Melatonin treatment improves adipose-derived mesenchymal stem cell therapy for acute lung ischemia-reperfusion injury

This study investigated whether melatonin-treated adipose-derived mesenchymal stem cells (ADMSC) offered superior protection against acute lung ischemia-reperfusion (IR) injury. Adult male Sprague-Dawley rats (n = 30) were randomized equally into five groups: sham controls, lung IR-saline, lung IR-melatonin, lung IR-melatonin-normal ADMSC, and lung IR-melatonin-apoptotic ADMSC. Arterial oxygen saturation was lowest in lung IR-saline; lower in lung IR-melatonin than sham controls, lung IR-melatonin-normal ADMSC, and lung IR-melatonin-apoptotic ADMSC; lower in lung IR-melatonin-normal ADMSC than sham controls and lung IR-melatonin-apoptotic ADMSC; lower in lung IR-melatonin-apoptotic ADMSC than sham controls (P < 0.0001 in each case). Right ventricular systolic blood pressure (RVSBP) showed a reversed pattern among all groups (all P < 0.0001). Changes in histological scoring of lung parenchymal damage and CD68+ cells showed a similar pattern compared with RVSBP in all groups (all P < 0.001). Changes in inflammatory protein expressions such as VCAM-1, ICAM-1, oxidative stress, TNF-α, NF-κB, PDGF, and angiotensin II receptor, and changes in apoptotic protein expressions of cleaved caspase 3 and PARP, and mitochondrial Bax, displayed identical patterns compared with RVSBP in all groups (all P < 0.001). Numbers of antioxidant (GR+, GPx+, NQO-1+) and endothelial cell biomarkers (CD31+ and vWF+) were lower in sham controls, lung IR-saline, and lung IR-melatonin than lung IR-melatonin-normal ADMSC and lung IR-melatonin-apoptotic ADMSC, and lower in lung IR-melatonin-normal ADMSC than lung IR-melatonin-apoptotic ADMSC (P < 0.001 in each case). In conclusion, when the animals were treated with melatonin, the apoptotic ADMSC were superior to normal ADMSC for protection of lung from acute IR injury.