[Effects of maxillary growth of Wistar rats with bilateral artificial cleft palate after premaxillary orthopedic treatment on expression of proliferating cell nuclear antigen(PCNA)].

OBJECTIVE: Being based on the principle of Latham's appliance, this experiment is designed to detect activity of osteoblasts in the maxillary sutures of Wistar rats with bilateral artificial cleft palate by immunohistochemistry technique, and evaluate the effects of this appliance on the growth and development of the maxilla.

METHODS: The animal models of male infant Wistar rats with bilateral cleft palate were made by removing some palatal bones, splitting a "V" gap of 1.5 cm wide at the line between premaxilla and segments of maxilla. A sort of appliances, which could be fixed in the mouth of Wistar rats with bilateral cleft palate for correcting protrusion premaxilla was constructed basing on the principle of Latham's appliance. Then the diferent pathological changes of osteoblast proliferation between the experimental group and the two controlled groups were examined. The jugomaxillary sutrues, temporomalar sutures and sphenoipalatine suture were harvested 7, 14 days after premaxillar orthopedic treatment, followed by 4% paraformaldehyde fixing about 1 hour, demineralization with 15% EDTA and 0.5% paraformaldehyde for 48 hours, distilled water washing for a night, dimethylbenzene transparant dealing, and paraffin wax embeding. Proliferating Osteoblasts in all these sutures were investigated using immunohiostochemical technique with monoclonal antibodies of proliferating cell nuclear antigen (PCNA).

RESULTS: Seven days after orthopedic treatment, no significant difference was observed between the experimental group and the two controlled groups. While after fourteen days, obvious PCNA-positive expression were observed in cells of all these sutures of the experimental group.

CONCLUSION: The distribution of proliferating cells and the degree of cell proliferation change after premaxillary orthopedic treatment. And significant cell proliferation is observed in the experimental group, but there are no significant differences between the two controlled groups.