Effect of vitamin K on carbon tetrachloride-induced cellular damage in primary cultured rat hepatocytes.

The effect of vitamin K on carbon tetrachloride-induced cellular damage of primary cultured hepatocytes was investigated by estimating prothrombin activity as a parameter of cellular function. Prothrombin activity was evaluated in primary cultured rat hepatocytes using synthetic fluorogenic peptide substrates (Boc-Val-Pro-Arg-MCA). Prothrombin activity significantly increased with the addition of vitamin K and decreased by the addition of warfarin (P less than 0.05). Carbon tetrachloride caused a significant decrease of prothrombin activity and cytotoxicity in a dose dependent manner. Prothrombin activity increased after addition of vitamin K when cells were previously exposed to carbon tetrachloride for a short period, but there was no change in cells treated for a long period. Carbon tetrachloride caused a modest increase of malondialdehyde formation after a short period of exposure and a significant increase following a long period of exposure. These results suggest that: 1) prothrombin activity is a good parameter for protein synthesis in cultured hepatocytes, 2) carbon tetrachloride-induced cytotoxicity results from different mechanisms in the early phase and the late phase of exposure, and 3) vitamin K has the ability to protect hepatocytes against the carbon tetrachloride-induced cellular damage in the early phase.