Expression and Significance of MMP-1 and TIMP-1 in Liver Fibrosis of Rats Infected with Paragonimus proliferus

Objective To investigate the dynamic changes of MMP-1 and TIMP-1 in rats infected with Paragonimus proliferus,and explore the roles of MMP-1 and TIMP-1 in liver fibrosis formation.Methods Twenty-five SD rats were randomly assigned into two groups: the control group(5 rats) and infection group(20 rats).The animal model were set up by the way of peritoneal injection of 8 P.proliferus cercarias to each rat in the infection group,while the equal amount of normal saline was injected to each rat in the control group.Infection group were divided into 4 groups according to infection time: at the 3rd,5th,7th and 9th week after infection,5 rats each group.All rats were killed in corresponding time points after being infected.The levels of MMP-1 and TIMP-1 in the serum were determined by enzyme-linked immunosorbent assay.The liver tissues were sectioned and dyed by HE to determine the extent of alveolitis and liver fibrosis.The protein expressions of MMP-1 and TIMP-1 in rat liver parenchyma were detected by immunohistochemistry.Results The results of HE staining: with prolonged infection time,the inflammation increased gradually in the liver tissue of rats,especially at the 5 th week,then liver cell degeneration necrosis increased gradually.The immunohistochemistry showed:with the progression of pathological changes,expressions of MMP-1 and TIMP-1 were increased gradually.Levels of MMP-1 and TIMP-1 detected by ELISA in the serum were increased,and the expression of TIMP-1 was continuously increasing.Conclusions P.proliferus could cause liver fibrosis in rats.Expressions of MMP-1 and TIMP-1 were different during the liver fibrosis formation.The extent of liver lesion was associated with the infection time and the expressions of MMP-1 and TIMP-1.MMP-1 and TIMP-1 played a role in liver fibrosis of rats infected with P.proliferus.