapy at 120 mg/kg to puerarin group only from 8 to 18 days for TD treatment. Thiram feeding to TD and puerarin group chickens caused lameness, mortality, and increased the aspartate aminotransferase (AST), alanine aminotransferase (ALT), malondialdehyde (MDA) levels and growth plate (GP) size and upregulated HIF-1α expression. Besides, the production parameters, alkaline phosphatase (ALP), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels and the expressions of TIMP-3 and BCL-2 were decreased (p < 0.05). Puerarin alleviated lameness, enhanced angiogenesis and growth performance and serum and antioxidant enzymes, decreased apoptosis and recuperated GP width by significantly downregulating HIF-1α and upregulating the TIMP-3 and BCL-2 mRNA and protein expressions in puerarin group chickens (p < 0.05). In conclusion, the toxic effects associated with thiram can be mitigated using puerarin.

Puerarin as potential treatment in diabetic retinopathy

Diabetic retinopathy (DR) is one of the most prevalent microvascular complications of diabetes, and the most leading cause of visual loss around the world. The lack of effective and approved treatment in DR is a major challenge for diabetic patients. Nowadays, natural compounds have got attention of the researchers for management of DR. Many evidences suggest that puerarin as a natural polyphenol exerts advantageous effects against DR. In the present review, we summarized the protective effects of puerarin against DR, and discussed the underlying mechanisms of these effects. Puerarin attenuates retinal neovascularization and neurodegeneration in diabetes mellitus, and the underlying mechanisms are related to antioxidant, anti-inflammatory, and antiapoptotic properties of the compound. In conclusion, puerarin might be a potential adjuvant agent for the prevention and treatment of DR. However, comprehensive studies are necessary to show its effectiveness and safety, particularly in human.

Management of Diabetes Mellitus with Puerarin, a Natural Isoflavone FromPueraria lobata

Diabetes mellitus (DM) has become one of the most challenging public health problems globally. The increasing prevalence and mortality rates call for more effective therapeutic agents, especially for DM complications. Traditional herbs have a long clinical application history for DM treatment. Puerarin is a natural isoflavone from Pueraria lobata (Wild.) Ohwi which has been consumed both as a functional food and herb in Eastern Asia countries. Documented data has shown that puerarin has cardio-protective, neuroprotective, anti-oxidative, anti-inflammatory and many other effects. In this review, we will summarize the beneficial effects and underlying mechanisms of puerarin on DM and complications. Puerarin may directly benefit DM by decreasing blood glucose levels, improving insulin resistance, protecting islets, inhibiting inflammation, decreasing oxidative stress and inhibiting Maillard reaction and advanced glycation end products (AGEs) formation. Furthermore, puerarin may also benefit DM indirectly by retarding and improving a series of DM complications, such as cardiovascular complications, diabetic nephropathy, diabetic retinopathy, diabetic neuropathy, etc. However, comprehensive studies of its effect and mechanisms are needed. In addition, its efficacy is relatively low, which is partially due to its pharmacokinetics profiles. Though puerarin shows low toxicity to experimental animals, its safety on human remains to be clarified. Collectively, we suggest that puerarin might be a potential adjuvant agent for the treatment of DM and DM complications in future.

Effects of puerarin on the retina and STAT3 expression in diabetic rats

The effects of puerarin on electroretinogram, oxidative stress and STAT3 expression were determined, in diabetic rat retina and serum. Forty Sprague-Dawley rats were randomly divided into the normal control (NC), the diabetic model (DM), the low dose (250 mg/kg) puerarin (LP) or the high dose (500 mg/kg) puerarin group (HP). A diabetic rat model was induced by streptozotocin and animals were continuously treated for 4 weeks; fasting blood glucose was measured at 2 and 4 weeks after modeling. An electroretinogram and serum and tissue levels of glucose, insulin, superoxide dismutase (SOD), malondialdehyde (MDA) and total antioxidant capacity (T-AOC) were measured; real-time PCR and ELISA were used to determine STAT3 mRNA and protein expression, respectively, from the retina. The blood glucose and insulin levels in the puerarin groups were significantly lower and higher, respectively than that in the DM group. The amplitude of b-wave of electroretinogram in the DM and the LP groups was significantly lower than that in the NC group; in the LP and HP groups it was significantly higher than the DM group. The serum and retinal tissue activity of SOD and MDA was significantly lower and higher, respectively, in the DM group compared to the NC group; both the LP and HP groups had significantly higher SOD and lower MDA than the DM group. The levels of STAT3 mRNA and protein levels in the DM, LP and HP groups were significantly higher than the NC group; and levels of STAT3 mRNA and protein expression were significantly lower in the LP and HP groups than the DM group. In summary, puerarin can reduce the oxidative stress damage of the retina, and its mechanism is related to the inhibition of STAT3 expression.

