The effect of chromium on established atherosclerotic plaques in rabbits.

Twenty-three rabbits were fed for 8 weeks with standard diet to which was added a 1.5% cholesterol supplement. After this the cholesterol supplement was discontinued, but 11 rabbits received a daily intraperitoneal injection of 20 micrograms of potassium chromate while the remaining 12 received distilled water. The aortas were examined after a further 30 weeks; their mean weight per unit length was 1.27 g (SE +/- 0.17) in the control group and 0.81 g (SE +/- 0.08) in the chromium treated group (t = 2.36; P < 0.05). The percentage area of intimal surface covered by plaques was 94.8% (SE +/- 1.7) and 62.6% (SE +/- 10.4), respectively (t = 3.53; P < 0.005), and the total cholesterol content per unit length of aorta was 729 mg/100 ml (SE +/- 44.0) and 457.8 mg/100 ml (SE +/- 117.1), respectively (t = 23; P < 0.05). The results show a significant effect of chromium on the regression of cholesterol-induced atherosclerotic plaques in rabbits.