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

关键词:  孕酮  缺血/再灌注  磁共振波谱  细胞凋亡  P2X₇受体

Key words:  progesterone  ischemia-reperfusion  magnetic resonance spectroscopy  apoptosis  P2X₇ receptor

摘要:

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。

Abstract:

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-α and 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-α and 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.