Protective effect of crocin and voluntary exercise against oxidative stress in the heart of high-fat diet-induced type 2 diabetic rats

Background Oxidative stress plays a critical role in the pathogenesis and progression of type 2 diabetes and diabetic-associated cardiovascular complications. This study investigated the impact of crocin combined with voluntary exercise on heart oxidative stress indicator in high-fat diet-induced type 2 diabetic rats. Materials and methods Rats were divided into four groups: diabetes, diabetic-crocin, diabetic-voluntary exercise, diabetic-crocin-voluntary exercise. Type 2 diabetes was induced by high-fat diet (4 weeks) and injection of streptozotocin (intraperitoneally, 35 mg/kg). Animals received crocin orally (50 mg/kg); voluntary exercise was performed alone or combined with crocin treatment for 8 weeks. Finally, malondialdehyde (MDA), activity of antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were measured spectrophotometrically. Results Treatment of diabetic rats with crocin and exercise significantly decreased the levels of MDA (p < 0.001) and increased the activity of SOD, GPx, and CAT compared with the untreated diabetic group. In addition, combination of exercise and crocin amplified their effect on antioxidant levels in the heart tissue of type 2 diabetic rats. Conclusion We suggest that a combination of crocin with voluntary exercise treatment may cause more beneficial effects in antioxidant defense system of heart tissues than the use of crocin or voluntary exercise alone.

Effects of crocin and voluntary exercise, alone or combined, on heart VEGF-A and HOMA-IR of HFD/STZ induced type 2 diabetic rats

BACKGROUND

Hyperglycemia is the main risk factor for microvascular complications in type 2 diabetes. Crocin and voluntary exercise have anti-hyperglycemic effects in diabetes. In this research, we evaluated the effects of crocin and voluntary exercise alone or combined on glycemia control and heart level of VEGF-A.

MATERIALS AND METHODS

Animals were divided into eight groups as: control (con), diabetes (Dia), crocin (Cro), voluntary exercise (Exe), crocin and voluntary exercise (Cro-Exe), diabetic-crocin (Dia-Cro), diabetic-voluntary exercise (Dia-Exe), diabetic-crocin-voluntary exercise (Dia-Cro-Exe). Type 2 diabetes was induced by a high-fat diet (4 weeks) and injection of streptozotocin (STZ) (i.p, 35 mg/kg). Animals received oral administration of crocin (50 mg/kg) or performed voluntary exercise alone or together for 8 weeks. Oral glucose tolerance test (OGTT) was performed on overnight fasted control, diabetic and treated rats after 8 weeks of treatment. Then, serum insulin and heart VEGF-A protein levels were measured.

RESULTS

Crocin combined with voluntary exercise significantly decreased blood glucose levels (p < 0.001) and insulin resistance (HOMA-IR) (p < 0.001) compared to diabetic group. VEGF-A level was significantly (p < 0.01) lower in Dia group compared to control group. The combination of crocin and voluntary exercise significantly enhanced VEGF-A protein levels in Dia-Cro-Exe and Cro-Exe group compared to diabetic and control groups, respectively; p < 0.001 and p < 0.05.

DISCUSSION

Crocin combined with voluntary exercise improved insulin resistance (HOMA-IR) and reduced glucose levels in diabetic rats. Since both crocin and voluntary exercise can increase VEGF-A protein expression in heart tissue, they probably are able to increase angiogenesis in diabetic animals.

OXIDATIVE STRESS IS MARKEDLY REDUCED BY COMBINED VOLUNTARY EXERCISE AND TESTOSTERONE IN THE HEART OF DIABETIC RATS

Objective

Cardiovascular disorders in diabetes condition arise from increased oxidative stress. Both regular mild exercise and testosterone influence on body's antioxidant system in diabetes. In this study, we evaluated treatment of testosterone and voluntary exercise, alone or together on oxidative stress in the heart and blood of diabetic rats.

Methods

Type 1 diabetes was induced by intraperitoneal injection of 50 mg/kg of streptozotocin in rats. Sixty three rats have been divided into eight groups as follows: Diabetes, diabetes+ testosterone, diabetes+ exercise, diabetes+ testosterone+ exercise, diabetes+ castration, diabetes+ castration+ testosterone, Diabetes+ castration+ exercise, Diabetes+ castration+ exercise+ testosterone. Type 1 diabetes was induced by intraperitoneal injection of 50 mg/kg of streptozotocin in the male Wistar rats and after a week, castration was performed. After 42 days of treatment with testosterone (2 mg/kg/day) or voluntary exercise alone or in combination, SOD, GPX and CAT activities and MDA levels were measured in the blood and heart tissue samples in the groups of study. In the end of study, SOD, GPX and CAT activities and MDA levels were measured in blood and heart tissue samples in the groups of study.

Results

SOD, GPX and CAT activities significantly (p<0.05) increased in groups that treated either testosterone or exercise and MDA level significantly (p<0.01) decreased in the blood and heart tissue of diabetic and castrated diabetic rats. Simultaneously, treatment with testosterone and exercise had a synergistic effect on antioxidant enzymes level in diabetic and diabetic castrated rats. In the castrated animals with diabetes, SOD, GPX and CAT activities significantly decreased (p<0.05) and MDA levels significantly increased (p<0.05) in blood and heart tissue.

Conclusion

Voluntary exercise and testosterone alone or together heightened body's antioxidant system and were able to reduce the MDA levels in blood and heart of diabetic and castrated diabetic rats.

Effect of voluntary exercise on intracellular signalling pathways of angiogenesis in the sciatic nerve of type 1 diabetic castrated male rats

Objectives

Impaired angiogenesis in sciatic nerve is a major complication of diabetic neuropathy. Protein kinase B (AKT) and extracellular signal regulated kinase (ERK) signaling pathways play critical roles during capillary-like network formation in the angiogenesis process.

