Objective:To study the structure change of liver and placenta and expression of NPY in the pregnant rats with intrahepatic cholestasis

and explore the reasons for intrauterine growth retardation and intrauterine fetal death in ICP.Methods:Rats pregnant for fifteen days were administered Estrogen and Progestrone to induce ICP.The structural changes of liver and placenta of the delivered rats were observed.And blood tests for biochemical criterion were conducted.The placentas of normal pregnancy(n=15)and ICP(n=15) were used for studying expression and quantification of NPY by immunohistochemistry staining and image analysis.Results:①in the experimental group

the levels of serum total bile salt(TBA)

serum aminotransferases(ALT)

aspartate transaminase(AST) significantly increased

(P <0.05)and structural changes of hepatocytes of intrahepatic cholestasis of pregnancy(ICP) in rats included swelling

finding bubble

capillary expanding

and dilation of the bile canaliculi.The placentas of ICP showed that the villi were swelling

the size of intervilli space was smaller

and the trophocytes were hyperplastic.②Almost all placenta villis in vivo of ICP group showed NPY strong positive immunoreaction

but in control group

some trophocytes appeared NPY positive immunoreaction

and capillary endothelium in placental villi showed NPY weak positive or negative immunoreaction

The results of image analysis showed that the staining intensity of NPYin ICP group was significantly higher than that in the control group(P <0.05).Conclusion:the placenta with ICP expressed more NPY than those of normal

which suggests that constructive vasoactive substance(NPY) might be important to cause fetal anoxia and death.