Effect of CO on vascular SMC growth.

(A) SMC proliferation was monitored in cells treated with serum (0%-5%) and SnPP (20 μM) for 4 days in the presence or absence of CO (100 ppm). (B) SMC DNA synthesis was monitored in cells treated with serum (0%-5%) and SnPP (20 μM) for 24 hours in the presence and absence of CO (100 ppm). (C) Concentration-dependent inhibitory effect of CO (0-200 ppm) on DNA synthesis in SMCs treated with serum (10%) and SnPP (20 μM) for 24 hours. Results are means ± SEM of 4 separate experiments. *Statistically significant effect of serum.⁺Statistically significant effect of CO.