Effects Of Carotid Baroreceptor Stimulation On Chronic Heart Failure Canines

Objective To study the effects of carotid baroreceptor stimulation(CBS)on the cardiac dysfunction and left ventricular remodeling of chronic heart failure(CHF)canines.Methods 30 male beagles were randomized into three groups:control group(Con,n=10),chronic heart failure group(CHF,n=10)and chronic heart failure with carotid baroreceptor stimulation group(CHF-CBS,n=10).All the beagles were implanted carotid baroreceptor stimulator and cardiac pacemaker subcutaneously by one time.CHF was induced by rapid right ventricular pacing(250 times/minute)and the intervention of the CHF was simultaneously taken by CBS.After the rapid pacing of 6 weeks,transthoracic echocardiography was performed,vein blood was collected for the detection of B-type natriuretic peptide(BNP),the discharging of left stellate ganglion(LSG)and left vagus nerve(LVN)were detected by multi-channel physiology recorder,left ventricular anterior wall tissue were prepared for the examination of histopathology and molecular biology.Results1.Comparing with Con group,cardiac function was significantly deteriorated and plasma BNP was elevated obviously in CHF group after 6 weeks' rapid pacing of right ventricular(P<0.05).Comparing with CHF,the abnormity of cardiac function and plasma BNP were alleviated significantly in CHF-CBS group(P<0.05).2.Comparing with Con group,the mean respiratory rate,heart rate,serum renin and angiotensin II were significantly higher in CHF group(P<0.05).Comparing with CHF,the abnormity above were ameliorated apparently in CHF-CBS group(P<0.05).3.The activity of LSG increased gradually among Con group,CHF-CBS group and CHF group.The activity of LVN decreased gradually among CHF-CBS group,CHF group and Con group.4.Comparing with Con group,ultrastructure disorganisation was obvious in CHF group.Comparing with CHF,ultrastructure disorganisation was alleviated significantly in CHF-CBS group.5.Comparing with Con group,myocardial cross sectional area increased significantly in CHF group(P<0.05).Comparing with CHF,myocardial cross sectional area decreased apparently in CHF-CBS group(P<0.05).6.Comparing with Con group,myocardial apoptosis index of left ventricular anterior wall were apparently elevated in CHF group(P<0.05).Comparing with CHF group,myocardial apoptosis index were declined apparently in CHF-CBS group(P<0.05).7.Comparing to Con group,collagen volume fraction of left ventricular anterior wall was apparently elevated in CHF group(P<0.05).Comparing with CHF group,collagen volume fraction of left ventricular anterior wall was alleviated apparently in CHF-CBS group(P<0.05).8.Comparing with Con group,plasma level of tumor necrosis factor-a(TNF-a)and interleukin-6(IL-6)were apparently higher in CHF group.Comparing with CHF group,plasma level of TNF-?and IL-6 were of no significant difference in CHF-CBS group.9.Comparing with Con group,expression levels of extracellular signal-regulated kinases 1/2(ERK1/2)was obviously downregulated while p38 kinase(p38)and c-Jun NH2-terminal kinase(JNK)were apparently upregulated in the ventricular anterior wall.Comparing with CHF group,the abnormity expression levels of ERK1/2 and JNK were ameliorated apparently(P<0.05)while the expression level of p3 8 was of no obvious difference in CHF-CBS group(P<0.05).Conclusions CBS ameliorated the cardiac dysfunction and remodeling of ventricular anterior wall tissue significantly in chronic heart failure canines via inhibiting the activation of sympathetic nerves and increasing the activity of vagus nerve.