Objective To investigate the expression of TGF-β1mRNA in pubescent Rhesus monkeys′condylar under ClassⅢ intermaxillary functional orthopedic force for different lengths of time.Methods Six pubescent Rhesus monkeywere divided into two test groups and a control group. Monkeys in the test groupsworeTMAⅢwhile the control groups did not. Histological method (HE staining) and in situ hybridization were employed in this study.Results ①The histological results showed that, compared with the control group, the anterior part of the condyle became thickerwhile the median part and the posterior part became thinner in 3 months group. However, in 6 months group,the change was similar to 3 months group.②The results of in situ hybridization showed that, in control group, TGF-β1 mRNAmildly expressed in the anterior part of the condyle while extensively in the median and posterior parts. In 3 months group, TGF-β1 mRNA expressed in all parts of condyle; the most intensive expressionwas in the anterior part. Comparedwith 3 months group, the expression ofTGF-β1 mRNAdecreased in 6 months group, butthe expression in anterior part was stronger than in median and posterior parts.Conclusion Under ClassⅢOrthopedic therapy, TGF-β1 mRNA probably participated in the endochrondral bone remodeling in the condyle, and the expressionwas closely related to loading time. In 3 months group, the expression ofTGF-β1 mRNAwas stronger than that in 6 months group. Itwas inferred that the remodeling of endochrondral bone was more active in 3 months group.
