水通道蛋白4在大鼠肺炎链球菌脑膜炎模型中的表达变化

The expression changes of aquaporin 4 in rat model of Streptococcus Pneumoniae meningitis

目的观察大鼠肺炎链球菌脑膜炎模型中水通道蛋白4(AQP4)的表达变化及调节机制。方法采用肺炎链球菌脑池内注射诱导建立大鼠细菌性脑膜炎模型,以注射等量生理盐水者为对照,在造模后24 h、48 h、5 d处死大鼠,用HE染色、干湿重法、荧光定量PCR和免疫印迹法(Western blot)分别检测其脑部炎症程度、脑组织含水量、AQP4 mRNA和蛋白的表达水平。采用半胱氨酰白三烯受体(CysLTs)选择性拮抗剂在造模前30 min和造模后30 min、12 h、24 h、48 h分别腹腔注射给药1次,于造模后48 h观察AQP4的表达变化。结果与对照组相比,光镜下可见模型组所有大鼠脑室内均有大量炎症细胞浸润,造模后48 h及5 d大鼠脑含水量显著升高(P<0.05)。PCR及Western blot结果显示,模型组大鼠脑组织AQP4 mRNA及蛋白的表达在24 h开始升高,48 h达高峰,与对照组相比,差异有统计学意义(P<0.05),5 d时又下降。CysLT2受体拮抗剂HAMI3379可显著抑制模型组AQP4的表达增加(P<0.05),而CysLT1受体选择性拮抗剂普鲁司特对模型组AQP4的表达增加无显著影响(P>0.05)。结论AQP4参与了大鼠肺炎链球菌脑膜炎脑水肿的形成,同时CysLT2受体可能通过对AQP4表达的调节以控制脑水肿。

Objective To observe the expression changes and regulation mechanism of aquaporin 4(AQP4)in a rat model of Streptococcus Pneumoniae meningitis.Methods Intracerebral injection of Streptococcus Pneumoniae was used to induce and establish a rat model of bacterial meningitis,and the rats injected with the same amount of normal saline were collected as controls.The animals were sacrificed at 24 h,48 h and 5 d after modeling.HE staining,dry and wet weight method,fluorescence quantitative PCR and western blot were used to detect the degree of cerebral inflammation,brain tissue water content,AQP4 mRNA,and protein expression levels.A selective antagonist of cysteinyl leukotriene receptor(CysLTs)was administered intraperitoneally once every 30 min before modeling and 30 min,12 h,24 h and 48 h after modeling.The expression changes of AQP4 were observed 48 h after modeling.Results Compared with the control group,under the light microscope,a large number of inflammatory cells infiltration could be seen in all rat ventricles in the model group.The brain water content of rats in the 48 h and 5 d groups were increased significantly after modeling(P<0.05).PCR and Western blot results showed that the expression of AQP4 mRNA and protein in the brain tissue of the model group began to increase at 24 h and reached a peak at 48 h.Compared with the control group,there was a significant difference(P<0.05),and the expression was decreased again at 5 d.CysLT2 receptor antagonist HAMI3379 could significantly inhibit the increased AQP4 expression in the model group(P<0.05),and the selective antagonist prulast of CysLT1 receptor has no significant effect on the increased AQP4 expression in the model group(P>0.05).Conclusion AQP4 is involved in the formation of cerebral edema due to Streptococcus Pneumoniae meningitis in rats.At the same time,CysLT2 receptor may control cerebral edema by regulating the expression of AQP4.