OBJECTIVETo test the differential Estrogen Receptor (ER) beta levels of mitochondrial proteome of mandibular condylar chondrocyte in the rat model of temporomandibular joints osteoarthritis (TMJOA).

METHODS25 SD rats were divided into experimental group (15 rats) and control group (10 rats) randomly. TMJOA models were created in left sides of TMJ of 15 SD rats by the partial resection of the articular disc. The experimental rats were killed 3 months after operation. After the chondrocytes culture, Immunohistochemistry, semiquantitative RT-PCR and Western blot were used to test the differential ER beta expression levels in mitochondrial proteome of mandibular condylar chondrocytes. Mitochondrial proteins identification was carried out by two-dimensional electrophoresis and peptide mass fingerprint (PMF).

RESULTSPMF showed that one of the differential proteins was ERP. Immunohistochemistry and Western blot results suggested the significant difference of ERbeta protein levels between operation-treated and control group. The operation-treated group had lower ERbeta levels (P < 0.01).

CONCLUSIONIt has been demonstrated that ERbeta protein levels were decreased in mitochondria of TMJOA mandibular condylar chondrocytes, which suggests a role for mitochondrial ERbeta in the effects on TMJOA. The pathological role of ERbeta in the regulation of TMJOA progress remains to be elucidated.