Objective The purpose of the study is to detectthe expression ofTGF-β1 mRNA in the maxillary sutures of puberty rhesus during different periods of the loading of intermaxillary classⅢorthopedic force.Methods The animal model was estab- lished with 6 puberty female rhesus, whichwere randomly divided into experimental group(wearing classⅢtwin-blockmagnet ap- pliance, each 2 rhesus for 3 and 6 month respectively) and control group(not wearing any appliance, each 1 rhesus for 3 and 6 month respectively ). Tissue sections were obtained perpendicular to the sutures. In situ hybridization was used to the expression of TGF-β1 mRNA, and the expression intensitywasmeasured and statisticswas performed by SPSS 11.0.Results Therewere no statistic differences of cellular density between palatomaxillary suture in vertical group and pterygomaxillary suture in horizontal group, but statistic differences were found between other groups. The expression of TGF-β1 mRNA was detected in the control group, but the expression intensity was obviously increased after the load of intermaxillary classⅢorthopedic force. Statistically significant differences were found among all groups exceptthe sixmonths experimental group and control group of temporozygomatic sutures and pterygomaxillary sutures. Experimental groups were more intensive than the control group and three months group was more intensive than the six months group.Conclusion The active tissue remodeling happened in the circummaxillary sutures by the effect of classⅢintermaxillary orthopedic force. Cell proliferation, extracellularmatrix synthesis and bone formationwere ac- celerated. During the different remodeling periods, the expression intensities were different, which may be related to the different force loading manners, the different reaction of sutures tothe orthopedic force and the different biological function ofTGF-β1 in the different periods.
