The effect of local application of 1,25-dihydroxycholecalciferol on osteoclast numbers in orthodontically treated rats.
Orthodontic tooth movement requires remodeling of periodontal tissues, especially alveolar bone. 1,25-(OH)2D3, the active form of vitamin D3, is known to be a potent stimulator of osteoclastic bone resorption. The purpose of this study was to investigate the effect of local application of 1,25-(OH)2D3 on osteoclast numbers induced by experimental tooth movement. A piece of orthodontic elastic band was inserted between the first and second upper molars of male Wistar rats weighing about 200 g each. Twenty microL of 1,25-(OH)2D3 (10(-12)-10(-7) mol/L) was injected locally into the submucosal palatal area of the root bifurcation of the right first molar. The left side was injected with phosphate-buffered saline (PBS). The number of osteoclasts was counted in a 700 x 1050 microns 2 area of the interradicular septum. The local injection of 1,25-(OH)2D3 caused a dose-dependent increase in osteoclast number. The effect of 1,25-(OH)2D3 reached a response plateau at 10(-10) mol/L when greater than a three-fold rise in osteoclast number was attained compared with the PBS-treated controls. While the insertion of a piece of elastic band for three days induced a significant increase in osteoclasts in the alveolar bone, daily injections of 20 microL of 10(-10) mol/M 1,25-(OH)2D3 for three days markedly stimulated the numbers of osteoclasts induced by the insertion of an elastic band. 1,25-(OH)2D3 was apparently synergistic with mechanical stimuli, resulting in enhancement of the numbers of osteoclasts induced by mechanical stimuli alone.(ABSTRACT TRUNCATED AT 250 WORDS)
Takano-Yamamoto
T
T
Department of Orthodontics, Faculty of Dentistry, Osaka University, Japan.
Kawakami
M
M
Kobayashi
Y
Y
Yamashiro
T
T
Sakuda
M
M
D000539:Alveolar Process / Q000187:drug effects / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D016723:Bone Remodeling / Q000187:drug effects*; D001862:Bone Resorption; D002452:Cell Count; D002762:Cholecalciferol / Q000494:pharmacology*; D003799:Dental Stress Analysis; D008297:Male; D009971:Orthodontics, Corrective; D010010:Osteoclasts / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains
D002762:Cholecalciferol