Effect of impaired glucose tolerance on atherosclerotic lesion formation: an evaluation in selectively bred mice with different susceptibilities to glucose intolerance.

OBJECTIVE: Impaired glucose tolerance (IGT) is an independent risk factor for atherosclerotic cardiovascular disease. However, due to the lack of appropriate animal models, the underlying mechanisms for IGT-induced atherosclerosis remain to be elucidated in vivo. We recently used selective breeding to establish 2 mouse lines with distinctively different susceptibilities to diet-induced glucose intolerance, designated selectively bred diet-induced glucose intolerance-resistant (SDG-R) and SDG-prone (SDG-P), respectively. Here, we assessed atherosclerotic lesion formation in these mice.
METHODS: Female SDG-R and SDG-P mice were fed an atherogenic diet (AD; 1.25% cholesterol, 0.5% sodium cholate, and 36% energy as fat) for 20 weeks (8-28 weeks of age). Oral glucose tolerance tests were performed during the AD-feeding period. Atherosclerotic lesion formation was quantitatively analyzed in serial aortic sinus sections by oil red O staining. Plasma lipids were measured after the AD-feeding period.
RESULTS: Glucose tolerance was impaired in SDG-P mice as compared to SDG-R mice over the 20-week AD-feeding period. No significant differences were observed in any plasma lipid measurement between the 2 mouse lines. Aortic sinus atherosclerotic lesion formation in SDG-P mice was approximately 4-fold greater than that in SDG-R mice.
CONCLUSION: In 2 mouse lines with different susceptibilities to diet-induced glucose intolerance, IGT accelerated atherosclerotic lesion formation. These mice may therefore serve as useful in vivo models for investigating the causal role of IGT in the pathogenesis of atherosclerosis.