Effect of superior cervical ganglion block on cardiac function and NLRP3 signaling pathway in a rat model of myocardial ischemia-reperfusion / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effect of superior cervical ganglion block (SCGB) on cardiac function and nucleotide like receptor protein 3 (NLRP3) signaling pathway in a rat model of myocardial ischemia-reperfusion (I/R).Methods:Sixty healthy SPF male Sprague-Dawley rats, weighing 250-300 g, aged 2-3 months, were divided into 4 groups ( n=15 each) using a random number table method: sham operation group (sham group), myocardial I/R group (IR group), myocardial I/R + normal saline group (IR+ NS group), and myocardial I/R + SCGB group (IR+ SCGB group). Myocardial I/R model was developed by ligation of the left anterior descending branch of the coronary artery for 45 min followed by restoration of blood flow in anesthetized aninals. IR+ SCGB group received SCGB (0.25% ropivacaine 0.1 ml) at 10 min before reperfusion once a day for 2 consecutive weeks, while 0.9% sodium chloride was given instead of ropivacaine in IR+ NS group. Blood samples were collected at 24 h and 14 days of reperfusion for determination of serum concentrations of norepinephrine (NE), troponin T (TnT), tumor necrosis factor-alpha (TNF-α), interleukin-18 (IL-18) and IL-1β by enzyme-linked immunosorbent assay. Echocardiography was performed before ischemia and at 14 days of reperfusion, and left ventricular short axis shortening rate (FS), ejection fraction (EF), and cardiac output (CO) were measured. The rats were sacrificed at 14 days of reperfusion and the hearts were taken for determination of the contents of norepinephrine (NE) in myocardial tissues in the infarction area (by enzyme-linked immunosorbent assay), percentage of myocardial fibrosis area (by Masson staining), M1 macrophage marker CD68 + cell count in the infarction area (by immunohistochemical method), and expression of NLRP3 and gasdermin D (GSDMD) in myocardial tissues (by Western blot). Results:Compared with Sham group, the serum concentrations of TnT, TNF-α, IL-18 and IL-1β, percentage of myocardial fibrosis area, and NE levels in serum and myocardial tissues were significantly increased, the expression of NLRP3 and GSDMD in myocardial tissues was up-regulated, CD68 + cell count was increased, and EF, CO and FS were decreased in IR group ( P<0.05). Compared with IR group, the serum concentrations of TnT, TNF-α, IL-18 and IL-1β, percentage of myocardial fibrosis area, and NE levels in serum and myocardial tissues were significantly decreased, the expression of NLRP3 and GSDMD in myocardial tissues was down-regulated, CD68 + cell count was decreased, and EF, CO and FS were increased in IR+ SCGB group ( P<0.05), and no statistically significant changes were found in the parameters mentioned above in IR+ NS group ( P>0.05). Conclusions:SCGB can improve the cardiac function in a rat model of myocardial I/R, and the mechanism may be related to the inhibition of NLRP3 signaling pathway.