Fig. 6: Bone regeneration using rBMSC-encapsulated shell-hardened macroporous hydrogels in rabbit models.

a Schematic depicting the surgical procedure for creating bone defects and filling them with hydrogel in New Zealand white rabbits. A defect (diameter ~5 mm) was created in the femoral condyle, followed by implantation of rBMSC-encapsulated hydrogel into the defect. Scale bar: 5 mm. b Overall views of the bone defect regions for the SP-low hydrogel and control groups 12 weeks post-implantation. The blank group served as the control. Scale bar: 5 mm. c Bone regeneration assessed through micro-CT analysis for different groups at 12 weeks post-implantation. Scale bar: 2.5 mm. d Quantitative micro-CT analysis for different groups, including bone volume/total volume (BV/TV), trabecular thickness (Tb. Th), trabecular number (Tb. N), and trabecular separation (Tb. Sp). Values represent the mean and the standard deviation (n = 5 independent samples). The p-values for the comparisons of BV/TV between the SP-low group and the control, NP-low, NP-high, and SP-high groups are 0.000001, 0.0001, 0.0024, and 0.0141, respectively. For Tb. Th, the p values are 0.0000009, 0.00002, 0.0058, and 0.0273, respectively. For Tb. N, the p values are 0.000002, 0.000004, 0.0010, and 0.0008, respectively. For Tb. Sp, the p values are 0.00000007, 0.0009, 0.0185, and 0.0480, respectively. Statistical significance between different groups and the SP-low group was assessed using two-tailed Student’s t-test. *p < 0.05; **p < 0.01; ***p < 0.001; NS: not significant. e, Representative histological images showing H&E staining, Masson’s trichrome staining, Trap staining, and immunofluorescence staining of Col I, Col X and IBSP (shown in red) for regenerated bones at 12 weeks post-implantation. Cell nuclei were counterstained with DAPI (blue) in immunostaining. The arrows indicate the specific areas of interest.