OBJECTIVE: To investigate the effect and mechanism of lead exposure on hypothalamic inflammatory factors in mice fed with high-fat diet. METHODS: Specific pathogen free healthy male Kunming mice were randomly divided into control group, high-fat diet group, lead exposure group, and combined exposure group, with 8 rats in each group. The control group and the lead exposure group were given regular diet, while high-fat diet group and combined exposure group were given high-fat diet. The lead exposure group and combined exposure group were given water with 250 mg/L lead acetate. The control group and high-fat diet group were given double distilled water. Continuous lead exposure was given for 9 weeks, 7 days per week. Body weights of the mice were measured every other week. After 9 weeks of exposure, the behavioral changes of mice were detected by open field test. The levels of triglyceride(TG), low density lipoprotein(LDL) and high density lipoprotein(HDL) in serum were detected by microplate reader. Western blotting was used to detect the relative protein expression of interleukin(IL)-1β, IL-6, IL-17 A, IL-22, tumor necrosis factor-α(TNF-α) and transforming growth factor-β(TGF-β) in the hypothalamus of mice. The relative expression of mRNA of IL-1β, IL-6, IL-17 A and TNF-α mRNA was detected by real-time fluorescence quantitative polymerase chain reaction. RESULTS: Beginning from the first week, the body weights of mice in the high-fat diet group and the combined exposure group were higher than that in the control group and the lead exposure group(P<0.05). The numbers of standing in the lead exposure group and the combined exposure group were lower than that in the control group and the high-fat diet group(P<0.05). The distances of central area activity in the high-fat diet group, the lead exposure group and the combined exposure group were lower than that in the control group(P<0.05). The total distances in the high-fat diet group and the combined exposure group were lower than that in the control group(P<0.05). The serum levels of TG and LDL in the combined exposure group increased(P<0.05), and the HDL level decreased(P<0.05), when compared with the control group and the lead exposure group. The relative protein expression of IL-1β, IL-6, IL-17 A and IL-22 in the hypothalamus of the high-fat diet group and lead exposure group was higher than those of the control group(P<0.05). The relative protein expression of TNF-α and TGF-β in the hypothalamus of the lead exposure group was higher than that in the control group(P<0.05). The relative protein expression of IL-1β, IL-6, IL-17 A, TGF-β in the hypothalamus of the combined exposure group was higher than the other 3 groups(P<0.05). The relative protein expression of IL-22 in the hypothalamus of the combined exposure group was higher than that of the control group(P<0.05), while the relative protein expression of TNF-α was higher than that of the control group and the high-fat diet group(P<0.05). The relative expression of IL-1β, IL-6, IL-17 A, and TNF-α mRNA in the hypothalamus of the high-fat diet group, the lead exposure group and the combined exposure group was higher than that in the control group(P<0.05). The above indicators of mice in the lead exposure group were higher than that in the high-fat diet group(P<0.05). The above indicators of mice in the combined exposure group were higher than those in the high-fat diet group and the lead exposure group(P<0.05). CONCLUSION: Lead exposure can promote neurobehavioral changes and hypothalamic inflammatory damage in high-fat diet mice. IL-1β, IL-6, IL-17 A, TGF-β and TNF-α might involve in the process of synergistic effect of lead and high-fat diet exposure on inflammatory hypothalamic injury.