Fig. 6

PEGS/20ICPN hydrogel improved both bone regeneration and vascularization in the regeneration zone. a Grouping scheme of rat tibial DO model. b Timeline for distraction protocol. c Application of external fixation and tibial osteotomy during surgery. Red arrow, osteotomy. Yellow arrow, application of PEGS/20ICPN hydrogel. d Representative 3D images of the distraction zone after consolidation for 4 weeks, indicating more continuous callus in the PEGS/20ICPN group. Red dotted lines illustrate the regeneration zone in between. e Representative images of HE, Masson, and immunohistochemical staining of RUNX2 and OCN. White arrows, cartilaginous tissue. Dotted arrows, fibrous-like tissue. Black arrows, newly regenerated trabecular bone. f, g Analysis of BMD and BV/TV of the new bone. h Mechanical properties including ultimate load, energy to failure and modulus of elasticity (E-modulus) of the regenerates. i, j Quantitative analysis of the immunohistochemical staining in (e). k, l Immunofluorescence images of CD31 and HIF-1α for the regeneration zone. m, n Quantitative analysis of the immunofluorescent staining in (k, l)