重复经口暴露氧化铁纳米颗粒在大鼠体内的分布和排泄

目的 探究氧化铁纳米颗粒经口暴露后，在大鼠体内的分布和排泄情况，为评估其安全性提供实验依据。方法 将64只雄性SD大鼠按体重随机分为溶剂对照组、低剂量组、中剂量组和高剂量组，分别灌胃等体积溶剂、50 mg/kg bw、100 mg/kg bw、200 mg/kg bw的氧化铁纳米颗粒悬浊液。灌胃后1、7、14、28天分批处死，检测大鼠的血液指标、生化指标、脏器重量和组织病理，以及血清、组织、尿液和粪便铁含量。结果 与对照组相比，灌胃1天后高剂量组大鼠肝脏脏器系数减小(P<0.05),连续灌胃14天后高剂量组大鼠肾脏脏器系数增大(P<0.05);连续灌胃14天后，中、高剂量组血清铁含量均增加(P<0.05);连续灌胃28天后，中剂量组脑组织和脾脏内铁含量增加(P<0.05);连续灌胃7、14、28天后，剂量组大鼠尿液中铁含量均增加(P<0.05),粪便中铁含量略有增加，但差异无统计学意义(P>0.05);组织病理学检查未见上述组织出现明显病理损害。结论 氧化铁纳米颗粒经口暴露后，主要分布于大鼠血清、脾和脑，代谢后主要经尿液排出，少部分经粪便排出。

Biodistribution and excretion of iron oxide nanoparticles in rats afterrepeated oral exposure

Objective To explore the distribution and excretion of iron oxide nanoparticles in rats after oral exposure and to provide experimental bases for their security assessment. Methods 64 male SD rats were randomly divided into solvent control group, low-dose group, middle-dose group and high-dose group according to body weight, and were given an equal volume of solvent, 50mg/kg bw, 100mg/kg bw and 200mg/kg bw of iron oxide nanoparticle suspension respectively. Four rats in each group were sacrificed on 1, 7, 14, 28 days after intragastric administration, and the rats’ hematological indices, biochemical indices, organ coefficients, histopathology, and iron content of serum, tissue, urine and feces were measured. Results Compared with the control group, the organ coefficient of rats’ liver in the high-dose group decreased after 1 day of exposure (P<0.05), the organ coefficient of rats’ kidney in the high-dose group increased after 14 days of continuous exposure (P<0.05); the serum iron content in the medium and high-dose groups increased after 14 days of continuous exposure (P<0.05); the iron content in brain and spleen in the medium-dose group increased after 28 days of continuous exposure (P<0.05); after 7, 14 and 28 days of continuous exposure, the iron content in the urine of rats in all experimental groups increased (P<0.05), the iron content in feces increased slightly, but the differences were not statistically significant (P>0.05); and histopathological examination showed no pathological damage to the above tissues. Conclusion After oral exposure of iron oxide nanoparticles, they are probably distributed to the rat’s serum, spleen and brain, and are mainly excreted by urine after metabolism, and a small part is excreted through feces.