Figure 4

LIPUS maintains cartilage homeostasis depending on autophagy. A) Reproductive strategies for transgenic mice. B) Genotyping by PCR to confirm the Cre recombinase and homozygous floxed ATG7 in product. C)ATG7 deletion was confirmed by immunohistochemistry of the articular cartilage. Scale bar, 50 µm. D) Quantification of ATG7‐positive cells in the articular cartilage (n = 3 mice). E) Schematic of the transgenic mice experiment procedures. F) Safranin O–Fast Green staining of the knee joint after LIPUS in ATG7cKO and control mice. Scale bar, 100 µm. The joint degradation was evaluated histologically by the OARSI recommended scoring system. Maximal scores G) and summed score H) were calculated for the MTP (n = 6 mice). I) Immunohistochemical staining of Collagen II and MMP‐13 in the articular cartilage of ATG7cKO and control mice. Scale bar, 20 µm. J) Quantification of MMP‐13‐positive cells (n = 5 mice). Data are presented as means ± SD. Statistical analysis was performed using Student's t test. ***(P < 0.001), **(P < 0.01), *(P < 0.05), ns (0.05 < P).