Studies on the inhibition of experimental liver fibrosis. 2. The mechanism of the inhibition of liver fibrosis of rats due to carbon tetrachloride by elastase.

In the previous experiments, it was demonstrated that high purity elastase extracted from porcine pancreas remarkably inhibits liver fibrosis of rats having chronic liver injury caused by carbon tetrachloride. This time, with the purpose to clarify the mechanism of inhibition of liver fibrosis by elastase, comparative study was made on the activity of lysosomal enzymes by measuring beta-glucuronidase, cathepsin and collagenolytic activity, with the rats administered with elastase and with those untreated, during the period of development of liver fibrosis and the recovery from it. In addition to it, in vitro experiments were made by having elastase act on the substrate comprising mixed collagen of acid soluble and neutral soluble collagens extracted from the skin of guinea pigs and by observing collagen components by disc electrophoresis. With any lysosomal enzymes, no marked difference was noticed between elastase group and non-administered group and thus the possibility of inhibition of liver fibrosis through activation of lysosomal enzyme by elastase was denied. The results of disc electrophoretic observation of the performance of elastase on collagen revealed that beta-component of collagen is disappeared but alpha-component remained. From the above, inhibition of liver fibrosis by elastase may be due to direct affection of elastase to telopeptide portion of collagen.