Apoptosis In Diabetic Rats Research Articles

Quercetin ameliorates diabetic kidney injury in rats by inhibiting the HMGB1/RAGE/NF-κB signaling pathway

To explore the effect of quercetin on renal inflammation and cell apoptosis in diabetic rats and its possible mechanisms. Twenty-four adult male SD rats were randomized equally into normal control group, high-glucose and high-fat feeding group, streptozotocin (STZ) -induced diabetic model group, and quercetin treatment (daily dose 100 mg/kg) group. Pathological changes of the renal tissues of the rats were observed with HE staining, serum inflammatory factor levels were determined with ELISA, and renal expression of NF‑κB was observed by immunohistochemistry. Fast blood glucose (FBG), serum levels of triglyceride (TG), BUN, and Scr, and 24-h urine protein content of the rats were measured, and renal expressions of HMGB1, RAGE, NF‑κB, Bax, Bcl-2, and caspase-3 were detected with Western blotting. The diabetic rats showed significantly increased levels of FBG, TG, BUN, and Scr, renal hypertrophy index, 24-h urinary protein content, serum IL-1β, IL-6 and TNF-α levels and renal expressions HMGB1, RAGE, NF‑κB, Bax, and caspase-3 with decreased renal expression of Bcl-2. All these changes were significantly alleviated by quercetin treatment of the rats. Quercetin can ameliorate kidney injury in diabetic rats possibly by inhibiting the HMGB1/RAGE/NF-κB inflammatory signaling pathway to reduce renal inflammation and renal cell apoptosis.

Nimbolide protects against diabetic cardiomyopathy by regulating endoplasmic reticulum stress and mitochondrial function via the Akt/mTOR pathway

Nimbolide has been demonstrated to possess protective properties against gestational diabetes mellitus and diabetic retinopathy. However, the role and molecular mechanism of nimbolide in diabetic cardiomyopathy (DCM) remain unknown. Diabetes was induced in rats via a single injection of streptozotocin (STZ) and then the diabetic rats were administered nimbolide (5 mg/kg and 20 mg/kg) or dimethyl sulfoxide daily for 12 weeks. H9c2 cardiomyocytes were exposed to high glucose (25 mM glucose) to mimic DCM in vitro. The protective effects of nimbolide against DCM were evaluated in vivo and in vitro. The potential molecular mechanism of nimbolide in DCM was further explored. We found that nimbolide dose-dependently decreased blood glucose and improved body weight of diabetic rats. Additionally, nimbolide dose-dependently improved cardiac function, alleviated myocardial injury/fibrosis, and inhibited endoplasmic reticulum (ER) stress and apoptosis in diabetic rats. Moreover, nimbolide dose-dependently improved mitochondrial function and activated the Akt/mTOR signaling. We consistently demonstrated the cardioprotective effects of nimbolide in an in vitro model of DCM. The involvement of ER stress and mitochondrial pathways were further confirmed by using inhibitors of ER stress and mitochondrial division. By applying a specific Akt inhibitor SC66, the cardioprotective effects of nimbolide were partially blocked. Our study indicated that nimbolide alleviated DCM by activating Akt/mTOR pathway. Nimbolide may be a novel therapeutic agent for DCM treatment.

Thymoquinone attenuates diabetes-induced hepatic damage in rat via regulation of oxidative/nitrosative stress, apoptosis, and inflammatory cascade with molecular docking approach

Diabetes mellitus (DM) is a complex metabolic condition that causes organ dysfunction. The current experiment sought to determine the effect of thymoquinone (TQ) on hyperglycemia, hyperlipidemia, oxidative/nitrosative stress, inflammation, and apoptosis in diabetic rats prompted by streptozotocin (STZ) (55 mg/kg body weight i/p). The animals were allocated into control, TQ (50 mg/kg B.W. orally administered for 4 succeeding weeks), Diabetic, and Diabetic + TQ groups. This study confirmed that TQ preserves the levels of insulin, fasting blood glucose, HOMA β-cell indices, HbA1c %, body weight, and lipid profile substantially relative to the DC group. Furthermore, hepatic antioxidant (CAT, GSH, and T-SOD) values were reduced. Conversely, the enzymatic activity of liver functions (AST, ALT, ALP, cytochrome P450, and hepatic glucose-6-phosphatase), lipid peroxidation (MDA), pro-inflammatory cytokines (IL-1β, TNF-α, and IL-6), nitric oxide (NO) and inflammatory marker (CRP) enhanced with STZ administration, which is substantially restored after TQ treatment. Relative to the diabetic rats, TQ reestablished the hepatic architectural changes and collagen fibers. Additionally, TQ downregulated the intensity of the immunohistochemical staining of pro-apoptotic marker (caspase-3), p53, and tumor necrosis factor-alpha (TNF-α) proteins in hepatic tissues. Furthermore, TQ displayed abilities to interact and inhibit the binding site of caspase-3, interleukin-6 receptor, interleukin-1 receptor type 1, TNF receptor superfamily member 1A, and TNF receptor superfamily member 1B in rats following the molecular docking modeling. All these data re-establish the liver functions, antioxidant enzymes, anti-inflammatory markers, and anti-apoptotic proteins impacts of TQ in STZ-induced DM rats. Founded on these outcomes, the experiment proposes that TQ is a novel natural supplement with various clinical applications, including managing DM, which in turn is recommended to play a pivotal role in preventing the progression of diabetes mellitus.

