Abstract

Diabetes mellitus (DM) is a metabolic disorder, and this disease is associated with degeneration and functional disorder of the nervous system. In the present study, we investigated the effects of treadmill exercise on memory, cell proliferation, and expressions of brain-derived neurotrophic factor (BDNF) and insulin-like growth factor 1 (IGF-1) in the hippocampus of the diabetic rats. Male Sprague-Dawley rats were used for this study. The animals were divided into four groups (n= 8 in each group): control group, exercise group, DM-induction group, DM-induction and exercise group. DM was induced by intraperitoneal injection of streptozotocin (50 mg/kg dissolved in 0.05 M citrate buffer, pH 4.5). The rats in the exercise groups were made to run on the treadmill for 30 min, five times a week for 6 weeks. For this study, step-down avoidance task, immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU), and western blot for BDNF and IGF-1 were performed. The present results showed that latency in the step-down avoidance task was decreased in the diabetic rats whereas treadmill exercise increased latency in the diabetic rats. Cell proliferation in the hippocampus was decreased in the diabetic rats, however treadmill exercise increased cell proliferation in the diabetic rats. The expressions of BDNF and IGF-1 protein in the hippocampus were decreased in the diabetic rats, in contrast, treadmill exercise increased the expressions of BDNF and IGF-1 in the diabetic rats. These results suggest that treadmill exercise may ameliorate DM-induced memory impairment by increasing cell proliferation through enhancing BDNF and IGF-1 expressions in the hippocampus. (Korean J Str Res 2011;19:175∼182)

• Keywords: Dabetes mellitus, Treadmill exercise, Cell proliferation, Memory impairment, Hippocampus