Change of gelatinase-A expression and distribution in the periodontal tissues of rats during tooth movement

Objective: To observe the expression and distribution of gelatinase-A（MMP-2） in the periodontal tissues of rats during tooth movement.Methods: Forty male Sprague-Dawley rats were used.The animals were sacrificed after 0d,3d,7d,14d and 21 days respectively.Immunohistochemistry was applied to localize and examine the expression of gelatinase-A（MMP-2） in periodontal tissue.The average optical density（OD） and integrated optical density（IOD） were calculated.Results: In tooth movement groups,the MMP-2 expression increased and was observed on both sides periodontium of movement tooth.Osteoclast,cementoblast,osteocyte,fibroblast,a part of osteoblast and cementoblast appear positive.Dynamic changes of OD occurred.OD reached the minimum on the 7th day and then increased slowly.IOD increased steadily,up to the peak on the 7th day,and then decreased,which still remained a high level on the 21st day.Conclusion: MMP-2′s activity changes regularly,in close relation with bone remodeling during the orthodontic tooth movement.