硫化氢对新生大鼠缺氧缺血性脑损伤后神经细胞凋亡的影响

Effect of hydrogen sulfide on neuronal apoptosis in newborn rats with hypoxia-ischemic brain damage

目的探讨硫化氢(H2S)在新生大鼠缺氧缺血性脑损伤(HIBD)后脑细胞凋亡中的作用。方法新生SD大鼠96只随机分成4组:假手术组、HIBD组、HIBD+硫氢化钠组(NaHS组)和HIBD+羟胺组(HA组),每组各24只;根据观察终点,再将以上4组分为12 h、24 h、48 h和72 h 4个亚组。生化反应法检测不同时间点大鼠皮质脑组织H2S水平,TUNEL法检测脑细胞凋亡数及免疫组化检测caspase-3表达。结果 4组大鼠在不同时间点的脑组织H2S浓度、神经元细胞凋亡数以及caspase-3表达差异均有统计学意义(P<0.01),而各时间点上4组之间上述各检测指标比较差异均有统计学意义(P均<0.01)。经两两比较发现,HIBD组大脑皮质凋亡细胞较假手术组明显增多(P=0.000),NaHS组凋亡细胞较HIBD组和HA组明显减少(P=0.000);HIBD组大脑皮层caspase-3表达较假手术组明显增多(P=0.000),NaHS组caspase-3表达明显低于HIBD组(P=0.000),HA组caspase-3表达较HIBD组增多(P=0.000)。相比HIBD组脑组织明显的病理变化,NaHS组病理变化明显减轻。结论 H2S可下调脑组织caspase-3表达,抑制神经细胞凋亡,对大脑有保护作用。

Objective To investigate the effect of hydrogen sulfide （H2S） on neuronal apoptosis in hypoxic-ischemic brain damage （HIBD） of the newborn rats. Methods 96 healthy 7-day old Sprague-Dawley newborn rats were randomly as-signed into 4 groups： sham operation group （n=24）, HIBD group （n=24）, HIBD＋sodium hydrosulfide （NariS） group （n=24）, and HIBD＋hydroxylamine （HA） group （n=24）. Each group was further divided into four sub-groups based on the end time of observation （12h, 24h, 48h and 72h）. The cortical tissue levels of H2S were measured at different times after HIBD by bio-chemical methods. Apoptotic cells were detected by TUNEL. Immunohistochemical technique was applied to measure the expression of caspase-3. Results The concentration of H2S, apoptotic cells numbers and expression of caspase-3 in cerebral cortex at different time points were significantly different among the four groups （P〈0.01）, and there were also significant dif- ferences in the above detection indices among the four groups at the same time point （P〈0.01）. By pairwise comparison, the number of apoptotic cells were more in HIBD group than in sham operation group （P=0.000） and were decreased rapidly in HIBD＋NaHS group as compared to HIBD group and HIBD＋HA group （P=0.000）. The expression of caspase-3 was signifi-cantly increased in HIBD group as compared to sham operation group （P=0.000）. The expression of caspase-3 in HIBD＋NaHS group was significantly lower than that in HIBD group （P=0.000）. The expression of caspase-3 was higher in HIBD＋HA group than that in HIBD group （P=0.000）. The pathological changes of the cortex in HIBD group were apparent and were relieved in HIBD＋NaHS group. Conclusions Hydrogen sulfide may have a protective effect on the brain through decreasing the expres-sion of caspase-3 and inhibiting neuronal apoptosis induced by hypoxic-ischemic brain damage.