Expression change of TrkA and NGF in cochleas of rats after whole cerebral ischemia-reperfusion

Objective To study the expressions of tyrosine kinase A (TrkA) and nerve growth factor (NGF) on cochlear corti in rats after whole cerebral ischemia-reperfusion. Methods Establishing a model of whole cerebral ischemia-reperfusion in rats; examining the expressions of TrkA and NGF on cochleas assuming the method of immunohistochemistry stain; and examining the time and distribution of the cochlear hair cell apoptosis through the terminal deoxynucleotidyl transferasemediated dUTP nick end labeling (TUNEL). Results After ischemia-reperfusion the 6 h NGF expression increased, the 24 h NGF expression reached the highest and then restored gradually. After ischemia-reperfusion the 24 h～7 d TrkA expression weakened or even didn’t expresse. During 3～7 d the cochlear hair cells presented with apoptoses. During 7～14 d TrkA expression restroed gradually. ConclusionTrkA expression mediats NGF to promote the sensory nerve cell surviving and for the biological effects of the repair of injury.