The effect of arnafant surfactant on respiratory distress syndrome in rats

Objectives: Acute respiratory distress syndrome (ARDS) is occurred by disruption of alveolar-capillary membrane and associated with an inflammation process. In the present study, the effect of arnafant surfactant on RDS in rats was compared to curosurf. Methods: RDS was induced in male Wister rats by surfactant washout using 10 times lung lavage with 3 ml saline at 37 o C through an intra-tracheal cannula after anesthetized with intrapritonal administration of 60 mg thiopental Na while animals were ventilated. Then chest was opened and stepwise increasing volume of air was administered and withdrawer from the lung while lung pressure was monitored and lung compliance was determined using lung volume-pressure curve. Total and differential white blood cells (WBC) as well as oxidative stress markers in the blood and bronco-alveolar lavage (BALF) were also examined. The study was performed in 4 groups (n=10 in each group) of rats including control and RDS, both traded with saline, RDS treated with arnafant and RDS treated with curosurf (2.5 ml contained 6.25 mg surfactant for both drugs). Results: The value of lung compliance in RDS group was significantly reduced compared to control group (P<0.001). However, in RDS group treated with arnafant, lung compliance was significantly increased compared to both untreated and to curosurf treated RDS groups (P<0.001 for both cases). Total and differential WBC counts in the blood of RDS group were significantly increased compared to the control group but in RDS group treated with arnafant, total WBC, and lymphocyte counts were significanty decreased compared to untreated RDS group (P<0.01-P<0.001). In the BALF of RDS group treated with curosurf, total and differential WBC were significantly increased but in RDS group treated with arnafant, only total WBC, eosinophil and lymphocyte counts were significanty increased compared to the control group (P<0.01-P<0.001). In the BALF, lung tissue and serum of untreated RDS group, all oxidative stress markers were significantly changed compared to the control group but in arnafant treated RDS group all markers and in curosurf treated RDS group, only thiol level and CAT activity in the BALF as well as MDA and thiol levels both in the lung tissue and serum were significanty improved compared to untreated RDS group (P<0.05-P<0.001). Conclusion: Treatment of RDS rats with arnafant significantly improved lung compliance as well as lung and systemic inflammation and oxidative stress and the effect of this surfactant drug was significantly higher than curosurf.