Figure 2

Dexamethasone upregulates SP-D but not SP-A production by type II cellsin vitro. Cells were isolated from lungs of adult rats and cultured in Waymouth's medium with 10% FBS, with 8-Br-cAMP (100 μM) and isobutylmethylxanthine (100 μM) with or without dexamethasone (10 nM). Cell lysates were prepared from freshly isolated cells and at the end of a 4-day culture period (A): SP-A and SP-D production was analyzed by Western blot. (B): Results are expressed as % of the "day 0" value. *p = 0.037 (n = 3) (C): Northern blot analysis of SP-D and SP-A mRNA expression was performed on total RNA (10 μg) extracted from type II cells as described. SP-D and SP-A cDNA probes labeled with [α³²P] dCTP were hybridized to mRNAs on nitrocellulose membranes. (D): Intensity was quantified by densitometric scanning and the hybridization signals were normalized to 28S rRNA probe labeled with [γ³²P] ATP. mRNA content is expressed as % of the "day 0" value. *p < 0.041 Mean ± SEM was calculated after deriving the average of the results from three independent experiments.