Estrogen attenuates neuron apoptosis by inhibiting ROS and bax expression following traumatic brain injury in rat

Objective To investigate the mechanism of estrogen's protection effect on neurons in traumatic brain injury(TBI) in rats.Methods The rat model of TBI was made according to the method of Marmarou's(1994).Male Sprague-Dawley rats were randomly divided into control,TBI and estrogen treatment groups.The rats in TBI and treatment groups respectively were divided into 7 subgroups according to the time phase after brain injury,which were 10 min,30 min,3 h,6 h,24 h,48 h and 72 h.The value of MDA was measured by thio-barbiturie acid.Theexpression of bax was detected by immunohistochemistry and the apoptosis of neurons wasdetected by TUNEL method.Results The value of MDA,immuno-activity of bax and thenumber of TUNEL positive cells of treatment group were lower than TBI group.Conclusion Estrogen attenuates the apoptosis of neurons by reducing oxygen free radical and then bax expression following traumatic brain injury in rats.