Pulp Regeneration By PTL Coating In Vivo

To investigate the in vivo dental pulp generation of phase-transited lysozyme (PTL) coated dentin scaffold composite with human dental pulp cells (HDPCs) by establishing a semi-in vivo model in nude mice. HDPCs were injected into the pretreated root segments which were divided into three groups: control group(without HDPCs or PTL),HDPCs group(without PTL) and PTL+HDPCs group, and then were heterotopically implanted into the subcutaneous tissue of male nude mice. After six weeks of feeding, samples were taken out, processed through fixation, decalcification, paraffin embedding ‌‌to make tissue sections. The regeneration effect of dental pulp tissue was evaluated by histological analysis using Thioflavin T staining, HE staining, Masson staining, immunofluorescence and immunohistochemistry staining. HE and Masson staining results showed that the PTL+HDPCs group had highest density of cells and collagenous fibers, richer extracellular matrix and formation of odontoblast-like cells, with higher proportion of new tissue area(P<0.05). Immunofluorescence staining results showed that the expression of DSPP and nestin in the PTL+HDPCs group were significantly higher than that in the HDPCs group. CD31 immunohistochemical staining result showed that the PTL+HDPCs group showed more vascular distribution and proportion than the HDPCs group(P<0.01). PTL coating has excellent in vivo stability and biological safety, and can promote the differentiation of HDPCs into odontoblast-like cells and vascularized pulp-like tissue formation in vivo, which has good application potential in pulp tissue engineering.