Role of endoplasmic reticulum stress in lung ischemia-reperfusion injury in rats

Abstract

Objective To investigate the role of endoplasmic reticulum stress in lung ischemia-reperfusion (I/R) injury in rats. Methods Fifty-six healthy male Sprague-Dawley rats, weighing 250-320 g, were randomly divided into 2 groups using a random number table: sham operation group (group S, n=16) and I/R group (n=40). Lung I/R was induced by clamping the left hilum of lung for 60 min followed by reperfusion.Before ischemia (T0) and at 0, 1, 2 and 4 h (T4) of reperfusion, PaO2 and PaCO2 were recorded.The rats were sacrificed, and lungs were removed for examination of pathological changes.Wet/dry lung weight ratio (W/D ratio) was calculated.The expression of molecular chaperones of 78-kDa glucose-regulated protein (GRP78) and C/EBP homologous protein (CHOP) protein and mRNA was detected in lung tissues using Western blot and real-time PCR, respectively. Results Compared with group S, PaO2was significantly decreased, PaCO2 and W/D ratio were increased, and the expression of GRP78 and CHOP protein and mRNA was up-regulated during reperfusion, and the pathological changes of lungs were found in group I/R.With the prolongation of reperfusion, the pathological changes of lungs were gradually aggravated, and the expression of GRP78 and CHOP protein and mRNA was gradually up-regulated in group I/R. Conclusion Excessive endoplasmic reticulum stress may be one of the pathophysiological mechanisms of lung I/R injury in rats. Key words: Endoplasmic reticulum; Stress; Reperfusion injury; Lung