Abstract： Objective To investigate the expression of adiponectin in placenta and its correlation with preeclampsia.Methods Placental tissues were collected from normal term pregnancies(normal pregnancy group,n=20),mild preeclampsia(mild preeclampsia group,n=12)and severe preeclampsia (severe preeclampsia group,n=22).The expression of adiponectin protein and the intensity of its mRNA in placenta were detected using immunohistochemistry and RT-PCR,respectively.Integral optical density (IOD)which represents the expression level of adiponectin protein,and the ratio of adiponectin cDNA PCR products to β-actin cDNA PCR products which represents the intensity of transcription of adiponectin mRNA in placenta were analyzed.Results (1)The expression of adiponectin protein was observed in cytoplasm of placental cytotrophoblasts and syncytiotrophoblasts among three groups.There was no significant difference in adiponectin protein expression between maternal side and fetal side of placenta in three groups(all P＞0.05);(2)The expression of adiponectin protein in placenta in severe preeclampsia group(30 984 ±14 604)was significantly lower than that of mild preeclampsia group(58 360±8910,P＜0.01)and of normal pregnancy group(53 246±17 554,P＜0.01).There was also no significant difference in the expression of adiponeclln protein in placenta between term delivery and preterm delivery in severe preeclampsia group(38 890±20 386 vs 29 319±8997,P＞0.05),however,the expression of adiponectin protein in placenta in term delivery of severe preeclampsia group was significantly lower than that ofterm delivery of normlal pregnancy group(38 890±20 386 vs 53 246±17 554,P＜0.05);(3)The expression of adiponectin mRNA was detected in placental tissues among three groups also.The intensity of transcription of adiponectin in placenta in severe preeclampsia group(1.0±0.2)was markedly lower than that of mild preeclampsia group(2.9±0.8,P＜0.05)and normal pregnancy group(3.3±1.1,P=0.000).Conclusion The expression of adiponectin decreases in placenta tissues of severe preeclampsia,indicating that the abnormal expression of adiponectin may be involved in the pathogenesis of preeclampsia.