大鼠脑创伤后ERK通路对皮质神经细胞c-fos蛋白表达及凋亡的影响

目的:探讨细胞外调节激酶(ERK)信号转导机制在颅脑创伤中的作用。方法:建立大鼠重型弥漫性颅脑创伤(TBI)模型,92只雄性SD大鼠分为创伤组和对照组,其中创伤组又分为伤后10min、30min、3h、6h、24h、48h和72h7个时相组,采用免疫组化、蛋白印迹方法分别定性、定量检测以上两组ERK的表达,用免疫组化法检测c-fos蛋白表达,用原位末端标记法检测凋亡细胞。结果:创伤组p-ERK1/2和c-fos的表达及TUNEL阳性细胞在不同时间大多高于对照组:创伤组p-ERK1/2蛋白表达在伤后10min已较对照组明显升高(P<0.05),伤后6h达高峰,24h仍有大量表达,仍明显高于对照组(P<0.01),至伤后48h降至对照组水平(P>0.05);创伤组c-fos免疫反应性在伤后10min开始升高(P<0.01),伤后6h达高峰(P<0.01),48h以后明显减弱,但仍高于对照组(P<0.01);镜下对照组未见TUNEL阳性细胞,创伤组伤后3h偶见TUNEL阳性细胞,6h明显增多,48h达高峰,均显著高于对照组(P<0.01)。结论:大鼠脑创伤后ERK通路过度激活,可能通过诱导c-fos蛋白表达,进而导致神经细胞凋亡。

Influence of ERK on Nerve Cell Apoptosis of Cortex Following Traumatic Brain Injury in Rats

Objective: To investigate the effect of extracellular-signal regulated protein kinase (ERK) signal transduction mechanism in traumatic brain injury(TBI) in rats. Methods: The rat model of TBI was made according to the method of Marmarou(1994). A total of 92 male Sprague-Dawley rats were randomly divided into control and TBI groups. The rats in group of TBI 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 expression of ERK was detected by immunohistochemical and Western blot methods. The expression of c-fos was detected by immunohistochemical method. The apoptosis of cortex cell was detected by TUNEL. Results: The activities of p-ERK1/2,c-fos and TUNEL positive cells were increased in TBI group compared to those in the control group. Conclusion: The excessive activation of ERK is one of mechanisms of nerve cell apoptosis by inducing c-fos protein following traumatic brain injury in rats.