Meeting Abstract

P1.37  Monday, Jan. 4  Do guinea pig fetuses express lung surfactant proteins after being exposed to betamethasone at seventy-percent gestation LAU, F.O.**; TAYLOR, K.N.; BAATZ, J.E.; DEAROLF, J.L.; Hendrix College, Conway, AR; the Medical College of Charleston, S.C. laufo@hendrix.edu

Glucocorticoids are used in clinical medicine because they stimulate the development of the lungs, which decreases the incidence of breathing problems in premature infants. But, the effects of these steroids on the development of other body systems are not as well known. Guinea pigs are an excellent model system to determine the effects of glucocorticoids on development, because they share physiological and developmental features with humans. However, the appropriate length of and earliest effective exposure to these steroids for guinea pigs have yet to be determined. The purpose of this study is to test the hypothesis that two intramuscular injections of betamethasone given to pregnant guinea pigs (0.5 mg/kg) twenty-four hours apart at 70% gestation is an effective steroid exposure protocol for these animals. To test this hypothesis, fetal lung samples were assessed for the presence of surfactant protein B. Lung samples from control (sterile water) and treated fetuses were prepared for polyacrylamide gel electrophoresis. The proteins were separated on 4-12% Tris/Glycine SDS-PAGE gels that ran at 200V for 50 minutes and transferred to nitrocellulose membranes at 25V for 90 minutes. This transfer allowed for Western Blots with membrane exposure to anti-lung surfactant protein B antibodies, which were then developed for chemiluminescence. Images of the blots were analyzed using Scion Image to measure sample density levels, which will be used to calculate the percent SP-B per milligram of protein in each fetal lung sample. These values will be compared to determine if all of the fetuses in the treated litters express SP-B, a finding that would support the hypothesized steroid exposure protocol for guinea pigs.