Exposure of rabbits to carbon monoxide and other gas phase constituents of tobacco smoke.

Non cholesterol-fed rabbits were exposed to carbon monoxide at concentrations in air of either 200, 2000, or 4000 ppm (= 0.02, 0.2, or 0.4% vol/vol). Further, exposure was performed to 0.5 ppm hydrogen cyanide alone or in combination with 200 ppm carbon monoxide or with 200 ppm carbon monoxide and 5 ppm nitric oxide and eventually to 50 ppm carbonyl sulphide. Duration of the continuous exposures were between 1/2 week and 12 weeks. Using the same criteria for intimal damage as in earlier morphological studies, no histotoxic effect on intimal/subintimal morphology of coronary arteries or the aorta could be demonstrated, when light-microscopic evaluation was performed blindly.