水産加工食品中のコレステロール酸化物とその細胞毒性

抄録

Cholesterol is easily oxidized enzymatically and non-enzymatically, producing various kinds of cholesterol oxides. Several kinds of cholesterol oxides are identified and quantitated in food and animal tissues. Cholesterol oxides have a wide variety of effects both in vitro and in vivo which may be involved in human diseases. However, the mechanism of biological effects of cholesterol oxides is not elucidated. In this study, we examined the contents of cholesterol oxides in Japanese traditional marine products, salted and semi-dried Shishamo and Surume, dried squid, and the biological effects of a few kinds of cholesterol oxides on cultured rat hepatocytes, which were freshly prepared by perfusing collagenase.

A very small amount of 7-α- and 7-β-hydroxycholesterol, 5α ,6α- , and 5β, 6β-epoxide, and 7-ketocholesterol were identified in both Shishamo and Surume.

7-Ketocholesterol, concentration of 100 μM, showed a strong cytotoxicity for hepatocytes, and it killed hepatocytes without the release of LDH to the culture medium. Moreover, carboxy-PTIO, the chemicals for the selective elimination of NO radical, increased viability of hepatocytes, indicating that NO radical is involved in the cell death of hepatocytes.