阿魏酸对阻断兔主动脉血流所致脊髓神经元凋亡的影响

目的探讨阿魏酸对阻断家兔主动脉血流所致脊髓神经元凋亡的影响及其可能的作用机制。方法将24只家兔按随机数字表法分为假手术组、缺血／再灌注（I／R）损伤组和阿魏酸组。采用阻断腹主动脉血流40min、再灌注7d制备脊髓I／R损伤模型；阿魏酸组于阻断腹主动脉前15min一次性静脉注射阿魏酸50mg／kg；假手术组仅松套腹主动脉，不阻断血流。分别测定腹主动脉阻断前10min（C-10）、开放前即刻（C40）及开放后60min（R60）和处死前即刻（R7d）血清丙二醛（MDA）、超氧化物歧化酶（SOD）水平；检测脊髓凋亡神经元以及Bax和Bcl-2蛋白的表达；观察术后动物后肢神经功能评分。结果①I／R损伤组MDA含量明显高于C-10值及假手术组相应时间点值（P〈0．05或P〈0．01），SOD活性变化与MDA变化相反；阿魏酸组MDA含量明显高于C-10值（P〈0．05），但显著低于I／R损伤组相应时间点值（P〈0．05或P〈0．01），较假手术组比较差异无显著性，SOD活性变化与MDA变化亦相反。②I／R损伤组Bax蛋白表达明显高于假手术组（P〈0．05），Bcl-2蛋白表达则明显低于假手术组（P〈0．01）；阿魏酸组Bax蛋白表达明显低于I／R损伤组，但显著高于假手术组（P〈0．01和P〈0.05），Bcl一2蛋白表达明显高于I／R损伤组及假手术组（P均〈0.01）。③I／R损伤组脊髓神经元凋亡指数明显高于假手术组（P〈0．01）；阿魏酸组明显低于I／R损伤组，但高于假手术组（P〈0．01和P〈0．05）。④阿魏酸组瘫痪发生率明显低于I／R损伤组，其后肢神经功能评分明显高于I／R损伤组（P均〈0．01）。结论阿魏酸能显著抑制阻断家兔主动脉所致脊髓神经元凋亡的发生，其机制可能与其通过抗氧化反应进而抑制Bax蛋白、增强Bcl-2蛋白的表汰有关．

Protective effect of ferulic acid on neuronal apoptosis of spinal cord subsequent to aortic blood cross-clamping in rabbits

OBJECTIVE: To investigate the protective effect of ferulic acid on neuronal apoptosis of the spinal cord after aortic blood cross-clamping and its mechanism in rabbits. METHODS: Twenty-four rabbits were randomly divided into sham operation group, ischemia/reperfusion (I/R) injury group and ferulic acid group. Spinal cord I/R injury model was replicated by clamping blood of the infrarenal aorta for 40 minutes followed reperfusion for 7 days. Ferulic acid 50 mg/kg was injected 15 minutes before aortic clamping in ferulic acid group. The aorta was not clamped in sham operation group. Contents of malondialdehyde (MDA) and superoxide dismutase (SOD) in plasma were assayed at 10 minutes before clamping (C-10), before removal of occlusion (C40), at 60 minutes (R60) and on the 7 th day (R7d) after reperfusion. Apoptosis of neurones of spinal cord and the expressions of Bax and Bcl-2 protein were assayed by immunohistochemical technique. Neurologic function score of hind limb was observed after operation. RESULTS: (1)The activity of MDA after I/R in I/R injury group was increased significantly compared with those before clamping and those in sham operation group (P<0.05 or P<0.01). The activity of MDA in ferulic acid group was significantly higher than that at C-10 (P<0.05), while significantly lower than those in I/R injury group at any time point (P<0.05 or P<0.01), but showed no significant difference compared with sham operation group. Changes in SOD activities were opposite to that of MDA. (2)The expression of Bax protein in I/R injury group was increased significantly (P<0.05), but the expression of Bcl-2 protein was decreased significantly compared with that in sham operation group (P<0.01). In ferulic acid group, the expression of Bax protein was significantly lower than that in I/R injury group and higher than that in sham operation group (P<0.01 and P<0.05), and the expression of Bcl-2 protein was higher than those in I/R injury group and sham operation group (both P<0.01). (3)The index of neuronal apoptosis in I/R injury group was significantly higher than that in sham operation group (P<0.01), and that in ferulic acid group was much lower than that in I/R injury group, but higher than sham operation group (P<0.01 and P<0.05). (4)The degree of paralysis in ferulic acid group was significantly lower than that in I/R injury group, and a higher neurologic score was observed (both P<0.01). CONCLUSION: Ferulic acid can reduce the spinal cord neuronal apoptosis as a result of aortic occlusion in rabbits. The possible mechanism is that it decreases protein expression of Bax, increases that of Bcl-2 and enhances antioxidation.