EFFECTS OF ETIDRONATE AND LOVASTATIN ON THE REGRESSION OF ATHEROSCLEROSIS IN CHOLESTEROL-FED RABBITS

Eighty New Zealand rabbits in eight groups (10 each) were fed a 0.5% c holesterol diet for 12 weeks. One group served as a control and was sa crificed at the end of 12 weeks. Seven other groups were shifted to a normal diet and received a drug(s) or placebo for the second 12 weeks. The high dose of etidronate (3 mg/kg/day) with lovastatin (6 mg/kg/da y) significantly reduced the percent of aortic atherosclerotic lesions [56 +/- 21 vs. 77 +/- 17% (mean +/- SD), p < 0.05] in the regression study. Compared to the control groups for etidronate and lovastatin, t he high or low dose (0.15 mg/kg/day) of etidronate significantly reduc ed aortic standardized plaque volume per unit (18.7 +/- 7.9 or 18.8 +/ - 9.1 vs. 28.4 +/- 11.8 mm.%, p < 0.05). Lovastatin reduced pulmonary artery maximum plaque thickness (0.13 +/- 0.10 vs. 0.23 +/- 0.11 mm, p < 0.05). There were no differences in serum lipid and calcium levels in the control and treated groups. The high dose of etidronate inhibit ed bone mineralization as expected, whereas the low dose of etidronate did not. These data suggest that etidronate with lovastatin can regre ss aortic atherosclerosis in the cholesterol-fed rabbit placed on a no rmal diet.