The effect of eight weeks of aerobic training on serotonin and tryptophan hydroxylase levels in hippocampus in type 2 diabetic rats

Backgrounds and Aim: Aerobic exercise has proven benefits in treating and reducing the incidence of complications of chronic diseases such as diabetes. In this study we evaluated the effect of aerobic training on serotonin and tryptophan hydroxylase levels in hippocampus in type 2 diabetic rats.
30 rats were randomly divided into healthy control,diabetic control, exercise diabetic groups. 2nd and 3rd groups were made diabetic by intraperitoneal injection of streptozotocin (37mg/kg), two weeks after receiving high-fat diet. Groups of aerobic exercise performed treadmill exercise 5 times/ week for 8 weeks with duration and intensity of 55min /d and 26m/min respectively in the final weeks. 24 hours after the last exercise blood samples and hippocampus tissue samples were obtained and concentrations of serotonin (µg/g) and tryptophan hydroxylase were measured by Elisa and western blotting methods respectively. We used ANOVA and Tukey post hoc test for data analysis.
Statistical analysis showed that the diabetic group had significantly lower serotonin levels compared to the healthy control group (P=0.001) and exercise diabetic group (P=0.01).The mean tryptophan hydroxylase level of the diabetic groups were significantly lower than that of the healthy control group (P=0.001). The amount of tryptophan hydroxylase was significantly higher in the exercise diabetic group compared to that in the diabetic control group (P=0.001)
In this study, diabetes led to reduction of serotonin and tryptophan hydroxylase levels in the hippocampus. Also eight weeks of aerobic exercise increased tryptophan hydroxylase level in the hippocampus of the diabetic rats.