Abstract
We examined the effect of five anaesthetic drugs commonly used in laboratory animal research (tribromoethanol, ketamine/xylazine, chloral hydrate, pentobarbital, and urethane) on the expression of four pro-inflammatory cytokines. The anaesthetic agents were applied at dosages normally used for deep surgical anaesthesia. Semiquantitative image analysis of interleukin (IL)-1β, IL-2, IL-6, and tumour necrosis factor alpha (TNFα) mRNA expression in the spleen of male Wistar rats 4 h after application of the anaesthetic drugs showed that these had moderate immunomodulatory effects. Ketamine/xylazine, chloral hydrate, and pentobarbital enhanced the basal expression of IL-1β and IL-6 mRNA in rat spleen, while urethane reduced splenic IL-1β mRNA expression. Tribromoethanol, ketamine/ xylazine, and urethane reduced the basal TNFα mRNA levels, whereas TNFα mRNA expression was unaffected by chloral hydrate and by pentobarbital. The data demonstrate that these anaesthetics have slight, but significant, effects on the basal immune status of rats.