Effect Of Endurance Exercise On The Expression Of NLRP3 Inflammasome In Rat Myocardium

Objective:The inflammatory response of the myocardium is closely associated with myocardial remodeling.While previous studies have demonstrated that intense exercise can increase intestinal permeability,allowing gut microbiota and metabolites to enter the bloodstream,there is a lack of research on the link between exerciseinduced intestinal permeability and myocardial inflammatory response.Thus,this study aimed to establish an eight-week endurance training model with antibiotic intervention in rats to explore the relationship between exercise-induced myocardial NLRP3 inflammasome activation and changes in intestinal barrier function.Methods:Forty eight-week-old male SPF-grade rats were randomly assigned to four groups: sedentary(C),exercise(Ex),antibiotic(AC),and antibiotic + exercise(AE).The rats underwent eight weeks of treadmill training,five days per week,one session per day,with a treadmill slope of 30°.The initial speed was set at 15 m/min and increased every three minutes until reaching 30 m/min.The training duration was one hour.Body weight was measured after each training session,and tissue samples were collected 24 hours after the completion of the eighth week of training.Western Blot analysis was conducted to measure the protein expression of NLRP3,ASC,and Caspase-1 in the myocardial tissue,as well as the protein expression of ZO-1 and Occludin in the colonic tissue.ELISA was used to measure the concentrations of lipopolysaccharide(LPS),lipopolysaccharide-binding protein(LBP),and soluble cluster of differentiation 14(s CD14)in the rat serum.Two-factor ANOVA analysis was performed using SPSS,with a significance level set at P < 0.05.Results:(1)Changes in body weight of rats during an 8-week training period:The exercise group rats showed a significant decrease in body weight compared to the sedentary group from the 2nd week until the end of the training(P<0.05).The antibiotic exercise group rats had a significantly lower body weight than the antibiotic group from the 2nd week until the end of the training(P<0.05).Additionally,they showed a significant decrease in body weight compared to the sedentary group from the 4th week until the end of the training(P<0.05),and a significant increase compared to the exercise group from the 7th week until the end of the training(P<0.05).(2)Changes in ZO-1 protein expression in colonic tissue: Compared to the sedentary group,the exercise group,antibiotic group,and antibiotic + exercise group exhibited significant reductions in ZO-1 protein expression(P < 0.05).The antibiotic+ exercise group showed significantly lower ZO-1 protein expression than the exercise group(P < 0.05),as well as significantly lower expression than the antibiotic group(P < 0.05).The expression of Occludin protein in colonic tissue was significantly reduced in the exercise group and antibiotic + exercise group(P < 0.05).(3)Changes in serum LPS concentration: Compared to the sedentary group,the exercise group showed a significant increase in serum LPS levels(P < 0.05),while the antibiotic + exercise group showed significantly lower levels than the exercise group(P < 0.05).Compared to the sedentary group,the exercise group exhibited a significant increase in serum LBP levels(P < 0.05),whereas the antibiotic + exercise group showed significantly lower levels than the exercise group(P < 0.05).In addition,compared to the sedentary group,the exercise group displayed a significant increase in serum s CD14 levels(P < 0.05),whereas the antibiotic + exercise group showed significantly lower levels than the exercise group(P < 0.05).(4)Protein expression of myocardial NLRP3 inflammasome-related proteins: Compared to the sedentary group,the exercise group showed significant increases in NLRP3 protein expression(P < 0.05),ASC protein expression(P < 0.05),and Caspase-1 protein expression(P < 0.05).In comparison to the exercise group,the antibiotic + exercise group exhibited significant decreases in NLRP3 protein expression(P < 0.05),ASC protein expression(P < 0.05),and Caspase-1 protein expression(P < 0.05).Conclusion: Eight weeks of endurance training can lead to increased expression of myocardial NLRP3 inflammasome related proteins,which may be associated with increased intestinal permeability.