Zuogui Jiangtang Jieyu Formula ameliorating hippocampal neuronal apoptosis in diabetic rats with depression by inhibiting JNK signaling pathway

ObjectiveTo investigate the effect of Zuogui Jiangtang Jieyu Formula (左归降糖解郁方, ZJJF) on hippocampal neuron apoptosis in diabetic rats with depression and to ascertain whether its mechanism involves the regulation of JNK signaling pathway. Methods(i) A total of 72 specific pathogen-free (SPF) grade male Sprague Dawley (SD) rats were randomly divided into six groups, with 12 rats in each group: control, model, metformin (Met, 0.18 g/kg) + fluoxetine (Flu, 1.8 mg/kg), and the high-, medium-, and low-ZJJF dosages (ZJJF-H, 20.52 g/kg; ZJJF-M, 10.26 g/kg; ZJJF-L, 5.13 g/kg) groups. All groups except control group were injected once via the tail vein with streptozotocin (STZ, 38 mg/kg) combined with 28 d of chronic unpredictable mild stress (CUMS) to establish diabetic rat models with depression. During the CUMS modeling period, treatments were administered via gavage, with control and model groups receiving an equivalent volume of distilled water for 28 d. The efficacy of ZJJF in reducing blood sugar and alleviating depression was evaluated by measuring fasting blood glucose, insulin, and glycated hemoglobin levels, along with behavioral assessments, including the open field test (OFT), forced swim test (FST), and sucrose preference test (SPT). Hippocampal tissue damage and neuronal apoptosis were evaluated using hematoxylin-eosin (HE) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining. Apoptosis-related proteins Bax, Bcl-2, caspase-3, and the expression levels of JNK/Elk-1/c-fos signaling pathway were detected using Western blot and real-time quantitative polymerase chain reaction (RT-qPCR). (ii) To further elucidate the role of JNK signaling pathway in hippocampal neuronal apoptosis and the pharmacological effects of ZJJF, an additional 50 SPF grade male SD rats were randomly divided into five groups, with 10 rats in each group: control, model, SP600125 (SP6, a JNK antagonist, 10 mg/kg), ZJJF (20.52 g/kg), and ZJJF (20.52 g/kg) + Anisomycin (Aniso, a JNK agonist, 15 mg/kg) groups. Except for control group, all groups were established as diabetic rat models with depression, and treatments were administered via gavage for ZJJF and intraperitoneal injection for SP6 and Aniso for 28 d during the CUMS modeling period. Behavioral changes in rats were evaluated through the OFT, FST, and SPT, and hippocampal neuron damage and apoptosis were observed using HE staining, Nissl staining, TUNEL staining, and transmission electron microscopy (TEM). Changes in apoptosis-related proteins and JNK signaling pathway in the hippocampal tissues of rats were also analyzed. Results(i) ZJJF significantly reduced the high blood glucose, insulin, and glycated hemoglobin levels in model rats (P < 0.01). It increased autonomous activity and decreased despair-like behaviors (P < 0.01), improved the pathological damage of hippocampal neurons, increased the number of neuronal nuclei (P < 0.01), and reduced the number of mechanocytes, vacuolar cells, and apoptotic neurons (P < 0.05, P < 0.01, and P < 0.01, respectively). ZJJF down-regulated the expression levels of pro-apoptotic proteins Bax and caspase-3 (P < 0.01), up-regulated the anti-apoptotic protein Bcl-2 (P < 0.01), and significantly inhibited the overexpression of phosphorylated JNK (p-JNK), Elk-1, and c-fos (P < 0.01). (ii) SP6 increased autonomous activity and reduced despair time in model rats (P < 0.05), although it had no significant effects on sucrose preference (P > 0.05). It increased the number of Nissl bodies in hippocampal neurons (P < 0.01), reduced the protein expression levels of Bax (P < 0.01) and caspase-3 (P < 0.05), and decreased the number of apoptotic neurons (P < 0.05). SP6 also increased the expression level of Bcl-2 (P < 0.01), and inhibited the high expression levels of p-JNK, Elk-1, and c-fos (P < 0.01, P < 0.01, and P < 0.05, respectively), suggesting that hippocampal neuronal apoptosis in diabetic rats with depression is associated with abnormal activation of JNK signaling pathway. Compared with ZJJF group, ZJJF + Aniso group showed a decrease in sucrose preference (P < 0.05) and an increase in despair time (P < 0.01) with more notable hippocampal neuronal damage. This group also exhibited a decrease in expression level (P < 0.01) Bcl-2 and an increase in expression levels of Bax, caspase-3, p-JNK, Elk-1, and c-fos (P < 0.01, P < 0.05, P < 0.05, P < 0.01, and P < 0.05, respectively), indicating that the antidepressant effects of ZJJF, its improvement of neuronal apoptosis, and regulation of JNK signaling molecules could all be reversed by a specific JNK agonist. ConclusionZJJF exerts a significant hypoglycemic effect and ameliorates the apoptosis of hippocampal neurons by inhibiting the activation of JNK signaling pathway, which is a promising formula for the treatment of diabetic depression in clinical settings.

