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目的观察大鼠蛛网膜下腔出血(subarachnoid hemorrhage,SAH)后大脑皮质中VDAC1表达和皮质神经元凋亡,以及两者之间的关系,探讨电压依赖性阴离子通道蛋白1(voltage-dependent anion channel1,VDAC1)参与SAH后早期脑损伤的发生机制。方法将SD大鼠108只按随机数字表法分为假手术组(n=18只)和SAH组(n=90,下设SAH后6、12、36、48、72 h 5个时相点,每个时相点18只)。采用视交叉前池注血法建立SAH模型,应用RT-PCR、免疫组化和Western blot分别检测大鼠SAH后不同时相点VDAC1在mRNA水平、蛋白质水平的表达变化。凋亡原位末端标记法(Tunel)观察SAH后不同时相点大脑皮质神经元凋亡。结果大脑皮质中VDAC1表达,无论在mRNA水平,还是在蛋白质水平,在SAH后12 h均明显增加[mRNA(2.40±0.19),蛋白(1.14±0.08)],于36 h时表达达最高峰[mRNA(3.40±0.65),蛋白(1.72±0.22)],于48 h开始下降[mRNA(1.94±0.30),蛋白(0.97±0.07)],至72 h时基本恢复正常(P>0.05)。TUNEL法检测显示大鼠SAH后12 h,大脑皮质中神经元凋亡细胞数开始增加,36 h达到高峰,之后逐渐降低(P<0.05),72 h时降至正常(P>0.05)。结论 SAH后不同时间点VDAC1表达水平的动态变化与神经元凋亡发生、发展的时相性是一致的,提示VDAC1可能通过细胞凋亡途径参与SAH后早期脑损伤的病理过程。
Objective To observe the expression of VDAC1 and apoptosis of cortical neurons in cerebral cortex after subarachnoid hemorrhage (SAH) in rats, and to investigate the relationship between the expression of voltage-dependent anion channel1 , VDAC1) participate in the pathogenesis of early brain injury after SAH. Methods One hundred and eight SD rats were randomly divided into sham operation group (n = 18) and SAH group (n = 90), and five time points of 6, 12, 36, 48, , Each time point 18). SAH model was established by optic chiasm in forebrain injection. The expression of VDAC1 at mRNA and protein levels at different time points after SAH was detected by RT-PCR, immunohistochemistry and Western blot respectively. Apoptosis of cerebral cortex neurons at different time points after SAH were observed by Tunel staining. Results The expression of VDAC1 in cerebral cortex increased significantly at 12 h after SAH [mRNA (2.40 ± 0.19), protein (1.14 ± 0.08)] both at the mRNA level and protein level, reaching the peak at 36 h [ mRNA (3.40 ± 0.65), protein (1.72 ± 0.22)], and began to decline at 48 h [mRNA (1.94 ± 0.30) and protein (0.97 ± 0.07)]. The levels returned to normal at 72 h (P> 0.05). TUNEL assay showed that the number of apoptotic neurons in cerebral cortex began to increase at 12 h after SAH, peaked at 36 h, then decreased gradually (P <0.05) and decreased to normal at 72 h (P> 0.05). Conclusions The dynamic changes of VDAC1 expression at different time points after SAH are consistent with the time-phasic development of neuron apoptosis, indicating that VDAC1 may be involved in the pathological process of early brain injury after SAH through the apoptotic pathway.