Effects of Ankaferd BloodStopper on dermal healing in diabetic rats

BACKGROUND/AIM

Diabetes mellitus inhibits wound-induced angiogenesis, impairs the wound healing process, and leads to the development of chronic wounds. Ankaferd BloodStopper (ABS) is a new and promising local haemostatic agent. Although the mechanism of ABS-mediated haemostasis is well established, little is known about the associated histological and biochemical tissue reactions. The aim of this study was to evaluate the effects of this new-generation local haemostatic agent on short-term soft-tissue healing in streptozotocin (STZ)-treated rats.

MATERIALS AND METHODS

The 24 Wistar albino rats used in this study were divided into STZ-treated (STZ, n = 12) and nontreated groups (control, n = 12). Four days prior to surgery, rats in the STZ group were subcutaneously administered 60 mg/kg STZ intraperitoneally, while rats in the control group were administered 1 mL saline/kg. An incision was made in the dorsal dermal tissue of all rats, and either ABS or no haemostatic agent (NHAA) was applied to the wound before suturing. All of the rats were euthanised on postoperative day 4. Blood and skin samples were evaluated biochemically and histologically.

RESULTS

The results showed that STZ treatment impaired soft-tissue healing, assessed by measuring glutathione and lipid peroxidation levels. Moreover, while good histological results were obtained in the control group treated with ABS, there were fewer benefits in the STZ-treated group.

CONCLUSION

ABS's benefits in the control group seemed to lose their effectiveness under STZ medication.

Puerarin ameliorates cognitive deficits in streptozotocin-induced diabetic rats

Previous research has indicated that Diabetes is a high risk of learning and memory deficits. Puerarin, an isoflavonoid extracted from Kudzu roots, has been reported to possess antioxidant, anti-inflammatory, anti-apoptotic and anti-diabetic properties which are useful in the treatment of various diseases. Recently, Puerarin was found to have the effects on learning and memory performances in humans and animal models. However, up to now, there is no detailed evidence on the effect of Puerarin on diabetes-associated cognitive decline (DACD). In this study, we designed to assess the effects of Puerarin on diabetes-associated cognitive decline (DACD) using a streptozotocin (STZ)-injected rat model and exploring its potential mechanism. Diabetic rats were treated with Puerarin (100 mg/kg per d) for 7 days. The learning and memory function was evaluated by morris water maze test. The acetylcholinesterase (AChE), choline acetylase (ChAT), oxidative indicators [malondialdehyde (MDA) and superoxide dismutase (SOD)] and inflammatory cytokine (TNF-a, IL-1β and IL-6) were measured in hippocampus by using corresponding commercial kits. mRNA and Protein levels of Bcl-2 were analyzed by RT-PCR and Westernblot. The results showed that supplementation of Puerarin improved the learning and memory performances compared with the STZ group by the morris water maze test. In addition, Puerarin supplement significantly prevented AChE and MDA activities, increased ChAT and SOD activities, and alleviated the protein level of TNF-α, IL-1β and IL-6 in the hippocampus compared with the STZ group. Moreover, the pretreatment with Puerarin also significantly increased the Bcl-2 expression. It is concluded that Puerarin possesses neuroprotection to ameliorate cognitive deficits in streptozotocin-induced diabetic rats by anti-inflammatory, antioxidant and antiapototic effects.

