The anti-apoptotic role of bilirubin in ischemia-reperfusion injury of rat lungs

Objective To study the anti-apoptotic role of bilirubin in ischemia- reperfusion injury of rat lungs. Methods Sixty healthy Wistar rats were randomized to receive surgical procedure (control group, group C), ischemia-reperfusion (group IR) and bilirubin intervention (group B). Rats from each group were sacrificed in fives at one of four time spots (45 min ischemia, 30, 60 and 120 min reperfusion), harvested for plasma samples and middle lobes of the right lung, and detected for dry-to-wet (D/W) weight ratio of lung tissue, histology, and apoptotic cells in the right middle lobe as measured by apoptosis index (AI) using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). Results ①After ischemia and reperfusion, the D/W ratio showed progressive decrease in groups IR and B (P0.01), but the change was much less in group B than in group IR (P0.05). ②At all time spots, the AI in group B was obviously lower than in group IR group (P0.05). ③Histological evaluation: while ischemia-reperfusion resulted in progressive deterioration of lung injury in group IR, group B was less affected in terms of congestion, edema and pro-inflammatory infiltration. Conclusion Bilirubin intervention appeared protective against lung injury caused by experimental ischemia-reperfusion in rats, which may be attributed to its anti-apoptotic effect.