Expression Of MMP-2and MMP-9mRNA In Gingival Tissue During Orthodontic Tooth Movement

Objective:1、To establish the gingival tissue remodeling model of orthodontic tooth movement, and to further study on gingival remodeling.2、To investigate the mRNA expression of MMP-2、MMP-9, and the possible role which play in during orthodontic tooth movement.Methods:Twenty-eight New Zealand rabbits were chosen and divided into three groups (no appliance control group, the sham appliance group, the experimental group). The mandibular incisor were used as anchorage, left mandibular first molar were mesially moved with NiTi coil springs or stainless steel wire ligation, the pressure side gingiva of mandibular first molar were processed to HE dyeing,and to investigate the mRNA expression of MMP-2^MMP-9by RT-q PCR.Results:1、The gingiva remodeling model was established successful-1y, which was proved by anatomy observation and histopathological study.2. RT-q PCR results showed the result of mRNA expression of MMP-2:the expression of the sham appliance group increased at first, then decreased, at last increased. The expression of Od group and3d group,7d group and14d group were not significant(p>0.05), the expression were significant between other groups (p<0.05); the MMP-2mRNA expression of experimental group increased continuely, the expression were significant between each group (P<0.05).3、RT-q PCR results showed the mRNA expression of MMP-9:the expression of the sham appliance group increased at first, then decreased, at last increased. The expression of Od group and3d group,7d group and14d group were not significant(p>0.05), the expression of other groups were significant (p<0.05); the MMP-9mRNA expression of experimental group increased continuely, the expression were not significant between Od and14d group (P>0.05), others were significant (p<0.05).Conclusion:The mRNA expression of MMP-2and MMP-9in gingiva were time-dependent during orthodontic tooth movement, which play an important role in collagen metabolism.