SELENIUM SUPPLEMENTATION AT LARGE DOSES INHIBITS SELENOENZYME GENE EXPRESSION AND CAUSES RAT LIVER LESION / 营养学报

ABSTRACT

Objective: To study the effects of sodium selenite at large doses on selenoenzyme gene expression and activity in rat livers. Methods: Rats were injected intra-peritoneally (ip) with 0, 20, 40, and 80 ?g /(kg?d) Se of sodium selenite dissolved in 0.9% physiological saline for 15 days. Livers were sampled and partly used for histological study. The rests were homogenized for reverse transcription-polymerase chain reaction to semi-quantitatively detect differential gene expressions of glutathione peroxidase (GSH-Px) and thioredoxin reductase (TR) in livers. Meanwhile, selenoenzyme activities, Se contents and MDA levels were also measured. Results: Compared with the control group, the mRNA levels and enzyme activities of both GSH-Px and TR increased in rats supplemented with 20 ?g/(kg?d) selenite. However, the mRNA levels and activities of both selenoenzymes decreased significantly in rats injected with selenite at doses of 40 and 80 ?g /(kg?d) respectively (P