Objective  To explore the influence of different doses of vinyl chloride (VC) on the development of neural tube in mice by observing the development and diversity of mouse embryo’s nervous system

the proliferation and apoptosis of the neuroepithelial cells

and to further investigate the underlying mechanism of neural tube defect (NTD). Methods  The pregnant mice were randomly divided into experimental group and control group. The mice of experimental group were intraper

itoneally injected by arachis oil with VC at the doses of 200

400 and 600 mg/kg in E6.5

meanwhile

the mice of control group was injected by arachis oil. Both of the groups were dissected in E12.5

and the embryo was immobilized by 4% PFA

paraffin-embedded and cut continuously. The expression of PCNA in the development of neural tube was detected by immunohistochemical staining. The apoptosis in the development of neural tube was observed by TUNEL assay. Results  The living embryo in the experimental group of middle dose was decreased

in which the incidence of abnormity was 51%

and 40% of them was NTD. In the experimental group of high dose

the living embryo was 55%

and the incidence of abnormity was 71%

of which 50% was NTD. Both of them had significant deviation compared with the control group (

P

<

0.05). ② The thickness of the neural epithelium in middle and high dose groups were of disparity. The majority of neural tube in high dose group was NTD

around which the swelling and unclear mesenchymal cells were found. ③ The positive cells of PCNA and TUNEL were widely distributed in neural tube of normal mouse (control group). The distribution of both kinds of positive cells in the experimental groups resembled with that of control group. But the higher dose of VC was injected to rats

the lesser positive cells of PCNA were seen and the more positive cells of TUNEL were observed. Conclusion  During early pregnancy

exposure to certain dose of VC makes the incidence of abnormity increased in rats

so did the rate of NTD. VC inhibits the proliferation of neural cells and induces the cell apoptosis

leads to the ratio of proliferation and apoptosis imbalance

which might be one significant reason for NTD induced by VC.