THE EFFECT OF CHRONIC AND ACUTE ETHANOL TREATMENT ON MORPHOLOGY, LIPID-PEROXIDATION, ENZYME-ACTIVITIES AND NA-SYSTEMS ON WRL-68 CELLS( TRANSPORT)

In this study we measured some parameters that are associated with eth anol damage to the liver. The method allowed us to determine the injur y that chronic and acute ethanol treatments produce at the cellular le vel without interference from homeostatic or compensatory mechanisms. The system used is a hepatic fetal human cell line, WRL-68, which reta ins, in culture, many of the liver-specific functions. WRL-68 cells do not metabolise ethanol, and consequently we could evaluate the effect of ethanol alone. We explored two different conditions: 30 days with 0.1 M ethanol (chronic treatment) and 24 h in the presence of 0.5 M et hanol (acute treatment). 1 The transmission electron microscopy studie s revealed, in both treatments, the presence of granules not usually p resent in the cytoplasm of control cells and morphological mitochondri al alterations in chronically treated cells. 2 Lipid peroxidation, mea sured as the rate of malondialdehyde production, increased three and a half times in acutely treated cells and about twofold in chronically treated cells. 3 The percentage of total activity (activity in the med ium/(activity in the medium + activity of the cells). 100) and the enz ymatic activity in the culture medium of gamma glutamyl transpeptidase (GGT), alanine amino transferase (ALAT), aspartate amino transferase (ASAT) and alkaline phosphatase (AI-P), increased. 4 We measured some parameters related to the transport of sodium across the membrane. cel ls chronically treated with ethanol had higher rate constants and effl uxes than control cells. There was no difference between the total and passive efflux. Ethanol treated cells apparently lacked the ouabain s ensitive pathway. In acutely treated cells, the total sodium efflux an d the rate constant were enhanced. Sodium pools in the acutely treated cells were diminished and active sodium pumping was seven times highe r than in control cells. 5 We determined the number of high affinity o uabain binding sites per cell. Ethanol did not alter the number of pum ps, rather it seems to induce a functional alteration. Our results ind icate that ethanol per se induces lipid peroxidation, alters enzymatic activities, sodium transport systems, sodium pools and cellular morph ology, and that all these changes may be partly responsible for ethano l-induced hepatotoxicity. The data compare favourably with those repor ted in the literature for many different systems. Therefore our model for studying the mechanism of alcohol effects appears to be valid, wit h the advantage of being able to compare experiments that can be done in the same system and under the same conditions.