Effect Of Physical Exercise On DG Neurogenesis And Ability Of Learning And Memory In Hippocampus-lesioned Adult Rats And Its Mechanism

Objective To investigate the time course of proliferation of dentate gyrus( DG ), the effect of physical exercise on DG neurogenesis and ability of learning and memory in unilaterally hippocampus-lesioned adult rats, and the possible role of insulin-like growth factor-1(IGF-1) in the effect of physical exercise.Method Unilateral hippocampal lesion was produced by intrahippocampal microinjection of kainic acid (KA). Bromodeoxyuridine (BrdU) was used to label dividing cells and DG neurogenesis was evaluated by BrdU immunohistochemical staining. Y maze training was conducted to reflect the ability of learning and memory. Physical exercise was established by wheel-running. Anti-IGF-1 antibody was injected subcutaneously to explore the possible mechanism of neurogenesis enhanced by physical exercise. Results DG proliferation increased bilaterally on day3 after lesion, peaked at day5 and returned to baseline by day9. Moderate-intensity running could obviously enhance the DG neurogenesis and ameliorate the ability of learning and memory in hippocampus-lesioned rats. Subcutaneous injection of anti-IGF-1 antibody blocked the enhancement of DG neurogenesis and the amelioration of learning and memory induced by moderate-intensity running. There was a positive correlation between DG neurogenesis and the ability of learning and memory.Conclusions Unilateral hippocampal lesion enhances DG proliferation bilaterally; Moderate physical exercise can further promote DG neurogenesisand increase the learning and memory ability; The beneficial effect of physical exercise on DG neurogenesis and learning and memory might be mediated by IGF-1.