Expression of nerve growth factor in cerebral cortex in chronic cerebral ischemia rats

Objective: To investigate the expression of nerve growth factor (NGF) in cerebral cortex of chronic cerebral ischemia rats, and to explore the mechanism of cerebral ischemia damage and recovery. Methods: Bilateral common carotid arteries of Wist-ar rats were ligated permanently to establish ischemia model. The rats were divided into control group. 30 d and 120 d chronic cerebral ischemia groups. The test of behavior was performed. ABC immunohistochemical staining was used and the number and gray density of positive neurons of NGF in cerebral cortex was counted. Results: After chronic cerebral ischemia was developed, the expression of NGF in 120 d group was increased compared with those in 30 day group and control group (P0. 05), but the expression in the 30 d group had no obvious difference with control group. Learning and memory ability of the rats declined during ischemia. Conclusion: During chronic cerebral ischemia, the expression of NGF in cerebral cortex increases with the time, protecting the affected neurons.