热应激复合敌敌畏中毒对小鼠全血乙酰胆碱脂酶和组织抗氧化能力的影响

目的研究热应激复合有机磷敌敌畏（O,O-dimethyl-O-2,2-dichlorovinylphosphate,DDVP）中毒对小鼠全血乙酰胆碱酯酶活性及组织脂质过氧化的影响。方法将54只小鼠随机分为对照组、热应激组和热应激复合DDVP中毒组。实验舱相对湿度控制在（60±5）%,对照组小鼠置于24℃环境下1 h,热应激组小鼠置于38或40℃的热环境下1 h。有机磷中毒组小鼠经腹腔注射给予9或15 mg/kg DDVP,对照组给予等量生理盐水。30 min后,取全血测量乙酰胆碱酯酶（AChE）活性,取心、脑和肝组织匀浆,测量其超氧化物歧化酶（SOD）活性、丙二醛（MDA）含量和羟自由基（.OH）抑制能力。实验期间观察小鼠一般情况,记录实验前后小鼠体质量。结果热环境（38或40℃）暴露使小鼠烦躁不安,活动量明显增加,摄水量降低,体质量减轻。与不同环境温度暴露的对照组相比,热应激复合DDVP中毒组小鼠全血AChE活性和心、脑和肝组织SOD活性和羟自由基抑制能力均明显下降（P〈0.05）,而MDA含量明显升高（P〈0.05）。热应激和DDVP中毒对上述指标的影响有交互作用。结论在本实验条件下,热应激和DDVP中毒对小鼠乙酰胆碱酯酶有显著的抑制作用,同时可引起组织脂质过氧化增强,提示氧化应激机制与高热复合DDVP中毒的加重效应有关。

Effects of heat stress with organophosphorus pesticide intoxication on blood AChE activity and tissue anti-oxidation ability in mice

Objective To explore the combined effect of heat stress with organophosphorus O,O-dimethyl-O-2,2-dichlorovinylphosphate（DDVP） intoxication on blood acetyl cholinesterase（AChE） activity and tissue lipid peroxidation.Methods Fifty-four mice were randomly divided into control group,heat stress group and heat stress combined with DDVP poisoning group（the combined group）.Mice were put into experiment chamber with（60±5）% relative humidity.The chamber temperature was 24℃ for control group,and 38 or 40℃ for heat stress group.One hour later,mice in combined group were intraperitoneally given 9 or 15 mg/kg DDVP.Saline of an equal volume was applied to control and heat stress groups.After 30 minutes,the mice were sacrificed and samples of the blood,heart,brain,and liver were collected.Blood AChE activity,tissue SOD activity,MDA content and ·OH inhibiting ability in tissue homogenates of the brain,heart and liver were determined respectively.Results Mice became agitated and restless with increased activity when exposed to 38 or 40℃ ambient temperature.Water intake and body mass were decreased.Compared with temperature-matched controls,the heat exposure combined with DDVP poisoning at 38 or 40℃ caused significant decline of blood AChE activity,tissue SOD activity and ·OH inhibiting ability,and increase of tissue MDA content in the brain,heart and liver（P〈0.05）.Heat stress and organophosphorus pesticide intoxication showed synergistic interaction between the above parameters.Conclusion Under present experimental conditions,both ambient temperature and organophosphorus poisoning can significantly suppress the blood AChE activity while causing enhanced tissue lipid peroxidation.These data suggest that oxidative stress plays a role in the aggregative effect of organophosphorus intoxication under high ambient temperature.