慢性苯染毒小鼠DNA损伤及体内抗氧化酶的变化

背景苯是重要的工业溶剂,长期接触可导致苯可导致 DNA损伤 ,染色体畸变 ,DNA加合物的形成,基因突变等. 目的了解苯对体内 DNA的损伤作用、机制以及抗氧化酶体系的变化情况. 设计随机对照的实验研究. 单位哈尔滨医科大学附属第一医院检验科,哈尔滨医科大学公共卫生学院. 材料实验在哈尔滨医科大学公共卫生学院动物室完成.选用健康雄性昆明种小鼠 24只 ,体质量 18- 22 g,由哈尔滨医科大学附属第二医院实验动物中心提供. 干预分为正常对照组、低剂量苯损伤组和高剂量苯损伤组.除对照组外,其余各组小鼠进行静式吸入苯蒸气染毒, 4 h/d, 2个月后处死,分离骨髓细胞及外周血淋巴细胞,取肝、脾、脑组织并制备匀浆.主要观察指标用单细胞凝胶电泳技术对骨髓细胞及外周血淋巴细胞 DNA损伤进行检测;同时检测肝、脾、脑组织中超氧化物歧化酶( superoxide dismulase, SOD )、谷胱肝肽过氧化物酶( glutathione peroxidase, GSH-Px)的活性及丙二醛( malondialdehyde, MDA )含量. 结果染毒组小鼠骨髓细胞及外周血淋巴细胞彗星百分率分别为骨髓细胞( 83.56± 10.28)% ,( 92.54± 15.93)%,外周血淋巴细胞 (41.27± 6.03)% ,( 65.79± 11.62)%,显著高于对照组( 4.13± 0.52)%, (2.21± 0.31)%( P< 0.01),并呈剂量-反应关系.高、低浓度组小鼠肝匀浆 SOD活力分别为( 11 573.31± 1938.72) ,( 12 574.68 ± 1938.72) nkat/g, GSH- Px活力分别为( 309.40± 82.85),( 375.41± 55.18) nkat/g,均显著低于对照组 分别为 (16 668.67 ± 3 137.96),(588.62± 110.52) nkat/g](P< 0.05),但不同剂量组间差异无显著性意义;高、低浓度组小鼠脾匀浆 GSH-Px活性分别为( 421.75± 124.02)、( 523.10± 45.18) nkat/g,均显著低于对照组( 618.42± 57.01) nkat/g (P< 0.05),且不同剂量组间差异有显著性意义( P< 0.05);高、低浓度组小鼠脑匀浆 GSH-Px活性分别为( 87.35± 19.84) ,( 95.02± 14.00 nkat/g,均显著低于对照组( 118.36± 7.67) nkat/g(P< 0.05), 但不同剂量组间无显著性差异;高浓度组小鼠脑匀浆 MDA含量为( 3.99± 1.15) μ mol/g ,显著高于对照组( 2.58± 0.53) μ mol/g( P< 0.05). 结论慢性苯染毒可致小鼠骨髓细胞及外周血淋巴细胞 DNA损伤,体内抗氧化酶活性降低.

Effects of chronic benzene poisoning on DNA and antioxidase of mice

BACKGROUND:As an important industrial solvent,benzene can cause DNA damage,chromosome aberrence,formation of DNA adducts and gene mutation. OBJECTIVE:To explore the effects of benzene on DNA and the mechanism,as well as the changes of antioxidase system it caused. DESIGN:Randomized case control study. SETTING:The Department of Clinical Laboratory of First Affiliated Hospital and Public Health College of Harbin Medical University. PARTICIPANTS:The experiment was completed in the Animal Centre in Public Health College,Harbin Medical University.Twenty-four healthy male mice of Kunming species weighed between 18 g to 22 g were chosen.The mice were provided by Experimental Animal Centre of Second Affiliated Hospital,Harbin Medical University. INTERVENTIONS:The mice were divided into control group,low dose benzene group and high dose benzene group.Inhaling benzene smoke method was used 4 hours per day to cause benzene poisoning to mice except those of the control group.The mice were executed two months later to separate marrow cells and peripheral lymphocytes and remove liver,spleen and brain to make homogenate. MAIN OUTCOME MEASURES:Single cell gel electrophoresis (SCGE) was used to assay the DNA damages of marrow cells and peripheral lymphocytes.Meanwhile,the contents of superoxide dismulase(SOD),glutathione peroxidase(GSH-Px) and malondialdehyde(MDA) in liver,spleen and brain tissues were also detected. RESULTS:The comet percentage of marrow cells and peripheral lymphocytes in two benzene poisoning groups were(83.56± 10.28),(92.54± 15.93)% ,and(41.27± 6.03)% ,(65.79± 11.62)% respectively which were much higher than those in control group(4.13± 0.52)% ,(2.21± 0.31)% ](P< 0.01) and represented dose-response relationship.The SOD activity of liver homogenate and GSH-Px activity of high dose and low dose groups were (11 573.31± 1 938.72),(12 574.68± 1 938.72) nkat/g and (309.40± 82.85),(375.41± 55.18) nkat/g respectively which were much lower than those in control group (16 668.67± 3 137.96),(588.62± 110.52) nkat/g] (P< 0.05).However, there was no significant difference between different dose groups. The GSH-Px activity in spleen homogenate in two experimental groups was(421.75± 124.02) and(523.10± 45.18) nkat/g respectively which was much lower than that of control group (618.42± 57.01) nkat/g](P< 0.05) and there was significant difference between two groups (P< 0.05).In the brain homogenate of both benzene groups,the GSH-Px activity was(87.35± 19.84) and(95.02± 14.00) nkat/g respectively which was much lower than that of control group(118.36± 7.67) nkat/g] (P< 0.05) and without difference between two groups.The MDA content in brain homogenate of high dose group was(3.99± 1.15) μ mol/mg which was much higher than that of control group (2.58± 0.53) μ mol/g] (P< 0.05). CONCLUSION:Chronic benzene poisoning can cause DNA impairment of marrow cells and peripheral lymphocytes and reduce the activity of antioxidase.