Fig. 7

The histopathological features of osteoarthritic lesions in the knee joints of rats at 21 days after intra-articular injection of monoiodoacetate (MIA). Ovariectomized (OVX) rats were provided with a 45 % fat diet containing (1) 0.4 % curcumin, (2) 0.4 % tetrahydrocurcumin (THC), (3) 30 μg/kg body weight 17β-estradiol + 0.4 % dextrin (positive control), (4) 0.4 % dextrin (control), or (5) 0.4 % dextrin (normal control for osteoarthritis). At the beginning of the fifth week, an articular injection of monoiodoacetate into the right knee was performed on all OVX groups except the normal-control group and the assigned diets were provided for an additional 3 weeks. Rats in the normal-control group had an articular injection of saline in the right knee. The depth and extent of cartilage damage and the quantification of the damage (a) and histology (b) were determined in hematoxylin-eosin-stained, paraffin-embedded knee joint sections from MIA-injected rats (magnifying power ×10). In addition, the depth and extent of cartilage damage and quantification of the cartilage damage (c) and histology (d) in the MIA-injected knees were evaluated in safranin-O fast green-stained, paraffin-embedded knee joint sections from the osteoarthritic rats (magnifying power ×10). Each bar and error bar represents the mean ± SD (n = 5). (a, b, c, d, e) Values of the bars with different superscripts were significantly different among groups by the Tukey test at P < 0.05