Semiquantitative evaluation of hepatic fibrosis by measuring tissue hydroxyproline

BACKGROUND/AIMS: It is important to evaluate the degree of hepatic fibrosis when diagnosing and treating hepatic cirrhosis. We focused on hydroxyproli ne, which is detected specifically in collagen, which plays a major role in hepatic fibrosis. The correlations between liver tissue hydroxyproline res idue levels and the degree of hepatic fibrosis were examined in dogs with d imethylnitrosamine-induced fibrotic livers. METHODOLOGY: Dimethylnitrosamine was administered to dogs to establish expe rimental hepatic fibrosis. Paraffinized sections of liver specimens, staine d with hematoxylin-eosin and azan, were examined and the degree of hepatic fibrosis was graded. About three-milligram samples of liver tissue were loa ded onto a fully automated liquid chromatograph and the levels of hydroxypr oline residues were measured. RESULTS: The liver tissue hydroxyproline appeared to reflect the degree of hepatic fibrosis. The liver tissue hydroxyproline levels and pathological h epatic fibrosis grades correlated significantly (p<0.05). CONCLUSIONS: Tissue hydroxyproline appears to be a more useful fibrosis mar ker, because hydroxyproline is influenced less by other factors. Furthermor e, our results demonstrate that a very small amount of liver tissue (wet we ight 3mg) was enough to enable the levels of hydroxyproline residues to be measured by an automated amino acid analyzer (JLC-3000) and hepatic fibrosi s is expressed as the numerical value by this analysis.