Effect of topical applications of silver sulfadiazine on the natural killer cell activity in a rat model of thermal injury.

The effect of topical application of silver sulfadiazine cream on the natural killer (NK) cell cytotoxicity was studied in a rat model of thermal injury. The rats were given a 30% total body surface area scald injury and the NK cell cytotoxicity was studied in rats at different days postinjury with or without treatment with silver sulfadiazine. The NK cell activity was observed to be significantly (P less than .0025) suppressed at day 7 postinjury in nontreated burned rats compared with control sham burned animals. Interestingly, in rats treated with silver sulfadiazine twice daily, no suppression in NK cell activity was observed. The application of base cream (without silver sulfadiazine) did not have any significant effect on the NK cell activity in burned rats. The data show that the effect of silver sulfadiazine on NK cell activity may be due to the sulfadiazine component, since the serum levels of sulfadiazine (33.7 +/- 1.9 micrograms/dL) were observed to be maximal at day 7 postinjury.