The role of Trans-placental RNAi mouse model in the study of congenital malformations

Objective To assess an economical and efficient technology to establish knock-down mouse by trans-placental RNAi-BMP4 (Bone morphogenetic protein) to mouse embryos.Methods After established BMP4 down-regulatory plasmid,the Ringer's,pSES and pSES-SiBMP4 were delivered to pregnant mouse via tail vein.Some embryos were taken out 48h after injection,then RTPCR and Western blotting were used to analyze the expression of BMP4 in embryos.The growth and development of newborn mouse were observed.Results The mRNA expression of BMP4 in pSES-SiBMP4 embryo group was downregulated by (29.4± 5.0)％,compared with Ringer's group and by (42.2 ±9.2)％ compared with pSES group (P＜0.05).The protein level of BMP4 in pSES-SiBMP4 embryo group was reduced by (27.0 ± 6.4)％ compared with Ringer's group and by (31.1 ± 5.8)％ compared with pSES group (P＜0.05).There was no significant malformation detected in Ringer's group or control group.In mouse embryos of pSES-SiBMP4 group,abnormalities in head,gastrointestinal tract or backbone were detected,and epilepsy,intestinal polyps and Hirschsprung were found in offsprings.Conclusions It is feasible to deliver plasmid to early staged mouse embryos,pSES-SiBMP4 can knock down BMP4 gene expression.This technique can potentially be used to evaluate gene function or to induce Hirschsprung's disease or intestinal polyps mouse model. Key words: RNA Interference;  Bone morphogenetic protein 4;  Mice