大鼠呼吸机相关肺损伤热休克蛋白70和核因子-κB的表达及其意义

Expression and significance of heat shock protein 70 and nuclear factor-κB in ventilator-induced lung injury in rats

目的 探讨呼吸机所致肺损伤（VILI）炎症反应中热休克蛋白70（HSP70）和核因子-κB（NF-κB）表达的意义.方法 健康SD大鼠30只,实施麻醉和气管切开术后分别接受不同潮气量（VT）的通气（通气时间均为4 h）.随机分为以下3组：对照组（A组）;常规通气组（B组,VT=10ml/kg）;损伤通气组（C组,VT=40ml/kg）.4 h后放血处死动物,测定肺湿/干比重、髓过氧化物酶（MPO）活性及肺泡灌洗液（BALF）中总蛋白含量,光镜下行白细胞（WBC）计数;Western blot检测肺组织HSP70及NF-κB的表达.结果 在大潮气量机械通气4 h后,BALF中总蛋白含量、肺湿干比、WBC计数和MPO水平（3.89±0.31、5.83±0.42、6.10±0.80、7.31±1.21）均明显更高（P＜0.05）;肺组织中HSP70、NF-κB表达水平（1.36±0.13、0.41±0.07）均显著增加,且两者呈负相关.结论 HSP70可通过抑制NF-κB的活性,保护肺组织避免VILI.

Objective To investigate the expression and significance of heat shock protein 70 （HSP70） and nuclear factor-κB （NF-κB） in a rat model of ventilator-induced lung injury （VILI）. Methods Thirty healthy SD rats were randomly divided into three groups （each 10 rats）： control group （group A, no ventilation）, conventional ventilation group （group B, VT = 10 ml/kg）, lung injury group （group C, VT =40 ml/kg）. After anesthesia and tracheotomy were performed, rats received ventilation with different volumes for 4 h. The rats were killed by exsanguinations. The lung wet/dry weight, myeloperoxidase （MPO） activity and total protein level and counts of white blood cells （WBC） in broncho-alveolar lavage fluid （BALF） were tested. The expression of HSP70 and NF-κB was detected by using Western blotting.Results After injurious ventilation for 4 h, the level of lung wet/dry weight, MPO activity and total protein level and counts of WBC were 5.83 ± 0.42, 7.31 ± 1.21, 3.89 ± 0.31, 6. 10 ± 0. 80, respectively.The average values of HSP70 and NF-κB proteins were 1.36 ±0.13, and 0. 41 ±0.07, respectively, and there was a negative correlation between them. Conclusion Tidal volume mechanical ventilation can induce lung tissue damage and HSP70 can inhibit the activity of NF-κB to protect lung tissue from VILI in rats.