Evaluation of the effects of glimepiride (Amaryl) and repaglinide (novoNorm) on atherosclerosis progression in high cholesterol-fed male rabbits

BACKGROUND: Atherosclerosis is an inflammatory disease of the blood vessel wall, characterized in early stages by endothelial dysfunction, recruitment and activation of monocyte/macrophages. Glimepiride is one of the third generation sulphonylurea drugs, useful for control of diabetes mellitus type two and it may exert anti inflammatory activity, by induction of nitric oxide production or through selective suppression of the cyclooxygenase pathway. Repaglinide is a new hypoglycemic agent, and a member of the carbamoylmethyl benzoic acid family. Some results from the literature demonstrate that repaglinide has favorable effects on the parameters of antioxidative balance. OBJECTIVES: The objective of the present study was to assess the effect of glimepiride and repaglinide on atherosclerosis via interfering with the inflammatory and oxidative pathways. MATERIALS AND METHODS: Twenty four local domestic male rabbits were involved in this study. The animals were randomly divided into four groups; Group I rabbits fed normal chow (oxiod) diet for 10 weeks. Group II rabbits were fed with 1% cholesterol enriched diet. Group III rabbits were fed with 1% cholesterol enriched diet together with Glimepiride (0.1 mg/kg once daily before morning feed). Group IV rabbits were fed with 1% cholesterol enriched diet together with Repaglinide (0.3 mg/kg once daily before morning feed). Blood samples were collected before (0 time) and every two weeks of experimental diets for measurement of serum triglycerides (TG), total cholesterol (TC), High-density lipoprotein cholesterol (HDL-C), high sensitive C - reactive protein (hsCRP), Interleukin – 6 (IL-6) and Tumor Necrosis Factor alpha (TNF-α) levels. At the end of 10 weeks, the aorta was removed for measurement of aortic Malondialdehyde (MDA), reduced glutathione (GSH) and aortic intimal thickness. RESULTS: Glimepiride and repaglinide treatment did show significant effect on lipid parameters compared with induced untreated group (P < 0.05). Also, they significantly reduced the elevation in hsCRP, IL-6, TNF-α, aortic MDA and aortic intimal thickness compared with induced untreated group (P < 0.05), and they helped to restore the aortic GSH levels (P < 0.05). CONCLUSIONS: Glimepiride and repaglinide may reduce atherosclerosis progression in hypercholesterolemic rabbits by interfering with the inflammatory and oxidative pathways without affecting lipid parameters.