APStracts 2:0064L, 1995.

Surfactant treatment and ventilation effects on surfactant sp-a, sp-b, sp-c mrna levels in preterm lamb lungs. Woods, Elizabeth, Tamaki Ohashi, Daniel Polk, Machiko Ikegami, Takashi Ueda, Alan H. Jobe. Perinatal Research Laboratories, Department of OB/GYNa and Pediatrics, Harbor-UCLA Medical Center, 1000 West Carson Street, Torrance, California 90509, TEL: (310) 222-1965, FAX: (310) 533 -0627

APStracts 2:0064L, 1995.

The effects of exogenous surfactant treatment combined with postnatal ventilation on SP-A, SP-B and SP-C steady-state mRNA levels were evaluated in preterm sheep at 120, 132, and 139 d gestation. Three groups were studied at each gestation: animals ventilated and treated with 100 mg/kg natural sheep surfactant, animals ventilated and not treated with surfactant, and a comparison group of lambs that were neither ventilated nor treated with surfactant. In unventilated lambs, SP-A and SP-C mRNA levels measured by densitometry from Northern blots increased between 120 and 132 d gestation (p < 0.05). At 120 d gestation, no differences in SP-A, SP-B or SP-C mRNA levels were noted among the three groups. At 132 d gestation, SP-A mRNA levels increased in both ventilated groups (p < 0.01), but no additional surfactant effect on SP-A mRNA expression was detected. There were no changes in SP-B or SP-C mRNA levels among the groups at 132 d gestation. At 139 d gestation, mRNA levels for both SP-A and SP-B increased after ventilation compared to the unventilated groups (p<0.05). Furthermore, an additional effect of surfactant treatment to increase SP-A mRNA levels relative to animals undergoing ventilation alone was noted (p < 0.05). We conclude that postnatal changes in mRNA levels for the surfactant proteins are gestationally regulated and protein specific.

Received 31 October 1994; accepted in final form 11 April 1995.
APS Manuscript Number L314-4.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 April 1995.