Protective effects of S-nitrosoalbumin on lung injury induced by hypoxia-reoxygenation in mouse model of sickle cell disease

Nitric oxide (NO) is a potential new therapeutic agent for sickle cell disease (SCD). We investigated the effects of NO donor on hypoxia-induced acute lung injury that occurs when transgenic sickle cell SAD mice are exposed to chronic hypoxia, a model for lung vasoocclusive sickle cell events. In wild-type and SAD mice, intraperitoneal injection of S-nitrosoalbumin (NO-Alb) produced no significant hematologic changes under room air conditions, whereas it induced mild temporary hypotension and inhibition of platelet aggregation. NO-Alb administration (300 mg/kg ip twice a day, equivalent to 7.5 mu M NO) in wild-type and SAD mice exposed to 46 h of hypoxia (8% oxygen) followed by 2 h of normoxia resulted in 1) reduction of the hypoxiainduced increase in blood neutrophil count, 2) prevention of hypoxiainduced increased IL-6 and IL-1 beta levels in bronchoalveolar lavage, 3) reduction of the lung injury induced by hypoxia-reoxygenation, 4) prevention of thrombus formation, and 5) prevention of hypoxiainduced increase of lung matrix metalloproteinase-9 gene expression. These effects provide new insights into the possible use of NO-Alb in the treatment of acute lung injury in SCD.