Avaliação da imunoexpressão de vimentina e de osteopontina no reparo ósseo precoce de defeitos preenchidos com enxerto bovino associado à terapia laser de baixa intensidade

Abstract

The aim of this study was to evaluate, by immunohistochemistry, the expression of vimentin and osteopontin during the early stages of repair of bone defects created in femurs of Wistar albinus rats treated with organic bovine bone graft Gen-ox® and associated with low level laser therapy. Twenty four embedded samples were randomly selected from the file of a previous experimental work, in which histological analysis and histomorphometry of the femurs of fifty rats was performed. Histological slides were obtained from blocks of different animals which were divided in accordance to previous treatment as follow: group I (control), group II (Gen-Ox ® ) and group III (LLLT and Gen-Ox ®). Four slides were prepared for each of the experimental time of 3, 5, 7 and 15 days for each group. Of the four slides, two were assessed for the expression of osteopontin and two of vimentin, in a total of 48 slides. On each slide two fields were considered for analysis: one in the bone-defect interface and the other near the periosteum, in a total of 96 fields. To perform the immunohistochemistry anti-vimentin and anti-osteopontin, we used the classical avidin-biotin peroxidase anti-peroxidase method. The positive staining was determined by identification of intracytoplasmic brown color in the reactions with both antibodies. The sections were analyzed in Zeiss microscope at a magnification of 200x, 400x and 1000x by two different observers. The average intensity of positive cells stained in the fields in each period was determined by a semiquantitative counting method which was classified by a scoring system as follow: 0 = no marking; + = mild labeling (up to one third of positive cells); + + = moderate labeling (up to two thirds of positive cells) and + + + = intense labeling (over two thirds of labeled cells). The results showed that all groups had marked for vimentin and osteopontin in all periods of the experiment. We observed a stronger cell labeling for vimentin in the initial healing period in group III. There were no differences in cell labeling for

osteopontin in animals subjected to low level laser therapy associated with graft as compared to other groups.