Effect of a load of Vitamin A after acute thioacetamide intoxication on dolichol, dolichol isoprenoids and retinol content in isolated rat liver cells.

This study examines how treatment with a single dose of thioacetamide, a known experimental hepatotoxin, alters the content of dolichol, dolichol isoprene units and retinol in isolated rat parenchymal and non-parenchymal liver cells at different times and when the animals are supplemented with Vitamin A. Thioacetamide (300 mg/kg i.p.) was administered in a single injection to rats, sacrificed at intervals of 0.5, 1, 2, 3, 4, 15 and 30 days. Rats supplemented, following thioacetamide, with Vitamin A, 3 days before sacrifice showed increased mortality and cellular necrosis on the third and fourth days. Parameters indicating tissue necrosis returned to normal values in surviving animals. Dolichol and retinol content showed a variable, reversible decrease, with normal levels being restored in 15-30 days. After Vitamin A, dolichol content only in hepatic stellate cells (HSC) was lower then the controls 3 and 4 days after thioacetamide treatment, in parallel with the decrease of retinol storage. The percentage of dolichol-18 is not modified by thioacetamide alone. When supplemented with Vitamin A the percentage of dolichol-18 always decreased after thioacetamide, showing that damage was still present. Mechanisms that might be operative in liver cells are briefly discussed. This approach would provide an indication to investigate how the length of the dolichol chain is determined.