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目的研究褪黑素(MT)对宫内缺氧胎鼠脑组织自由基和细胞凋亡的影响。方法妊娠19 d SD大鼠随机分为假手术(S)组、缺血-再灌注(I-R)组和MT处理组。建立大鼠30 min I-R宫内窘迫模型。MT组孕鼠在阻断血供前1 h腹腔注射MT(10 mg/kg)。分别于再灌注1、6和24 h剖宫取胎鼠,测定胎鼠脑组织的超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)和丙二醛(MDA)水平,HE染色观察脑组织病理变化,TUNEL法测定脑细胞凋亡指数。结果 I-R组较S组胎鼠脑组织中SOD、GSH-PX活力下降,MDA含量上升,大脑皮质神经细胞凋亡指数增加;同时随着再灌注时间的延长,上述改变亦趋于明显。与I-R组比较,MT组能提高胎鼠脑组织中SOD、GSH-PX活力,降低MDA含量,减少脑皮质神经细胞的凋亡指数。结论 MT有较强的抗氧化和自由基清除作用,减轻胎鼠脑组织宫内缺氧性损伤。
Objective To study the effects of melatonin (MT) on the free radicals and apoptosis in brain tissue of hypoxic-exposed fetal rats. Methods Sprague - Dawley rats were randomly divided into sham operation (S) group, ischemia - reperfusion (I - R) group and MT treatment group. Establishment of 30 min I-R intrauterine distress model in rats. The pregnant rats in MT group were intraperitoneally injected with MT (10 mg / kg) 1 h before block blood supply. The rats were sacrificed at 1, 6 and 24 h after reperfusion, respectively. The contents of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and malondialdehyde (MDA) ), The pathological changes of brain tissue were observed by HE staining, and the apoptosis index of brain cells was measured by TUNEL method. Results Compared with group S, the activity of SOD and GSH-PX in brain tissue of I-R group increased and the content of MDA increased. The apoptotic index of cerebral cortex increased in I-R group, and the change became obvious with the extension of reperfusion time. Compared with I-R group, MT group increased the activity of SOD and GSH-PX in fetal rat brain tissue, decreased the content of MDA and decreased the apoptosis index of cerebral cortex neurons. Conclusion MT has a strong antioxidant and free radical scavenging effect, reduce intrauterine hypoxic injury of fetal rat brain tissue.