Objective   To explore the molecular mechanism of p38 mitogen-activated protein kinase and Bax in the development of neural tube defects induced by hyperthermia.  Methods   Totally 72 pregnant golden hamsters were randomly divided into 2 groups

group 1 (normal control) and group 2 (hyperthermiainduced neural tube defects). Water bath at 37 or 42 ℃ for 20 min was respectively given to the hamsters of group 1 or group 2 at gestational day 8. The pregnant golden hamsters were sacrificed at 2

8

16

24

48

and 72 h after water bath (n=6 for each time point)

and the embryos were taken out for brain tissues. Changes in p38MAPK

P-p38MAPK and Bax expression were detected by Western blot analyses using special antibodies directed against p38MAPK and Bax.  Results  Bax was steadily expressed in control group at all time points. The expression was obviously increased in the hyperthermia group at 8 to 48 h after water bath

with a significant difference with the corresponding control groups (P0.05)

and the peak appeared at 8 and 16 h (P0.01). P-p38MAPK activity was increased compared with the control group in the hyperthermia group at 8 to 48 h (P0.05)

and the peak appeared at 16 h (P0.01). In contrast

the level of total p38MAPK was not changed in the whole course of experiment.  Conclusion  Hyperthermia may promote the expressions of p38MAPK and Bax during development

induce excessive apoptosis in embryo

and thereby result in the development of neural tube defects.