[Repair of buccal mucosal defects by tissue engineered oral mucosa lamina propria]

To evaluate the effect of using tissue engineered oral mucosa lamina proprias to repair buccal mucosal full-thickness defects in rats.

Cultured oral mucosal fibroblasts(OMF) of Wistar rat were incorporated into chitosan-collagen to construct tissue engineered oral mucosa lamina proprias, then the OMFs were labeled with 5-BrdU. Full-thickness round mucosal defects were made with round knife (diameter of 0.8 cm) on the buccal mucosas of 21 Wistar rats(21-25 weeks old) which were divided in fibroblast-populated chitosan collagen lattices(FPCCL) group with FPCCLs transplantation and control group covered with gauges alone. All wounds were observed by macrograph or under optical microscopy and measured on 4th, 7th, 14th and/or 21st day postoperatively. The data were analyzed by SPSS11.5 software package for Student's t test.

There were no infection through the wound healing process. On the 7th day after grafting, the wounds of two groups were covered by yellow membrane, on the 14th, 21st day, the wounds of two groups were covered by new epidermis thoroughly, the color of new epidermis was similar to the normal one. On the 7th day, the wound diameter of control group was significantly smaller than that of FPCCL group (P<0.05). Under optical microscopy each mucosal wound in two groups was only partly keratinocyted with new granular tissue rich in inflammatory cells, fibroblasts, new vessels on the 7th day postoperatively. The wounds in two groups were keratinocyted thoroughly with rete ridges and horny layer on 14th and 21st day. OMFs with 5-BrdU appeared in the granular tissue and new lamina propria on 7th, 14th and 21st day postoperatively by immunohistochemical staining, OMFs together with granular tissue were joined in the repair of buccal mucosal defects without allergic reaction through the whole wound healing process.

It is suggested that OMFs as the seed cells can join in the repair of buccal mucosa defects effectively; chitosan-collagen lattices have good histocompatibility; Limitation of contraction of recipient wounds will be closely related to FPCCLs; therefore, FPCCLs can repair buccal mucosal defects effectively.