Knee sections, stained with Toluidine blue, showing effects of sham operation (a,c) or ovariectomy (b,d) in 7-month-old rats. In (c) and (d), the structure of the collagen fibers is visualized by polarized light. The sham-operated rat (a,c) shows a healthy articular cartilage surface, whereas the ovariectomized rat (b,d) shows surface erosion (b, framed area) and alterations in the structure of the collagen fibers (d, framed area). Scale bars: 200 μm.
Høegh-Andersen et al. Arthritis Res Ther 2004 6:R169-R180 doi:10.1186/ar1152