A Verification of Neogenesis of Vascular Cells by BrdU Immunohistochemistry During Callotasis of the Tibiae in Sprague-Dawley Rats

ABSTRACT

The callotasis is widely used in lengthening of bones without bone graft. We thought that the accompanying vessels is critical in the viability of distal tissue to the lengthened area and has an important effect on the bone-lenthening itself. So we made an assumption that the accompanying vessels is adapted to the lengthening via neogenesis more than simple physical stretching. At this, we placed a pair of small external fixator in the left tibiae of ten Spraugue-Dawley rats and made an osteotomies. At two weeks after 25% lengthening, vessels of both lengthened and unlengthened side was harvested and five sections from each vessels were stained with BrdU immunohistochemical staining. We investigated the DNA synthesis counting the number of BrdU labeled cells. The number of BrdU labeled cells is significantly increased in the lenthened side arteries(p<0.0001). The synthesis of DNA was significantly increased in the center rather than the ends (p<0.0001). And there was no difference between the number of the BrdU labeled cells of proximal part and that of distal parts(p=0.316). It means that the accompanying vessles in the distraction-lengthening are adapted to the lengthening not only by just physical stretching but also by neogenesis of vascular cells.