Objective: To study the influence of Wuzi Yanzong pills on apoptosis of neural tube cells in neural tube defects (NTDs) model induced by all-trans-retinoic acid (ATRA). Method: BALB/c females and males (ratio 2:1) were caged together overnight. Checked for the presence of a vaginal plug

the females were diagnosed as pregnant mice. Pregnant mice were randomly divided into normal group

model group

the group of early administration of Wuzi Yanzong pills

the group of simultaneous administration of Wuzi Yanzong pills and ATRA

and the group of late administration of Wuzi Yanzong pills. Each Wuzi Yanzong pills group was divided into three subgroups of high

middle and low doses (4.20

2.10

1.05 g·kg-1). Model group and three subgroups of group of early administration of Wuzi Yanzong pills and group of simultaneous administration of Wuzi Yanzong pills and ATRA and group of late administration of Wuzi Yanzong pills were once fed with 50 mg·kg-1 ATRA at embryo 7 d. After pregnant mice were sacrificed at embryo 11 d

embryos were separated. The embryos were performed by preparation for sections using the staining of HE and TUNEL

which were used to observe the development of neural tube and calculate apoptotic index. Result: The neural tube developed well and completely closed in normal group. The neural tube appeared dysplasia in model group. The neural tube developed well

and consisted of ependymal layer

mantle layer and marginal layer

and neuroepithelial cells arranged in order in groups of early administration of middle and high dose Wuzi Yanzong pills and groups of simultaneous administration of middle and high dose Wuzi Yanzong pills and ATRA. The neural tube appeared dysplasia

and neuroepithelial cells reduced and arranged in disorder in groups of late administration of middle and high dose Wuzi Yanzong pills and the groups of low dose Wuzi Yanzong pills. Compared with the normal group

the apoptotic index in the group of early administration of high dose Wuzi Yanzong pills have no statistically significant difference

but the apoptotic index in other groups were significantly increased. Compared with the model group

the apoptotic index in the groups of early administration of middle and high dose Wuzi Yanzong pills and the groups of simultaneous administration of middle and high dose Wuzi Yanzong pills and ATRA were significantly decreased;but the apoptotic index in the groups of late administration of middle and high dose Wuzi Yanzong pills and the groups of low dose Wuzi Yanzong pills showed no statistically significant decline. Conclusion: Wuzi Yanzong pills can inhibit the apoptosis of neural tube cells in NTDs model.