饮水暴露六价铬对SD大鼠外周血DNA损伤和氧化应激的影响

Oral Exposure to Hexavalent Chromium by Drinking Water Increases DNA Damage and Oxidative Stress in Peripheral Blood of SD Rats

[目的]研究饮水摄入六价铬对大鼠外周血DNA损伤和血浆氧化应激的影响。[方法]取雌、雄SD大鼠各40只随机分为4组,每组10只,每笼2只,4组分别自由摄入饮用水(对照)及30、100、300mg/L重铬酸钾(K2Cr2O7)水溶液4周,每周3次记录每笼饮水量并更换现配的K2Cr2O7溶液。实验结束时测定体重及心、肝、肾、肺、胃、脾组织重量,计算脏器系数和大鼠平均每日饮水量,并测定外周血DNA损伤及血浆中8-羟基脱氧鸟苷(8-hydroxydeoxyguanosine,8-OHdG)和丙二醛(malondialdehyde,MDA)的含量。[结果]雌鼠300mg/L组的体重增加量低于对照组(P<0.05);雌鼠300mg/L组、雄鼠100mg/L和300mg/L组的平均每日饮水量均低于对照组(P<0.05,P<0.01)。300mg/L组雌、雄大鼠DNA损伤均加重(P<0.05)。雌鼠100mg/L和300mg/L组血浆中8-OHdG含量及雌鼠3个剂量组和雄鼠100、300mg/L组血浆中MDA含量均显著高于对照组(P<0.05,P<0.01)。[结论]饮水暴露Cr(VI)可致大鼠外周血DNA损伤加重,并使血浆中8-OHdG和MDA的含量升高。

[ Objective ] To study changes of DNA damage and oxidative stress in peripheral blood of rats induced by hexavalent chromium exposure through drinking water. [ Methods ] Forty male and forty female SD rats were randomly divided into 4 groups with 10 in each group and 2 in each cage. The rats were exposed to potassium dichromate （K2Cr2OT） through drinking water at doses of 0, 30, 100, and 300 mg/L for 4 weeks, respectively. Water consumption per cage was recorded 3 times a week and the water was replaced by freshly prepared K2Cr207 solution. The rats were neutralized after 4 weeks. Body weight and weights of heart, hver, kidney, lung, stomach, and spleen were recorded, and organ coefficients and mean daily water consumption per rat were calculated. The DNA damage of whole blood cells and the contents of $-hydroxydeoxyguanosine （8-OHdG） and malondialdehyde （MDA） in rat plasma samples were measured. [ Results ] The body weight increment in the 300mg/L female rat group was significantly lower than that of the controls （P 〈 0.05）. The mean daily water consumption per rat in the 300 mg/L female rat group and in both the 100mg/L and 300mg/L male rat groups was significantly decreased than that in the control group （P〈0.05, P〈0.01）. Blood DNA damage increased significantly in both the male and female rats administrated with 300 mg/L K2Cr207 as compared with the controls （P 〈 0.05）. The contents of 8-OHdG in the 100 mg/L and 300 mg/L female rat groups were significantly increased （_P 〈 0.05, P 〈 0.01）. The contents of M DA in the plasma samples of female rats in all exposed groups and male rats in the 100 mg/L and 300 mg/L groups increased significantly compared with the controls （P 〈 0.05, P 〈 0.01）. [ Conclusion ] The increments of blood DNA damage and the contents of 8-OHdG and MDA in rat plasma may due to hexavalent chromium exposure throuch drinking water.