MATERIALS AND METHODS: Six control and five DM Wistar rats were evaluated. DM was induced at 11 weeks of age using streptozotocin (STZ; 60 mg/kg, intraperitoneal). Animals were monitored up to 38 weeks of age, when plasma glucose, lipid profile, and markers specific for systemic inflammation, endothelial dysfunction, and oxidative stress were measured. The amount of fat within the aortic wall was assessed semiquantitatively using Oil Red O staining.
RESULTS: Diabetic rats presented significantly higher plasma glucose (p < 0.001), total cholesterol and triglycerides (both p = 0.02), high-sensitivity C-reactive protein (p = 0.01), and vascular endothelial growth factor (p = 0.04) levels, and significantly lower interleukin-10 (p = 0.04), superoxide dismutase (p < 0.01), and glutathione peroxidase (p = 0.01) levels than the control rats. Mild (grade 1) atherosclerotic lesions were observed in the aortic wall of 80% of the diabetic rats and in none of the control rats.
CONCLUSIONS: This study presents a STZ-induced type 1 DM rat model with one of the longest follow-ups in the literature. In this model, long-term DM created a highly pro-atherogenic environment characterised by hyperglycemia, dyslipidemia, systemic inflammation, endothelial dysfunction, and oxidative stress that resulted in the development of early aortic atherosclerotic lesions.
METHODS: Diabetes was induced using streptozotocin (60 mg/kg, i.v.) followed by nicotinamide (210 mg/kg, intraperitoneal (i.p.)). MAD (50 mg/kg) was administered orally for 4 weeks, commencing 15 days after induction of diabetes; resveratrol (10 mg/kg) was used as a positive control. Fasting blood glucose, plasma insulin, HbA1c, liver and lipid parameters were measured, along with antioxidant enzymes and malondialdehyde as an index of lipid peroxidation; histological and immunohistochemical studies were also undertaken.
KEY FINDINGS: MAD normalized the elevated fasting blood glucose levels. This was associated with increased plasma insulin concentrations. MAD alleviated oxidative stress by improving enzymatic antioxidants and reducing lipid peroxidation. Histopathological examination showed significant recovery of islet structural degeneration and an increased area of islets. Immunohistochemical staining showed increased insulin content in islets of MAD-treated rats.
CONCLUSIONS: The results demonstrate an antidiabetic effect of MAD associated with preservation of β-cell structure and function.
MATERIALS AND METHODS: Male rats were rendered diabetes mellitus via intraperitoneal injection of streptozotocin and nicotinamide. Following diabetes development, wound was created at the back of the neck. 1% and 2% mangiferin gel and 1% silver sulphurdiazine (SS) gel (positive control) were applied to the wound for twenty-one (21) days. Fasting blood glucose (FBG) levels were weekly monitored. At the end of the treatment, rats were sacrificed and wound was excised and subjected for histopathological and molecular biological analysis.
RESULTS: No changes to serum FBG levels was noted throughout the period of mangiferin treatment. Albeit, a significant decrease in the size of the wound with increased in the skin thickness of surrounding the wound were observed. Increased expression and distribution of EGF, FGF, TGF-β, VEGF, PI3K, MMP and Nrf2 and decreased expression and distribution of TNFα and NF-κB p65 were observed in diabetic wound treated with topical mangiferin.
CONCLUSIONS: Mangiferin has potential to be used as an agent to promote wound healing in diabetic condition.