Effect Of Aerobic Exercise On The Learning And Memorizing Abilities And Hippocampal Vegf In Depressive Rats

Abstract

PURPOSE: Depression model building in rats based on 4 weeks of CUMS (Chronic Unpredictable Mild Stress) and the investigation of the effect of aerobic exercise intervention on hippocampal VEGF expression and spatial learning and memorizing ability in depressive model rats. METHODS: 30 male SD rats randomly divided into 3 groups: the Control group (C), the Model group (M), and the Exercise group (E). M and E were subjected to CUMS stimulation and/or aerobic exercise for 4 weeks respectively. E received swimming training for 4 weeks (60 min/day, 6 days/week). SPT was used to test rat’s sucrose preference and detect the success of model. MWZ was performed to evaluate their spatial learning and memorizing ability. The expression of VEGF was tested by RT-PCR and WB. The experimental data was reported as mean±SE. The threshold of significance level was set at P<0.05. RESULTS: 1) SPT: there was no difference in the total water consumption in each group (P >0.05). But depressive rats (M: 36.67±10.61; E:36.00±16.43) showed significant difference compared with C in consumption of sugar water (C:53.83±10.93, P<0.05); 2)MWM detection: during 6 days of navigation experiment, M showed more difficulty to find the platform compared with C and E(P<0.05), while there was no significant difference between C and E (P>0.05); During the space exploring experiment, M spent much time to find the platform compared with C and E (C:3.14±0.38; M:1.57±0.79; E:2.57±0.53, P<0.05); 3) mRNA and protein detection: compared with C, the mRNA(C:1.24±0.22;M:0.57±0.25;E:1.14±0.07) and protein level of VEGF (C:0.90±0.06;M:0.52±0.11;E:0.81±0.05) significantly decreased in group M, while increased in group E(P<0.05). CONCLUSIONS: 4 weeks of aerobic exercise intervention effectively reverses the depression symptoms and improves their spatial learning and memorizing ability in rats pretreated by CUMS stimulation. In addition, aerobic exercise can rescue and significantly up-regulate the expression of VEGF in hippocampus which suppressed by CUMS stimulation. The correlation between the VEGF expression level and depressive behaviors in rats suggests that the enhanced expression of VEGF in hippocampus might be one of the neurobiological mechanisms mediating the effects of aerobic exercise on depression and spatial learning and memorizing ability.