肺炎链球菌溶血素致脑损伤中细胞凋亡及凋亡诱导因子的变化及意义

目的 探讨肺炎链球菌溶血素(PLY)致感染性脑损伤中细胞凋亡及凋亡诱导因子(AIF)的表达及意义. 方法 SD大鼠80只按随机数字表法分为PLY组[颈内动脉注射0.2 mL(7μg) PLY]和生理盐水(NS)组(颈内动脉注射等体积NS),每组40只.每组按观察时间点分为6h、12h、24 h、48 h4个亚组,每亚组10只,其中5只注射髓,甲酰胺法测定脑组织EB含量判断血脑屏障(BBB)的破坏程度.5只不注射EB,取脑组织切片,应用免疫组化和TUNEL染色分别检测脑组织神经元特异性烯醇化酶(NSE)、胶质纤维酸性蛋白(GFAP)、AIF蛋白含量和细胞凋亡. 结果 与NS组比较,造模后各时间点PLY组大鼠脑组织EB、NSE、GFAP、AIF蛋白含量均较高,细胞凋亡较多,差异均有统计学意义(P＜0.05); PLY组大鼠脑组织凋亡细胞数与AIF蛋白的表达呈正相关关系(r=0.959,P=0.000). 结论 细胞凋亡参与了PLY诱导的脑损伤的发展过程,AIF可能介导了神经细胞的凋亡.

Expression of apoptosis inducing factor and apoptosis of nervous cells in infectious brain injury rat models induced by pneumolysin and their significance

Objective To explore the expression ofapoptosis inducing factor (AIF) and the apoptosis ofnervous cells in infectious brain injury rat models induced by pneumolysin (PLY) and their significance.Methods A total of 80 infant SD rats were randomly divided into normal saline treatment group (NS group,n=40) and PLY treatment group (PLY group,n=40).Each group was divided into 4 subgroups:NS observation subgroups at the 6,12,24 and 48 h of treatment and PLY observation subgroups at the 6,12,24 and 48 h of treatment (n=10).Five rats in these subgroups were injected with Evan' s blue (EB) to determine the damage of BBB by measuring the content of EB in the brain tissues;the other 5 rats in these subgroups were not given EB,and their brain tissues were obtained to detect the protein expressions of NSE,GFAP and AIF by immunohistochemistry,and their apoptosis was examined by TUNEL staining.Results As compared with those in the NS treatment subgroups,the brain EB content and the expression levels of NSE,GFAP and AIF in the PLY treatment subgroups were significantly higher,and the number of apoptotic cells was significantly increased (P＜0.05).The number of apoptotic cells was positively correlated to the protein expression level of AIF in the PLY treatment group (r=0.959,P=0.000).Conclusion Apoptosis plays a role in the formation and development of infectious brain injury of rats and AIF might involve in the apoptosis ofneurocyte.