镉对LLC─P_1细胞增殖与DNA合成的影响及硒的保护效应

Effect of cadmium on the viability and DNA, RNA and protein synthesis in LLC PK 1 cells and the protective effects of selenium

观察了镉（Ｃｄ）对猪肾近曲小管上皮细胞（ＬＬＣ－ＰＫ１）增殖和ＤＮＡ合成代谢的影响，及亚硒酸钠和硒代蛋氨酸的保护作用。结果表明，Ｃｄ对ＬＬＣ－ＰＫ１细胞增殖有明显的抑制作用；低浓度Ｃｄ（３μｍｏｌ／Ｌ）与细胞作用３小时，对ＤＮＡ合成有一定的促进作用；当Ｃｄ浓度达到１６μｍｏｌ／Ｌ时ＤＮＡ合成受到明显的抑制；Ｃｄ与细胞作用１２小时，对ＲＮＡ及蛋白质合成也具有明显的抑制作用。结果还显示，Ｎａ２ＳｅＯ３对Ｃｄ抑制的ＤＮＡ合成作用无任何保护作用，而Ｄ，Ｌ－ＳｅＭｅｔ在一定程度上能减轻Ｃｄ对ＬＬＣ－ＰＫ１细胞ＤＮＡ合成的抑制作用；Ｄ，Ｌ－ＳｅＭｅｔ提前或与Ｃｄ同时加入的两种给药方式，其保护作用没有明显差异。

In the present study, the pig renal cell line LLC PK 1 was utilized in studying mechanism of nephrotoxicity induced by cadmium and the protective effect of sodium selenite and D,L selenomethionine. At dose of 32μmol/L cadmium, the cell viability of LLC PK 1 after a 6h of exposure was decreased significantly. After 12h exposure to cadmium a dose dependent decrease in cell viability was observed with a IC 50 value of 12 2μmol/L. The inhibition of DNA synthesis was evident as early as 3h post treatment. In addition, the inhibition of RNA and protein syntheses were observed after exposure to cadmium for 12h. The effect of sodium selenite and D, L selenomethionine on cadmium induced inhibition of the H thymidine in corporation was investigated in LLC PK 1 cells. Sodium selenite at 10μmol/L unchanged the inhibition of the DNA synthesis induced by cadmium at 4 or 8μmol/L when added to the culture medium either before or after the cadmium, however, the inhibition of DNA synthesis by cadmium was significantly decreased by similar addition of D,L selenomethionine either before or after the cadmium. It was suggested that sodium selenite and selenomethionine have different protective effect against cadmium induced inhibition of DNA synthesis. \ \