Effects of ginkgo biloba extract on promotion of neurogenesis in the hippocampal dentate gyrus in C57BL/6 mice

Abstract

Ginkgo biloba leaf extract (Gb) has been known to improve blood flow and preclude the tissue from free radical damage. Effects of Gb were examined by using Ki67, a specific proliferative marker for cellular proliferation, and doublecortin (DCX), a marker for immature neurons, indicating degree of neuroblast differentiation in the hippocampal dentate gyrus (DG) of adult C57BL/6 mice. The mice were fed with Gb at 40 and 100 mg/kg once daily for 28 days. The increase of Ki67- and DCX-immunoreactive cells in the DG was increased in a dose-dependent manner. Especially, the group having 100 mg/kg Gb showed a significant increase of DCX-immunoreactive neuroblasts with well-developed tertiary dendrites. Expression of DCX protein in the Gb groups was also significantly increased upon compared with the vehicle group. The results suggested that repeated intake of Gb would enhance cell proliferation and neuroblast differentiation in the mouse DG.