Influence of methotrexate on bone healing of a defect simulating a fracture in rat mandible / Avaliação do efeito do metotrexato na reparação tecidual em um defeito ósseo simulando fratura de mandíbula em ratos

AUTOR(ES)

Leonardo Toledo de Aguiar

DATA DE PUBLICAÇÃO

2008

RESUMO

Purpose: The present study aims to verify the effect of high and low dose of methotrexate (MTX) treatment on bone repair of mandibular fractures in rats. Methods: The experimental model employed consists in creating a defect in rat mandible, similar to a fracture. Eighty rats were distributed in 4 groups of 20 animals that received, intraperitoneally: saline (1 ml, after surgery); dexametazone (DX, 0.15 mg/Kg, one dose at surgery); high dose MTX (1.6 mg/Kg, weekly); low dose MTX, (0.25 mg/Kg, weekly). Groups of five animals were sacrificed on the 1st, 7th, 15th and 30th day after surgery. Mandibles were submitted to radiographic analysis to measure the distance between bony edges and the area of osteotomy. Histopathological evaluation was performed in digitalized images using an analyzer software to examine cartilage and bone formation. Results: The treatments did not alter any evaluated parameters on days 1 and 7 after surgery. Control animals sacrificed on the 15th day after surgery had a reduction of the distance between bony ends and in the area of osteotomy, as well as a great increase in cartilage formation. The pattern of these parameters in animals treated with low dose MTX and DX did not differ from control group. However, animals treated with higher dose of MTX kept increasing the distance between bony ends and the area of osteotomy, and the increase in cartilage formation was practically inexistent. On the 30th day after surgery, control animals had pratically recovered the fracture region, as well as those treated with low dose MTX. The group treated with higher dose MTX and DX still had an open bone defect. Conclusions: This study clearly shows that low dose MTX did not affect bone healing of mandibular fractures in rats, in contrast to a higher dose, which promotes impairment of bone regeneration.

ASSUNTO(S)

calo ósseo consolidação da fratura mandibular fractures/surgery ratos wistar bone fractures mandibular fractures/radiography fraturas mandibulares/ fisiopatologia fraturas mandibulares/cirurgia fracture healing dexametasona metotrexato bony callus methotrexate fraturas ósseas dexamethasone fraturas mandibulares/radiografia mandibular fractures/physiopathology rats wistar

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