Mitragyna Parvifolia- Effective Against Hyper Glycaemia, Proinflammatory Markers and Liver Apoptosis in Streptozotocin Induced Diabetic Rats

Background Ethanolic extract of Mitragyna pareidolia leaves were used as a traditionally use in the treatment of diabetic conditions. The aim of the current study was to find out the effect of Mitragyna pareidolia ethanolic leaves extract (MPE) on hyperglycemia developed by streptozotocin (STZ) induced type 2 diabetes in rats. Materials and Method An animal model of diabetes type 2 was developed by administration of STZ 90 mg/Kg to two-day old neonatal rat pups. Oral glucose test and parameters were examined of diabetic rat after the different dose of extracts. The rats were existing into following groups: Group I –Normal control, Group II – STZ diabetic control, Group III –STZ Diabetic –orally administered MPEx at doses of 300 mg/kg, Group IV STZ-Diabetic – orally administered at doses of 500 mg/kg, Our study was confirmed that 8 weeks chronic treatment with MPE in a dose dependent manner (300 and 500 mg/kg) reduced hyperglycemia and significantly increased serum insulin, C-peptide. Histology of liver was performed after sacrificing the rats with euthanasia. Result The ethanolic extract of MP was not show any acute toxicity up-to the dose of 2000 mg/kg and it was shown better glucose consumption in oral glucose tolerance test. Orally treatment of different doses of MP leaves extract decreased the level of serum glucose, reduce elevated levels of tumor necrosis factor α (TNF-α), interleukin IL-6 in the serum of diabetic rats. After the study, we found that elevated blood glucose and lipids were bring back to near normal. In addition, MPE also reduce elevated levels of tumor necrosis factor α (TNF-α), interleukin IL-6 in the serum of diabetic rats. Conclusion We conclude that MPE exerted antidiabetic effects and reduced its associated complications such as dyslipidemia and inflammation. HE and confocal image of TUNEL assay showed that MPE reduced inflammation and apoptosis in diabetic rats.

Geniposide promotes wound healing of skin ulcers in diabetic rats through PI3K/Akt pathway

Continuously hyperglycation-induced lesion and poor blood flow contributed to the wound incurable and susceptible to infection. About fifteen percent of people with diabetes would develop ulcers during their lifetime, especially on the feet, which could lead to severe tissue destruction and eventual amputation. Various strategies were limited to accelerate wound healing in diabetic patients for high cost and unsatisfied effects. Geniposide is well-known for its anti-inflammation and anti-apoptosis in several pathological tissues. This study is to explore the protective effect of geniposide on wound healing rate, inflammatory response, nutritional function and cellular apoptosis in diabetic rats. Diabetic rats was induced by streptozotocin and defined as plasma glucose >300 mg/dl. Western blot and immunostaining technologies were performed to mark and quantify the target proteins. The oral administration of geniposide (200 mg/kg and 500 mg/kg) could significantly promote wound healing by the increment of lesion retraction in diabetic rats compared to model group. In the apoptotic study of skin wound in diabetic rats, the TUNEL-positive cells were greatly decreased in geniposide subgroups (P < 0.05). The levels of TNF-α, IL-1β and IL-6 were significantly inhibited by geniposide with the IC50 value of 470 mg/kg, 464 mg/kg and 370 mg/kg body weight respectively, which might be related to the enhancement of the phosphorylation of PI3K and Akt proteins. Geniposide enhanced the repairment of skin wound in diabetic rats by inhibiting inflammatory response and apoptosis.

Alpha-lipoic acid enhances ischemic postconditioning-mediated improvement of myocardial infarction and apoptosis in diabetic rats with ischemia/reperfusion injury.

