纳米级与微米级二氧化硅粉尘对小鼠胚胎毒性的比较研究

目的比较研究纳米级(nm-)与微米级二氧化硅粉尘(μm-SiO2)对小鼠胚胎的影响,并观察胚胎Connexin32(Cx32)和Cx40基因有无点突变改变。方法5个实验组(零剂量粉尘组、μm-SiO250mg/m3组、μm-SiO2200mg/m3组、nm-SiO250mg/m3组、nm-SiO2200mg/m3组)共25只雌性小鼠,妊娠0日(E0)至E17日连续呼吸道染尘,观察妊娠期间母鼠体重变化,E18日取出胚胎,观察胚胎发育情况,并采用常规聚合酶链式反应(PCR)、聚合酶链式反应-单链构像多态性(PCR-SSCP)技术对胚胎的Cx32和Cx40基因进行点突变检测。结果E18日,各染尘组的母鼠体重均显著低于对照组;各染尘组的胚胎数、活胎数、胚胎体重显著低于对照组,nm-SiO2200mg/m3组活胎数显著低于nm-SiO250mg/m3组和μm-SiO2200mg/m3组,nm-SiO2200mg/m3组胚胎体重显著低于μm-SiO2200mg/m3组;nm-SiO2200mg/m3组死胎率和吸收胎率均显著高于对照组。Cx32和Cx40基因经检测未发现有突变者。结论SiO2粉尘具有小鼠胚胎毒性,微米级粒子粒径改变为纳米级后,毒性作用增强,且纳米级SiO2粉尘对小鼠胚胎有致死作用。两种粒径的二氧化硅粉体均未发现有致Cx32和Cx40基因点突变。

Comparative study of effects of nanosized and microsized silicon dioxide dust on mouse embryos

Objective To compare the effect of mouse embryonic toxicity between nanosized and microsized dioxide silicon, and detect the point mutation of Cx32 and Cx40 genes after the interference with nm-SiO_2 and μm-SiO_2 on pregnant mice. Methods Twenty-five male mice in 5 groups(control,μm-SiO_250mg/m3,μm-SiO_2200mg/m3,nm-SiO_250mg/m3,nm-SiO_2200mg/m3groups)were treated through respiration from E_0 to E_ 17 , study pregnant mice weights change trend, take out the embryos on E_ 18 ,observe embryonic development circumstance and detect the point mutation of Cx32 and Cx40 genes with general PCR,PCR-SSCP methods. Results Pregnant mice weights in all interfered groups were lower than that in control group on E_ 18 .Embryo numbers,living embryo numbers and embryo weights in all experimental groups had decreased in contrast with control. Lliving embryo numbers in nm-SiO_2 200mg/m3 group had lessened comparing with nm-SiO_2 50 mg/m3 and μm-SiO_2 200mg/m3 groups. Embryo weights in nm-SiO_2200mg/m3 group reduced as compared with μm-SiO_2 200mg/m3 group. Dead fetus frequency and absorbed fetus frequency in nm-SiO_2200mg/m3 group was higher statistically than control. Cx32 and Cx40 genes hadn't been found any point mutation. Conclusion Dioxide silicon had embryonic toxic effects on mouse, which was severe with nanosized diameter Nanosized dioxide silicon was also wondered to have embryonic mortality toxicity impact on mouse. There was no found point mutation toxicity on Cx32 and Cx40 genes for the two kind of researched material.