Lung Injury and aquaporin-1mRNA expression during cardiopulmonary bypass / 中华胸心血管外科杂志

ABSTRACT

Objective To testify the lung injury induced by cardiopulmonary bypass(CPB) in canine model and observe the influence of CPB on the aquaporin-1 ( AQP1 ) mRNA expression in canine lung. Methods 8 mongrel dogs were used to perform the cardiopulmonary bypass. The hearts arrested for 90 minutes with mild hypothermia and rebeated for 6 hours. The hemodynamics, the ratio of lung dry weight and wet weight, the plasmic osmotic pressure, and the characteristics of light and fine structure were analyzed. The retro-transcription polyase chain reaction ( RT-PCR ) was used to measure the expression of AQP1 mRNA during the CPB. Results The hemodynamic data were stable in different time point during the CPB (P ＞0.05 ). The ratio of lung dry weight and wet weight was getting lower ( P ＜0.001) and the plasmic osmotic pressure was getting higher due to the prolongation of the CPB time and reperfusion time ( P ＜0.01). The light and electron microscopy showed the prominent aggregation of the white blood cell, severe interstitial edema and mild tear of respiratory membrane after 3 hour and 6-hour rebeat. AQP1 mRNA expression in lung was downregulated, 78.4% after 3-hour reperfusion and 55.5% after 6-hour reperfusion respectively, comparing to the level before CPB. Conclusion We recognize that the lung injury and lung edema were severe following 3-hour and 6-hour rebeat in CPB and hypothesize that the down-regulation of lung AQP1 mRNA expression may be a sign of pulmonary interstitial capillary injury induced by CPB.