Fig. 4

Ipriflavone (IP) reduced the degeneration of cartilage by blocking the Indian hedgehog pathway in vivo. a The results of Safranin O staining indicated that there was less surface damage with stronger Safranin O staining in articular cartilage specimens from IP-treated animals compared with the ACLT group at 12 weeks after the operation. Cartilage destruction was quantified and compared with the ACLT group, and the summed OARSI scores were significantly decreased in the IP treatment group. Data are expressed as means ± SDs. (n = 10), *P < 0.05 **P < 0.01. b Type II collagen expression in articular cartilage was higher in IP-treated and sham-operated rats than in rats that underwent ACLT without treatment. In contrast, degraded collagen II (type II collagen-C fragment), type X collagen, and matrix metalloproteinase 13 (MMP-13) staining levels were elevated in rats that underwent ACLT without treatment with respect to the IP-treated and sham-operated rats, which is consistent with reduced OA damage. c Real-time PCR results indicated that the expression of key genes in the Ihh pathway (Smo, Gli-1, Gli-2, Gli-3) was increased in rats that underwent ACLT without IP treatment and reduced in IP-treated rats at 12 weeks after the ACLT operation, especially Smo and Gli-2. Concomitantly, type II collagen and Agg expression in articular cartilage was elevated in IP-treated and sham-operated rats compared with rats that underwent ACLT without treatment. In contrast, type X collagen and matrix metalloproteinase 13 (MMP-13) were elevated in rats that underwent ACLT without IP treatment, and their expressions were reduced in IP-treated rats at 12 weeks after the ACLT operation, consistent with the reduced OA damage. Values are the mean ± SEM. P < 0.05 versus the ACLT and IP treatment group