Abstract
OBJECTIVE: The study aimed at investigating the effects of administering melatonin and a probiotic to streptozotocin-induced diabetic rats on hyperglycaemia, oxidative stress biomarkers and beta-cells. DESIGN: Type 1 diabetes was induced in 5 months-old male Wistar rats by single intraperitoneal (i.p.) administration of freshly-prepared STZ (60 mg/kg body weight). Six groups of 10 rats were used and treated once daily for six weeks; (1) Healthy control: normal saline only; (2) Pre-treated with Melatonin (MEL); (3) Diabetic control; (4) Diabetic + Treated with MEL; (5) Diabetic + Treated with Probiotic (Prob); (6) Diabetic + Treated with MEL + Prob. Blood glucose, body weight, activities of antioxidant enzymes and malondialdehyde concentration in serum and tissues, reduced glutathione and immunohistochemical assay. Data obtained were expressed as mean ± standard error of the mean (Mean ± SEM) and subjected to ANOVA followed by Tukey's post hoc test. RESULTS: Melatonin + Probiotic significantly decreased blood glucose concentrations in diabetic treated rats, compared to the diabetic control rats. MEL + Probiotic increased (p < 0.05) superoxide dismutase activity in serum and liver of diabetic rats. MEL + Probiotic reduced (p < 0.05) malondialdehyde concentration in the serum, liver and kidneys, respectively. MEL + Probiotic treated diabetic rats displayed islets with much greater content of insulin. CONCLUSION: Melatonin + Probiotic combination was more effective in mitigating hyperglycaemia, oxidative stress, and exerted cytoprotective effect on the beta-cells.