Fig. 7. Ex vivo microCT and histological evaluation of femoral defect healing induced by engineered hMSC condensate tubes and sheets.

a Representative 3-D microCT defect reconstructions, implanted with hMSC tubes or sheets containing TGF-β1 + BMP-2-loaded microparticles, with b mid-shaft transaxial (top) and sagittal (bottom) sections at week 12, selected based on mean bone volume. Scale bars, 2 mm. Morphometric analysis of c bone volume fraction, d trabecular number, e trabecular thickness, f trabecular separation, and g ectopic bone volume (i.e., bone extending beyond the 5-mm defect diameter) (n = 4 (tubes) or 3 (sheets) biologically independent samples per group; blue circles = hMSC tubes; cyan squares = hMSC sheets; open symbols = non-bridged; closed symbols = bridged) shown with reference data from large hMSC sheets containing TGF-β1 + BMP-2-loaded microparticles in c–f (from ref. ³³), or BMP-2 soaked on collagen in g (from ref. ³³). h Representative histological Hematoxylin & Eosin (H&E), Masson’s Trichrome (TC), and Safranin-O/Fast-green (Saf-O) staining of sagittal defect explant sections showing the defect margin and central defect; images oriented distal-to-proximal from bottom-to-top. i Representative H&E staining and in situ hybridization for human Alu repeats of sagittal defect explant sections. Scale bars, 100 μm (dotted squares in insets show region of interest in high magnification image). Individual data points are shown with mean ± SD. Analyzed by unpaired Student’s t-test (p < 0.05 or lower considered significant).