Comparing Study Of Mouse Embryotoxicity Between Nanosized And Microsized Silicon Dioxide

PrefaceNanosized particles are generally defined as the particles with diameter at the range of 0. 1 ~ 100nm. Nanosized particles have physical and chemical property different from lots of large particles, also their property and powerty of biological effect has natural difference. Once micrometer materials are made into nanosized diameter, their biological effect change following the modification of diameters. The same material acts different toxic effect in different diameters. Nanosized materials have more chance to pass bio — membrance because of their small size. The huge specific surface areas enlarge the ability of combining with biomacro molecule and appear new toxicity. Nanosized materials emerge free radical then cause oxide damage on biological membrance, DNA protein or the macromolecular. There is a lot of pathway for nanosized material to ingression body. Among them respiratory passage touch is one of the main path. But the research on embryotoxicity and genetic damage was rare.Nanosized silicon dioxide with predominant properties such as stability, dispersing and confluence is applied to rubber, dope, medicine and paper making. Any new nanomaterial needs careful evaluation with regard to its toxicological and environmental risk perception before introducing it to the marketplace and into the product chain. So this research will compare the embryotoxicity and gene point mutation between nanosized and microsized dioxide silicon.Materials and Methods1. Animals and treatmentAdult health kunming strain pregnant mice were divided randomly into five groups-, control group,microsized silicon dioxide 50mg/m3group (/urn—SiO250mg/m3group) , ^m —SiO2200mg/m3group, nanosized~SiO2 50mg/m3 group ( nm — SiO2 5Omg/m3 group) , nm — SiO2 200mg/m3 group. Mice were exposed to particles of nanosized and microsized silicon dioxide everyday , two hours each time for 18 days from embryonic 0(E0) to E17. The volume of the all — glass whole body inhalation chambers was 50 liters. Mice were fed a rodent chow and water adlibitum. The experiment lasted 18 days and mice were sacrified at the end of the exposure.2. Observation and determination2. 1 Generally observed index: Observe the weight changing trend of pregnant mice. Count living embryo number ^ average living embryo weight per unit, and dead fetus number^ absorbed fetus number per group.2. 2 Detect fetus about the point mutation of the Cx32 and Cx40 genes with general PCI^ PCR—SSCP methods.3. Analysis of resultsThe variances were analyzed by software SPSS 12. 0,data were expressed in means dbSEM. Comparison between nanosized and microsized or between the particles of different dose levels was made by One — way ANOVA linear regression or ^2 test. There was no obvious point mutation in all treated groups after general PCR ^ PCR—SSCP observation.ResultsThe concept weight on E18 day decreased contrasting with which in control group(P