一重和多重脑震荡大鼠前额叶髓鞘脂蛋白(PLP)的变化

A change of the expression of PLP in the prefrontal cortex of brain after pure cerebral concussion and multiple cerebral concussions in rats

目的:为探索一重(pure cerebral concussion,PCC)和多重脑震荡(multiple cerebral concussion,MCC)后大鼠前额叶中隔断面髓鞘脂蛋白(myelin protein lipoprotein,PLP)分布与表达变化规律。方法:采用自制单摆式机械打击装置复制PCC和MCC大鼠模型,伤后随机分为PCC中1、2、4、8、16和24 d组(n=6),MCC中1、2、4、8、16和24 d组(n=6),另设正常对照组(n=6)。用小鼠抗-PLP单克隆抗体免疫组织化学SP法染色,观察致伤后大鼠中隔断面区PLP表达的动态变化。结果:正常状态下,PLP主要表达于皮质分子层和颗粒层的白质纤维;中隔区核团包括前脑内侧束(Mfb)、斜角带垂直支(VDB)、外侧隔核中间部(LSI)和杏仁核(amygdaloid nucle-us,AN);胼胝体(cc)、纹状体(CPu)和前联合(an)。PCC后多数脑区PLP表达变化无差异;MCC后皮质前额叶分子层、斜角带垂直臂核和纹状体脑区的PLP表达明显下调(P<0.05)。结论:结果提示MCC可能存在损伤累积效应,加重了中隔断面区神经纤维的损伤。

Objective： This study aimed to investigate the distribution and expression changes of the myelin protein lipoprotein（PLP） in prefrontal-septum areas after pure cerebral concussion（PCC） and multiple cerebral concussions（MCC）.Methods： PCC and MCC rat models were created by using a metallic pendulum-striker concussive device.The rats were randomly divided into PCC 1,2,4,8 and 16 d（n=6 for each time point） and MCC 1,2,4,8 and 16 d（n=6 for each time point） groups after injury.One control（normal） group（n=6） was used.The distribution and immnoexpression changes of the PLP were observed by S-P immuno-histochemical staining in the prefrontal-septum areas after injury.Results： The results showed that PLP immunoreactivity was localized in the white matter and was widely associated with the nerve fibers in the molecular and granular layer of cerebral cortex and prefrontal-septum areas including medial forebrain bundle（Mfb）,vertical diagonal band（VDB）,lateral septal nucleus,intermediate part（LSI）,amygdaloid nucleus,corpus callosum（cc）,caudate putamen（CPu） and anterior commissure（ac） in the control rats.Following PCC,the expression level of PLP in most areas was remained unaltered（P〉0.05） compared to that of the control groups.However,in MCC groups,PLP expression was reduced significantly（P〈0.05） in the molecular layer of prefrontal cortex,VDB as well as the CPu when compared with the control and PCC rats.Conclusion：The present results suggest that MCC may have cumalative effects on the injury,thus aggravating the damage to the nerve fibers of the prefrontal-septum.