Effects of mechanical stress and deficiency of dihydrotestosterone or 17β-estradiol on temporomandibular joint osteoarthritis in mice. Effects of mechanical stress and deficiency of dihydrotestosterone or 17β-estradiol on temporomandibular joint osteoarthritis in mice

Temporomandibular joint osteoarthritis (TMJ-OA), a subtype of temporomandibular joint dysfunction (TMD), is characterized by progressive cartilage degradation, subchondral bone erosion, and chronic pain. Although there has been extensive research on TMJ-OA, its etiology remains unknown. Age, hormonal factors, and excessive mechanical stress on the TMJ are proposed risk factors for TMJ-OA. Using microarrays, we discovered two disease susceptibility genes that have been suggested to be involved in the pathogenic mechanism of TMJ-OA. Overall design: For experimental groups, orchiectomy (ORX) or ovariectomy (OVX) was performed on sexually mature 8-week old mice. To apply excessive mechanical stress (MS) on mandibular condyles, a metal plate was attached to the posterior surface of the maxillary incisors. Male mice were divided into control, ORX, MS, and ORX+MS group, while female mice were divided into control, OVX, MS, and OVX+MS groups. Microarray analysis was conducted using a Clariom S Assay (Mouse, Thermo Fisher Scientific) for comprehensive analysis of related genes.