饮水铅暴露对大鼠脑组织过氧化氢、羟自由基和脂质过氧化的影响

Effects of lead exposure in drinking water on hydrogen peroxide, hydroxyl free radicals and lipid peroxidation levels in brain tissues of rats

目的探讨乙酸铅对大鼠大脑皮质、小脑、海马组织自由基和脂质过氧化的影响。方法 48只刚断乳雄性SD大鼠,按体质量采用随机区组法分为4组(对照组和低、中、高剂量组),对照组大鼠饮用去离子水,低、中、高剂量组分别饮用200、400、800 mg/L的乙酸铅溶液。连续染毒60 d后,取血进行血铅测定,取各组脑组织(大脑皮质、小脑和海马)进行羟自由基抑制活力、过氧化氢(H2O2)水平及丙二醛(MDA)含量的测定。结果与对照组相比,各染铅组大鼠血铅含量显著升高,大脑皮质、小脑和海马组织羟自由基抑制活力明显下降,且随染铅剂量的升高呈逐渐下降趋势(P<0.05);大脑皮质、小脑和海马组织H2O2水平及MDA含量高于对照组,并随着染铅剂量的升高呈逐渐升高趋势(P<0.05);大脑皮质、小脑和海马组织的羟自由基抑制活力与血铅含量呈负相关(r分别为-0.505、-0.414、-0.448,P<0.05),H2O2和MDA含量均与血铅含量呈正相关(r分别为0.301、0.411、0.378和0.404、0.324、0.510,P<0.05)。结论铅可通过诱发自由基产生,导致大鼠脑组织发生脂质过氧化反应。

Objective To explore the effects of lead acetate on free radicals and lipid peroxidation in the cerebral cor-tex, cerebellum, and hippocampus in rat brains. Methods SD rats （n=48）, who were just weaned, were randomly divided in-to 4 groups base on their weight. Then the rats were fed with lead acetate in drinking water at the final concentrations of 0 mg/L （deionized water）, 200 mg/L, 400 mg/L, 800 mg/L respectively. Blood lead level as well as the hydroxyl free radical inhibiting activity, the levels of hydrogen peroxide （H2O2） and malondialdehyde （MDA） in cerebral cortex, cerebellum, and hippocam-pus were measured 60 days after lead contamination in water. Results Upon lead exposure, blood lead levels increased sig-nificantly as compared with the control. The hydroxyl free radical inhibiting activity in cerebral cortex, cerebellum, and hip-pocampus decreased significantly in a dose dependent manner of lead（P 〈 0.05）. And they all correlated negatively with blood lead level （r=-0.505,-0.414,-0.448, P〈0.05）. By contrast, blood lead level was positively correlated with H2O2 and MDA in these brain tissues （r=0.301, 0.411, 0.378, and 0.404, 0.324, 0.510,P 〈0.05）. Conclusion Lead exposure can lead to lipid peroxidation of rat brain tissues through inducing free radicals.