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. 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.

颞下颌关节骨关节炎（Temporomandibular joint osteoarthritis, TMJ-OA）是颞下颌关节紊乱病（Temporomandibular joint dysfunction, TMD）的亚型之一，以进行性软骨退变、软骨下骨侵蚀及慢性疼痛为主要病理与临床特征。尽管针对TMJ-OA已开展了大量研究，但其确切病因仍未明确。年龄、激素因素及颞下颌关节承受的过度机械应力，被认为是TMJ-OA的潜在危险因素。本研究通过基因芯片（microarrays）筛选得到两个疾病易感基因，二者被推测参与了TMJ-OA的致病机制。在实验操作中，研究人员对8周龄性成熟小鼠实施睾丸切除术（orchiectomy, ORX）或卵巢切除术（ovariectomy, OVX）；为在下颌髁突处施加过度机械应力（mechanical stress, MS），研究人员在上颌切牙的后表面粘贴了一块金属板。雄性小鼠被分为对照组、ORX组、MS组及ORX+MS组；雌性小鼠则划分为对照组、OVX组、MS组及OVX+MS组。本研究采用Clariom S小鼠基因芯片检测试剂盒（赛默飞世尔科技，Thermo Fisher Scientific）开展基因芯片分析，以对相关基因进行全面检测。