The effects of chronic carbon monoxide treatment on diet-induced obesity and Rev-erb-alpha target gene expression in adipose tissue

Abstract

The present study determined if carbon monoxide (CO) treatment reversed diet-induced obesity and insulin resistance. Because CO is a potential ligand for the nuclear receptor Rev-erb-α, we also determined if CO treatment altered the mRNA expression of Rev-erb-α targets. Mice were fed a low fat diet (LFD) or a high fat diet (HFD) for 150 days. Following 110 days of the dietary intervention the HFD-fed mice were assigned to a CO inhalation group or a control group. The HFD-CO group was exposed to 250 ppm CO for one hour per day for 40 consecutive days. Body weight and edpididymal white adipose tissue (EWAT) mass were significantly elevated in HFD and HFD-CO mice compared to LFD mice, but no differences existed between HFD and HFD-CO mice. Area under the insulin-assisted glucose tolerance curve was significantly elevated in HFD and HFD-CO mice compared to LFD mice, but no differences existed between HFD and HFD-CO mice. Heme oxygenase-1 (HO-1) mRNA was significantly higher in EWAT of HFD-CO compared to HFD mice, indicating effective delivery of CO to adipose tissue. CO treatment did not alter Rev-erb-α expression or Rev-erb-α targets. These results indicate that CO inhalation does not attenuate diet-induced obesity/insulin resistance.