Corticosteroids found ineffective for phosgene-induced acute lung injury in rats

Abstract Various therapeutic regimes have been proposed with limited success for treatment of phosgene-induced acute lung injury (P-ALI). Corticoids were shown to be efficacious against chlorine-induced lung injury but there is still controversy whether this applies also to P-ALI. This study investigates whether different regimen of curatively administered budesonide (BUD, 10 mg/kg bw, i.p. bid; 100 mg/m 3  × 30 min, nose-only inhalation), mometasone (MOM, 3 mg/kg bw, i.p. bid) and dexamethasone (DEX, 10, 30 mg/kg bw, i.p. bid), show efficacy to alleviate P-ALI. Efficacy of drugs was judged by nitric oxide (eNO) and carbon dioxide (eCO 2 ) in exhaled air and whether these non-invasive biomarkers are suitable to assess the degree of airway injury (chlorine) relative to alveolar injury (phosgene). P-ALI related analyses included lung function (enhanced pause, Penh), morbidity, increased lung weights, and protein in bronchial alveolar lavage fluid (BALF) one day postexposure. One of the pathophysiological hallmarks of P-ALI was indicated by increased Penh lasting for approximately 20 h postexposure. Following the administration of BUD, this increase could be suppressed; however, without significant improvement in survival and lung edema (increased lung weights and BALF-protein). Collectively, protocols shown to be efficacious for chlorine ( Chen et al., 2013 ) were ineffective and even increased adversity in the P-ALI model. This outcome warrants further study to seek for early biomarkers suitable to differentiate chlorine- and phosgene-induced acute lung injury at yet asymptomatic stage. The patterns of eNO and eCO 2 observed following exposure to chlorine and phosgene may be suitable to guide the specialized clinical interventions required for each type of ALI.