积雪草酸对大鼠蛛网膜下腔出血后IL-33/ST2信号通路及小胶质细胞的影响

Effects of asiatic acid on IL-33/ST2 signaling pathway and microglia after subarachnoid hemorrhage in rats

目的探讨积雪草酸对大鼠蛛网膜下腔出血后IL-33/ST2信号通路及小胶质细胞的影响。方法72只280-330 g的雄性SD大鼠随机分为4组:假手术组(sham组)、实验性蛛网膜下腔出血组(eSAH组)、积雪草酸低剂量组、积雪草酸高剂量组,每组18只。采用血管内穿刺法制备大鼠实验性蛛网膜下腔出血(eSAH)模型。sham组仅将尼龙线头端送至右颈内动脉,但不刺破动脉管壁;eSAH组、积雪草酸低剂量组和积雪草酸高剂量组制备eSAH模型。积雪草酸低剂量组和积雪草酸高剂量组分别于模型制备后0,6,12 h腹腔注射50 mg/kg和75 mg/kg积雪草酸。eSAH后24 h检测脑水含量,Western blot法检测损伤侧脑皮层IL-33和ST2的蛋白表达,TUNEL法检测凋亡指数,免疫荧光染色法检测ED-1阳性小胶质细胞密度。结果与sham组比较,eSAH组大鼠左大脑半球、右大脑半球及小脑的含水量显著增加(P<0.05),ED-1阳性小胶质细胞数及凋亡指数显著上调(P<0.05);与eSAH组比较,积雪草酸低剂量组和积雪草酸高剂量组左大脑半球和右大脑半球含水量明显减少(P<0.05),IL-33和ST2蛋白表达明显上调(P<0.05),ED-1阳性小胶质细胞数及凋亡指数显著减少(P<0.05);与积雪草酸低剂量组比较,积雪草酸高剂量组IL-33和ST2蛋白表达明显上调(P<0.05),而脑含水量、ED-1阳性小胶质细胞数及凋亡指数未见显著差异(P>0.05)。结论积雪草酸可减轻大鼠蛛网膜下腔出血后小胶质细胞激活及细胞凋亡,其作用机制可能与激活IL-33/ST2信号通路相关。

Objective To investigate the effects of asiatic acid on IL-33/ST2 signaling pathway and microglia after subarachnoid he-morrhage in rats.Methods A total of 72 male Sprague-Dawley rats,weighing 280-330 g,were randomly divided into four groups(n=18):sham operation group(sham group),experimental subarachnoid hemorrhage group(eSAH group),low dose asiatic acid group(low dose group)and high dose asiatic acid group(high dose group).The experimental subarachnoid hemorrhage(eSAH)model was established by an endovascular puncture.The nylon thread tip was merely delivered to the end of the right internal carotid artery without piercing the arterial wall in sham group.The rats in eSAH group,low dose group,and high dose group were subjected to the establishment of eSAH model.The rats in low dose group and high dose group were intraperitoneally injected with 50 mg/kg and 75 mg/kg asiatic acid immediately,6 h,and 12 h after the onset of eSAH,respectively.The brain water content was detected at 24 h after eSAH.The protein expression of IL-33 and ST2 in the injured cortex was detected by Western blot.The apoptotic index was detected by TUNEL method.The density of ED-1 positive microglia was detected by immunofluorescence staining.Results Compared with sham group,the water contents in the left cerebral hemisphere,right cerebral hemisphere,and cerebellum were significantly increased in eSAH group(P<0.05),and the number of ED-1-positive microglia and the apoptotic index were significantly up-regulated(P<0.05).Compared with eSAH group,the water content in the left cerebral hemisphere and right cerebral hemisphere in low dose group and high dose group were reduced(P<0.05),the expression of IL-33 and ST2 protein was significantly raised(P<0.05),the number of ED-1-positive microglia and the apoptotic index were significantly diminished(P<0.05).Compared with low dose asiatic acid group,the expression of IL-33 and ST2 protein was significantly elevated in high dose group(P<0.05),whereas there was no statistical difference in water content,ED-1-positive microglia and apoptotic index between two groups(P>0.05).Conclusion Asiatic acid can mitigate the microglial activation and the apoptosis after subarachnoid hemorrhage,which may be related to the activation of IL-33/ST2 signaling pathway.