This work evaluated the combined effects of alpha-lipoic acid (ALA) and ischemic postconditioning (Post) on myocardial infarction and cell death in rats with chronic type-II diabetes following ischemia/reperfusion injury. The rats received a high-fat diet and were given one intraperitoneal injection of 35 mg/kg streptozotocin to induce chronic diabetes. They were then pretreated with ALA (100 mg/kg/day, orally) for 5 weeks before undergoing ischemia/reperfusion (I/R) insult. The hearts experienced 35 min regional ischemia through ligating the left anterior descending coronary artery, followed by 60 min reperfusion. The Post protocol involved 6 cycles of a 10/10 s algorithm, applied during the early stage of reperfusion. The use of Post alone did not significantly alter lactate dehydrogenase and infarct size levels, while ALA showed positive effects. Similar findings were observed for apoptotic changes with single treatments. However, the concurrent administration of ALA and Post significantly reduced the protein expressions of Bax, Bax/Bcl2, and cleaved caspase-3 while increasing Bcl2 expression. Additionally, the histopathological findings of the combined therapy were superior to those of single treatments. The concomitant use of ALA and Post effectively inhibited apoptosis, leading to cardiac recovery after I/R injury in diabetic conditions. This strategy could improve outcomes for preserving diabetic hearts following I/R insults.

Neuroprotective Effect of Wharton's Jelly-Derived Mesenchymal Stem Cell-Conditioned Medium (WJMSC-CM) on Diabetes-Associated Cognitive Impairment by Improving Oxidative Stress, Neuroinflammation, and Apoptosis.

According to strong evidence, diabetes mellitus increases the risk of cognitive impairment. Mesenchymal stem cells have been shown to be potential therapeutic agents for neurological disorders. In the current study, we aimed to examine the effects of Wharton's jelly-derived mesenchymal stem cell-conditioned medium (WJMSC-CM) on learning and memory, oxidative stress, apoptosis, and histological changes in the hippocampus of diabetic rats. Randomly, 35 male Sprague Dawley rats weighing 260-300 g were allocated into five groups: control, diabetes, and three diabetic groups treated with insulin, WJMSC-CM, and DMEM. The injections of insulin (3 U/day, S.C.) and WJMSC-CM (10 mg/week, I.P.) were done for 60 days. The Morris water maze and open field were used to measure cognition and anxiety-like behaviors. Colorimetric assays were used to determine hippocampus glutathione (GSH), malondialdehyde (MDA) levels, and antioxidant enzyme activity. The histopathological evaluation of the hippocampus was performed by Nissl staining. The expression levels of Bax, Bcl-2, BDNF, and TNF-α were detected by real-time polymerase chain reaction (RT-PCR). According to our findings, WJMSC-CM significantly reduced and increased blood glucose and insulin levels, respectively. Enhanced cognition and improved anxiety-like behavior were also found in WJMSC-CM-treated diabetic rats. In addition, WJMSC-CM treatment reduced oxidative stress by lowering MDA and elevating GSH and antioxidant enzyme activity. Reduced TNF-α and enhanced Bcl-2 gene expression levels and elevated neuronal and nonneuronal (astrocytes and oligodendrocytes) cells were detected in the hippocampus of WJMSC-CM-treated diabetic rats. In conclusion, WJMSC-CM alleviated diabetes-related cognitive impairment by reducing oxidative stress, neuroinflammation, and apoptosis in diabetic rats.

Therapeutic effects of diosgenin on alveolar bone loss and apoptosis in diabetic rats with experimental periodontitis.

The present study aims to evaluate the efficacy of administered diosgenin (DG) which has anti-oxidant and anti-inflammatory effects, on alveolar bone loss (ABL) and apoptosis in diabetic rats with periodontitis. Forty male Wistar albino rats (n=40) were divided into five subgroups; control (non-ligated), periodontitis (P), diabetes mellitus (DM), P+DM, and P+DM+DG. To stimulate experimental periodontitis, a ligature was embedded at the gingival margin of the lower first molars for each rat, and diabetes was induced by streptozotocin (STZ) for DM groups. Then, DG (96 mg/kg daily) was performed on the P+DM+DG group by oral gavage for 29 days. At day 30, all animals were euthanized and the distance from the cement-enamel junction to the alveolar bone margin was measured using cone-beam computed tomography as ABL. In addition, immunohistochemical analyses were used to evaluate the expression levels of alkaline phosphatase (ALP), osteocalcin (OCN), bone morphogenetic protein 2 (BMP-2), receptor activator of NF-κB ligand (RANKL), collagen type I (Col-1), B-cell lymphoma-2 (Bcl-2), and Bcl-2-associated X protein (Bax). Induction of periodontitis and diabetes significantly increased ABL (P<0.05). DG administration significantly reduced ABL, expression of RANKL and Bax, and enhanced the expression of ALP, OCN, BMP-2, Bcl-2, and Col-1 in the P+DM+DG group compared with the P+DM group (P<0.05). It is revealed that DG considerably enhanced bone formation and contributed to periodontal healing in this experimental study performed in diabetic rats.

OEA alleviates apoptosis in diabetic rats with myocardial ischemia/reperfusion injury by regulating the PI3K/Akt signaling pathway through activation of TRPV1.

