Short-interval exposure to ambient fine particulate matter (PM2.5) exacerbates the susceptibility of pulmonary damage in setting of lung ischemia-reperfusion injury in rodent: Pharmacomodulation of melatonin

This study tested the hypothesis that exposure to ambient fine particulate matter (PM2.5) pollution increased susceptibility of rat lung to damage from acute ischemia-reperfusion (IR) injury that was reversed by melatonin (Mel) treatment. Male-adult SD rats (n = 30) were categorized into group 1 (normal control), group 2 (PM2.5 only), group 3 (IR only at day 8 after PM2.5 exposure), group 4 (PM2.5 + IR) and group 5 (PM2.5 + IR + Mel), and all animals were sacrificed by day 10 after PM2.5 exposure. Oxygen saturation (%) was significantly higher in group 1 than in other groups and significantly lower in group 4 than in groups 2, 3 and 5 but it did not differ among the latter three groups (p