大鼠体外循环后肺损伤的实验研究

Lung injury after cardiopulmonary bypass in rats

Objective To investigate the influence of cardiopulmonary bypass （CPB） on lung injury in rats and its related mechanism. Methods Twenty four male Sprague Dawley rats were randomly divided into two groups ： sham operation group （Sham） and CPB group. Sham group establish CPB model, but without CPB bypass. After establish the CPB, the flow rate was gradually adjusted to the maximum[ i〉 100 ml/（ kg min）l and maintained for 60 rain. Blood samples were collected at the beginning and the end of CPB, 1 h,2 h, 12 h for assays of tumor necrosis factor-α （TNF-α）, matrix metalloproteinase-9 （MMP-9） and arterial blood gas analy- sis. Bronchoalveolar lavage fluid （BALF） and lung tissue were obtained 12 h after the operation for detection of TNF-α, MMP-9 and NF-KB protein expression levels, histological examination was also performed. Results Compared with Sham group, inflammatory cyto- kines of TNF-α,MMP-9 of the CPB group in serum,lung tissue and BALF significantly increased and NF-KB protein expression levels in the lung samples were obviously higher after CPB （P 〈 0.05）. Histological examination revealed that the CPB group showed neutro- phil infiltration,interstitial pulmonary edema, hemorrhage, hyaline membrane formation and necrosis. Conclusion Lung injury induced by CPB is related to NF-KB activation and thus increase of TNF-α,MMP-9.