Table I.

Effect of CO on MCT-induced changes in body weights, cardiac weights, and pulmonary hemodynamics in rats

	No MCT		MCT
	Air	CO	Air	CO (days 1–14)	CO (days 15–28)	CO (days 29–42)
Number (n)	6	6	8	6	6	9
BW (g)	288 ± 31	291 ± 37	249 ± 52	303 ± 56	296 ± 53	301 ± 70
mPAP (mmHg)	15.8 ± 0.75	16.1 ± 1.0	34.6 ± 2.8#	15 ± 2*	19.8 ± 2.7*	21.1 ± 4.0*
RV mass (mg)	143 ± 21	137 ± 19	414 ± 27#	165 ± 21*	207 ± 51*	214 ± 59*
LV + IVS (mg)	524 ± 29	530 ± 33	696 ± 15	617 ± 178	639 ± 196	690 ± 156
RV/BW	0.49 ± 0.01	0.47 ± 0.04	1.66 ± 0.15#	0.54 ± 0.06*	0.69 ± 0.1*	0.71 ± 0.2*
RV/LV + IVS	0.26 ± 0.01	0.26 ± 0.03	0.60 ± 0.05#	0.28 ± 0.05*	0.33 ± 0.06*	0.31 ± 0.07*

PAH was assessed on day 43 following MCT treatment. MCT induced significant PAH (air vs. no MCT) as assayed by mPAP, RV mass, and the ratios of RV/BW and RV/LV + IVS. CO treatment, when started on days 1–14, 15–28, or 29–42, prevented or reversed MCT-induced changes in the heart and lung parameters listed. n = number of animals/group. #, P < 0.01 versus no MCT; and *, P < 0.01 versus air + MCT. BW, body weight.