Early changes in the endothelium of alveolar bone microvasculature with continuous tooth loading: ET-1 and alpha-SMA...

A continuous load of 100 g (approximately 1 N) was applied externally to the mandible of rats for three hours and transferred to the alveolar bone via a molar interocclusal rubber pad. The animals were perfusion fixed and undecalcified sagittal molar slices approximately 150 microns thick were immunolabelled with endothelin-1 (ET-1) and alpha-smooth muscle actin (alpha-SMA) antibodies conjugated with CY5 and CY3 fluorophores, respectively. A confocal laser scanning microscope was used to capture the images as digital files in stacked layers for 3-D reconstructions. Blood vessel endothelium ET-1 immunolabelling occurred at disparate sites in the microvascular bed of normal and loaded alveolar bone. Three principal patterns of immunolabelling occurred: vessels labelled with either ET-1 or alpha-SMA, and vessels labelled with both antibodies. Short-term continuous loading produced upregulation of ET-1 immunofluorescence in the blood vessel endothelium, the surface cells of Haversian canals and bone marrow spaces. Pericytes were numerous along arterioles and postcapillary-sized venules.