Abstract: Objective To determine the expression of leptin receptor(OBR） in the normal and fibrotic liver,and to investigate the dynamic expression of the long form of leptin receptor(OB-Rb） in carbon tetrachloride(CCl₄) induced hepatic fibrosis in rats.Methods One hundred and twelve male Wistar rats were randomized into control group(16 rats） and model group(96 rats）.In model group 40% CCl₄ in olive oil was injected subcutaneously two times per week for 8 weeks at the dosage of 5(mL·kg^-1) body weight for the first shot and 3 mL·kg^-1 body weight for the next shots,while rats in the normal control group were treated with olive oil.Six rats were sacrificed each time 1,4,7,10,14,28,42,56 d after administration of CCl₄ and liver tissues were taken for pathological examination,whereas two normal rats were sacrificed as control each time.Expression of OB-R protein was measured by immunohistochemistry.Gene expression of OB-Rb was detected by reverse-transcription polymerase chain reaction(RT-PCR） and analyzed semi quantificationally.Results OB-R was slightly expressed in the portal and perivascular area of the normal liver,located in the cytoplasm and cell membrane of mesenchymal cells.It was up-regulated in the portal area,the perisinus of the lobule and the hepatic septum in the rats with the CCl₄ treatment.The OB-Rb mRNA was increased after 4 d of CCl₄treatment,and the level of OB-Rb mRNA was correlated with hepatic fibrosis stage positivly(r_s= 0.804,P= 0.000).Conclusion In the process of the hepatic fibrosis induced by CCl₄ in rats,expression of OB-Rb was elevated from the early stage and correlated with fibrosis stage positively,aggravating the fibrosis.

Key words: hepatic fibrosis, long form of leptin receptor, RT-PCR, immunohistochemistry