Pituitary Adenylate Cyclase Activating Polypeptide, A Potential Therapeutic Agent for Diabetic Retinopathy in Rats: Focus on the Vertical Information Processing Pathway

Pituitary adenylate cyclase activating polypeptide (PACAP) is a neurotrophic and neuroprotective peptide that has been shown to exert protective effects in different neuronal injuries, such as retinal degenerations. Diabetic retinopathy (DR), the most common complication of diabetes, affects the microvasculature and neuronal architecture of the retina. We have proven earlier that PACAP is also protective in a rat model of DR. In this study, streptozotocin-induced DR was treated with intravitreal PACAP administration in order to further analyze the synaptic structure and proteins of PACAP-treated diabetic retinas, primarily in the vertical information processing pathway. Streptozotocin-treated Wistar rats received intravitreal PACAP injection three times into the right eye 2 weeks after the induction of diabetes. Morphological and molecular biological (qRT-PCR; Western blot) methods were used to analyze retinal synapses (ribbons, conventional) and related structures. Electron microscopic analysis revealed that retinal pigment epithelium, the ribbon synapses and other synaptic profiles suffered alterations in diabetes. However, in PACAP-treated diabetic retinas more bipolar ribbon synapses were found intact in the inner plexiform layer than in DR animals. The ribbon synapse was marked with C-terminal binding protein 2/Bassoon and formed horseshoe-shape ribbons, which were more retained in PACAP-treated diabetic retinas than in DR rats. These results are supported by molecular biological data. The selective degeneration of related structures such as bipolar and ganglion cells could be ameliorated by PACAP treatment. In summary, intravitreal administration of PACAP may have therapeutic potential in streptozotocin-induced DR through maintaining synapse integrity in the vertical pathway.

Puerarin attenuates severe burn-induced acute myocardial injury in rats

BACKGROUND

Puerarin, the main isoflavone glycoside extracted from the root of Pueraria lobata, is widely prescribed for patients with cardiovascular disorders in China. This study investigates the effect of puerarin on severe burn-induced acute myocardial injury in rats and its underlying mechanisms.

MATERIALS AND METHODS

Healthy adult Wistar rats were divided into three groups: (1) sham group, sham burn treatment; (2) burn group, third-degree burns over 30% of the total body surface area (TBSA) with lactated Ringer's solution for resuscitation; and (3) burn plus puerarin group, third-degree burns over 30% of TBSA with lactated Ringer's solution containing puerarin for resuscitation. The burned animals were sacrificed at 1, 3, 6, 12, and 24 h after burn injury. Myocardial injury was evaluated by analyzing serum creatine kinase MB fraction (CK-MB) activity and cardiac troponin T (cTNT) level. Changes in cardiomyocyte ultrastructure were also determined using a transmission electron microscope. Tumor necrosis factor (TNF)-α concentration in serum was measured by radioimmunoassay. Cardiac myeloperoxidase (MPO) activity and malondialdehyde (MDA) concentration were measured to determine neutrophil infiltration and oxidative stress in the heart, respectively. The expression of p38 mitogen-activated protein (MAP) kinase in the heart was determined by Western blot analysis.

RESULTS

After the 30% TBSA full-thickness burn injury, serum CK-MB activities and cTnT levels increased markedly, both of which were significantly decreased by the puerarin treatment. The level of serum TNF-α concentration in burn group at each time-point was obviously higher than those in sham group (1.09±0.09 ng/ml), and it reached the peak value at 12 h post burn. Burn trauma also resulted in worsen ultrastructural condition, elevated MPO activity and MDA content in heart tissue, and a significant activation of cardiac p38 MAP kinase. Administration of puerarin improved the ultrastructural changes in cardiomyocytes, decreased TNF-α concentration in serum as well as suppressed cardiac MPO activity and reduced MDA content, and abolished the activation of p38 MAP kinase in heart tissue after severe burn.

CONCLUSIONS

These results suggest that puerarin attenuates inflammatory responses, reduces neutrophil infiltration and oxidative stress in the heart, and protects against acute myocardial injury induced by severe burn.

AGEs Promote Oxidative Stress and Induce Apoptosis in Retinal Pigmented Epithelium Cells RAGE-dependently

