Cathepsin B, D, H, and Acid Phosphatase Activities in Cholestatic Rat Liver

Abstract

To evaluate lysosomal changes in cholestatic liver, the activity changes of lysosomal enzymes (cathepsin B, D, H and acid phosphatase) were studied in the cholestatic rat liver induced by common bile duct (CBD) ligation over a period 42 days. Light and electron microscopic studies were also done at the 2 day after CBD ligation. The activity of cathepsin B in the cholestatic liver increased between the 14th day and the 42nd day after CBD ligation, and that of cathepsin D increased between the 2nd day and the 42nd day. However, there was no significant increase in the activity of cathepsin H. The lysosomal acid phosphatase activity in the cholestatic rat liver increased between the 3rd day and the 42nd day. The light microscopic study of CBD ligated liver showed large focal necrosis of the liver cells with infiltration of inflammatory cells. And electron microscopic study showed necrotic degeneration of hepatocytes and associated secondary lysosomes. This study indicates that among the lysosomal enzymes, cathepsin D reacts first to the inflammatory and necrotic changes in cholestasis induced by CBD ligation. The increase of lysosomal enzyme activity begins after the 2nd day of CBD ligation and it continues as long as hepatic damages exist for the scavenge of necrotic cells. The results suggested that the synthesis of lysosomal enzyme is increased under the cholestasis.