Estimation of collagen content of liver specimens. Variation among animals and among hepatic lobes in cirrhotic rats

We undertook a study to evaluate the correlation between morphometric evaluation and colorimetric determination of hepatic collagent content, and to analyze the variation among animals as well as among lobes of the same liver in hepatic collagen content after CCl₄-induced micronodular cirrhosis. The results revealed a significant correlation (r = 0.9458; p < 0.001) between the morphometric and colorimetric methods of collagen evaluation of liver specimens; both methods also significantly distinguished data obtained from controls and from cirrhotic rats (p < 0.0005). After induction of micronodular cirrhosis by chronic CCl₄ administration, a highly significant variation in hepatic collagen content was observed among animals (p < 0.0001). By contrast, no significant difference in collagen content was observed (p < 0.05) among hepatic lobes of a given animal. These results indicate that in this animal model of liver cirrhosis, interpretation of biochemical data would benefit by being related to the severity of the hepatic collagen infiltration of each animal. Our data also show that representative values for total hepatic collagen infiltration can be obtained from a single liver specimen; we suggest, however, that the specimen be taken from a major lobe of the liver and that a sufficiently large number of animals be used to avoid occasional sampling errors.