Expression of PTHrP in the condyle cartilage after traction of the mandibular ramus and zygomatic arch in rabbits / 实用口腔医学杂志

Objective:To understand the roles of PTHrP in the pathogenesis of temporomandibular joint after over mechanical loading. Methods:Fifteen adult New Zealand rabbits were subjected to traction between the mandibular ramus and zygomatic arch in the postero-superior direction unilaterally using elastic force. The rabbits were killed respectively at 2, 4 and 6 weeks and the histologic changes were observed by Hematoxylin & Eosin staining. The expression of PTHrP in the condyle of TMJ was observed by immunohistochemistry. Results:Stronger expression of PTHrP could be found in proliferation cell layers and upper hypertrophy cell layers in the early stage after operation, and weaker expression in mid stage, but stronger near the chondrocyte clusters. Conclusion:It is suggested that PTHrP might relate to the regeneration of condyle cartilage.

Experimental study on chitosan-polyelectrolyte complex as a scaffold for cartilage regeneration in vivo / 实用口腔医学杂志

Objective:To investigate whether chitosan-polyelectrolyte complex (CS-PEC) can be used as scaffold for chondrocyte culture and for cartilage regeneration in vivo.Methods:Condylar chondrocytes of fetal mouse were seeded onto the three-dimension gel scaffolds of CS-PEC and cultured.The cultured chondrocytes/CS-PEC complex samples were transplanted subcutaneously into nude mice and the CS-PEC scaffold without chondrocyte was used as the control.The animals were sacrificed 4 and 8 weeks after operation respectively.Cartilage formulation was observed by histological and immunohistochemical methods.Results:In the in vitro culture the majority of cells attached to the CS-PEC surface and expanded rapidly. 4 weeks after transplantation,in the chondrocytes/CS-PEC complex the scaffold maintained mostly the original structure. Hypertrophic chondrocytes appeared in scaffold materials. CollagenⅡwas positive in the new cartilage. 8 weeks after transplantation the scaffold degraded almost completely and new cartilage could be observed. CollagenⅡ and cartilage matrix was positive in the new cartilage and the collagen I was positive in the surrounding fibroblast-like cells. In control transplants,8 week after transplantation some fibre-like tissue formed in the circumference, but there was no new cartilage formation and the collagen II and the cartilage matrix was negative.Conclusions:CS-PEC may be used as scaffold for fibre-cartilage regeneration.