Figure 4.

Regeneration of tubular tissues in vivo using a 3D micropatterned matrix. The cell/matrix constructs were implanted in nude mice for 4 weeks. (a–d) Masson’s trichrome staining shows a thick layer of well-organized tubular dentin that was regenerated in the tubular matrix group (a, c); while no tubular dentin structure was formed in the non-patterned control group (b, d). In addition, a palisading odontoblast layer was aligned along the surface of the newly formed tubular dentin. (b) and (d) are the high magnification images of (a) and (b), respectively. (e, f) SEM images of cell/matrix constructs after being implanted in vivo for 4 weeks. The long processes of cells embeded in the fibrous matrix were clearly observed in the micropatterned group (yellow arrowheads in e), but not in the non-patterned group (f). (g, h) Immunohistochemical staining of DSPP in both the tubular micropatterned and non-micropatterned groups. DSPP, which is considered the dentin-specific marker of odontoblasts, was highly expressed in the tubular micropatterned group (yellow arrows in g), but not in the non-micropatterned control group, indicating the pivotal role of the tubular architecture in odontoblastic differentiation and tubular dentin regeneration.