中等强度运动对大鼠DDT累积代谢、肝脏应激及结构影响

The Changes of DDT Accumulation Metabolism,Liver Oxidative Stress and Structure Intervened by Moderate Intensity Exercise

目的：研究全民健身背景下有氧运动对持续性有机污染物代谢的影响,揭示有氧运动对DDT在体内累积代谢、对肝脏应激及结构的影响。方法：90只雄性Wistar大鼠随机分为对照组（CON）、安慰剂组（PG）、有氧运动组（AG）、正常饲养DDT组（CDG）、有氧运动DDT组（ADG）。其中,CDG和ADG以40mg/kg（体重）的比例喂食DDT溶液2周,ADG和AG每天以18m/min运动30min。在运动第15天、30天、45天后取材,经研磨和冷冻干燥后采用气相色谱法测定不同组织中DDT的浓度分布;采用黄嘌呤氧化酶法测定肝脏SOD活性、硫代巴比妥酸比色法测定肝脏MDA含量、酶速率法测试肝脏GSH-Px活性、可见光法测定肝脏CAT活性;HE染色肝脏组织切片、醋酸铀和柠檬酸铅对超微结构染色,分别采用DP70数码显微镜成像系统及Tecnai Spirit 120KV透射电子显微镜及成像系统观察、拍照。结果：CDG肝脏中DDT浓度在停止喂食DDT后呈逐渐下降趋势,而ADG中则出现浓度先上升后下降的趋势。在15-30天中,ADG肝脏中DDT浓度显著高于CDG（P〈0.01）,而45天则显著低于CDG（P〈0.05）;与CDG比较,ADG心脏中DDT浓度在15天和45天时显著升高,而30天时DDT浓度低于CDG组;CDG骨骼肌DDT浓度呈递减趋势,ADG中呈逐渐上升趋势;在15-30天,ADG血液DDT浓度显著低于CDG（P〈0.01）;CDG中粪便DDT浓度呈逐渐下降趋势,ADG中浓度呈现较为稳定的趋势。氧化应激研究发现,有氧运动促进ADG中SOD活性在15-45天持续升高,且显著性高于CDG（P〈0.05）;MDA含量在15-30天内显著性升高（P〈0.05）,但在45天时呈现显著性下降（P〈0.01）;GSH-Px及CAT活性15天和30天时均显著升高（P〈0.05）,在45天时则受到显著抑制（P〈0.05）。DDT摄入影响肝脏超微结构,并随着DDT在肝脏中积累而加重,施加有氧运动干预后期能明显改善DDT摄入引起的超微结构的变化。结论：中等强度运动通过改变DDT在体内分布,减少了DDT在肝脏中的富集,但增加了运动初期心脏和骨骼肌中DDT分布及DDT排出体外的速度;改善肝脏的氧化应激状态,特别有利于运动初期肝脏中氧化应激状态的改善;有利于DDT富集引起的肝组织结构变化恢复。

Objective：To reveal the influence of aerobic exercise on DDT accumulation metabolic rules,changes of oxidative stress and structure in liver induced by DDT under the background of national fitness.Methods：90 male Wistar rats were randomly assigned into control group（CON）,placebo group（PG）,aerobic exercise group（AG）,CON with DDT group（CDG）and aerobic exercise with DDT group（ADG）.CDG and ADG were fed with DDT solution according to 40 mg/kg body weight for 2 weeks;ADG and AG were exercised with 18 m/min speed movement for 30 min every day.During 15 d,30dand 45 dafter exercise,DDT concentration was investigated by gas chromatography after grinding and freeze-drying and the distribution of DDT in different organizations were studied;the activities of SOD,GSH-Px and CAT were evaluated by xanthine oxidase method,enzyme kinetic method and visible light method respectively,the MDA content was determined with glucosinolates barbituric acid colorimetric method.The live samples were stained with HE for liver biopsy,and uranium acetate,citrate for liver ultrastructure,then observed and took photos with DP70 digital microscope imaging system and Tecnai Spirit transmission electron microscope and imaging system（120kv）.Results：DDT concentrations decreased gradually in CDG liver,whereas it rose first and then fell in ADG liver.DDT concentrations in ADG liver were significantly higher than that in CDG from 15 dto 30d（P〈0.01）,and lower than the CDG at 45d（P〈0.05）.Compared with the CDG,DDT concentrations in ADG heart showed a significant rise at 15 dand 45d,and a significant decline at 30 d.DDT concentrations in CDG skeletal muscle decreased gradually but rose in ADG.From 15 dto 30d,DDT concentrations in ADG blood was significantly lower than that in CDG（P〈0.01）.DDT concentrations in CDG feces declined gradually but were relatively stable in ADG feces.Aerobic exercise can promote SOD activity in ADG from 15dto45 dwhich was significantly higher than that of the CDG（P〈0.05）,increase MDA content within 15-30dsignificantly（P〈0.05）and decline it significantly after 30d（P〈0.05）,activate GSH-Px and CAT activity within 15 dand 30dafter feeding DDT（P〈0.05）and inhibit it significantly at 45d（P〈0.05）.DDT intake affected liver ultrastructure,and the damage was aggravating with the accumulation of DDT.The changes of ultrastructure induced by DDT accumulation could be improved with aerobic exercise intervention（45d）.Conclusion：Aerobic exercise can change the distribution of DDT in rats,reduce the concentration of DDT in liver,but increase the DDT distribution in heart and skeletal muscle during the early exercise period and increase the speed of DDT discharge for a long time exercise;Aerobic exercise can improve liver oxidative stress,particularly benefit the changes of oxidative stress at the early movement.Aerobic exercise is conducive to tissue recovery induced by the DDT enrichment.