Expressions of nestin and NGF of cochlea in rats after whole cerebral ischemia-reperfusion

Objective: To investigate the expressions of neuroepithelial stem cell protein(nestin) and nerve growth factor(NGF) in cochlear cells of rats after the whole cerebral ischemia/reperfusion.Methods: A total of 66 healthy Sprague-Dawley rats were randomly divided into the normal group,sham group,and cerebral ischemia/reperfusion(I/R) group.The whole cerebral ischemia/reperfusion injury models were established using the four-artery-occlusion-method.At the different time points of 6 h、1 d、3 d、7 d、14 d after 30 min of cerebral ischemia-reperfusion the expressions of nestin and NGF in cochlear cells were respectively observed with the methods of immunofluorescent staining and immunohistochemistry SABC.Results: Nestin had no expression or weak expressions and NGF moderate expressions within the cochleae cells of the adult rats in the normal group and sham group.After cerebral ischemia/reperfusion injury the nestin expression within cochlear tissue increased slightly in 1 day,increased markedly in 3 days,peaked in 7 days,then decreased gradually until at the 14th day,but were still higher than that in the sham group,and the NGF expression increased significantly in 6 h,increased markedly in 1 day,peaked in 3 days,decreased gradually during the 7th-14th days,but were still higher than that in the sham group.Conclusion: The study implies that cerebral ischemia/reperfusion can upregulate the expressions of nestin and NGF in cochleae cells of adult rats,and induce the in-situ activation of endogenous cochlear stem cells.