小鼠脑外伤后Apelin-13对自噬相关蛋白表达的影响

The effect of Apelin-13 on autophagy-associated protein expression in mouse cerebral cortex after traumatic brain injury

目的观察Apelin-13对小鼠脑外伤(Traumatic brain injury,TBI)自噬相关蛋白的影响,并初步探讨其对小鼠脑外伤后自噬相关蛋白调节的作用机制。方法取健康雄性CD-1小鼠,随机分为假手术(sham)组、生理盐水(saline)组、Apelin-13组。Apelin-13组和saline组在建立脑外伤模型前10min,分别注射Apelin-13(0.3μg/g)或等量生理盐水于侧脑室,然后利用Western-Blot检测脑外伤后24h、48h组大脑皮质自噬相关蛋白LC3、P62、Beclin-1和Bcl-2等的表达情况。结果与sham组相比,在脑外伤后24h、48h,saline组自噬相关蛋白LC3-Ⅱ/LC3-Ⅰ比值,Beclin-1的蛋白表达均被显著上调(P<0.01);同时Bcl-2、P62的蛋白表达水平被显著下调。然而,与saline组相比,Apelin-13组可显著下调自噬相关蛋白LC3-Ⅱ/LC3-Ⅰ比值和Beclin-1的蛋白表达水平(P<0.01);同时显著上调Bcl-2和P62的表达水平;亦明显降低Beclin-1/Bcl-2的比值。结论 Apelin-13可以明显抑制脑外伤后小鼠大脑皮质细胞的自噬活性,这一作用可能是通过调节Beclin-1、Bcl-2蛋白表达水平来实现的。

Objective To observe the effect of apelin-13 on traumatic brain injury （TBI）, and explore the relationship between apelin-13 and autophagy in TBI. Methods 30 mice were randomly divided into sham, saline and apelin-13 groups. Apelin-13 and saline groups were pretreated with an injection of apelin- 13（0.3μg/g） and saline into the mouse brain lateral ventricle respectively 10 min before TBI. The autoph- agy-associated proteins LC3, P62, Beclin-1 and Bcl-2 in the mouse cerebral cortex were assessed by Western-Blot 24h and 48h after TBI. Results Compared with sham group, protein LC3-Ⅱ/LC3-Ⅰ ratio and Beclin-1 expression were up-regulated, while protein Bel-2 and P62 were down-regulated in saline group 24h or 48h after TBI. However, compared with saline group, Apelin-13 decreased protein LC3-Ⅱ/LC3-Ⅰratio and Beclin-1 expression, increased protein Bcl-2 and P62 expression ,and down-regulated protein Beclin-1/ Bcl-2 ratio 24h or 48h after TBI. Conclusion Apelin-13 suppresses autophagy in TBI possibly by down-regulating protein Beclin-1/Bcl-2 ratio.