ABSTRACT
<p><b>OBJECTIVE</b>To investigate the changes in expression of gelatinase (MMP-2, MMP-9) in young rat condylar cartilage during functional mandibular advancement.</p><p><b>METHODS</b>Sixty male 5-week old SD rats were divided into experimental and control groups. The mimic functional appliances were used in experimental group rats. The animals were sacrificed after 1, 2, 4 weeks. The immunoreactivity of gelatinase was detected by immunohistochemistry.</p><p><b>RESULTS</b>In normal mandibular condylar cartilage, the immunoreactivity of MMP-2 was rather strong, the immunoreactivity of MMP-9 was very weak. Following functional mandibular advancement, the expression of MMP-9 was significantly increased (P < 0.01), but immunoreactivity of MMP-2 had no significant changes.</p><p><b>CONCLUSION</b>Gelatinase plays an important role in the adaptive remondling of young rat condylar cartilage during functional mandibular advancement.</p>