大鼠弥漫性神经轴索损伤后AQP4的表达

目的:复制大鼠DAI损伤模型,应用Gless染色法观察轴索损伤的病理形态学变化,分析DAI损伤的发生机制,对AQP4表达在DAI的诊断和损伤时间推断中的应用价值进行探讨.方法:雄性SD大鼠60只,体重250~300g.随机分为正常对照组和实验组,实验组又按不同时间分为伤后0.5h、1h、3h、6h、12h、1d、3d、7d及10d组.按Marmarou法复制大鼠DAI损伤模型,应用湿重干重法,测定脑组织的水含量,脑组织常规取材后在进行Gless神经纤维轴索染色观察基础上,应用免疫组织化学染色方法观察AQP4的表达.结果:Gless染色在伤后0.5h可见轴索损伤的形态学变化,12h见明显的轴索收缩球,1~2d收缩球明显增多,3d后出现恢复期变化.大鼠DAI损伤后1~3h出现脑水肿,24~72h脑水肿达高峰,随后逐渐消退.AQP4的表达与脑水肿的发生、发展有明显的相关性,其表达量在损伤后6h增加,3d达高峰,10d后基本恢复正常.结论:AQP4与DAI的发生、发展有明显的相关性,对DAI的诊断和损伤时间的推断有一定的应用价值.

Primary Research on Expression of Aquaporin-4 After Diffuse Axonal Injury in Rats

Objective: To establish an model of diffuse axonal injury(DAI) for observing the morphological changes of axonal injury,and further investigating the relationship between the DAI and the expression of aquaporin-4(AQP4).Methods: 60 healthy male SD rats were divided randomly into normal control and injury groups.The animal model of DAI was made according to the method described by Marmarou.Gless staining and immunohistochemical methods were used to observe the changes of the expression of AQP4 and morphological significance of the axonal at 0.5h、 1h、3h、6h、12h、1d、3d、7d、10d asthe time elapsed after the DAI injury.Results: In the brain of normal control,no significant change was found.In the brain of injury group,the mor-phological changes of axonal were showed as twisted、broken and swellen at 0.5h in brain stem,and the myelin sheaths was observed a broken,the retraction ball was found at 12h.Those mor-phology changes further progressed at 12h,reached to peack up to 1d,then repaired at 3d,and re-covered at 10d,meanwhile the analysis of the water content in the brain show a time-dependent dif-ference as follow: edema begin at 3h,reached to maximize at 1d,returned to basal level at 10d.The expression of AQP4 was shown a very closely relationship with the brain edema,which begin to expression at 6h,reached to maximize at 3d,returned to basal level at 10d.Conclusion: AQP4 has a relevant relationship with the arisen and development of the brain edema after DAI,and it could be used as a important tool for the diagnosis and deduce the time of the DAI.