AIM:To investigate the location and expression of TIMP-1and TIMP-2 in the liver of normal and experimental hepaticfibrosis in rats.METHODS:The rat models of experimental immunityhepatic fibrosis (n=20) were prepared by the means ofimmunologic attacking with human serum albumin (HSA),and normal rats (n=10) served as control group.Bothimmunohistochemistry and in situ hybridization methodswere respectively used to detect the TIMP-1 and TIMP-2mRNA and related antigens in liver.The liver tissue wasdetected to find out the gene expression of TIMP-1 andTIMP-2 with RT-PCR.RESULTS:The TIMP-1 and TIMP-2 related antigens in liversof experimental group were expressed in myofibroblasts andfibroblasts (TIMP-1:482±65 vs 60±20;TIMP-2:336±48 vs50±19,P<0.001).This was the most obvious in portal areaand fibrous septum.The positive signals were located incytoplasm,not in nucleus.Such distribution and location wereconfirmed by situ hybridization (TIMP-1/β-acton:1.86±0.47vs 0.36±0.08;TIMP-2/β-actin:1.06±0.22 vs 0.36±0.08,P<0.001).The expression of TIMP-1 and TIMP-2 was seenin the liver of normal rats,but the expression level was verylow.However,the expression of TIMP-1 and TIMP-2 in theliver of experimental group was obviously high.CONCLUSION:In the process of hepatic fibrosis,fibroblastsand myofibroblasts are the major cells that express TIMPs.The more serious the hepatic fibrosis is in the injured liver,the higher the level of TIMP-1 and TIMP-2 gene expression. AIM: To investigate the location and expression of TIMP-1 and TIMP-2 in the liver of normal and experimental hepatic fibrosis in rats. METHODS: The rat models of experimental immunity of chronic fibrosis (n = 20) were prepared by the means of immunologic attacking with human serum albumin (HSA), and normal rats (n = 10) served as control group. Studimmunohistochemistry and in situ hybridization methodswere respectively used to detect the TIMP-1 and TIMP-2 mRNA and related antigens in liver. The liver tissue wasdetected to find out the gene expression of TIMP-1 and TIMP-2 with RT-PCR .RESULTS: The TIMP-1 and TIMP-2 related antigens in liversof experimental groups were expressed in myofibroblasts and fibroblasts (TIMP- 1: 482 ± 65 vs 60 ± 20; 2: 336 ± 48 vs 50 ± 19, P <0.001). This was the most obvious in portal area and fibrous septum. The positive signals were located in notystlasm, not in nucleus. Distribution and location wereconfirmed by situ hybridization. (TIMP-1 / β -acton: 1.86 ± 0.47 vs 0.36 ± 0.08; TIMP-2 / β-actin: 1.06 ± 0.22 vs 0.36 ± 0.08, P <0.001). The expression of TIMP-1 and TIMP-2 was seen in the liver of normal rats, but the expression level was very low. However, the expression of TIMP-1 and TIMP-2 in the liver of fibrosis is in the injured liver, the higher level of TIMP-1 and TIMP -2 gene expression.