摘要目的 观察小鼠暴露于异氟醚后前脑Caspase-3蛋白和氧自由基的变化,以了解氧自由基(reactive oxygen spceies,ROS)在异氟醚神经损伤中的作用.方法 56只雄性C57BL/6J小鼠按随机数字表法分为异氟醚组(Iso组,n=20)、二甲基硫脲±异氟醚组(DMTU±Iso组,n=8)、二甲基硫脲组(DMTU组,n=8)和对照组(Con组,n=20).Iso组和DMTU±Iso组暴露于1.4%异氟醚2 h,重复3次,其中DMTU组在氧气暴露前、DMTU±Iso组在首次暴露前各30 min腹腔注射50 mg/kg的自由基清除剂DMTU.用免疫组化法观察小鼠前额皮质Caspase-3的表达,并测定超氧化物歧化酶(superoxide dismutase,SOD)活性和丙二醛(malondialdehyde,MDA)的变化.结果 免疫组化结果显示,与Con组相比,前脑的Caspase-3阳性细胞数在Iso组显著增加(为Con组的3.38倍,P＜0.05),而DMTU±Iso组(为Con组的1.43倍)和DMTU组(为Con组的0.74倍)无明显变化(P＞0.05).Iso组的SOD活性(25±10)U/mgprot与Con组(20±6)U/mgprot相比差异无统计学意义(P＞0.05),而Iso组MDA含量(13.7±6.1)nmol/mgprot比Con组(5.7±2.7)nmol/mgprot明显升高(P＜0.05).结论 1.4%异氟醚可以引起小鼠脑组织Caspase寻蛋白表达上调,其机制可能与ROS增加有关.

abstractsObjective By observing the changes of Caspase-3 protein and reactive oxygen species (ROS) in the forebrain of mice induced by isoflurane inhalation to study the role of ROS in neural damages of isoflurane. Methods Fifty-six male C57BL/6Jmice were randomly divided into isoflurane group(Iso, n=20), dimethylthiourea group(DMTU,n=8), imethylthiourea plus isoflurane group(DMTU+lso, n=8), and control group(Con,n=20). Mice in Iso and DMTU+Iso groups were exposed to three segments of 1.4%isoflurane, 2 h for each segment. Thirty min before oxygen inhalation in DMTU group and first segment of isoflurane inhalation in DMTU+Iso group, 50 mg/kg of radical scavenger DMTU were intraperitoneally injected to the mice in the two groups. The changes of caspase-3 expression in prefrontal cortex were observed by immunocytochemical staining. And the activities of superoxide dismutase (SOD) and the amount of MDA were detected. Results Compared with Con group, the number of caspase-3 positive cells in Iso group increased significantly (3.38 times, P＜0.05); but in DMTU+Iso group( 1.43 times of Con group) and DMTU group(0.74 times of Con group),it did not change obviously (P＞0.05). There was no significant difference in the activities of SOD between Iso group [(25±10) U/mgprot] and Con group [(20±6) U/mgprot](P＞0.05), but lipid peroxidation malondialdehyde (MDA) content in Iso group [(13.7±6.1 ) nmol/mgprot] was significantly higher than that in Con group [(5.7±2.7) nmol/mgprot](P＜0.05). Conclusion 1.4% isoflurane exposure significantly increase the expression of caspase-3 in the forebrain of mice and its molecular mechanism may be related to the increase of free radicals.