Changes in the microvasculature after mechanical pressure on the hamster cheek pouch.
The reaction of the microvasculature in the periodontal ligament to mechanical pressure is considered a very important phenomenon with respect to the biological background to orthodontic tooth movement. For clarification of the microvascular reaction to mechanical pressure, an experimental model that incorporated a hamster cheek pouch was established. This in vivo model solves some of the problems of other experimental models of the microvasculature of the periodontal ligament. Blood plasma permeation in this model was examined by means of a blue dye (pontamine sky blue), and histological observation was performed by light and transmission electron microscopy. Increased vascular permeability was observed within 30 min after removal of the mechanical stimulation. The threshold weight resulting in dye leakage was between 1 and 5 g applied for 60 min. From the histological observations, some large gaps between the endothelial cells in venules were found, while most basement membranes remained undisturbed. These observations suggest that the plasma leakage was due to mild traumatic injury to the endothelial cells. Both leukocytes and platelets were observed in the gaps between the endothelial cells in the venule. These types of microvascular reactions to mechanical pressure could initiate tissue changes in the periodontal ligament during orthodontic tooth movement.
Iida
J
J
First Department of Orthodontics, School of Dentistry, Tokyo Medical and Dental University, Japan.
Inage
S
S
Kurihara
S
S
Miura
F
F
D000818:Animals; D001391:Azo Compounds; D002199:Capillary Permeability; D002610:Cheek / Q000098:blood supply; D003250:Constriction; D006224:Cricetinae; D004730:Endothelium, Vascular / Q000293:injuries* / Q000648:ultrastructure; D007511:Ischemia / Q000209:etiology*; D008297:Male; D008647:Mesocricetus; D008833:Microcirculation / Q000293:injuries* / Q000648:ultrastructure; D010513:Periodontal Ligament / Q000098:blood supply*; D011312:Pressure; D013314:Stress, Mechanical; D014343:Trypan Blue; D014699:Venules / Q000293:injuries / Q000648:ultrastructure
D001391:Azo Compounds; C009000:pontamine sky blue; D014343:Trypan Blue