颈交感神经阻滞对重度烧伤大鼠肝脏的保护机制初探

Protective effect of cervical sympathetic block on severely burned rat liver and its related mechanism

目的观察颈交感神经阻滞(cervical sympathetic block,CSB)对严重烧伤大鼠肝脏功能与结构的保护作用,并对其可能保护机制进行探讨。方法将动物按随机数目表随机分为对照组、严重烧伤组和CSB治疗组,制作重度烧伤模型(TBSA20%Ⅲ度),CSB治疗组伤后以0.1%罗哌卡因行颈交感神经双侧阻滞。通过检测肝功能、肝组织抗氧化能力、Bcl-2表达以及肝组织病理改变判断CSB对肝脏的保护作用。通过检测监测血压变化及检测肝脏、下丘脑血流灌注量来推断其可能机制。结果 CSB组大鼠伤后血浆白蛋白下降及谷丙转氨酶上升不明显,1、3、5、7d时相点血浆白蛋白含量分别为(48.98±6.89)、(38.61±4.35)、(24.05±3.62)和(22.57±4.10)mmol/L,血浆ALT浓度分别为(48.15±7.37)、(58.21±5.43)、(62.07±8.16)、(56.87±5.88)IU/L,较烧伤组为好(P<0.01);CSB组肝组织总抗氧化能力分别为(3.16±0.17)、(2.88±0.15)、(2.71±0.16)、(2.61±0.58)U/mg,较烧伤组明显增强(P<0.01);CSB组大鼠伤后血压较为稳定,伤后1、3、5、7d时相点分别为(90.58±5.69)、(82.69±3.81)、(70.61±9.51)、(82.05±2.36)mmHg,与烧伤组相比差异显著(P<0.01);CSB组动物伤后脏器血流灌注较好,伤后即刻、1、3、5d时相点肝血流量分别为(0.302±0.041)、(0.284±0.024)、(0.16±0.023)、(0.256±0.03)ml/(min.g),下丘脑血流量分别为(1.013±0.113)、(0.721±0.110)、(0.944±0.438)、(0.765±0.316)ml/(min.g),均较烧伤组有明显升高(P<0.01);肝组织Bcl-2的表达明显增高;CSB组大鼠伤后肝组织病理改变较轻,主要表现为肝细胞浊肿,嗜酸性变,肝细胞脂肪变性。结论颈交感神经阻滞对重度烧伤大鼠肝脏具有保护作用,这种保护作用可能是通过调节下丘脑HPA轴和交感-肾上腺轴来进行的。

Objective To study the protective effect of cervical sympathetic block （CSB） on liver function and structure of severely burned rats and its possible mechanism. Methods A rat model of severe burn （TBSA 20% Ⅲ） was induced by blocking bilateral cervical sympathetic nerves with 0.01% Ropivacaine. The rats were divided into control group,burn group and CSB group. Protective effect of CSB on liver function,antioxidation,Bcl-2 expression and pathologic change in liver tissue was detected. Its mechanism was studied by measuring blood pressure and blood perfusion volume in liver and hypothalamus. Results The levels of plasma-albumin in CSB group were 48.98±6.89,38.61±4.35,24.05±3.62 and 22.57±4.10 mmol/L respectively 1,3,5 and 7 d after burn. The levels of ALT were higher in CSB group （48.15±7.37,58.21±5.43,62.07±8.16 and 56.87±5.88 IU/L respectively 1,3,5 and 7 d after burn）than in burn group,（P0.01）. The hepatic T-AOC values were higher in CSB group （3.16±0.17,2.88±0.15,2.71±0.16,and 2.61±0.58 respectively 1,3,5 and 7d after burn） than in burn group（P0.01）. The blood pressures were more stable in CSB group （90.58±5.69,82.69±3.81,70.61±9.51 and 82.05±2.36 mmHg respectively 1,3,5 and 7 d after burn） than in burn group （P0.01）. The hepatic and hypothalamic blood flow volumes were higher in CSB group [0.302±0.041,0.284±0.024,0.16±0.023,0.256±0.03 ml/（min·g） and 1.013±0.113,0.721±0.110,0.944±0.438,0.765±0.316 ml/（min·g） respectively burned instantly,1,3 and 5 d after burn] than in burn group（P0.01）.The pathologic changes of liver structure were milder while the expression level of Bcl-2 in liver was higher in CSB group than in burn group. Conclusion CSB can protect the liver of severely burned rats by regulating the hypothamus axis and sympathetic-kidney axis.