Objective     To study the effects and related mechanism of low-dosed methyl-mercury chloride (MMC) on the epithelial apoptosis of fetal mice intestine.      Methods     Pregnant mice on E12.5 d and E13.5 d were injected with different doses of MMC (0

1

2

4 mg/kg) intraperitoneally. After 48 h

their duodenum and colon were dissected out and sliced into the paraffin sections. Some sections were stained with HE to count the numbers of apoptotic bodies (NAB) with stereological method. The others were stained with the immunohistochemical method to observe the expression of apoptosis-associated proteins Bcl-2

Bax and immediate early gene c-fos.      Results     ①In all experimental groups

the NAB in the epithelium were higher than that of control groups (P0.05)

and there was a positive correlation between the doses of MMC and the NAB (P0.01). ②In all experimental groups

the expression of Bcl-2 in the epithelium was lower than that of control groups (P0.05)

and there was a negative correlation between the doses of MMC and the expression of Bcl-2 (P0.01). However the expression of Bax and c-fos were higher than that of in control groups (P0.05). There was a positive correlation between the doses of MMC and the expression of these proteins (P0.01).      Conclusion     In vivo

MMC can increase the epithelial apoptosis in fetal mouse intestine

by the mechanism of restraining the expression of Bcl-2 and promoting the expression of Bax and c-fos.