Advanced glycation end products (AGEs) are extremely accumulated in diabetes mellitus, particularly in retinal vascular and epithelium cells, and are confirmed to contribute to diabetic retinopathy (DR). In the present study, we determined the promotion by AGEs to the oxidative stress and mitochondrial dysfunction in retinal pigmented epithelium ARPE-19 cells and investigated the influence by the knockdown or the overexpression of receptor for AGEs (RAGE) on the AGE-promoted oxidative stress and mitochondrial dysfunction. Furthermore, we determined the induction by AGEs to the cell apoptosis and to the activation of B-cell lymphoma 2 (Bcl-2) families in the AGE-BSA-induced apoptosis, and examined the RAGE-dependence in such induction. Results demonstrated that AGE-BSA upregulated the hydrogen peroxide production and induced mitochondrial dysfunction in ARPE-19 cells, dose-dependently. And the further investigation indicated that the AGE-RAGE interaction was required for the induction of oxidative stress and mitochondrial dysfunction. Moreover, the AGE-BSA treatment promoted a significantly high level of apoptotic cells, and the Bcl-2 family was implicated in the AGE-BSA-induced apoptosis, there was a significant high level of Cyt c release, Bcl-2-associated X protein (Bax) induction, Bcl-2 reduction, and caspase 9 activation in the AGE-BSA-treated cells. In conclusion, the present study recognized the apoptosis induction by AGE-BSAs in the retinal epithelium ARPE-19 cells, RAGE-dependently. The mitochondrial dysfunction was induced, and the Bcl-2 family was deregulated during the AGE-BSA-induced ARPE-19 cell apoptosis.

Effects of delayed puerarin treatment in long-term neurological outcomes of focal ischemic stroke in rats

Objective:

The present study aimed at investigate the therapeutic effects of delayed puerarin treatment in neurological outcomes after middle cerebral artery occlusion (MCAO) in rats.

Materials and Methods:

Male Wistar rats were subjected to MCAO for 120 min followed by reperfusion for 14 days. Puerarin (0, 50, 100, 200 mg/kg, intra-peritoneally) was administered at 24 h after stroke onset and repeated daily for 14 days. Neurological deficits were evaluated at 1, 4, 7, 14 days after stroke. Brain infarct volume and peri-infarct context vessel density were examined at 14 days after stroke.

Results:

Puerarin significantly improved neurological functions up to 14 days after stroke and decreased the infarct volume with doses of 50 mg/kg and 100 mg/kg compared with saline controls. Puerarin treatment also significantly increased peri-infarct context vessel density at 14 days after stroke.

Conclusions:

Delayed treatment of puerarin initiated at 24 h after stroke is beneficial with improved long-term neurological outcomes and reduced infarction volume in focal ischemic stroke in rats. Enhanced vascular remodeling by puerarin might at least partially contribute to its beneficial effects.

Silybin reduces obliterated retinal capillaries in experimental diabetic retinopathy in rats

Silybin has been previously reported to possess anti-inflammatory properties, raising the possibility that it may reduce vascular damage in diabetic retinopathy. Present study was designed to investigate this potential effect of silybin and its underlying mechanisms in experimental diabetic retinopathy. Diabetes was induced with streptozotocin (STZ) plus high-fat diet in Sprague-Dawley rats, and silybin was administrated for 22 weeks after the induction of diabetes. Histochemical and immunofluorescence techniques were used to assess the obliterated retinal capillaries, leukostasis, and level of retinal intercellular adhesion molecule-1 (ICAM-1). Western blot was performed to quantitate the expression of retinal ICAM-1. Results showed that silybin treatment significantly prevented the development of obliterated retinal capillaries in diabetes, compared with vehicle treatment. In addition, leukostasis and level of the retinal ICAM-1 were found to decrease considerably in silybin-treated diabetic groups. In conclusion, these results indicate that silybin reduces obliterated retinal capillaries in experimental diabetes, and the recovered retinal vascular leukostasis and level of ICAM-1 at least partly contributes to the preventive effect of silybin.

Neuropeptides, trophic factors, and other substances providing morphofunctional and metabolic protection in experimental models of diabetic retinopathy

Vision is the most important sensory modality for many species, including humans. Damage to the retina results in vision loss or even blindness. One of the most serious complications of diabetes, a disease that has seen a worldwide increase in prevalence, is diabetic retinopathy. This condition stems from consequences of pathological metabolism and develops in 75% of patients with type 1 and 50% with type 2 diabetes. The development of novel protective drugs is essential. In this review we provide a description of the disease and conclude that type 1 diabetes and type 2 diabetes lead to the same retinopathy. We evaluate existing experimental models and recent developments in finding effective compounds against this disorder. In our opinion, the best models are the long-term streptozotocin-induced diabetes and Otsuka Long-Evans Tokushima Fatty and spontaneously diabetic Torii rats, while the most promising substances are topically administered somatostatin and pigment epithelium-derived factor analogs, antivasculogenic substances, and systemic antioxidants. Future drug development should focus on these.

