Fig. 6

Histological photomicrographs showing defects after 6 weeks in different studied groups; non-interventional group (Panels A and E), Panel A shows the overall structure of the defect site that is filled with GT with very thin Nb radiating from Pb, Panel E focuses on Nb that of Wb in nature. Collagen group (Panels B and F), Panel B shows the defect filled with GT with very thin Nb radiating bridging Pb and covered with P, Panel F focuses on Nb which is Wb in nature enclosing Mc. hDPSCs’ secretome group (Panels C and G), and hGMSCs’ secretome group (Panels D and H), Panels C and D show the defect obliterated with thick Nb covered with P, Panels G and H show thick Nb which is Wb in nature enclosing Mc. Some Haversian systems could be detected (yellow circles) (GT: Granulation tissue, Pb: Parent bone, P: Periosteum, Nb: Newly formed bone, Wb: Woven bone, MC: Bone marrow cells). (Hx & E stain, panels A, B, C & D: Orig. Mag. 40 and panels: E, F, G & H: Orig. Mag. 400).