[Changes of dentin, dental pulp and periodontium tissue in tail-suspended rats].
OBJECTIVE
To investigate the metabolic changes of calcium and phosphorus in dentin, dental pulp and periodontium in tail-suspended rats, and the functions of TGF-beta 1, c-fos, collagen-I and collagen IV in dentin, dental pulp and periodontium.


METHODS
Relative percentage contents of Ca, P in dentin, dental pulp and periodontium were measured with scanning electron microscope and energy spectrum analytical system in 3 groups of rats. The expression of TGF-beta 1, c-fos, collagen-I and collagen IV were also observed.


RESULTS
In the suspension group, the relative percentage content of Ca declined significantly, while P increased slightly. There were no significant differences of Ca, P in alveolar bone. The expressions of TGF-beta 1, c-fos and collagen-I declined, but the expression of collagen-IV in pulp vessel increased. There were no significant changes of expressions of TGF-beta 1, c-fos, collagen-I and collagen-IV in the vicinity of PDL. After adopting artificial countermeasures, the above expressions restored partly.


CONCLUSIONS
Weightlessness might cause abnormal mineralization in dentin, and 1.5 G artificial countermeasures could eliminate the above changes of mineral metabolism. The poor mineralization of dentin might be associated with the reduced secretion of TGF-beta 1, c-fos and collagen-I in tail-suspended rats.
Department of Pediatric Dentistry, Stomatological College, The Fourth Military Medical University, Xi'an, China. yuanlintian@vip.sina.com
Lin-tian
LT
Yuan
Ling-ying
LY
Wen
Ya-ning
YN
Luo
Pei-zhen
PZ
Hu
Wei-zhong
WZ
Jiang
Xing-yu
XY
Wu
D000818:Animals; D002118:Calcium / Q000378:metabolism; D024042:Collagen Type I / Q000378:metabolism; D024141:Collagen Type IV / Q000378:metabolism; D003782:Dental Pulp / Q000378:metabolism* / Q000648:ultrastructure; D003804:Dentin / Q000378:metabolism* / Q000648:ultrastructure; D019417:Hindlimb Suspension / Q000502:physiology*; D018471:Hypergravity; D008855:Microscopy, Electron, Scanning; D010519:Periodontium / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D014074:Tooth Calcification / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000378:metabolism; D018544:Weightlessness Countermeasures; D018474:Weightlessness Simulation
D024042:Collagen Type I; D024141:Collagen Type IV; D016760:Proto-Oncogene Proteins c-fos; D016212:Transforming Growth Factor beta; D010758:Phosphorus; D002118:Calcium