Unlocking the biology of RAGE in diabetic microvascular complications

The discovery of the receptor for advanced glycation end-products (RAGE) set the stage for the elucidation of important mechanisms underpinning diabetic complications. RAGE transduces the signals of advanced glycation end-products (AGEs), proinflammatory S100/calgranulins, and high mobility group box 1 (HMGB1), and is a one of a family of receptors for lysophosphatidic acid (LPA). These ligand tales weave a theme of vascular perturbation and inflammation linked to the pathogenesis of the chronic complications of diabetes. Once deemed implausible, this concept of inflammatory cues participating in diabetic complications is now supported by a plethora of experimental evidence in the macro- and microvasculature. We review the biology of ligand-RAGE signal transduction and its roles in diabetic microvascular complications, from animal models to human subjects.

Puerarin: a review of pharmacological effects

Puerarin is the major bioactive ingredient isolated from the root of the Pueraria lobata (Willd.) Ohwi, which is well known as Gegen (Chinese name) in traditional Chinese medicine. As the most abundant secondary metabolite, puerarin was isolated from Gegen in the late 1950s. Since then, its pharmacological properties have been extensively investigated. It is available in common foods and is used in alternative medicine. It has been widely used in the treatment of cardiovascular and cerebrovascular diseases, diabetes and diabetic complications, osteonecrosis, Parkinson's disease, Alzheimer's disease, endometriosis, and cancer. The beneficial effects of puerarin on the various medicinal purposes may be due to its wide spectrum of pharmacological properties such as vasodilation, cardioprotection, neuroprotection, antioxidant, anticancer, antiinflammation, alleviating pain, promoting bone formation, inhibiting alcohol intake, and attenuating insulin resistance. However, the direct molecular mechanisms and targets remain unclear. This review provides a comprehensive summary of the pharmacological effects of puerarin.

Streptozotocin induced diabetic retinopathy in rat and the expression of vascular endothelial growth factor and its receptor

AIM

To establish the rat model of streptozotocin (STZ)-induced diabetic retinopathy (DR), which is the most common cause of visual loss and blindness in patients with diabetes, and observe the gene expression of vascular endothelial growth factor (VEGF) and its receptors during the development of DR.

METHODS

A rat model of diabetes was established by intraperitoneal injection of STZ. The diabetic rats were housed for 2, 3 and 4 months after the development of diabetes. Retinal histopathological observation was performed. The retinal vessels were observed by immunofluorescence staining by CD31. The mRNA expression of VEGF, VEGF receptor 1 and 2 (VEGFR1/2) in rat retina was detected by reverse transcription-polymerase chain reaction (RT-PCR) analysis.

RESULTS

Retinal histopathological observation showed the morphological changes of inner nuclear layer (INL) and outer nuclear layer (ONL) at any time-point, and also demonstrated the increased new vessels at both 3, 4 months after the development of diabetes. The CD31 staining results showed that the number of vessels was increased in the retinas of diabetic rats at both 3 and 4 months after the development of diabetes. As compared to the normal rats, the mRNA expression of VEGF was increased in retinas of diabetic rats at 3 months after the development of diabetes, while VEGFR1 and VEGFR2 mRNA expression was increased at 2, 3 and 4 months after the development of diabetes.

CONCLUSION

Taken together, our results demonstrated that DR was occurred at 3 months after the development of diabetes, and the mRNA expression of VEGF, VEGFR1 and VEGFR2 were increased in the process of DR. The present study further evidenced the involvement of VEGF and its receptors in the process of DR.

Molecular strategies to prevent, inhibit, and degrade advanced glycoxidation and advanced lipoxidation end products

The advanced glycoxidation end products (AGEs) and lipoxidation end products (ALEs) contribute to the development of diabetic complications and of other pathologies. The review discusses the possibilities of counteracting the formation and stimulating the degradation of these species by pharmaceuticals and natural compounds. The review discusses inhibitors of ALE and AGE formation, cross-link breakers, ALE/AGE elimination by enzymes and proteolytic systems, receptors for advanced glycation end products (RAGEs) and blockade of the ligand-RAGE axis.