Reperfusion therapy after myocardial infarction may lead to myocardial injury, which can be complicated and exacerbated by diabetes. The existing therapeutic methods for myocardial ischemia-reperfusion injury (MIRI) in diabetic patients are not ideal. Oleoylethanolamide (OEA) has been found to have protective effects on diabetes and acute cerebral ischemia. This study aimed to determine whether OEA can alleviate MIRI in diabetic rats, and to explore the underlying mechanism. The model of diabetic rats with MIRI was established by blocking the left coronary artery for 30min, followed by restoring blood flow stability for 120min. The myocardial enzyme spectrum, area of MIRI, and expression levels of apoptosis-related proteins were detected. The results showed that OEA pretreatment could reduce myocardial infarction area, protect myocardial tissue structure, and reduce myocardial cell apoptosis in diabetic rats with MIRI. Meanwhile, the levels of creatine kinase (CK)-MB (CK-MB), lactate dehydrogenase (LDH), and malondialdehyde (MDA) were reduced, while superoxide dismutase (SOD) level was elevated. H9C2 cells were treated with high glucose and oxygen-glucose deprivation/reperfusion (OGD/R) to establish an in vitro model. Capsazepine (CPZ), an antagonist of transient receptor potential vanilloid subtype 1 (TRPV1), and LY294002, an inhibitor of PI3K, were used to treat H9C2 cells in vitro. Apoptosis level and the expression levels of apoptosis-related proteins were measured. It was found that OEA activated TRPV1 and the PI3K/Akt signaling pathway, downregulated the expression levels of apoptosis-related proteins (Bcl-2 and cleaved caspase-3), and ameliorated the apoptosis of H9C2 cells treated with high glucose and OGD/R. This study clarified that OEA, as a TRPV1 agonist, could reduce myocardial cell apoptosis by activating the PI3K/Akt signaling pathway in diabetic rats with MIRI. The findings may provide a theoretical basis for administration of OEA as a potential therapeutic agent into diabetic patients with MIRI.

Lignan matairesinol illustrates anti-diabetic effect via inhibition of DPP-4 and hepato-protective effect via inhibition of apoptosis in diabetic rats

Lignan matairesinol illustrates anti-diabetic effect via inhibition of DPP-4 and hepato-protective effect via inhibition of apoptosis in diabetic rats

Ursolic acid mitigates cognitive dysfunction through amelioration of oxidative stress, inflammation and apoptosis in diabetic rats

&#x0D; &#x0D; &#x0D; &#x0D; Purpose: To determine the effect of ursolic acid (UA) on diabetes-induced cognitive defect, as well as its mechanism of action in streptozotocin (STZ)-induced diabetic rats.&#x0D; Methods: A rat model of diabetes was established by administration of STZ. The rats received UA via gastric perfusion for 56 successive days. Learning and memory functions were assessed using Morris water maze. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels in hippocampus tissues were determined spectrophotometrically. Tumor necrosis factor-a (TNF-a), interleukin-1β (IL-1β) and interleukin-6 (IL-6) levels were assayed by quantitative real-time polymerase chain reaction (qRT- PCR) and enzyme-linked immunosorbent assay (ELISA). The protein expression levels of nuclear factor erythroid-2-related factor-2 (Nrf-2), heme oxygenase-1 (HO-1), Bcl-2 and Bax were evaluated by western blotting.&#x0D; Results: Learning and memory impairment in STZ-induced diabetic rats was mitigated by UA (p &lt; 0.05). In hippocampus tissue, UA reduced oxidative stress by enhancing SOD activity and reducing MDA levels. Furthermore, UA reduced inflammatory response by downregulating TNF-α, IL-1β and IL-6 levels (p &lt; 0.05). Concomitantly, the lower protein concentrations of Nrf-2 and HO-1 were elevated by administration of UA. Furthermore, UA suppressed Bax/Bcl-2 ratio to ameliorate apoptosis (p &lt; 0.05).&#x0D; Conclusion: UA reduces diabetes-induced hippocampal oxidative stress, inflammation and apoptosis. Thus, it might be a potential drug candidate for delaying diabetes-associated cognitive decline (DACD).&#x0D; &#x0D; &#x0D; &#x0D;

Galangin Attenuates Liver Injury, Oxidative Stress and Inflammation, and Upregulates Nrf2/HO-1 Signaling in Streptozotocin-Induced Diabetic Rats

