The Effects of CGRP in TMJ Degeneration in a Senescence Accelerated Mouse (SAM)

Objectives: Mandibular condyle of SAMP8 mice is early-onset age-related degenerative changes in TMJ’s articular surface (Chen et al., 1989). Calcitonin gene related peptide (CGRP) is derived peripheral and central neurons which plays vasodilator in the transmission of pain. Osteopontin is an important factor in bone remodeling relate to anchoring osteoclasts. Osteocalcin is also a marker for the bone formation process produced by osteoblasts. However, relation between CGRP with remodeling markers is a little information for TMJ disorder in during aging. Our study is to identify molecular mechanisms of CGRP underlying TMJ disorder in SAMP 8 mice.

Methods: The senescence-accelerated SAMP8 mouse (males, 12 weeks of age n=4, 24 weeks of age n=4) were prepared for light microscopic studies for in situ hybridization levels respectively using WinROOF Version 5.5 (Mitani Corporation, Tokyo, Japan).
Results: The visible hybridization with an anti-sense probe for Osteocalcin and Calcitonin were mainly detected condyle articular and calcified cartilage zone and neck of condyle process compared with the sense probe for these markers in compared with CGRP detected scattered in the neck of condyle.
Conclusions: Our data gave an information for TMJ articular cartilage degeneration accompanied by CGRP expression levels between 12 weeks and 24 weeks. The statistical significance of differences in the percentages of positive cells was analyzed by two-tailed, unpaired Student's t test (**P<0.01). These different localizations of each marker also may indicate pain mechanism related to CGRP in mandibular condyle.
COI:none