Abstract: Objective To study the effect of 1，25-dihydroxyvitamin D3[1，25（OH）2D3] on hepatic hypoxia inducible factor（HIF） and myeloid cell triggering receptor-1（TREM-1） expression in rats with liver fibrosis and to investigate the protective effect of 1，25（OH）2D3 in this process.Methods 48 male SD rats were randomly divided into TREM-1 knockout，model，1，25（OH）2D3-intervened and control group. The model was established by 0.5%DMN intraperitoneal injection for 8 weeks，and the rats in TREM-1 gene knockout group had the related gene knockout by using iRNA method. The rats in different groups were given 1，25（OH）2D3 and peanut oil solution or peanut oil solution alone gavage. After 8 weeks，the rats were executed under anesthesia，and liver pathological examination were done by routine HE and Masson staining. The hepatic HIF-1 alpha and TREM-1 protein and their mRNA were detected by immunohistochemical and RT-PCR techniques，respectively.Results At the end of eighth week，the hepatic fibrosis in rats in model group was significantly serious than in the control group，while the fibrotic scores in TREM-1 gene knockout group and 1，25（OH）2D3-intervened group（4.216±0.328，6.301±1.625，respectively） were significantly lower than in the model（14.417±3.019，P＜0.05）；the HIF-1α expression were（146.183±6.913，132.804±6.281，respectively），much lower than in the model（105.226±5.374，P＜0.05）；there was no hepatic TREM-1 expression in TREM-1 gene knockout group，while its expression（127.386±6.021） in 1，25（OH）2D3 group was much lower than in the model（113.093±5.257，P＜0.05）；the hepatic HIF-1α mRNA levels in TREM-1 gene knockout and 1，25（OH）2D3 group（0.813±0.097，0.824±0.101，respectively） were much lower than in the model（1.136±0.142，P＜0.05）；the hepatic TREM-1 mRNA level in 1，25（OH）2D3 group（0.986±0.124） was significantly lower than in the model（1.319±0.343，P＜0.05）.Conclusion TREM-1 participates in the occurrence and development of liver fibrosis，and 1，25（OH）2D3 may play an antifibrotic role by inhibiting the expression of TREM-1 and HIF-1.

Key words: Liver fibrosis, Hypoxia inducible factor-1α, Myeloid cell triggering receptor-1, 1, 25-dihydroxy vitamin D3, Rats