Chronic hyperglycemia increases the risk of liver damage. Oxidative stress and aberrant inflammatory response are entangled in diabetes-associated liver injury. This study evaluated the protective effect of the flavonoid galangin (Gal) on glucose intolerance, liver injury, oxidative stress, inflammatory response, and Nrf2/HO-1 signaling in diabetic rats. Diabetes was induced by streptozotocin (STZ), and the rats received Gal for six weeks. STZ-induced rats showed glucose intolerance, hypoinsulinemia, elevated glycated hemoglobin (HbA1c), and decreased liver glycogen. Gal ameliorated glucose intolerance, reduced HbA1c%, increased serum insulin and liver glycogen and hexokinase activity, and suppressed glycogen phosphorylase, glucose-6-phosphatase and fructose-1,6-biphosphatase in diabetic rats. Circulating transaminases, ALP and LDH, and liver ROS, MDA, TNF-α, IL-1β, and IL-6 were increased and GSH, SOD, and CAT were diminished in diabetic rats. In addition, diabetic rats exhibited multiple histopathological alterations and marked collagen deposition. Treatment with Gal mitigated liver injury, prevented histopathological alterations, decreased ROS, MDA, pro-inflammatory cytokines, Bax and caspase-3, and enhanced cellular antioxidants and Bcl-2. Gal downregulated hepatic Keap1 in diabetic rats and upregulated Nrf2 and HO-1 mRNA as well as HO-1 activity. Molecular modeling studies revealed the ability of Gal to bind to and inhibit NF-κB and Keap1, and also showed its binding pattern with HO-1. In conclusion, Gal ameliorates hyperglycemia, glucose intolerance, oxidative stress, inflammation, and apoptosis in diabetic rats. Gal improved carbohydrate metabolizing enzymes and upregulated Nrf2/HO-1 signaling.

Green tea protects against hippocampal neuronal apoptosis in diabetic encephalopathy by inhibiting JNK/MLCK signaling.

Although diabetic encephalopathy (DE) is a major late complication of diabetes, the pathophysiology of postural instability in DE remains poorly understood. Prior studies have suggested that neuronal apoptosis is closely associated with cognitive function, but the mechanism remains to be elucidated. Green tea, which is a non-fermented tea, contains a number of tea polyphenols, alkaloids, amino acids, polysaccharides and other components. Some studies have found that drinking green tea can reduce the incidence of neurodegenerative diseases and improve cognitive dysfunction. We previously found that myosin light chain kinase (MLCK) regulates apoptosis in high glucose-induced hippocampal neurons. In neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease, activation of the JNK signaling pathway promotes neuronal apoptosis. However, the relationship between JNK and MLCK remains to be elucidated. Green tea serum was obtained using seropharmacological methods and applied to hippocampal neurons. In addition, a type 1 diabetes rat model was established and green tea extract was administered, and the Morris water maze test, Cell Counting Kit-8 assays, flow cytometry, western blotting and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling assays were used to examine the effects of green tea on hippocampal neuronal apoptosis in diabetic rats. The results demonstrated that green tea can protect against hippocampal neuronal apoptosis by inhibiting the JNK/MLCK pathway and ultimately improves cognitive function in diabetic rats. The present study provided novel insights into the neuroprotective effects of green tea.

Astragaloside II Ameliorated Podocyte Injury and Mitochondrial Dysfunction in Streptozotocin-Induced Diabetic Rats.

Astragaloside II (AS II), a novel saponin purified from Astragalus membranes, has been reported to modulate the immune response, repair tissue injury, and prevent inflammatory response. However, the protective effects of AS II on podocyte injury in diabetic nephropathy (DN) have not been investigated yet. In this study, we aimed to investigate the beneficial effects of AS II on podocyte injury and mitochondrial dysfunction in DN. Diabetes was induced with streptozotocin (STZ) by intraperitoneal injection at 55 mg/kg in rats. Diabetic rats were randomly divided into four groups, namely, diabetic rats and diabetic rats treated with losartan (10 mg·kg−1·d−1) or AS II (3.2 and 6.4 mg·kg−1·d−1) for 9 weeks. Normal Sprague-Dawley rats were chosen as nondiabetic control group. Urinary albumin/creatinine ratio (ACR), biochemical parameters, renal histopathology and podocyte apoptosis, and morphological changes were evaluated. Expressions of mitochondrial dynamics-related and autophagy-related proteins, such as Mfn2, Fis1, P62, and LC3, as well as Nrf2, Keap1, PINK1, and Parkin, were examined by immunohistochemistry, western blot, and real-time PCR, respectively. Our results indicated that AS II ameliorated albuminuria, renal histopathology, and podocyte foot process effacement and podocyte apoptosis in diabetic rats. AS II also partially restored the renal expression of mitochondrial dynamics-related and autophagy-related proteins, including Mfn2, Fis1, P62, and LC3. AS II also increased the expression of PINK1 and Parkin associated with mitophagy in diabetic rats. Moreover, AS II facilitated antioxidative stress ability via increasing Nrf2 expression and decreasing Keap1 protein level. These results suggested that AS II ameliorated podocyte injury and mitochondrial dysfunction in diabetic rats partly through regulation of Nrf2 and PINK1 pathway. These important findings might provide an innovative therapeutic strategy for the treatment of DN.

Ganglion cells apoptosis in diabetic rats as early prediction of glaucoma: a study of Brn3b gene expression and association with change of quantity of NO, caspase-3, NF-κB, and TNF-α.

