Pioglitazone alleviates inflammation in diabetic mice fed a high-fat diet via inhibiting advanced glycation end-product-induced classical macrophage activation.

Classically activated macrophages (M1) are associated with inflammation in diabetic patients. Inflammation is a known risk factor in diabetes. The present study tested the hypothesis that pioglitazone (PIO) alleviates inflammation in diabetic mice fed a high-fat diet by inhibiting advanced glycation end-product (AGE)-induced classical macrophage activation. It was found that AGE treatment promoted the transcription of pro-inflammatory molecules and M1 surface markers, whereas PIO increased the expression of anti-inflammatory genes and decreased the expression of pro-inflammatory mediators in bone marrow-derived macrophages (BMDMs) in a dose-dependent manner. Furthermore, pretreatment with PIO abrogated the effects of AGE on pro-inflammatory markers and partly inhibited AGE-induced nuclear factor-κB (NF-κB) activation. PIO treatment partly reduced the inflammatory phenotype in diabetic ApoE(-/-) mice, and significantly reduced NF-κB activation in plaques. Therefore, we conclude that PIO blocks classical activation of macrophages and attenuates inflammation in mouse models of diabetes.