高压氧预处理对脊髓损伤大鼠神经元线粒体凋亡通路的影响

The effects of hyperbaric oxygen preconditioning on the mitochondrial apoptosis of spinal cord neurons

目的研究高压氧预处理（HBO-PC）对大鼠脊髓损伤（SCI）后运动功能及线粒体凋亡通路的影响。方法共选取健康雄性Wistar大鼠36只，采用随机数字表法将其分为对照组、模型组及高压氧预处理组。高压氧预处理组大鼠经7次高压氧预处理后，采用Allen’s法将高压氧预处理组及模型组大鼠制成SCI模型，对照组未给予特殊处理。于制模2周后采用BBB运动功能评分对各组大鼠肢体运动功能进行评定，同时采用实时荧光定量PCR技术检测各组大鼠脊髓组织内caspase-3、细胞色素C（CYC）、Bak、Bax、Bcl-X及Bcl-2mRNA表达量。结果制模2周后发现模型组及高压氧预处理组BBB评分[分别为（6．15±1．24）分和（10．80±2．16）分]均较对照组[（21．00±0．00）分]明显降低（P〈0．05）；并且模型组BBB评分亦显著低于高压氧预处理组（P〈0．05）。制模2周后模型组caspase-3mRNA表达量（2．46±O．60）较对照组（1．86±0．53）显著增高（P〈0．05）；高压氧预处理组caspase-3mRNA表达量（1．97±0．28）亦较对照组有增高趋势，但差异无统计学意义（P〉0．05）；同时高压氧预处理组caspase-3mRNA表达量较模型组显著降低（P〈0．05）；高压氧预处理组CYCmRNA表达量（1．58±0．22）较对照组（1．98±0．62）及模型组（2．69±0．50）均显著降低（均P〈0．05）。高压氧预处理组、模型组BakmRNA表达量[分别为（2．15±0．78）和（1．93±0．61）]均较对照组（1．21±0．46）显著增高（P〈0．05）。结论高压氧预处理能改善SCI大鼠肢体运动功能，其治疗机制可能与减弱SCI大鼠神经元线粒体凋亡通路激活程度有关。

Objective To study the effects of hyperbaric oxygen （HBO） preconditioning （PC） on motor function and mitochondrial apoptosis after spinal cord injury （SCI） in rats. Methods Thirty-six healthy, male Wistar rats were randomly divided into 3 groups （each n = 12） ： a control （CON） group, an SCI model group and an HBO-PC group. The SCI group and the HBO-PC group after 7 sessions of HBO-PC treatment were subjected to SCI modeling using Allen＇s method. The CON group was not given any special treatment. Two weeks after the modeling, Basso, Beattie, and Bresnahan BBB scale was used to rate the rats＇ locomotor function, and the Ts segment of the rats＇ spinal cords was removed. After extracting total RNA from the spinal cord tissue, real-time quantitative PCR was used to detect the mRNA expression levels of easpase-3, cytochrome C （CYC） , Bak, Bax, Bel-x and Bcl-2 in the spinal cord tissue. Results Two weeks after modeling, compared with the CON group, the average BBB locomotion score of the SCI model group had decreased. In contrast, caspase-3, CYC, Bak and Bax mRNA expressions had in- creased significantly. Compared with the CON group, the average BBB locomotion score of the HBO-PC group had decreased, easpase-3 expression had increased, and Bax mRNA expression had decreased, but the differences in the changes between the two groups were not statistically significant. Bak mRNA expression increased and CYC expres- sion decreased, and the difference between the two groups was statistically significant. Compared with the SCI model group, the average BBB locomotion score of the HBO-PC group increased while caspase-3, CYC, Bak and Bax mRNA expressions decreased, but none of these differences between the two groups was statistically significant. Bak mRNA expression increased and CYC mRNA expression decreased, and those differences between the two groupswere statistically significant. Bcl-x and Bcl-2 mRNA expression in the CON, HBO-PC and SCI model groups were significantly different. Conclusion HBO-PC can reduce the loss of motor function after SCI, at least in rats. The mechanism may be related to reducing neuron mitochondrial apoptosis.