Fermented mealworm extract prevents concurrent bone and muscle loss by modulating RANKL-NFκB/MAPK signaling in ovariectomized mice.

This study investigated whether fermented mealworms extract (FME) can simultaneously improve postmenopausal osteoporosis and muscle atrophy, along with the underlying mechanisms. Female C57BL/6 N mice were divided into five groups: sham-operated, ovariectomized (OVX), OVX treated with two doses of FME (200 and 500 mg/kg, oral), and OVX treated with alendronate (Alen, 500 μg/kg, oral) as a positive control, for 15 weeks. FME500 significantly increased grip strength, whereas FME200 showed no significant improvement compared to the OVX group. Muscle cross-sectional area significantly increased in both FME groups compared to the OVX group. FME500 also enhanced muscle protein synthesis markers (MyoD1 and MHC) and more effectively suppressed muscle degradation markers (MuRF-1, atrogin-1, myostatin, and polyubiquitinated proteins) than FME200. In bone, both FME doses improved bone density and serum levels of RANKL and CTX-1 compared to the OVX group. FME500 more effectively downregulated RANKL, IL-6, and TNF-α expression in both bone and muscle than FME200 in OVX group. Mechanistic analyses were performed mainly in the FME500 group, which downregulated NFκB/MAPK and upregulated IGF-1-PI3K-Akt in both bone and muscle. These results indicate that FME suppresses the postmenopausal concurrent bone and muscle loss by regulating RANKL-NFκB/MAPK and IGF-1-PI3K-Akt signaling pathways.