Abstract
Objective To analyze the amount of surfactant protein (SP)-B and lecithin/sphingomyelin (L/S)
ratio in response to betamethasone (BMS) alone as compared with magnesium sulfate
(Mg2+), indomethacin (Indo), and nifedipine (Nif) with or without BMS.
Study design NCI-H441 human lung cells were grown and distributed into eight plates. BMS and tocolytics
were added and the final plates were: control, BMS only, and each tocolytic ± BMS.
Cells were stained with SP-B antibodies and relative fluorescence was measured. Lipids
were also extracted, identified, and examined for relative densities. The L/S ratio
was calculated.
Results Nine independent measurements were obtained for each plate. The protein analysis
revealed that among all eight plates, SP-B levels were highest among BMS only. There
was a nonsignificant decrease in SP-B in each of the combinations of tocolytics +
BMS as compared with BMS only. Compared with BMS only, L/S ratio was decreased in
Mg2+ + BMS (p = 0.041), Indo + BMS (p = 0.042), and Nif + BMS (p = 0.025).
Conclusion In our in vitro human lung cell model, SP-B and L/S ratio increased in response to
BMS administration alone. The addition of tocolytics to BMS resulted in no increase
in L/S ratio and no changes seen in SP-B production compared with BMS alone.
Keywords
tocolytics - surfactant - lecithin - betamethasone - NCI-H441 cell line
