RESUMEN
Objective To investigate the effect of afferent blockade of visceral adipose tissue(VAT)on cardiac function and cardiac neural remodeling in rats after myocardial infarction(MI).Methods After 30 healthy SPF-grade male SD rats were subjected,12 of them were randomly divided into control group(n=6)and activation group(n=6).In the activation group,low-dose capsaicin(1 mmol/L)was used to activate VAT afferent nerves,while in the control group,an equal amount of normal saline was injected,and real-time blood pressure and heart rate were monitored for 30 min.The other 18 rats were randomly assigned into sham group(n=6),MI group(n=6),and high-dose capsaicin blockade group(n=6).The MI model was established by ligating the left anterior descending coronary artery.After MI modeling,the high-dose capsaicin blockade group was give 33 mmol/L capsaicin to block VAT afferent nerve,and the sham opera-tion group and MI group were injected with the same amount of normal saline.After 2 weeks,car-diac function was measured by echocardiography,infarct size was measured by TTC staining,heart rate variability was analyzed,and myocardial tyrosine hydroxylase(TH)was measured.The levels of myocardial superoxide dismutase(SOD)and malondialdehyde(MDA)were measured by biochemical methods.Results More significant changes in blood pressure and heart rate were observed in the activation group than the control group(P＜0.01).The MI group had obviously larger infarct size,higher LVEDD and LVESD,and increased myocardial TH density and MDA level,but lower LVEF and myocardial SOD activity than the sham group(P＜0.05).However,the infarct size,LVEDD(9.15±0.37 mm vs 10.1±0.85 mm),LVESD(6.33±0.40 mm vs 7.87±0.86 mm)were obviously decreased,while LVEF[(67.04±3.34)％vs(47.10±3.89)％]and myocar-dial FS[(33.26±2.50)％vs(20.81±2.14)％]activity were greatly increased in the high dose capsaicin group than the MI group(P＜0.05).Conclusion Activation of VAT afferent nerve can increase blood pressure and heart rate;while its blockade can reduce the infarct size,protect cardiac function and inhibit cardiac nerve remodeling in MI rats,possibly by reducing oxidative stress.