纳米和微米SiO_2吸入染毒对大鼠氧化损伤指标的比较研究

目的比较雄性大鼠吸入纳米二氧化硅(nmSiO2)与微米二氧化硅(μmSiO2)对其不同脏器氧化损伤的影响,以及不同时间变化情况。方法36只雄性Wistar大鼠按体重随机分为6组,分别为纳米、微米SiO2300mg/m3组及对照组各2组,进行一次吸入染毒2h。24h和48h后各处死1组,分别取肝、肾、脑,匀浆后用于测定SOD、CAT和GSH-Px活性及H2O2、GSH和MDA含量。结果H2O2含量在各脏器纳米组均高于对照组,而微米组只在肝、肾24h及脑48h高于对照组(P<0.05);CAT活性与此相反,在各脏器两个时点的纳米组均较微米组降低(P<0.01),在肝、脑纳米组48h比24h更低。超氧阴离子含量只在纳米组脑中比对照增加明显,SOD活性在肾24h和脑纳米组降低显著,但与微米组无明显差别。而GSH含量只在肝24h纳米组较对照降低;GSH-Px酶活性水平在所有纳米组均低于对照组,而且在脑组织中显著低于微米组。MDA含量在肝脏、肾脏、脑组织中纳米组比对照组高,而微米虽在肝和脑中较对照组高(P<0.05),但其幅度均较纳米小。总抗氧化能力纳米组各脏器两个时点均比对照组降低(P<0.05),而微米组只在肾脏24h和脑中较对照组降低(P<0.05),脑48h纳米组比微米组下降显著;而肾48h纳米组较24h升高。结论纳米SiO2致氧化损伤作用较微米SiO2明显,通过不同时点的比较发现48h时SiO2引起的氧化损伤弱于24h时的变化。

Comparative study of the effect on oxidative damage in rats inhaled by nano-sized and micro-sized silicon dioxide

Objectlve To compare the changes of oxidative damage in rats inhaled by nano-sized and micro-sized silicon dioxide. Methods 36 male rats were randomly divided into two contlol groups and four experimental groups which was inhaled by nano-sized and micro-sized silicon dioxide respectively at the concentration of 300mg/m^3 for 2 hours and the activities of SOD, CAT and GSH-Px and the contents of H2O2 , GSH and MDA of the liver, kidney, brain were determinated 24h and 48h after inhalation. Results The contents of H2O2 in all organs in nano-sized groups increased significantly while increased in micro-size groups only in liver and kidney at 24h and in brain at 48h. On the contrary, the activities of CAT in nano-sized group were lower than those in micro-sized group. Superoxide anion contents increased only in the brain of nano-sized group. The activities of SOD decreased significantly in nano-sized groups in kidney at 24h and brain but not in micro-sized groups. The content of GSH decreased only in liver at 24h. The activities of GSH-PX decreased significantly in nano-sized compared with control group and were lower significantly in brain than those in micro-sized group. The contents of MDA increased in all nano-sized groups but only in liver and brain in micro-sized group. The total anti-oxygen activities decreased in all nano-sized groups, but only in kidney at 24h and brain in micro-sized group, especially more significantly in brain at 48h in nano-sized than micro-sized group. While the activity in kidney in nano-sized group increased at 48h comparing to at 24h. Conclusion Nano-sized silicon dioxide could induce oxidative damage more easily than micro-sized silicon dioxide. Through comparing different interval, it was found that the degree of oxidative damage at 48h after inhalation inferior to that at 24h after inhalation, which could be associated with the repair of the body against the oxidative damage.