Fig. 1.

a H&E stain of cartilage tissue for the sham group, ×200 magnification Grade 0 (arrows represented the smooth cartilage surface and organised chondrocytes). b H&E stain of cartilage tissue for the PEMF group, ×200 magnification Grade 1 (arrows represented retention of the articular surface layer). c H&E stain of cartilage tissue for the estrogen group, ×200 magnification Grade 1 (arrows represented retention of the articular surface layer). d H&E stain of cartilage tissue for the OVX group, ×200 magnification Grade 2 (arrows represented focal discontinuity of the cartilage superficial zone)