Microvascular response in the periosteum following mucoperiosteal flap surgery in dogs: angiogenesis and bone resorption and formation.
BACKGROUND
When surgical stress reaches the periosteum, bone resorption and formation that occur as a periosteal response are closely related to angiogenesis and hemodynamics. Thus, we investigated bone remodeling in the healing process after mucoperiosteal flap surgery, focusing our attention on the microcirculation.


METHODS
Mucoperiosteal flap surgery was performed on 12 adult beagle dogs. The periosteal vascular plexus was observed on days 7, 14, 21, and 28 after surgery, using three different techniques: in histological specimens into which India ink was injected into blood vessels, under a light microscope; in ultrathin sections, using a transmission electron microscope; and in acryl plastic-injected vascular corrosion cast specimens, under a scanning electron microscope.


RESULTS
On day 7 after surgery, the interstitum of the elevated mucoperiosteal vascular plexus was filled with sinusoidal new blood vessels. Bone resorption by osteoclasts was observed around these new blood vessels and many highly permeable fenestrations were present in the vascular endothelium. On day 14 after surgery, sinusoidal new blood vessels were more markedly developed and some regions exhibited glomeruluslike morphology consistent with bone resorption cavities. Activated osteoblasts were present around these new blood vessels and highly permeable vesicles, which were considered to be possible vesiclo-vacuolar organelles (VVOs) and caveolae, were noted in the vascular endothelium. On days 21 and 28 after surgery, the mucoperiosteal vascular plexus was dissected through regression of endothelial cells and fibroblasts and reconstructed into a rough mesh structure, and simultaneously the bone surface became smooth.


CONCLUSIONS
The morphology of the mucoperiosteal vascular plexus changed with bone metabolism and these changes contributed to transport of substances involved in periodontal repair.
Nobuto
Takahiro
T
Department of Periodontology, Osaka Dental University, Osaka, Japan. imai-h@cc.osaka-dent.ac.jp
Suwa
Fumihiko
F
Kono
Tomoo
T
Taguchi
Yoichiro
Y
Takahashi
Tsurayuki
T
Kanemura
Naoko
N
Terada
Shoichiro
S
Imai
Hisao
H
D000539:Alveolar Process / Q000098:blood supply / Q000601:surgery*; D000818:Animals; D016723:Bone Remodeling; D016319:Corrosion Casting; D004285:Dogs; D004730:Endothelium, Vascular / Q000648:ultrastructure; D005260:Female; D008297:Male; D008833:Microcirculation / Q000648:ultrastructure; D008854:Microscopy, Electron / Q000379:methods; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010521:Periosteum / Q000098:blood supply*; D013524:Surgical Flaps