Objective To investigate the effects of lumbar epidural block of renal sympathetic nerve on cardiac function and serum inflammatory factors in rats with myocardial infarction.Methods Thirty healthy male Sprague Dawley rats were divided into asham operation group,myocardial infarction group and sympathetic nerve block group according to the random number table method,with 10 rats in each group.Lumbar epidural catheterization was applied in all rats in the 3 groups.After catheter insertion,myocardial infarction was induced by ligation of the anterior descending branch of the left coronary artery of rats in the myocardial infarction group and the sympathetic nerve block group,while the left anterior descending branch of rats in the sham operation group was not ligated.After myocardial infarction,the rats in the sympathetic nerve block group were injected with 50 μL of ropivacaine(volume fraction:0.2％)via a lumbar epidural catheteronce every 24 hours,and the injection lasted until 14 days after surgery.In the myocardial infarction group,50 μL of 9 g·L-1sodium chloride was injected into the rats through a lumbar epidural catheteronce every 24 hours,and the injection lasted until 14 days after surgery.Rats in the sham group did not receive the injection of any drugs.At 14 days after operation,echocardiography was performed on rats in the 3 groups to measure ejection fraction(EF),left ventricular short-axis shortening rate(FS)and cardiac output(CO).A total of 1 mL of cervical venous blood was extracted from each rat in the 3 groups at 24 h after surgery,and 5 mL of abdominal aortic blood was extracted from rats in the 3 groups at 14 days after surgery.Serum levels of norepinephrine(NE),cardiac troponin I(cTnl),interleukin-18(IL-18),interleukin-1β(IL-1 β)and tumor necrosis factor-α(TNF-α)were detected by enzyme-linked immunosorbent assay.At 14 days after surgery,the rats in the 3 groups were anesthetized by intraperitoneal injection of 100 g·L-1 chloral hydrate(300 mg·kg-1),and the thoracic cavity of the rats was opened to remove the heart.The myocardial infarction area of the rats was detected by 2,3,5-triphenyltetrazolium chloride staining,and the proportion of the myocardial infarction area was calculated.Results On the 14th day after surgery,EF,FS and CO of rats in the myocardial infarction group and sympathetic nerve block group were significantly lower than those in the sham operation group,while EF,FS and CO of rats in the sympathetic nerve block group were significantly higher than those in the myocardial infarction group(P＜0.05).The serum cTnI level of rats in the myocardial infarction group and sympathetic nerve block group was significantly higher than that in the sham operation group(t=68.260,15.110;P＜0.05),and the serum cTnI level of rats in the myocardial infarction group was significantly higher than that in the sympathetic nerve block group(t=27.920,P＜0.05).The proportion of the myocardial infarction area of rats in the sympathetic nerve block group was significantly lower than that in the myocardial infarction group(t=14.182,P＜0.001).There was no significant difference in the serum NE,IL-18,IL-1 β and TNF-α levels of rats between 24 hours and 14 days after surgery in the sham operation group(P＞0.05).The serum NE,IL-1 β and TNF-αlevels of rats at 14 days after surgery were significantly higher than those at 24 hours after surgery,and the IL-18 level of rats was significantly lower than that at 24 hours after surgery in the myocardial infarction group(P＜0.05).The serum NE,IL-18 and TNF-α levels of rats at 14 days after surgery were significantly lower than those at 24 hours after surgery,and the IL-1 βlevel of rats was significantly higher than that at 24 hours after surgery in the sympathetic nerve block group(P＜0.05).At 24 hours and 14 days after surgery,the serum NE,IL-18,1L-1 β and TNF-α levels of rats in the myocardial infarction group and sympathetic nerve block group were significantly higher than those in the sham operation group,while the serum NE,IL-18,IL-1 β and TNF-α levels of rats in the sympathetic nerve block group were significantly lower than those in the myocardial infarction group(P＜0.05).Conclusion Lumbar epidural block of renal sympathetic nerve in rats can significantly reduce the levels of serum inflammatory factors and NE,and improve cardiac function.
维普
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