Abstract:

Abstract:Objective To study the expression levels of Sox9 and collagen Ⅱ in condylar chondrocytes after treated with different modes of mandibular advancement in rats,and to clarify the effects of different modes of mandibular advancement on the expressions of Sox9 and collagen Ⅱ as well as formation of cartilage in condyle.Methods  Twenty-eight male 35-day-old Wistar rats were randomly divided into dynamic,static,functional and control groups(n=7),and received different modes of mandibular advancement according to their groups.2 weeks 　after the experiment,temporomandibular joint sections were prepared for immunohistochemical staining,and the expression levels of Sox9 and collagen Ⅱ in condylar chondrocytes were semi-quantitatively evaluated.Results The number of Sox9 positive cells in control group,dynamic group and functional group was significantly higher than that in static group(P<0.01),the Sox9 positive expression areas in dynamic group and control group were statistically larger than those in static group and functional group(P<0.01),the positive expression area of collagen Ⅱ in functional group was significantly higher than those in the other three groups(P<0.01),and the positive  expression area of collagen Ⅱ in static group was higher than that in control group(P<0.05).Conclusion The modes and duration of mandibular advancement play a key role in regulating the expressions of Sox9 and collagen Ⅱ in condylar chondrocytes.

Key words: mandibular advancement, Sox9, collagen Ⅱ, endochondral ossification