Does Chronic Sleep Deprivation Cause A Comparable Histological Effect On Temporomandibular Joint Versus Knee Joint?

Introduction: Although chronic sleep deprivation (CSD) is becoming more common in our life, it is still unclear how it affects the knee joint, or temporomandibular joint (TMJ), and how it causes histological changes. Aim of the work: Compare the effect of CSD on the TMJ versus knee joint in rats. Materials & Methods: The study used 20 albino rats, between 8 and 10 weeks old, and weighing 246± 20 g. They were divided into two equal groups, control group (Group I) and chronic sleep deprivation group (Group II). Rats was kept the same room but in separate home cages with free access to water and food. Group II was sleep deprived for four weeks by using Modified Multiple Method (MMPM) for eighteen hours a day. After a month, rats were killed, sacrificed, and their right TMJ and right knee joints were removed for histologic examination. Results: H&E-stained sections of knee joint of Group II revealed destruction of menisci, destruction of the femur articular surface, fragmented trabeculae of subchondral bone, clusters of chondrocytes, and interrupted tidemark. The synovium showed an apparent thickening of intima with infiltration of subintima. On other hand, TMJ of Group II showed thinning, and fusion of the articular disc to the fibrous layer, cracks, and loss of cells in fibrous layer. The synovium showed congested blood vessel with hemorrhage. Also, there was a highly significant morphometric changes between Group I and Group II in both TMJ and knee joints in all parameters.