Fig. 4

Dexamethasone increases apoptosis in 21 day monocrotaline (MCT)-treated rat pulmonary arterial smooth muscle cells (PASMC). Rat PASMC were isolated from control rats and from rats 21 days after exposure to MCT and treated with an increasing concentration of dexamethasone (Dex) and appropriate controls. Apoptosis, as measured by DNA fragmentation, was increased from baseline in serum-starved cells (0 % FCS) in control PASMC by Dex (10⁻⁸–10⁻⁶ M) at both 48 h (grey bars) and 72 h (black bars) (a). There was a significant difference between control and MCT-exposed cells at 48 h (b) and 72 h (c) following 10⁻⁷ M and 10⁻⁶ M Dex treatment. However this difference was lost when data were normalised to baseline serum starvation levels at 48 h (d) and 72 h (e). Results represent mean ± SEM from n = 3–5, compared using 1-way ANOVA and Bonferroni’s post-test. *p < 0.05, **p < 0.01, ***p < 0.001