Ovariectomized hamster:: A potential model of postmenopausal hypercholesterolemia

Abstract

A suitable and economical animal model of ovarian hormone deficiency can greatly enhance the understanding of postmenopausal-elevated risk of coronary heart disease. The male Golden Syrian hamster is a well-established small animal model of hypercholesterolemia, but the effect of ovariectomy on lipid profile in the female hamster is unclear. The objective of this study was to determine whether ovariectomized hamsters develop hypercholesterolemia and experience changes in body fat distribution consistent with changes observed in postmenopausal women. Twenty-two 90-day-old female Golden Syrian hamsters were divided into two groups and were either ovariectomized or sham-operated and given free access to a standard cholesterol-free laboratory diet for 65 days. Ovariectomized hamsters had significantly ( P < 0.05) elevated serum total cholesterol concentrations (16.6%) as well as abdominal fat mass (56%; P< 0.01) despite equal food intake compared with the sham-operated group. In contrast, the mean intestinal weight and in vivo rate of sterol biosynthesis were significantly ( P < 0.002 and P = 0.01, respectively) lower in the ovariectomized compared with the sham-operated group. In vivo rates of hepatic sterol biosynthesis were directionally lower ( P = 0.1) in the ovariectomized group. No significant differences were observed in final body weight, serum triglycerides, or liver total cholesterol and lipids between the two groups. In conclusion, ovariectomized hamsters undergo changes in serum cholesterol and fat distribution similar to those experienced by postmenopausal women, and thus may serve as an appropriate model for postmenopausal hypercholesterolemia.