3种粒径纳米氧化锌与常规氧化锌对大鼠的亚慢性毒性

Sub-chronic toxicity of three scales of nano-and micron-zinc oxide in rats

目的:比较不同粒径的纳米氧化锌(ZnO)和常规ZnO对大鼠的亚慢性毒性。方法:将40只SD大鼠随机分5组,分别为3种粒径的纳米ZnO(30、50、100 nm)染毒组,常规ZnO(≤1μm)染毒组和阴性对照组(生理盐水),每组8只,雌雄各半。每日1次、连续42d经腹腔注射(10 mg/kg)给予受试物。试验结束后,计算肝、脾、肺、肾和睾丸的脏器系数;检测血象、血清生化指标;显微镜下观察附睾精子畸形率;主要器官(肝脏、肾脏、脾脏、肺脏及睾丸)做病理切片和HE染色;TUNEL法检测睾丸生殖细胞凋亡指数。结果:与对照组比较,3种粒径纳米和常规ZnO组的肝、脾、肾、肺的脏器系数均有不同程度的变化。与常规ZnO比较,30 nm和50nm ZnO组脾的脏器系数均升高(P<0.05);30、50和100 nm组肺的脏器系数均下降,差异均有统计学意义(P<0.05)。3种粒径纳米ZnO和常规ZnO组的红细胞数目、中性粒细胞比例、血小板数目较对照组均显著升高(P<0.05),而淋巴细胞比例均显著降低(P<0.05)。30和50 nm ZnO组的血小板数目较常规ZnO组明显升高(P<0.05),而血红蛋白显著下降(P<0.05)。30 nm与50 nm组诱发的精子畸形率分别为1.05%和0.81%,与对照组(0.24%)相比明显升高,差异均有统计学意义(P<0.05)。与对照组比较,病理切片可见3种粒径纳米ZnO组睾丸组织管壁上生精细胞数量明显减少且排列紊乱;TUNEL法检测可见纳米ZnO组生精细胞凋亡指数明显升高,差异均有统计学意义(P均<0.05)。结论:纳米ZnO的亚慢性毒性明显高于常规ZnO。纳米ZnO的作用靶器官可能是睾丸、肝、骨髓和肾;有随着粒径的降低,受影响的器官数和损伤程度加重的趋势。

OBJECTIVE： To compare the sub-chronic toxicity caused by three scales of nano-zinc oxide and micron-zinc oxide in rats. METHODS：SPF SD rats were randomly divided into 5 groups with 8 rats （four females and four males） per group. Once a day for 42 days,rats received intraperitoneal injection of the same dose （10 mg/kg） of different scales nano-ZnO（30 nm,50 nm,100 nm） and micron-ZnO（≤1 μm）. The negative control group was injected with saline. At the end of the experiment, organ coefficients of the liver,spleen,lung,kidney and testis;haematology and blood biochemical parameters;the sperm abnormality rate of the epididymis were determined. The main organs were used to prepare for pathological sections and HE staining. TUNEL method was used to detect testicular germ cell apoptosis. RESULTS：Compared with the negative control group,there were different degree of changes to the organ coefficients of liver,spleen,kidney and lung in the three scale nano- and micron-ZnO groups. Compared with the micron-ZnO group,the organ coefficients of spleen in 30 nm and 50 nm ZnO groups were all increased,while the organ coefficients of lung in 30,50 and 100 nm groups were decreased （P〈0.05）. The number of erythrocytes （RBC）,neutrophil ratio （NEUT,%） and platelet count （PLT） in the three scale of nano and micron-ZnO groups were significantly higher than the negative control group,while the lymphocyte ratio was significantly decreased （P〈0.05）. The number of PLT in the 30 and50 nm ZnO groups was significantly higher than that in the micron-ZnO group （P〈0.05）,but the hemoglobin （HGB） was decreased （P〈0.05）. The sperm abnormality rate induced by 30nm and 50nm ZnO group was 1.05% and 0.81%,respectively,and it was statistically significant （P〈0.05） compared with the negative control group（0.24%）. The number of spermatogenic cells on the wall of the testis tissue of the three scale of nano-ZnO group was significantly lower than that of the control group. Apoptosis of the spermatogenic cells was observed by TUNEL method,and the apoptosis frequency of the nano-ZnO group was statistically different （P〈0.05）. CONCLUSION：The nano-ZnO caused higher sub-chronic toxicity than micron-ZnO. The target organs of nano-ZnO included the testicle,liver,bone marrow and kidney. With the decrease of particle sizes,the number of affected organs and the degree of damage increased.