ABSTRACT
AIM:To observe the effects of transection of right cervical sympathetic trunk(TCST)on inflam-matory response and expression of high mobility group box 1(HMGB1)and TLR4/NF-κB signaling pathway in the rats af-ter acute myocardial infarction(AMI).METHODS: AMI model was established by ligation of left anterior descending coronary artery in SD rats,then the model rats were randomly divided into MI group and MI +TCST group.MI+TCST model was performed by transection of right cervical sympathetic trunk after left anterior descending coronary artery ligation. The rats in MI group and MI+TCST group were divided into 1,3,7,14 and 28 d subgroups,and another sham operation group threading without ligation, with 8 rats in above each group.After modeling for 4 weeks, the cardiac function was measured by echocardiography.All rats were killed to harvest the hearts for mesuring cardiac hypertrophy index.The myo-cardial tissue close to infarction was observed with HE staining.The relative mRNA expression levels of HMGB1, tumor necrosis factor α(TNF-α)and interleukin(IL)-6 at different time points were detected by real-time PCR.The protein ex-pression of HMGB1 and TLR4 at different time points after AMI was determined by Western blot.The effect of transection of right cervical sympathetic trunk on the expressions of HMGB 1 and TLR4/NF-κB signaling pathway was also analyzed. RESULTS:Compared with the MI group,left ventricular ejection fraction(LVEF)and left ventricular shorterning fraction (LVFS)were significantly higher(P<0.05),left ventricular end-diastole dimension(LVEDd),left ventricular end-sys-tole dimension(LVESd)and cardiac hypertrophy index were significantly lower(P<0.05), and the mRNA levels of HMGB1,TNF-αand IL-6 decreased significantly in MI +TCST group(P<0.05).Western blot results revealed that the protein expression level of HMGB1 increased in the infarct border zone at 3 d,and reached its peak at 7 d,then gradually decreased,and at 28 d after MI in MI group was still significantly higher than that in sham group(P<0.05).The protein expression of TLR4 was consistent with that of HMGB1.Transection of right cervical sympathetic trunk reduced protein ex-pression of HMGB1 and TLR4/NF-κB signaling pathway-related proteins(P<0.05).CONCLUSION: Transection of right cervical sympathetic trunk improves ventricular remodeling and maintaining cardiac function.The mechanism may be related to inhibiting HMGB1/TLR4/NF-κB signaling pathway to reduce inflammatory response.