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BioMed Research International
Volume 2014, Article ID 563463, 10 pages
Research Article

Histological, Histochemical, and Protein Changes after Induced Malocclusion by Occlusion Alteration of Wistar Rats

Department of Morphology, Physiology and Basic Pathology, Ribeirão Preto School of Dentistry, University of São Paulo, FORP/USP, P.O. Box 14040-904, Ribeirao Preto, SP, Brazil

Received 28 February 2014; Accepted 24 April 2014; Published 17 June 2014

Academic Editor: Beatrice Charreau

Copyright © 2014 Carolina de Souza Guerra et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Although disorders of the stomatognathic system are common, the mechanisms involved are unknown. Our objective was to study the changes in the masseter muscles after unilateral exodontia. Molar extraction was performed on Wistar rats (left side), and the animals were sacrificed after either 14 or 26 days. The masseter muscle was processed for histological analysis, conventional and in situ zymography, and immunohistochemistry. The morphological analysis showed unique and specific characteristics for the experimental group. By conventional zymography no significant values of 72 kDa MMP-2 ( ) were found in both of the sides of masseter muscle after 14 and 26 days of unilateral extraction. The in situ zymography showed gelatinolytic activity on all deep masseter muscles, with significant increase on the contralateral side after 14 and 26 days ( ). The immunohistochemistry demonstrated greater expression of MMP-2 than MMP-9 and MMP-14 in all masseter muscles and there were few differences in the staining of 4 TIMPs. This knowledge about morphology and molecular masticatory muscle remodeling following environmental interventions can be used to develop clinically successful treatments.