Abstract: Objective To investigate the expressions of glial cell line-derived neurotrophic factor(GDNF)and its receptors,GFRα-1 and Ret,in cortex of rats after closed traumatic cerebral injury.Methods Male Sprague-Dawley rats were divided into normal control,sham and injury groups.The rats of injury groups were subjected to Marmarou's closed traumatic cerebral injury and then were subdivided into 1 h,2 h,4 h,8 h,12 h,24 h,48 h,72 h and 5 d groups according to the time elapsed after injury.The expression of GDNF and its receptors were determined with immunohistochemistry.Results Mild expression of GDNF and its receptors were observed in cortex of rats in control groups.The number of GDNF positive neurons reached the peak level in cortex 2 h after injury,and that of GFRα-1 and Ret positive neurons reached the peak level 4 h after injury.Conclusion The expressions of GDNF and its receptors increased significantly at the early time in cortex of rats after injury,as well as its receptors.It suggests that GDNF and its receptors play an important role after traumatic cerebral injury.

Key words: traumatic cerebral injury, glial cell line-derived neurotrophic factor(GDNF), receptor, rat