AIM:To investigate the role and possible mechanisms of disulfiram(DSF)in a rat model of heart failure with preserved ejection fraction(HFpEF)induced by high-fat diet(HFD)and nitric oxide blocker Nω-nitro-L-argi-nine methyl ester(L-NAME).METHODS:The HFpEF rat model was constructed using HFD and L-NAME.Sprague-Dawley rats were randomly divided into 3 groups:control group(fed with a normal diet and water),HFpEF group(fed with HFD and drinking water containing 0.5 g/L L-NAME),and DSF+HFpEF group(treated with DSF in addition to HFD and L-NAME).After 5 weeks,cardiac function of the rats was examined using echocardiography and exercise test.Myo-cardial pathological changes were detected using hematoxylin-eosin and wheat germ agglutinin staining,the degree of car-diac fibrosis was assessed using Masson staining,and apoptosis levels were observed using TUNEL staining.Western blot was performed to detect the expression of nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3),cleaved caspase-1,gasdermin D N-terminal fragment(GSDMD-N)in the myocardium,and serum level of N-terminal pro-brain natriuretic peptide(NT-proBNP),and interleukin(IL)-1β and IL-18 in the myocardium were detected by ELISA.RESULTS:Compared with control group,the rats in HFpEF group showed increased body weight,systolic blood pres-sure,diastolic blood pressure,E/E′ ratio,left ventricular anterior wall thickness at diastole and serum NT-proBNP level(P<0.05),and decreased E/A ratio and absolute value of global longitudinal strain(GLS;P<0.05).In contrast,the rats in DSF+HFpEF group showed decreased body weight,E/E′ ratio,diastolic blood pressure and serum NT-proBNP level(P<0.05),and increased E/A ratio and absolute value of GLS(P<0.05),with no significant changes in systolic blood pressure,left ventricular posterior wall thickness at diastole and left ventricular ejection fraction(P>0.05).The rats in HFpEF group had increased myocardial fibrosis area,cardiomyocyte cross-sectional area,and apoptotic rate compared with control group(P<0.05),while these indexes were reduced in DSF+HFpEF group(P<0.05).The results of Western blot and ELISA showed that the levels of NLRP3,cleaved caspase-1,GSDMD-N,IL-1β and IL-18 were increased in the myocardium of rats in HFpEF group compared with control group(P<0.05),but decreased in DSF+HFpEF group com-pared with HFpEF group(P<0.05).CONCLUSION:Disulfiram improves cardiac function and attenuates myocardial remodeling in HFpEF rats.The mechanism may be related to the modulation of NLRP3/caspase-1/GSDMD signaling path-way and the reduction of myocardial inflammatory response.