PDTC对全脑缺血再灌注大鼠神经元损伤保护作用及机制

发布时间：2018-09-15 19:08

【摘要】：目的：初步观察核转录因子κB（nuclear factor-κB，NF-κB）抑制剂吡咯烷二硫代氨基甲酸盐(pyrrolidine dithiocarbamic, PDTC）对全脑缺血再灌注(global cerebral ischemia reperfusion，GCIR)大鼠神经元损伤的保护作用及其机制。方法：采用夹闭两侧颈总动脉20min合并全身低血压的方法建立GCIR模型。通过Morris水迷宫进行空间学习记忆能力的检测，HE常规染色观察大鼠海马神经元数目及形态的变化，RT-PCR检测大鼠海马环氧酶2（cyclooxygenase2, COX2）的mRNA表达，免疫组化检测海马NF-κB、COX2蛋白表达，ELISA测定大鼠海马中前列环素（prostacyclin，PGI2）和血栓素A2（thromboxaneA2，TXA2）含量。结果：与假手术组（sham）比较，GCIR大鼠的空间学习记忆能力显著下降；海马神经元凋亡30min开始出现（P 0.05），7d达到高峰（P 0.05）；NF-κB蛋白表达30min时开始升高，，24h达到高峰，15d仍明显高于假手术组（P 0.01）；COX2mRNA表达2h时开始升高，48h达到高峰，15d仍高于假手术组（P 0.05）；COX2蛋白表达2h开始升高，7d达到高峰，15d仍高于假手术组（P 0.01）；PGI2/TXA2的比值再灌注30min时开始升高，再灌注48h达到高峰后逐渐下降，15d时仍显著高于假手术组（P 0.05）。与GCIR组比较，PDTC预处理组（在缺血前1小时分别给予100mg·kg-1和200mg·kg-1PDTC腹腔注射）第7至12天大鼠寻台潜伏期明显缩短；再灌注第12天神经元核固缩减少，NF-κB蛋白、COX2mRNA及蛋白表达减少，PGI2/TXA2比值降低。结论：NF-κB活化可能上调GCIR大鼠海马神经元中COX2表达水平，使PGI2/TXA2比值升高，进而参与脑损伤病理生理过程的调节。PDTC对GCIR后大鼠神经元损伤有长时程保护作用，其机制可能涉及抑制NF-κB，下调COX2表达，降低PGI2/TXA2比值。
[Abstract]:Aim: to investigate the protective effect of pyrrolidine dithiocarbamate (pyrrolidine dithiocarbamic, PDTC), an inhibitor of nuclear transcription factor 魏 B (nuclear factor- 魏 B (NF- 魏 B), on neuronal injury in rats with global cerebral ischemia-reperfusion (global cerebral ischemia reperfusion,GCIR). Methods: GCIR model was established by clipping bilateral common carotid artery (20min) with systemic hypotension. Morris water maze was used to detect spatial learning and memory ability. The number and morphology of hippocampal neurons in rats were observed by HE routine staining. RT-PCR was used to detect the mRNA expression of cyclooxygenase-2 (cyclooxygenase2, COX2) in hippocampus of rats. The expression of COX2 protein in hippocampus of NF- 魏 B was detected by immunohistochemistry. The levels of prostacyclin (prostacyclin,PGI2) and thromboxane A2 (thromboxaneA2,TXA2) in hippocampus of rats were determined by Elisa. Results: compared with the sham-operated group, the spatial learning and memory ability of (sham) rats decreased significantly, and the apoptosis of hippocampal neurons 30min began to appear (P0. 05) and reached the peak at 7 days (P0. 05). The expression of NF- 魏 B protein was significantly higher than that of sham operation group (P 0.01) at the beginning of 24 h and reaching the peak at 24 h and reaching the peak at 15 d (P0. 01). The expression of COX-2 mRNA in sham operation group was significantly higher than that in sham operation group (P 0. 05). The expression of COX2 protein increased at 2 h and reached the peak at day 7 and reached the peak at day 15. The ratio of PGI2 / TXA2 in sham-operated group was still higher than that in sham operation group (P0.01). The ratio of PGI2 / TXA2 in sham operation group was significantly higher than that in sham-operation group after 48 hours of reperfusion, and then gradually decreased at 48h after reperfusion (P0. 05). Compared with the GCIR group, the incubation period of the rats in the PDTC pretreatment group (intraperitoneal injection of 100mg kg-1 and 200mg kg-1PDTC at 1 hour before ischemia) was significantly shortened on the 7th to 12th day. On the 12th day after reperfusion, the expression of COX2 mRNA and protein of NF- 魏 B protein decreased and the ratio of PGI 2 / TXA2 decreased. Conclusion the activation of fraction NF- 魏 B may up-regulate the expression of COX2 in hippocampal neurons of GCIR rats, increase the ratio of PGI2/TXA2, and participate in the regulation of pathophysiological process of brain injury. PDTC has a long-term protective effect on neuronal injury after GCIR. The mechanism may involve inhibition of NF- 魏 B, down-regulation of COX2 expression and reduction of PGI2/TXA2 ratio.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R965

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