Effects of pioglitazone on the expression of aortic VCAM-1 in rabbits fed with high-fat diets

Objective To exam the effects of Pioglitazone on the expression of aortic VCAM-1 in rabbits fed with high-fat diets. Methods Fifteen healthy male New Zealand rabbits were randomly divided into three groups to receive 8 weeks of normal diet (control group, n=5), high cholesterol diet (high-cholesterol group, n=5) or high cholesterol diet plus 3 mg·kg·d-1 pioglitazone added from the fourth week of cholesterol diet (pioglitazone treatment group, n=5). The pathomorphology of rabbit aorta was studied with haematoxylin-eosin staining, and expression of VCAM-1 in rabbit aorta detected using immunohistochemistry. Results Pioglitazone appeared to decrease intimal hyperplasia and smooth muscle cell proliferation in aorta of rabbits fed with high-cholesterol diet. Furthermore, pioglitazone significantly improved the level of high density lipoprotein but showed no effects on TG, TC and LDL-C. Expression of aortic VCAM-1 was also markedly reduced with Pioglitazone treatment as compared with rabbits on high-fat diet alone (0.42±0.11 vs 0.78±0.16,P0.01). Conclusion Pioglitazone may inhibit the upregulation of VCAM-1 in aorta of hypercholesterolemic rabbits, possibly resulting from its effects on nucleus transcription factors. These findings provide new insights into a potentially novel anti-atherosclerotic pathway by thiazolidinediones.