Skeletal muscle protein degradation induced by high-fat diet is decreased by macadamia oil supplementation: Role of E3 ubiquitin enzyme ligase MuRF-1 and atrogin-1

This study aimed to assess the effect of macadamia oil (MO) on expression of genes involved in proteolytic pathways (Murf-1 and Atrogin-1) in diet-induced obese C57/BL6J mice. Mice were fed a control or a high-fat diet (HFD) and supplemented or not with MO (2.5 mg/kg) for eight weeks. mRNA levels of MuRF-1 and atrogin-1/MAFbx were evaluated in EDL muscle by real-time PCR. Mice fed a HDF presented decreased EDL weight when compared to control diet (0.28 vs 0.39, respectively), suggesting muscle atrophy. MO supplementation decreased this effect (0.28 vs control 0.34; p<0.05). A significant two-fold increase in mRNA levels of MuRF-1 and atrogin-1/ MAFbx, in EDL muscle, was found in mice fed a HFD. On the other hand, MO supplementation restored mRNA levels of Murf-1 and Atrogin-1 in mice fed a HFD to control levels, suggesting a protective effect on the pathways involved in the HFD-induced proteolysis. Our data suggest that the increased skeletal muscle degradation induced by HDF is decreased by MO supplementation by a mechanism that involves reduced RNAm expression of Murf-1 and Atrogin-1. Support: FAPESP, CNPq, CAPES, Dean's Office for Research/USP, Clear, INOD, and NEL.