颈交感神经离断对颅脑损伤大鼠的肺保护作用机制

Study on the protective mechanism of transection of cervical sympathetic trunk on the lungs of rats with traumatic brain injury

目的观察颈交感神经离断(TCST)对颅脑损伤(TBI)大鼠肺的保护机制。方法将90只雄性SD大鼠随机分为假手术组(C组)、颅脑损伤组(A组)和颈交感神经离断+颅脑损伤组(B组),每组30只。C组不做任何处理,A组建立TBI模型,B组建立TBI模型后行左侧TCST。将三组大鼠分别于建模后第1天(T_(1))、2天(T_(2))、3天(T_(3))、1周(T_(4))、6周(T_(5))各取6只检测血气分析,HE染色观察肺组织病理改变,计算肺水肿干湿质量比(D/W),ELISA法检测肺泡灌洗液(BALF)中白细胞介素(IL-6)、肿瘤坏死因子-α(TNF-α)、肺表面活性蛋白D(SP-D)含量,免疫组化检测肺组织中SP-D表达。结果氧合指数及D/W值:与C组比较,A组在T_(1)~T_(5)时间点明显减低(P<0.05);与A组比较,B组在T_(1)~T_(5)时间点明显增高(P<0.05)。肺组织及BALF中SP-D:与C组比较,A组在T_(1)~T_(5)时间点明显减低(P<0.05);与A组比较,B组在T_(1)~T_(5)时间点明显增高(P<0.05)。BALF中IL-6含量:与C组比较,A组在T_(1)~T_(5)时间点明显增高(P<0.05);与A组比较,B组在T_(2)~T_(5)时间点明显减低(P<0.05)。BALF中TNF-α含量:与C组比较,A组在T_(1)~T_(5)时间点明显增高(P<0.05),B组在T_(1)~T_(4)时间点明显增高(P<0.05);与A组比较,B组在T_(1)~T_(2)及T_(4)时间点明显减低(P<0.05)。结论TBI后大鼠BALF中IL-6、TNF-α含量明显增加,SP-D含量明显减低,三者在TBI并发急性肺损伤(ALI)的发生中可能发挥着作用;TCST可以抑制TBI并发ALI时的严重炎症反应,从而改善氧合指数及防止肺水肿形成,对TBI并发的ALI起到保护作用。

Objective To observe the effects of transection of cervical sympathetic trunk( TCST) on tumor necrosis factor-α( TNF-α),interleukin-6( IL-6) and surfactant protein D( SP-D) in the bronchoalveolar lavage fluid( BALF) of rats with traumatic brain injury( TBI) in order to explore the protective mechanism of TCST on the lungs of rats with TBI. Methods 90 male SD rats were randomly divided into sham operation group( group C,n = 30 rats),TBI group( group A,n = 30 rats),TCST + TBI group( group B,n = 30 rats). Group C did not do any treatment. Group A was set up with TBI models,group B underwent left TCST after the establishment of TBI models. Six rats in group A,group B and group C were selected on 1 st day( T_(1)),2 nd day( T_(2)),3 rd day( T_(3)),1 st week( T_(4)) and 6 th week( T_(5)) after modeling respectively. Blood gas analysis was detected,HE staining was used to observe lung pathological changes,D/W value of pulmonary edema was calculated,and IL-6,TNF-α,SP-D content in BALF were detected by ELISA,and SP-D expression in lung tissue was detected by immunohistochemistry. Results Compared with group C,oxygenation index and D/W in group A were significantly reduced on T_(1)-T_(5)( P < 0. 05);compared with group A,oxygenation index and D/W in group B increased significantly on T_(1)-T_(5)( P < 0. 05). Compared with group C,the expression of SP-D in group A was significantly reduced on T_(1)-T_(5)( P < 0. 05);compared with group A,the expression of SP-D in group B increased significantly on T_(1)-T_(5)( P < 0. 05). Compared with group C,the content of IL-6 in BALF of group A was significantly higher on T_(1)-T_(5)( P < 0. 05);compared with group A,the IL-6 content in BALF of group B was significantly reduced on T_(2)-T_(5)( P <0. 05). Compared with group C,the content of TNF-α in BALF of group A was significantly higher on T_(1)-T_(5)( P < 0. 05) the content of THF-α in BALF of groug B was obvieusly higer on T_(1)-T_(4)( P <0. 05);compared with group A,the content of TNF-α in BALF of group B was significantly reduced on T_(1)-T_(2) and T_(4)( P < 0. 05). Conclusions After TBI,the contents of IL-6 and TNF-α in the BALF of rats are significantly increased,and the content of SP-D is significantly reduced. The three indexes may play a role in the occurrence of TBI complicated with ALI;it is speculated that TCST can inhibit the severe inflammatory response when TBI complicated with ALI,so as to improve the oxygenation index and prevent the formation of pulmonary edema,and play a protective effect on ALI complicated with TBI.