Methods

Twenty-four adult male Wistar rats (weight: 250–300 g) were used in the research. The rats were randomly divided into four groups (n = 6): (1) diabetic (Dia), (2) diabetic + castration (Dia-Cas), (3) diabetic + exercise (Dia-E), and (4) diabetic + castration + exercise (Dia-Cas-E). Type 1 diabetes (T1D) was induced with streptozotocin (50 mg/kg). After 6 weeks, sciatic nerve was separated and used for histological evaluation and determination of phosphorylated AKT (P-AKT) and phosphorylated ERK (P-ERK) levels by ELISA method.

Results

Glucose levels decreased in the Dia-E group compared to the Dia-Cas group (p < 0.01). In addition, our finding shows that exercise in the Dia-Cas group diminished blood glucose levels compared to the Dia-Cas group but this effect of exercise was not significant. Voluntary exercise in the diabetic castrated group decreased P-AKT protein and increased P-ERK 1/2 protein levels in the sciatic tissue compared to the diabetes group significantly (p < 0.05). Histopathological findings showed that Dia-Cas group with 6-week exercise training significantly raised the number of microvascular density in the sciatic tissue of diabetic rats compared to the diabetic group (p < 0.05).

Conclusions

Voluntary exercise in diabetic rats increases angiogenesis in the sciatic nerve. The possible mechanism is the increase of P-ERK 1/2 but not P-AKT levels in the sciatic nerve of T1D rats.

Voluntary wheel running and testosterone replacement increases heart angiogenesis through miR-132 in castrated diabetic rats

OBJECTIVE

Low levels of testosterone in men with diabetes are associated with cardiovascular complications. We investigated the effect of testosterone and voluntary exercise on heart angiogenesis in castrated diabetic rats.

METHODS

Sixty-three diabetic rats were treated with testosterone 2 mg/kg/day or voluntary exercise alone or combination of these two for 6 weeks. At the end of the study, heart tissue samples were collected and used for CD31 detection by immunohistochemical method and determination of miR-132 levels.

RESULTS

miR-132 levels and CD31 of heart tissue were higher after testosterone administration and in the voluntary exercise group in diabetic rats after 6 weeks. Combination of testosterone and voluntary exercise had synergistic effect on angiogenesis and miR-132 level. In castrated diabetic rats, there were significantly lower levels of miR-132 and CD31 in heart tissue compared to the diabetic group, whereas testosterone and exercise reversed these effects. In addition, testosterone supplementation plus exercise had an additive effect on miR-132 levels and CD31 in castrated diabetic rats.

CONCLUSIONS

It was concluded that castration in rats leads to reduced miR-132 levels and subsequently decreased angiogenesis in diabetes. Testosterone plus voluntary exercise improved angiogenesis possibly through enhancement of miR-132 levels in heart of castrated diabetic rats.

THE EFFECT OF TESTOSTERONE AND VOLUNTARY EXERCISE, ALONE OR TOGETHER, ON miRNA-126 EXPRESSION CHANGES IN HEART OF DIABETIC RATS

Methods

Ninety Wistar male rats were used in this study. Type 1 diabetes was induced by i.p injection of 50 mg/kg of streptozotocin in all animals. After 42 days of treatment with testosterone (2mg/kg/day) or voluntary exercise alone or in combination, the heart of the rats has been removed and MicroRNA was extracted from the heart using miRCURYTM RNA isolation kit.

Results

Our results showed that either testosterone or exercise increased miRNA-126 expression levels in the heart of diabetic rats. Treatment of diabetic rats with testosterone and exercise at the same time had a synergistic effect on miRNA-126 levels in the heart. Furthermore, in castrated diabetes group, miRNA-126 levels were significantly decreased in heart, whereas either testosterone treatment or exercise training enhanced expression of this miRNA. Also, simultaneous treatment of castrated diabetic rats with testosterone and exercise had an additive effect on miRNA-126 expression levels.

Conclusion

This study showed that testosterone and exercise promote an increase in the expression of miRNA-126 in the heart tissue and this may be related to cardiac angiogenesis. These results may indicate that testosterone and exercise can help to prevent progression of diabetic cardiomyopathy due to impaired angiogenesis in the heart.

Opioid-mediated Sertoli cells apoptosis is involved in testicular homeostasis and/or reproductive dysfunction

OBJECTIVES

 The opioid system may exert positive direct and/or indirect effects on spermatogenesis at multiple levels including the levels of the central nervous system and at the testes/sperm levels. However, long term opioid use could be associated with several reproductive complications that place the users at risk of hypogonadism and even infertility. There is little available information regarding the contribution of opioids and their apoptotic effects on testis Sertoli cells. Here, the effects of DAMGO (mu opioid receptor's agonist), DPDPE (delta opioid receptor's agonist) and DYN 1-9 (kappa opioid receptor's agonist) on Sertoli cell viability and apoptosis were investigated.

METHODS

Cultured Sertoli cells were exposed to each agonist (0.1-100 µM, for 24 or 48 hours) and their apoptotic effects were investigated.

RESULTS

Cell viability was decreased and apoptosis was increased in the cells exposed to DAMGO in a concentration-dependent manner, while in the cells exposed to DPDPE, no significant changes were observed. In cells exposed to DYN 1-9, the viability did not significantly change, however apoptosis increased significantly, following the exposure to the high concentration of DYN 1-9.

CONCLUSION

These data suggest that mu and Kappa, but not delta receptors mediated apoptosis in Sertoli cells may be involved, at least in part, in testicular homeostasis and/or reproductive dysfunction (Tab. 1, Fig. 3, Ref. 52).