Albanir Gabriel Borrasca

Repair process of surgical defects filled with autogenous bone grafts in tibiae of diabetic rats

From a biological standpoint, the best material for reconstruction of bone defects is the autogenous bone graft. However, as tissue healing is affected under diabetic conditions, major changes might take place in the revascularization, incorporation, replacement and remodeling phases of the grafted area. The purpose of this study was to assess the bone healing process in surgical wounds prepared in tibiae of diabetic rats and filled with autogenous bone. Forty male rats (Rattus norvegicus albinus, Wistar) were randomly assigned to receive an endovenous injection (penile vein) of either citrate buffer solution (Group 1 - control; n=20) or streptozotocin dissolved in citrate buffer solution (35 mg/kg) to induce diabetes (Group 2 - diabetic; n=20). After determination of glycemia, the animals were anesthetized and the anterolateral regions of the tibiae of both limbs were shaved, antisepsis was performed and longitudinal incisions were made in each limb. The tibiae were exposed and two 2-mm-diameter surgical cavities were prepared: one in the right limb, filled with particulate autogenous bone and the other in the left limb, filled with blood clot. The animals were euthanized at 10 and 30 postoperative days. The anatomic pieces were obtained, submitted to laboratory processing and sections were stained by hematoxylin and eosin and Massons Trichrome for histomorphologic and histometric analyses. In both groups, the wounds filled with autogenous bone graft showed better results than those filled with blood clot. The control group showed higher new bone formation in wounds filled with autogenous bone graft at 30 days than the diabetic group, but without statistical significance. It may be concluded that, in general, the new bone formation occurred with autogenous graft was quantitatively similar between control and diabetic groups and qualitatively better in the control group.

Histomorphometric analysis of the repair process of autogenous bone grafts fixed at rat calvaria with cyanoacrylate

Objective The purpose of this study was to perform histological and histometric analyses of the repair process of autogenous bone grafts fixed at rat calvaria with ethyl-cyanoacrylate adhesive. Material and Methods Thirty-two rats were divided into two groups (n=16), Group I - Control and Group II - Adhesive. Osteotomies were made at the right parietal bone for graft obtainment using a 4-mm-diameter trephine drill. Then, the bone segments were fixed with the adhesive in the parietal region of the opposite side to the donor site. After 10 and 30 days, 8 animals of each group were euthanized and the calvarias were laboratorially processed for obtaining hematoxylin and eosin-stained slides for histological and histometric analyses. Results An intense inflammatory reaction was observed at the 10-day period. At 30 days, this reaction was less intense, despite the presence of adhesive at the recipient-site/graft interface. Graft incorporation to the recipient site was observed only at the control group, which maintained the highest graft size at 10 and 30 days. Conclusions Although the fragment was stable, the presence of adhesive in Group II did not allow graft incorporation to the recipient site, determining a localized, discrete and persistent inflammatory reaction.

Bone Repair of Surgical Defects Filled with Autogenous Bone and Covered with Demineralized Bone Matrix Membrane or Polytetrafluoroethylene Membrane in Rats

PURPOSE The aim of this study was to evaluate the behavior of a demineralized bone matrix membrane and a polytetrafluoroethylene (PTFE) membrane in the process of bone repair of surgical defects filled with autogenous bone in rats. MATERIALS AND METHODS Sixty rats weighing approximately 250 g each were selected and separated into three groups: control group without membrane, demineralized bone matrix membrane group, and PTFE membrane group. Bilaterally, surgical defects of 2 mm in diameter were prepared in the tibiae. The defect in the left tibia was filled with particulate autogenous bone collected during the creation of the two defects and was left uncovered (control) or was covered with the membranes investigated by the present study. At 10 or 60 days postoperatively, the rats were euthanized and the left tibiae were submitted to routine laboratory processing for histomorphometric analysis. All groups were evaluated separately on the 10th and 60th days after surgery. The Kruskal-Wallis test was used for group comparison. RESULTS The membrane-treated defects showed a delay in healing. Sites treated with demineralized bone matrix membrane showed, as early as day 10, more newly formed bone and slow replacement until day 60. At day 60, the sites covered with demineralized bone matrix membrane and with synthetic membrane showed statistically significant results. CONCLUSION The demineralized bone matrix membrane proved to be biocompatible. In terms of newly formed bone area, both membranes showed similar performance.