Inhibitory effect of heparin on collagen fiber formation in hepatic cells in culture

When M cells derived from rat liver and then transformed by treatment with 4-dimethylaminoazobenzene were cultured in vitro, the culture became covered with a collagen fiber network. When the M cells were cultured in the presence of more than 10 mu g/ml heparin, no collagen fiber formation was observed. The inhibitory effect was evident at 5 mu g/ml but was not significant at 1 mu g/ml. High performance liquid chromatography (HPLC) showed that about 50% decrease in hydroxyproline content occurred in the presence of 10 mu g/ml heparin. The inhibition by heparin reached a plateau at 10 mu g/ml. Other glycosaminoglycans such as heparan sulfate, keratan sulfate, chondroitin sulfate B and chondroitin sulfate C did not show a significant effect on hydroxyproline content. Modified heparins slightly decreased hydroxyproline content, but the collagen fibers were still observed. These results indicate that the native structure of heparin is important to attain the complete inhibition of collagen fiber formation; the basic structure, (-GlcUA or IdUA beta 1-4 GlcNSO(3)-)n, is important. HPLC, Northern blot analysis and Western blot analysis for rat type I collagen revealed that collagen synthesis is independent of heparin, but that collagen fiber formation is prevented by heparin.