To find a new concept to show whether or not apoptosis of retinal ganglion cells (RGCs) can be determined in the histology of acute hyperglycemia in the role of expressed Brn3b gene related to nitric oxide (NO), caspase-3, nuclear factor kappa-B (NF-κB), and tumor necrosis factor-α (TNF-α) as an early predictor of primary open angle glaucoma (POAG) eyes and their associations. Experimental in vivo study was carried out using adult male, white Sprague-Dawley rats aged ≥2mo, weighing 150-200 g. The animals were divided into two groups, one group receiving intraperitoneal injection of streptozotociz 50 mg/kg in 0.01 mol/L citric buffer and pH 4.5 and a comparison made with the control group. Retinal tissue was divided into two parts (both experimental and control groups respectively): a) right retina for immunohistochemistry (IHC; caspase-3 and TNF-α); b) left retina was divided into two parts for the purpose of real-time polymerase chain reaction (PCR) test (RNA extraction for Brn3b gene expression analysis) and ELISA test (NO and NF-κB). The experimental group showed a decrease in Brn3b gene expression compared to the control group (1.3-fold lower in 2nd month; 1.1-fold lower in 4th month and 2.5-fold lower in 6th month). However, there was a decrease of NO, caspase-3, and an increase of NF-κB and TNF-α quantity. The expression of mRNA Brn3b gene is inversely proportional to apoptosis in RGCs. The quantity of NO, caspase-3, NF-κB and TNF-α is influential in expression of Brn3b in RGCs caused by hyperglycemia in diabetic rats.

The novel GLP-1/GIP dual agonist DA3-CH is more effective than liraglutide in reducing endoplasmic reticulum stress in diabetic rats with cerebral ischemia-reperfusion injury

Background and aimsDiabetes is one of the most important risk factors and comorbidities of ischemic stroke. Endoplasmic reticulum stress (ERS) is considered to be the major injury mechanism of ischemic stroke with diabetes. Studies have found that incretin can inhibit ERS in ischemia-reperfusion injury of the liver and heart. We aimed to explore the effects of GLP-1/GIP double agonist DA3-CH and GLP-1 single agonist liraglutide on ERS and apoptosis in diabetic rats with cerebral ischemia-reperfusion injury. Methods and results72 Sprague–Dawley (SD) male rats were randomly divided into 4 groups: ① blank group (Sham group, n = 18); model group (Saline group, n = 18); DA3 treatment group (DA3 group, n = 18); liraglutide treatment group (Lir group, n = 18). The Sham group was not given any treatment and was only raised in the same environment as the other groups. The remaining 3 groups used STZ-induced diabetes models. After the successful membrane formation of diabetes, DA3-CH and liraglutide (10 mmol/kg, once-daily for 14 days) were injected intraperitoneally. Thereafter, rats were subjected to middle cerebral artery occlusion followed by 24-h reperfusion. Animals were evaluated for neurologic deficit score, infarct volume, and biomarker analyses of the brain after ischemia. The DA3-CH-treated and liraglutide-treated groups showed significantly reduced scores of neurological dysfunction and cerebral infarction size, and reduced the expression of ERS markers GRP78, CHOP and Caspase-12, and the expression of apoptosis marker bax. Anti-apoptotic markers bcl-2 and neuronal numbers increased significantly. ConclusionsDA3-CH and liraglutide have obvious neuroprotective effects in a rat model of cerebral ischemia-reperfusion injury with diabetes, which can reduce the infarct size and the neurological deficit score. Their exert neuroprotective effects in a rat model of cerebral ischemia-reperfusion injury with diabetes by inhibiting endoplasmic reticulum stress and thereby reducing apoptosis. DA3 is better than liraglutide.

Protective effects of gliclazide on myocardium of diabetic rats and its mechanism

