OBJECTIVETo investigate the change and correlation of carbon monoxide/heme oxygenase and nitrogen monoxide/nitric oxide synthase system in atherosclerosis and the influence of the two systems on atherosclerotic progress.

METHODSThe rabbits received 1% cholesterol diet (chol group, n = 8), or 1% cholesterol diet plus L-arginine (L-arg group, n = 8) or L-NAME (L-NAME group, n = 8) by drinking water, or 1% cholesterol diet plus heme-L-lysinate (Heme group, n = 8) or ZnPP-IX (ZnPP group, n = 8) by injection in abdominal cavity for 10 weeks.

RESULTSCompared with those in control group, aortic NO production and expression of NOS decreased markedly; while CO production (P < 0.01) and HO-1 activity increased obviously in chol group. The aortic plaques area was (40.2 +/- 8.9)% in chol group. Compared with those in chol group, aortic areas [(26.6 +/- 9.2)%] reduced distinctly in heme group, aortic CO production and NOS activity increased obviously (P < 0.01) in L-arg group. However, compared with those in control group, HO-1 expression and CO production decreased markedly (P < 0.01) in heme group, while they were not different from those in chol group. Compared with those in chol group, aortic cNOS activity and NO production increased obviously and aortic plaques area [(28.1 +/- 7.7)%] greatly reduced (P < 0.01) in L-arg group. However, HO-1 expression and CO production of L-arg group decreased distinctly compared with those of control group, but they were similar to those of chol group. The aortic c-myc and c-fos expressions in both heme group and L-arg group reduced markedly compared with those in chol group, while they were similar to those in ZnPP and L-NAME group.

CONCLUSIONThe reciprocal relationship between heme oxygenase/carbon monoxide and nitric oxide synthase/nitrogen monoxide system in atherosclerosis may play the inhibitory role against atherosclerotic lesion.