Hematologic and biochemical profiles of selectively bred WHHL rabbits

In Watanabe heritable hyperlipidemic (WHHL) rabbits, hypercholesterolemia and hypertriglyceridemia develop from birth, because of a deficiency of low-density lipoprotein receptors, and are followed by a consequent early development of aortic atherosclerosis. This closely resembles human familial hypercholesterolemia. Starting in 1984, we have developed a closed colony by breeding two male and two female homozygous WHHL rabbits, obtained from Japan (Dr. Watanabe, Kobe University). In our facility, the application of a selective breeding program, strictly based on mating parents that both have high serum lipid concentrations, has produced markedly elevated cholesterol (701 +/- 172 mg/dl, mean +/- SD) and triglyceride (780 +/- 325 mg/dl) concentrations in weaning rabbits. Clinical chemical analysis revealed no kidney or liver function abnormalities even in animals with extremely high lipid concentrations, and hematologic profiles were very similar in WHHL and age-matched New Zealand White rabbits, with the exception of platelet count, which was significantly higher in WHHL rabbits. Platelet aggregation induced by collagen and platelet-activating factor was significantly reduced in WHHL rabbits, whereas thrombin and prothrombin times appeared normal when compared with those in New Zealand White rabbits.