慢性缺氧对大鼠延髓呼吸中枢的损伤作用及其对氧化应激和细胞凋亡的影响

The damage of chronic hypoxia on the respiratory center of the medulla oblongata and its effects on oxidative stress and apoptosis in rats

目的研究慢性缺氧对大鼠延髓呼吸中枢的损伤作用及对氧化应激与细胞凋亡的影响。方法将同批次实验大鼠随机分为对照组和实验组两组,对照组接受空气实验,实验组接受慢性缺氧处理,两组均连续处理14 d,每天6 h。缺氧处理最后一天将实验组5只存活大鼠和5只对照组大鼠麻醉后抽取动脉血0.2 ml进行血气指标测定,评估慢性缺氧大鼠模型制备效果。将10只大鼠处死后取延髓,采用尼氏染色法评估慢性缺氧对大鼠延髓呼吸中枢的损伤情况,采用生物化学方法测定大鼠延髓丙二醛(MDA)和氧化物歧化酶(SOD)评估慢性缺氧对氧化应激的影响,采用RT-PCR方法检测分析延髓组织内Bax和Bcl-2 mRNA表达水平,以评估评估慢性缺氧对细胞凋亡的影响。结果实验组大鼠PO2和HCO_(3)^(-)低于对照组,差异有统计学意义(P<0.05),两组pH和PCO_(2)比较差异无统计学意义(P>0.05);实验组大鼠pre-BotC、Amb、NTS、FN、HN尼氏染色光密度值均低于对照组,差异有统计学意义(P<0.05);实验组大鼠MDA低于对照组,差异有统计学意义(P<0.05),两组SOD比较差异无统计学意义(P>0.05);RT-PCR和Western blotting分别检测实验组大鼠Bcl-2蛋白表达量低于对照组,差异有统计学意义(P<0.05),两组Bax表达量无统计学意义(P>0.05)。结论慢性缺氧严重损伤大鼠延髓呼吸中枢系统,其机制可能与影响大鼠氧化应激及细胞凋亡具有密切的联系。

Objective To study the damage of chronic hypoxia on the respiratory center of the medulla oblongata in rats and its effects on oxidative stress and apoptosis.Methods The rats of the same batch were randomly divided into the control group and the experimental group.Rats in control group were given air test,and rats in experimental group were given chronic hypoxia treatment.Both groups were consecutively treated for 14 days,6 hours a day.On the last day of the hypoxia treatment,0.2ml of arterial blood was drawn for blood gas measurement to evaluate the preparation effect of chronic hypoxia rat models,from 5 alive rats in the experimental group and 5 rats in the control group after anesthesia.10 rats were killed and medulla oblongata were obtained.The damage of chronic hypoxia to the respiratory center of the medulla oblongata in rats was evaluated by Nissl staining,the effects of chronic hypoxia on oxidative stress in the medulla oblongata were evaluated by measuring malondialdehyde(MDA)and oxide dismutase(SOD)in the medulla oblongata of rats with biochemical methods.The expression levels of Bax and Bcl-2 mRNA in the medulla oblongata were detected and analyzed by RT-PCR to evaluate the effects of chronic hypoxia on apoptosis of medulla cells.Results PO_(2) and HCO_(3)^(-)in the experimental group were lower than those in the control group(P<0.05).There was no significant difference in pH and PCO2 between the two groups(P>0.05).The optical density values of pre-PotC,Amb,NTS,FN,HN by Nissl staining in the experimental group were lower than those in the control group(P<0.05).The concentration of MDA of rats in the experimental group was lower than that in the control group(P<0.05),however,there was no significant difference in SOD between the two groups(P>0.05).The expression of Bcl-2 gene and protein in the experimental group were lower than those in the control group by RT-PCR and Western blotting(P<0.05).However,there was no significant difference in Bax expression between the two groups(P>0.05).Conclusions Chronic hypoxia severely damages the medullary respiratory central system in rats,and its mechanism may be closely related to the effects of oxidative stress and apoptosis in rats.