Alendronate induces postnatal maxillary bone growth by stimulating intramembranous ossification and preventing premature cartilage mineralization in the midpalatal suture of newborn rats.

Cleft palate is a common malformation of craniofacial development, and postnatal deficiencies in palate formation may occur. The aim of this study was to determine whether alendronate treatment could induce maxillary mineralization and thus reduce the need for surgical procedures. The effects of alendronate on maxillary bone development, the midpalatal suture, and the levels of transforming growth factor beta-1 (TGF-ß1), bone morphogenetic protein 2 (BMP-2), collagen I and II, and V-ATPase were evaluated in newborn rats. Thirty newborn rats were placed in a control group and 30 in a group that received intraperitoneal alendronate (2.5 mg/kg/day). The animals were euthanized on day 7 or 12, and the heads were subjected to histological and immunohistochemical analyses. Specimens from rats that received alendronate presented larger bone matrix deposition in areas of intramembranous ossification of the maxillary bone when compared to controls. Furthermore, higher levels of TGF-ß1, BMP-2, and collagen I were observed, whereas osteoclasts showed no V-ATPase. The alendronate group also showed higher levels of TGF-ß1 and collagen II in the midpalatal suture, whereas BMP-2 levels were lower than in controls. These results coincided with an expansion of the chondroid. In conclusion, alendronate increased the intramembranous ossification in the maxillary bone in association with increased expression of TGF-ß1, BMP-2, and collagen I and decreased V-ATPase. The drug induced an expansion of chondrocytes and a decrease in mineral bone deposition despite the high levels of TGF-ß1 in this area. Alendronate may therefore be useful in the treatment of diseases affecting bone growth.

The value of molecular expression of KIT and KIT ligand analysed using real-time polymerase chain reaction and immunohistochemistry as a prognostic indicator for canine cutaneous mast cell tumours.

This study investigated the correlation between KIT gene expression determined by immunohistochemistry and real-time polymerase chain reaction (RT-PCR) and the rate of tumour recurrence and tumour-related deaths in dogs affected with mast cell tumour (MCT). Kaplan-Meier curves were constructed to compare tumour recurrence and tumour-related death between patients. The log-rank test was used to check for significant differences between curves. KIT-I, KIT-II and KIT-III staining patterns were observed in 9 (11.11%), 50 (61.73%) and 22 (27.16%) tumours, respectively. Tumour recurrence rates and tumour-related deaths were not associated with KIT staining patterns (P = 0278, P > 0.05), KIT (P = 0.289, P > 0.05) or KIT ligand (P = 0.106, P > 0.05) gene expression. Despite the lack of association between KIT staining pattern and patient survival time, the results suggest a correlation between aberrant KIT localization and increased proliferative activity of MCTs. RT-PCR seems to be a sensible method for quantitative detection of KIT gene expression in canine MCT, although expressions levels are not correlated with prognosis.

L-PRP diminishes bone matrix formation around autogenous bone grafts associated with changes in osteocalcin and PPAR-γ immunoexpression.

Leucocyte- and platelet-rich plasma (L-PRP) is an autogenous platelet concentrate enriched with leukocytes that releases various growth factors responsible for the proliferation, regulation, and differentiation of mesenchymal cells during wound healing. Since the bone and medullary tissue are contiguous and share the same origin, this study evaluated the effect of L-PRP on the repair of calvaria bone using histomorphometric analysis of the newly formed bone, and compared the results in the presence of osteocalcin (OC) and peroxisome proliferator-activated receptor gamma (PPAR-γ) detected by immunohistochemistry. Artificial circular bone defects (5mm diameter) were produced in the calvaria of 42 rats. The defects were treated with autograft, autograft combined with L-PRP, or without grafting material (sham). The animals were euthanized at 15 or 40 days postsurgery (n=7 in each group). Data obtained were analyzed by Student-Newman-Keuls test for histomorphometric and immunohistochemical interpretation. The development of bone matrix was significantly less in the defects treated with L-PRP, while the medullary area composed of fatty cells was larger. This coincided with the minor expression of OC and expressive presence of PPAR-γ. These results suggest that L-PRP may impair osteoneogenesis and alter the ratio of differentiation between bone matrix and fatty cells, increasing the medullary tissue.