Background: Exposure to fine particulate matter (PM2.5) has been associated with respiratory morbidity and mortality. Identification of interventional measures that are efficacious against PM2.5-induced toxicity may provide public health benefits. This study examined the inhibitory effects of nutritional supplementation with fish oil as a source of omega-3 fatty acids and vitamin E (Vit E) on PM2.5-induced lung toxicity in rats.
Method: Sixty four male Sprague Dawley rats were gavaged with phosphate buffered saline (PBS), corn oil (5 ml/kg), fish oil (150 mg/kg), or Vit E (75 mg/kg), respectively, once a day for 21 consecutive days prior to intratracheal instillation of PM2.5 (10 mg/kg) every other day for a total of 3 times. Serum and bronchoalveolar lavage fluids (BALFs) were collected 24 h after the last instillation of PM2.5. Levels of total proteins (TP), lactate dehydrogenase (LDH), superoxide dismutase (SOD), 8-epi-prostaglandin F2α (8-epi-PGF2α), interleukin-1β (IL-1β), C-reactive protein (CRP), IL-6, and tumor necrosis factor-ɑ (TNF-ɑ) were analyzed for markers of cell injury and inflammation. Additionally, histological alterations of lung tissues were examined by hematoxylin-eosin staining.
Result: Exposure to PM2.5 resulted in lung toxicity, represented as increased levels of total proteins, LDH, 8-epi-PGF2α, IL-1β and TNF-α, and increased infiltration of inflammatory cells, and decreased SOD in the BALFs, and systemic inflammation, as evinced by increased levels of CRP and IL-6 in serum. Strikingly, supplementation with fish oil but not Vit E significantly ameliorated PM2.5-induced lung toxicity and systemic inflammation.
Conclusion: PM2.5 exposure induces oxidative stress, lung injury and inflammation, which is ameliorated significantly by fish oil and partially by Vit E.
Keywords: Fish oil; Inflammation; Lung toxicity; Oxidative stress; PM2.5; Vitamin E.