Toxic effects of 70-hydroxycholesterol on rat liver primary cultures, epithelial lines and co-cultures.

The toxic effects of 7,8-hydroxycholesterol (7β-OHC) on cultures and co-cultures of rat hepatocytes, rat liver epithelial cell lines, and rat liver fibroblast lines were investigated. Hepatocytes in primary culture or co-cultured with proliferative epithelial cells, were not affected by the presence of 7,8-OHC at a concentration of 400µM over a period of 72 hours. In contrast, Proliferative cultures of liver epithelial cell lines and liver fibroblast lines were killed by 50 µM 7β-OHC within the first 24 hours. Established liver epithelial cells (hyperploid) were more sensitive to 7,8-OHC than the same line at early passages (diploid). When hepatocytes and liver epithelial cells were co-cultured and treated with 100 µM 7β-OHC only epithelial cells were lysed. A concentration of 50 µM 7β-OHC was toxic to co-cultures of liver epithelial cell and fibroblasts together. In a serum free medium, the cytotoxic concentration of 7β-OHC was lower than that in the serum-supplemented medium. Thus, liver epithelial cells cultured alone or co-cultured with hepatocytes were killed at 12.5 µM and 50 µM 7β-OHC, respectively. Finally, cholesterol concentrations four fold that of 7β-OHC antagonized the lethal effects of 7β-OHC in the serum free medium.