Abstract: BACKGROUND ＆ AIM: To observe the effects of deltamethrin(DM) on the neuroimmunological functions of rats by the changes of IL-1β in the cortex, hippocampus and hypothalamus. MATERIAL AND METHODS: 65 male adult SD rats were separated into 3 groups，one group included 15 rats for RT-PCR, the second group included 25 rats for immunohistochemistry, and the third included 25 rats for detecting the activities of ATPase. Each group was separated randomly into 5 sub-groups including 1 control and 4 DM treated. The DM treated rats received intraperitonea injection of 12.5 mg/kg DM. At 1, 6, 24 and 48 h after injection,we used RT-PCR and immunohistochemistry to characterize the changes of IL-1β mRNA expression and the protein content in different encephalic regions. Then we detected the activities of Na＋－K＋－ATPase as biomarker to explore the relationship between IL-1β and neural toxicity of DM. RESULTS: From 1 h to 6 h after DM administration, the IL-1β protein content in cortex increased while the gene expression of IL-1β rose after 24 h to 48 h, without neural toxicity in cortex. In the hippocampus, after IL-1β protein increased at 1 h with transient increase of IL-1β mRNA. The activity of Na＋－K＋－ATPase decreased at 6 h, and recovered at 24 h, but decreased again at 48 h. The IL-1β mRNA of hypothalamus increased rapidly in 1 h, reaching maximum at 6 h, whilst the IL-1β protein remained higher than that of the control group until 24 h. The activity of Na＋－K＋－ATPase only showed an apparent reduction at 1 h after injection. CONCLUSION: IL-1β may play different roles in above-mentioned cerebral regions in mediating the neural toxicity of DM in rats.

Key words: IL-1β, deltamethrin, neuroimmunology