Lin He1, Tao-ping Li, Li-hua Zhu. 1. Emergency Department, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
Abstract
OBJECTIVE: To observe the changes of the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in acutely isolated alveolar type II (ATII) cells from rats with acute respiratory distress syndrome (ARDS), and test the effects of terbutaline on the cAMP and cGMP levels. METHODS: SD rats were randomized into the control, ARDS, and terbutaline treatment groups, in which the cAMP and cGMP contents in the ATII cells were measured using radioimmunoassay, and the extravascular lung water (EVLW) content was quantified with gravimetric measurement. RESULTS: The cAMP level in the ATII cells was significantly lowered whereas cGMP level and EVLW content increased in rats with oleic acid-induced ARDS. In terbutaline-treated rats with ARDS, the EVLW content were lower than that of non-treated rats, but still higher than that of the control rats. Terbutaline treatment also increased the content of cAMP but produced no significant effect on cGMP content in the ATII cells of the rats with ARDS. CONCLUSION: Alveolar fluid clearance rate is decreased in rats with oleic acid-induced ARDS, and terbutaline can improve the capacity of alveolar fluid clearance, the mechanism of which may involve elevated cAMP content in the ATII cells. cAMP and cGMP in ATII cells might participate in the molecular pathogenesis of ARDS.
OBJECTIVE: To observe the changes of the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in acutely isolated alveolar type II (ATII) cells from rats with acute respiratory distress syndrome (ARDS), and test the effects of terbutaline on the cAMP and cGMP levels. METHODS: SD rats were randomized into the control, ARDS, and terbutaline treatment groups, in which the cAMP and cGMP contents in the ATII cells were measured using radioimmunoassay, and the extravascular lung water (EVLW) content was quantified with gravimetric measurement. RESULTS: The cAMP level in the ATII cells was significantly lowered whereas cGMP level and EVLW content increased in rats with oleic acid-induced ARDS. In terbutaline-treated rats with ARDS, the EVLW content were lower than that of non-treated rats, but still higher than that of the control rats. Terbutaline treatment also increased the content of cAMP but produced no significant effect on cGMP content in the ATII cells of the rats with ARDS. CONCLUSION: Alveolar fluid clearance rate is decreased in rats with oleic acid-induced ARDS, and terbutaline can improve the capacity of alveolar fluid clearance, the mechanism of which may involve elevated cAMP content in the ATII cells. cAMP and cGMP in ATII cells might participate in the molecular pathogenesis of ARDS.