Fig. 4

At 24 weeks in PVA/n-HA+PA66 implant group, immunohistochemical detection of type II collagen showed positive staining on the surface and in the peripheral region of the polyvinyl alcohol implant (×100) (a). At 24 weeks in the PVA implant group, weak type II collagen staining was observed in the gap between the PVA biomaterial and the adjacent tissue(×100) (b). At 24 weeks in the control group, a small amount of type II collagen was present, presenting as weak positive staining on the surface of the defect (×100) (c)