Comparative effects of phytosterol oxides and cholesterol oxides in cultured macrophage-derived cell lines

The cytotoxicity of cholesterol and a mixture of beta -sitosterol/campester ol (50%/40%) and their oxides was examined in a cultured-derived macrophage cell line, C57BL/6. Cell numbers, lactate dehydrogenase (LDH) leakage, pro tein content, lipid uptake, and mitochondria dehydrogenase activity were de termined after exposure of cell mononlayers to sterols and sterol oxides at a concentration of 200 mug/mL for up to 120 h. Results indicate that the o xides of cholesterol, beta -sitosterol, and campesterol exhibited similar p atterns of toxicity as indicated by LDH leakage, cell viability, and mitoch ondria dehydrogenase activity. Greatest cell damage was associated with tre atments containing 5 alpha ,6 alpha -epoxide or cholesterol oxides, followe d by beta -sitosterol/campesterol oxides, cholesterol, and beta -sitosterol . The oxides of beta -sitosterol/campesterol. caused less LDH leakage and l ess of an effect on protein content. Results of this study demonstrate that phytosterols contained in vegetable oils, when subjected to frying conditi ons, do oxidize and may cause cellular damage in an in vitro cell line simi lar to cholesterol oxides, although less severe.