PT - JOURNAL ARTICLE AU - Gisella Borzone AU - Pedro Ayala AU - Joaquin Araos AU - Rafael Contreras AU - Andrea CutiƱo AU - Manuel Meneses TI - Orotracheal instillation of gastric juice: Species variations in acute lung injury relate to differences in matrix metalloproteinase activity DP - 2014 Sep 01 TA - European Respiratory Journal PG - P3922 VI - 44 IP - Suppl 58 4099 - http://erj.ersjournals.com/content/44/Suppl_58/P3922.short 4100 - http://erj.ersjournals.com/content/44/Suppl_58/P3922.full SO - Eur Respir J2014 Sep 01; 44 AB - Gastric content aspiration is common in the elderly and people with neurological conditions. It is unknown if early events predict final outcomes after aspiration. To gain further knowledge we studied rat and hamster species variations in acute lung injury (ALI) by a single orotracheal dose of gastric juice (GJ). Under Ketamine/Xylazine, Sprague-Dawley rats and Syrian Golden hamsters received 1.5ml/Kg body wt. of GJ from a pool for each species (similar pH, pepsin activity and particle type). ALI markers (lung wet/dry weight ratio, histological changes, and BALF protein content) and lung matrix metalloproteinase-9 (MMP-9) activity were measured 4, 12, 24h, and 4 days(d) later (n=10/time point/species). Statistical analysis: ANOVA.In rats, lung wet/dry weight ratio increased at 4h (p<0.01) returning to control at 12h, whereas hamsters exhibited a more pronounced and longer-lasting increment in this ratio (p<0.05). Bronchiolocentric fluid accumulation with PMNn and red cell infiltration was more severe in hamsters (p<0.05). In rats, BALF protein content increased 16 times at 4h (p<0.001) returning to baseline at 4d, whereas a larger increment (p<0.01) was seen in hamsters. MMP-9 activity in rats increased at 4h (p<0.05) returning to control values at 12h whereas in hamsters it remained elevated up to 24h (p<0.001).Conclusion: ALI by a single dose of GJ is more severe in hamsters than in rats and is associated with a long-lasting increase in MMP-9 activity. Early species variations in MMP-9 activity could be associated with species differences in chronic damage if aspiration events become repetitive.Funding: FONDECYT 1120943.