Abstract: Objective To investigate the effects of pentoxifylline(PTX)on the expressions of metalloproteinase-9(MMP-9) and transforming growth factor β1(TGF β1) in hepatic tissue of rats with nonalcoholic steatohepatitis(NASH).Methods Rat model of NASH was established by giving a fat-rich diet.Forty Sprague-Dawley rats were randomly divided into four groups,control group(n=10),12 week model group(n=10),16 week model group(n=10) and PTX-intervention group(n=10).The area of liver fibrosis was determined by Masson staining.The expression of MMP-9 and TGFβ1 were detected by immunohistochemistry.Results The results of immunohistochemical staining shown that the expression of MMP-9 was significantly higher in rats of model groups and PTX-intervention group than control group(P<0.05);The expression of TGFβ1 was higher in rats of 16 week model group and PTX-intervention group than control group(P<0.05);Comparing with the 16 week model group,the expression of TGFβ1 in PTX-intervention group decreased significantly(P<0.05).The fibrosis area of masson staining was higher in rats of model groups and PTX-intervention group than control group(P<0.05);The area in 16 week model group was higher than 12 week model group(P<0.05);Comparing with the 16 week model group,the area in PTX-intervention group decreased significantly(P<0.05).Conclusion PTX interventional reduced the content of TGFβ1,while that of MMP-9 expression was unchanged.These may improve the degree of hepatic fibrosis.PTX may be useful in the treatment of NASH and liver fibrosis.

Key words: nonalcoholic steatohepatitis, pentoxifylline, hepatic fibrosis area, metalloproteinase-9, transforming growth factor β1