患儿体外循环中应用右美托咪定对TLR4/NF-κB胆碱能抗炎通路的影响

Effect of Dexmedetomidine on TLR4/NF-κB Cholinergic Anti-inflammatory Pathway in Children with Cardiopulmonary Bypass

目的探讨患儿体外循环(cardiopulmonary bypass,CPB)中应用右美托咪定对胆碱能抗炎通路的影响。方法本研究共纳入80例接受先天性心脏病手术的患儿,采用随机数字表法将其分为4组(n=20),分别于诱导后静脉输注右美托咪定0.25μg/(kg·h)(Dex1组)、0.5μg/(kg·h)(Dex2组),或麻醉后静脉输注乌司他丁1.2万U/(kg·h)(UTI组)以及静脉输注等量生理盐水(NS组),均维持至手术结束。ELISA法检测心肌损伤标志物血清肌酸激酶-同工酶(CK-MB)、心肌型脂肪酸结合蛋白(H-FABP)、心肌肌钙蛋白(cTnI)浓度,脑损伤标志物S100β蛋白、神经元特异性烯醇化酶(NSE)浓度;血气分析仪检测动脉-颈静脉血氧浓度差(Ca-jvO_(2))、脑氧摄取率(ERO_(2));实时荧光定量PCR检测TLR4 mRNA及NF-κB mRNA表达;流式细胞仪检测Th17和Treg细胞的比例;Western blot法检测高迁移率族蛋白B1(HMGB1)含量。结果①Dex2组、UTI组术后6、24、48 h时CK-MB水平明显低于NS组(均P<0.05);Dex1组、Dex2组、UTI组术毕及术后6、24 h时H-FABP水平明显低于NS组(均P<0.05);Dex2组、UTI组术后6、24 h时cTnI水平明显低于NS组(均P<0.05)。②Dex2组、UTI组术毕及术后6、24、48 h时S100β水平明显低于NS组(均P<0.05);Dex2组、UTI组术后6、24 h时NSE水平明显低于NS组(均P<0.05);Dex2组、UTI组CPB后30 min、CPB结束、术毕时Ca-jvO_(2)水平明显高于NS组,ERO_(2)水平明显低于NS组(均P<0.05)。③Dex2组及UTI组外周血单个核细胞(PBMCs)中TLR4 mRNA及NF-κB mRNA表达显著低于NS组(均P<0.05)。④Dex2组及UTI组HMGB1蛋白水平均显著低于NS组(均P<0.05)。⑤UTI组、Dex2组PBMCs中Th17占比明显低于NS组(均P<0.05),Treg细胞占比明显高于NS组(均P<0.05);Dex1组Th17占比明显高于Dex2组、UTI组,Treg细胞占比明显低于Dex2组、UTI组(均P<0.05)。结论0.5μg/(kg·h)右美托咪定可对心脑起到良好的器官保护作用。其机制可能是通过抑制HMGB1和TLR4的表达,降低Th17细胞比例,升高Treg细胞比例,阻断TLR4/NF-κB通路来调节Th17/Treg平衡,从而缓解CPB所致的炎症反应。

Objective To explore the effect of a2 adrenergic receptor agonist dexmedetomidine on cholinergic anti-inflammatory pathway in children with cardiopulmonary bypass.Methods Totally,80 children treated with congenital heart disease surgery were randomly selected.According to random number grouping method,they were divided into 4 groups(n=20 each group).For Dex1 and Dex2 groups,the patients received intravenous injection of 0.25 and 0.5μg/(kg·h)dexmedetomidine after induction,respectively.For UTI group,the patients were intravenously injected with 12000 U/(kg·h)of Ulinastatin after anesthesia(UTI group).For NS group,the patients received equivalent normal saline(NS group),maintained until the end of the operation.ELISA method was used to detect myocardial injury markers serum creatine kinase-isoenzyme(CK-MB),myocardial fatty acid binding protein(H-FABP),cardiac troponin(cTnI)concentration,brain injury markers S100βprotein,neurons specific enolase(NSE)concentration.Blood gas analyzer was used to detect the difference in arterial-jugular blood oxygen concentration(Ca-jvO_(2)) and cerebral oxygen uptake rate(ERO_(2)),real-time fluorescent quantitative PCR to detect the expression of TLR4 mRNA and NF-κB mRNA,flow cytometry to detect the ratio of Th17 to Treg cells;Western blotting to detect high mobility group protein B1(HMGB1).Results①The levels of CK-MB in the Dex2 group and the UTI group were significantly lower than those in the NS group at 6,24,and 48 h after operation(all P<0.05).The levels of FABP in Dex1 group,Dex2 group and UTI group were significantly lower than that of the NS group(all P<0.05);the cTnI levels of the Dex2 group and the UTI group were significantly lower than that of the NS group at 6 h and 24 h after the operation(all P<0.05);②In the Dex2 group and the UTI group at the end of the operation and after the operation,the level of S100βat 6,24 and 48 h after operation was significantly lower than that of NS group(all P<0.05);the NSE level of Dex2 group and UTI group at 6 h and 24 h after operation was significantly lower than that of NS group(all P<0.05);Dex2 group and UTI group had significantly higher levels of Ca-jvO_(2) at 30 min after CPB,at the end of CPB,and at the end of surgery than NS group(all P<0.05);the levels of ERO_(2) in Dex2 and UTI groups were significantly lower at 30 min after CPB,at the end of CPB,and at the end of surgery.In NS group(both P<0.05);③TLR4 mRNA and NF-κB mRNA expression in PBMCs of Dex2 group and UTI group were significantly lower than those of NS group(all P<0.05);④HMGB1 protein of Dex2 group and UTI group were significantly lower than that in the NS group(all P<0.05);⑤The proportion of Th17 in peripheral blood mononuclear cells(PBMCs)in the UTI group and Dex2 group was significantly lower than that in the NS group(all P<0.05).The proportion of Treg cells in the UTI group and Dex2 group was significantly higher than that in the NS group(all P<0.05).The proportion of Treg cells in the group was significantly lower than that in the Dex2 group and the UTI group(all P<0.05).Conclusion Dexmedetomidine dose 0.5μg/(kg·h)can exert a good organ protection effect on the heart and brain;it may inhibit the expression of HMGB1 and TLR4,reduce the expression of Th17 cells,increase the level of Treg cells,and block TLR4/NF-κB pathway to regulate Th17/Treg imbalance and relieve CPB inflammation.