Abstract:

Objective   To investigate the involvement of Wnt in ischemia-induced adult nerve regeneration and explore the mechanism of the two members．Methods   44 normal male Wistar rats were randomly divided into 2 groups: the normal control group and the cerebral ischemia group. Cerebral ischemia-reperfusion rat models were established by inserting a proper thread in the right middle cerebral artery and removing the thread after 90min.Infarction and neurological deficit scores were evaluated after the operation. RT-PCR was used to investigate the expression of Wnt7b mRNA in hippocampus. Immunohistochemistry was used to investigate  expressions of Wnt7b and β-catenin proteins in the dentate gyrus of hippocampus. Results   Severe infarction appeared 1 day after ischemia-reperfusion, with  obvious neurological deficit. Neural function′s were  improved as time progressed. Expressions of Wnt7b mRNA in health side and  ischemic side were significantly upregulated, and  it  was more obvious in  ischemic side  （P＜0.01）than  in contralateral side（P＜0.05）. Consistent with the level of Wnt7b mRNA, the amount of Wnt7b positive cells dramatically increased in close proximity to the subgranular zone (SGZ) of the dentate gyrus in hippocampus（P＜0.01）, and the immunostaining of β-catenin, a primary element of classical Wnt signalling pathway, also significantly increased（P＜0.01）. Conclusion   Ischemia injury stimulated the expressions of Wnt7b and β-catenin in SGZ of hippocampus in adult rats. Wnt7b might be involved in the neurogenesis in SGZ of adult hippocampus after  cerebral ischemia by the classical Wnt signalling pathway.

Key words: Cerebral ischemia; Gene,Wnt7b; β-catenin protein; Hippocampus; Neurogenesis; Rats, Wistar