Occlusal stimuli influence on the expression of IGF-1 and the IGF-1 receptor in the rat periodontal ligament.
OBJECTIVE
To test the hypothesis that hypofunction/recovered occlusal function has no effect on the changes in insulin-like growth factor-1 (IGF-1) and IGF-1 receptor expressions and cell proliferation of periodontal ligament (PDL) cells.


METHODS
To produce occlusal hypofunction, the appliances were attached to the rats' maxillary and mandibular incisors. Subsequently, occlusal contact of the molar area was thoroughly recovered by removal of the appliances.


RESULTS
In periodontal sections, localization of IGF-1, the IGF-1 receptor, and proliferating cell nuclear antigen (PCNA) immunoreactive cells was significantly more expressed in the control group compared with the hypofunctional group (P < .01). In addition, after the recovery of the occlusion, IGF-1, IGF-1 receptor, and PCNA were detected significantly much more than in the hypofunction group (P < .01).


CONCLUSIONS
The hypothesis was rejected. This study suggests that occlusal stimuli induce cell proliferation of PDL cells by increasing IGF-1 and IGF-1 receptor expression.
Termsuknirandorn
Saewadee
S
Department of Orofacial Development and Function, Division of Oral Health Science, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. kae1orts@tmd.ac.jp
Hosomichi
Jun
J
Soma
Kunimichi
K
D000818:Animals; D001732:Bite Force; D049109:Cell Proliferation; D003799:Dental Stress Analysis; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis*; D008297:Male; D010513:Periodontal Ligament / Q000166:cytology / Q000378:metabolism*; D010812:Physical Stimulation; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017526:Receptor, IGF Type 1 / Q000096:biosynthesis*
D018809:Proliferating Cell Nuclear Antigen; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1