孕酮对缺血/再灌注脑损伤大鼠脑磁共振波谱和ATP-P2X7R信号通路的影响

Effects of Progesterone on Magnetic Resonance Spectroscopy and ATP-P2X7R Signaling Pathways in Rats with Cerebral Ischemia-reperfusion Injury

目的探讨孕酮(progesterone,PROG)对缺血/再灌注(ischemia-reperfusion,I/R)脑损伤大鼠的神经保护作用及其可能机制。方法138只大鼠随机等分为假手术(Sham)组、大脑中动脉栓塞(middle cerebral artery occlusion,MCAO)组和PROG+MCAO组,分别采用Longa法和Morris水迷宫试验评估大鼠运动功能和认知功能;脑组织TTC染色法、磁共振波谱(magnetic resonance spectroscopy,MRS)法和Annexin V-FITC/PI双染法评估神经细胞损伤情况;ELISA法检测脑脊液ATP、IL-6、TNF-α和COX-2含量;Western blotting法检测脑组织P2X7R和NF-κB蛋白表达的变化。结果与MCAO组相比,PROG+MCAO组大鼠Longa评分(第5~7天)和Morris水迷宫试验潜伏期(第4~7天)下降(P<0.05或P<0.01),而目标交叉次数增高(P<0.05);PROG+MCAO组大鼠NAA/Cr和Cho/Cr比值较MCAO组升高,脑梗死体积和细胞凋亡率较MCAO组明显降低(P<0.05);MCAO组脑脊液ATP、COX-2、TNF-α和IL-6的含量明显高于Sham组,PROG+MCAO组上述指标含量明显低于MCAO组(P<0.05);MCAO组脑组织P2X7R和NF-κB蛋白的表达水平高于Sham组,而其在PROG+MCAO组表达水平又明显低于MCAO组(P<0.05)。结论PROG通过降低神经细胞凋亡率、减轻神经元损伤及髓鞘降解而改善I/R脑损伤大鼠运动和认知功能,这一保护作用与其抑制ATP-P2X7R信号通路密切相关。

OBJECTIVE To investigate the neuroprotective effects of progesterone(PROG)on cerebral in rats with ischemia-reperfusion(I/R)brain injury and its possible molecular mechanism.METHODS One hundred and thirty-eight rats were randomly divided into Sham group,middle cerebral artery occlusion(MCAO)group and PROG+MCAO group.Motor function and cognitive function of rats was evaluated by Longa method and Morris water maze test.TTC staining,magnetic resonance spectroscopy(MRS)and Annexin V-FITC/PI double staining were used to evaluate nerve cell injury.The levels of ATP,IL-6,TNF-αand COX-2 in rat cerebrospinal fluid was determined by ELISA.The expression of P2X7 receptor(P2X7R)and NF-κB protein in brain tissue was detected by Western blotting.RESULTS Compared with the MCAO group,the Longa score(Day 5-7)and the latency of Morris water maze test(Day 4-7)in the PROG+MCAO group decreased(P<0.05 or P<0.01),while the number of target crossovers increased(P<0.05).The ratio of NAA/Cr and Cho/Cr in the PROG+MCAO group was higher than that in the MCAO group,and the cerebral infarction volume and apoptosis rate were all significantly lower than that in the MCAO group(P<0.05).The levels of ATP,COX-2,TNF-αand IL-6 in the cerebrospinal fluid of MCAO group were significantly higher than those in sham group,and the PROG+MCAO group were significantly lower than MCAO group(P<0.05).The expression level of P2X7 receptor and NF-κB in MCAO group were higher than that of the Sham group,while the PROG+MCAO group was significantly lower than that of the MCAO group(P<0.05).CONCLUSION PROG improves motor and cognitive function in rats with I/R brain injury by reducing neuronal apoptosis rate and alleviating neuronal damage and myelin degradation.This protective effect is closely related to its inhibition of ATP-P2X7R signaling pathway.