Histological evaluation of ipsilateral knees (A) Safranin O/Fast Green (SO/FG) staining showed degenerated cartilage with lesions in OA animals, while OA + US animals showed less severe developed OA (top row). Magnified image of the red box in the first row (middle row). Increased tartrate-resistant acid phosphate 5 b activity was observed in OA, and suppression of the activity in OA + US (bottom row). Scale bar = 100 μm (B) SO/FG scoring showed significantly increased cartilage degeneration in OA and mitigated symptoms in OA + US animals (C–D) Osteoclast surface per bone surface (Oc.S/BS) and a number of osteoclasts per bone surface (N.Oc/BS) showed a significant increase in OA animals and reduced expression in OA + US. ∗:p < 0.05, ∗∗:p < 0.01, ∗∗∗:p < 0.001, ∗∗∗∗:p < 0.0001, #:p < 0.10. Results are shown as mean ± SD. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)