THE EFFECT OF PARATHYROID HORMONE ON CYCLIC AMP LEVEL AND DISTRIBUTION IN PERIODONTAL CELLS IN TENS10N SITES DURING ORTHODONTIC TREATMENT

교정적 치아이동시 부갑상선홀몬이 긴장측 치주세포의 cAMP농도에 미치는 영향

Parathyroid hormone (PTH) is known to exert its effects on bone cells through the mediation of adenosine 3', 5'-monophosphate (cAMP). Orthodontic forces have also been shown to alter the cAMP content of paradental cells, particularly the alveolar bone osteoblasts. The objective of this experiment was to determine whether a combined orthodontic treatment-PTH administration regimen would have an additive effect on cAMP content in paradental cells in sites of periodontal ligament (PDL) tension. Seven groups of 4 one year old female cats each were treated for 1,3,6,12,24 h, 7 and 14 d by tipping one maxillary canine. PTH was administered twice daily, 30u/kg. Maxillary horizontal sections were stained immunohistochemically for cAMP and the degree of cellular staining intensity was determined microphotometrically as per cent light transmittance at 600nm. Alveolar bone osteoblasts, progenitor cells, PDL fibroblasts and cementoblasts in tenion sites were measured and the data were analyzed statistically by a mixed model analysis of variance. PTH administration increased the cAMP staining of nonorthodontically treated paradental cells in comparison to cells untreated by force or hormone. Cells in PDL tension sites of PTH-treated cats demonstrated significantly darker cAMP staining than cells in non-orthodontically-treated sites. Osteoblasts demonstrated the greatest response in terms of cAMP elevation, while in PDL fibroblasts orthodontic force did not increase cAMP levels above those measured in non-stretched hormonally-treated cells. These results demonstrate that PTH increases cAMP levels in paradental cells, particullarly in osteoblasts, and that the effects of PTH and orthodontic forces on paradental target cells may approach additivity.