Abstract： Objective To investigate the relationship between interleukin-18(IL-18)and the pathogenesis of type 2 diabetes melli-tus.Methods 72 healthy Sprague-Dawlay male rats were randomly divided into four groups, NC group,NCS group,HF group and HFS group.At the end of the 8th week,NCS group and HFS group were injected with STZ(25mg/kg)into abdominal cavity.At the end of the 10th week,diabetic rats were screened by oral glucose tolerance test(OGTT).The blood sample was collected when the rats were killed at the end of the 14th and 20th week.The levels of serum IL-18,IL-6 and tumor necrosis factor-α(TNF-α)were assayed with ELISA.Results Most rats in HFS group were achieved the diagnostic standard of diabetic rat, and their insulin sensitivity index(ISI)were decreased.At the end of the 14th week and 20th week,the levels of serum IL-18,IL-6 and TNF-α in HFS group were significantly higher than those in NC group(P＜0.01).In HFS group,the levels of serum IL-18,IL-6 and TNF-α at the end of the 20th week were higher than those at the end of the 14th week,but it had no statistic significance(P＞0.05).Pearson linear correlation analysis showed that the level of serum IL-18 in HFS group was positive correlated with FBG,IL-6,and TNF-α(r=0.90,P＜0.01 or r≥0.73,P＜0.05),and negative correlated with ISI(r=-0.86,P＜0.01).Condusions Our results show that IL-18 is related with the pathogenesis of type 2 diabetes mellitus and chronic inflammation plays an important role in the development of type 2 diabetos mellitus.