幼龄和老龄大鼠液压脑损伤后NGF、Bcl-2、Bax蛋白的表达

目的:研究衰老因素对神经生长因子(nerve growth factor,NGF)和凋亡相关蛋白(Bcl-2和Bax)表达的影响,探讨老年颅脑损伤恢复不良的分子生物学机制。方法:采用侧方液压打击颅脑损伤模型,应用免疫组化方法和计算机显微图像分析技术,比较幼龄(2～3个月)和老龄(15个月)大鼠脑损伤后12 h脑内NGF、Bcl-2、Bax蛋白表达水平的差异。结果:液压打击伤后NGF、Bcl-2、Bax蛋白在损伤侧大脑皮质、海马表达明显增强,老龄组大鼠伤侧皮质NGF蛋白表达和Bcl-2/Bax蛋白表达比率显著低于幼龄组(P<0.05)。结论:老龄和幼龄大鼠液压脑损伤后NGF、Bcl-2和Bax蛋白表达的差异提示老龄哺乳动物受损神经元修复和生存能力下降,为认识创伤性脑损伤后年龄相关性神经功能缺失的病理生理学机制提供了帮助。

Expression of nerve growth factor,Bcl-2 and Bax protein in young and aged rats brain following fluid percussion injury

Objective: To study the effect of aging on the expression of nerve growth factor(NGF) ,Bcl-2 and Bax protein after traumatic brain injury(TBI). Methods: TBI was established in young (2-3 months old) and aged (15 months old) SD rats by fluid percussion brain injury. The expression of NGF,Bcl-2 and Bax protein was analyzed by immunohistochemical method and computer micrograph analysis. Results: In the ipsilateral cerebral cortex and hippocampus, the expression of NGF,Bcl-2 and Bax protein increased 12 h after fluid percussion brain injury both in young and aged rats. However, the level of the NGF protein and the ratio of Bcl-2/Bax were lower in aged rat cerebral cortex compared to that in the young (P<0. 05). Conclusion: The present study demonstrates that the expression of NGF,Bcl-2 and Bax protein after fluid percussion brain injury is influenced by aging, the low level of NGF expression and the decrease of Bcl-2/Bax ratio may play an important role in the age-related neurological deficits after TBI.