[Experimental study on selenium preventing nasopharyngeal carcinoma].
In this study, we observed the effect of selenium (Se) on nasopharyngeal carcinoma (NPC) induced by dinitrosopi erazine (DNP) in rats through adding sodium selenite into drinking water. One hundred and sixty Wistar rats were divided into five groups: (1) blank control group (BG), no treatment; (2) Se control group (SG), given 50.7 mumol/L Se in drinking water for the first 3 weeks and then 31.7 mumol/L until the end of the experiment; (3) DNP control group (DG), injected subcutaneously 15mg/kg DNP twice a week from the 4th week to the 35th week; (4) Se prevention group (PG), given Se as done in SG and injected DNP as done in DG; (5) Se therapy group (TG), injected DNP as done in DG and given 50.7 mumol/L Se in drinking water from the 36th week to the end of the experiment. The experimental duration was one year. The result showed that there was no NPC in BG and SG and that the incidence of NPC in PG was reduced by 54.3% as compared with that in DG, which was significantly different (P < 0.01). In addition, the incidences of precancerous lesions of nasopharynx were significantly different between the two groups. But the incidences of NPC were not significantly different between TG and DG. In the process of carcinogenesis, the blood Se concentration of DG decreased. The blood Se concentration of rats could be elevated by supplementing Se in drinking water. Our result suggested that elevating the level of Se in rats can prevent the NPC.