OBJECTIVETo study the role of the synthesis and degradation of collagen at the transcription level during liver fibrogenesis due to schistosomiasis japonica in rabbits.

METHODSNew Zealand rabbits challenged by cercariae of Schistosoma japonicum (S. japonicum) were served as animal models for liver fibrosis. Liver specimens were collected through operations at 4, 6, 8, 10, 12, 16, 20, 24 and 28 wks after challenge. Type I collagen, type III collagen, type IV collagen, MMP-1 and MMP-9 mRNA levels of liver tissue were detected by RT-PCR + Dot blot. The size of egg granulomas and the degree of liver fibrosis were measured by histopathological examinations.

RESULTSType I collagen, type III collagen, type IV collagen, MMP-1 and MMP-9 mRNA levels increased simultaneously in the early stage after challenge. Most of them reached their peak at 10 weeks, and compared with normal controls, type I collagen, type III collagen, type IV collagen, MMP-1 and MMP-9 mRNA levels increased by 12.0-, 11.0-, 6.6-, 10.0- and 11.0-fold, respectively, coinciding with the change of egg granulomas, i.e., the change in the inflammatory process. Then both collagen and collagenase mRNA levels decreased. Type I, III and IV collagen mRNA levels declined to 2-fold to 3-fold as compared with normal controls (P < 0.05), while MMP-1 and MMP-9 mRNA levels declined close to normal levels (P > 0.05) at 28 wks. This study shows that the synthesis and degradation of collagen keep a dynamic balance at the early stage of schistosomiasis japonica challenge, while at the later stages the quantity of collagen synthesis was higher than that of collagen degradation.

CONCLUSIONSIt was confirmed at transcription level that when the quantity of collagen synthesis was higher than that of collagen degradation liver fibrogenesis may be resulted in.