Objective: To investigate the protective effects of gliclazide on myocardium of diabetic rats and its possible mechanisms. Methods: Sixty healthy SD rats were randomly divided into two groups: normal group (NC, n=10) and model group (n=50). Rats in model group were fed with high glucose and high fat diet for 4 weeks and then intraperitoneally injected with STZ (45 mg/kg) to establish a diabetic model and randomly selected FBG ≥ 16.7 mmol / L as a successful diabetes model. Thirty-eight diabetic rats were randomly divided into model group (MC, n=9), gliclazide group (Glic, 80 mg/kg, n=10), glibenclamide group (Glib, 2.5 mg/kg, n=10) and fasudil group (Fas, 10 mg/kg, n=9). NC group and MC group were given equal volume distilled water by gavage, Glic group and Glib group were treated with gliclazide or glibenclamide by gavage, and the Fas group was treated with fasudil by intraperitoneal injection. Rats in each group were given once a day and recorded body mass and fasting blood glucose (FBG) weekly for 8 weeks. At the end of the experiment, the heart weight was measured, and the heart weight index (HWI) was calculated; the contents of glycosylated hemoglobin (HbA1c), total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL-C), low density lipoprotein (LDL-C), the level of serum malondialdehyde MDA) and the activity of superoxide dismutase (SOD) were measured; the pathological changes of myocardial tissue were observed by HE and Masson staining. The expressions of RhoA, ROCK1, eNOS, Bcl-2 and Bax protein were detected by Western blot. Results: Compared with NC group, in MC group, the levels of FBG, HWI, HbA1c, TC, TG, LDL-C, MDA, myocardial collagen deposition and cardiomyocyte apoptosis rate and RhoA, ROCK1, Bax protein in myocardial tissue were increased significantly, while the SOD activity, the levels of HDL-C, eNOS, Bcl-2 and body weight were decreased significantly (P＜0.01). Compared with MC group, Glic treatment decreased the levels of FBG, HWI, HbA1c, LDL-C, TG, TC and MDA, increased the levels of SOD activity and HDL-C (P＜0.01 or P＜0.05); decreased myocardial collagen deposition, inhibited cardiomyocyte apoptosis (P ＜ 0.01); decreased the expression levels of RhoA, ROCK1 and Bax protein; increased the levels of eNOS and Bcl-2 protein (P＜0.01 or P＜0.05). Compared with Glic group, in Glib group, the levels of blood lipids, BM, FBG, HWI, MDA, myocardial fibrosis and cardiomyocyte apoptosis rate were increased, the levels of SOD and Bcl-2 were decreased, and the expressions of RhoA, ROCK1 and Bax in myocardial tissue were upregulated (P＜0.01 or P＜0.05). Conclusion: Gliclazide significantly alleviates myocardial injury and reduces myocardial apoptosis in diabetic rats, and its mechanism may be related to lowering blood glucose, improving oxidative stress and regulating RhoA / ROCK1 / eNOS signaling pathway.

The Effect of 4-Week Voluntary Wheel Running on Hippocampus Levels of Semaphorin 3B and Hydrogen peroxide and Apoptosis in Diabetic Rats

Background: One of the complications of diabetes is the occurrence of apoptosis in the brain that can lead to cognitive impairment. The aim of this study was to investigate the effect of 4 weeks of voluntary wheel running on hippocampus semaphorin 3B, hydrogen peroxide, and apoptosis in streptozotocin-diabetic rats. Methods: In this experimental study, 32 male Wistar rats weight 235±10gr were assigned randomly to 4 groups (n=8): healthy control (C), healthy exercise (E), control-diabetic (D) and diabetic-exercise (ED). Rats were diabetic by intra-peritoneal injection of STZ dissolved in citrate buffer. The experimental groups ran voluntarily in the wheel running for 4 weeks. The subjects were sacrificed 48 hours after the last training session, then hippocampus tissue was extracted from the brain, and ELISA measurements were performed after homogenization and centrifugation of the tissue. One-way ANOVA and independent t-test were used to evaluate the data. Results: The levels of semaphorin 3B, hydrogen peroxide and apoptosis in D group were significantly higher than C group (P≤0.05). In the ED group, semaphorin 3B, hydrogen peroxide and apoptosis levels were significantly lower than D group (P≤0.05). Semaphorin 3B and apoptosis levels in the E group were significantly lower than C and ED groups (P≤0.05). Conclusion: The results showed that experimental diabetes induction increases semaphorin 3B, hydrogen peroxide and apoptosis rate in the brain hippocampus. Four weeks of voluntary running was associated with a decrease in the hippocampus levels of semaphorin 3B, hydrogen peroxide and apoptosis.

Lipoic Acid Decreases the Expression of Poly ADP-Ribose Polymerase and Inhibits Apoptosis in Diabetic Rats.

PurposeTo study the effects of lipoic acid on poly ADP-ribose polymerase (PARP) expression and apoptosis in diabetic rats.Materials and MethodsSprague–Dawley rats (n=30) with high-fat diet- and streptozotocin-induced diabetes were randomly divided into two groups: diabetic model (DM) group and lipoic acid (LA) treatment group; another 10 rats were selected as normal controls (NC). The serum levels of 8-hydroxy-2ʹ-deoxyguanosine, nitrotyrosine, and 8-isoprostane; sciatic nerve cell apoptosis index; and PARP expression were detected in the rats, and morphological changes in the sciatic nerve were recorded.ResultsThe blood glucose level in the DM and LA groups was significantly higher than that of the NC group (P<0.01). Compared to the NC group, the DM group showed demyelinating changes to sciatic nerve fibers. PARP expression; serum levels of 8-hydroxy-2-deoxyguanosine, nitrotyrosine, and 8-isoprostane; and the apoptosis index of sciatic nerve cells were significantly higher than those of the NC group (P<0. 01). Following LA treatment, the above indices showed significant improvement (P<0.01).ConclusionLipoic acid may improve the symptoms of diabetic neuropathy by reducing PARP activity and inhibiting apoptosis.