MORPHOLOGICAL CHANGES IN THE STRUCTURES OF THE TEMPOROMANDIBULAR JOINTS IN EXPERIMENTAL HYPERGLYCEMIA

Abstract

The prevalence of diabetes mellitus, its complications, as well as diseases of the temporomandibular joints  is constantly increasing. However, there are no data on changes in the structure of this diarthrosis in this endocrine pathology.

The aim – to determine the peculiarities of structural changes of the temporomandibular joints in hyperglycemia.

Material and Methods. The temporomandibular joints of 60 white adult male-rats, which were divided into 4 groups, were experimentally studied. Streptozotocininduced diabetes mellitus was simulated in animals of groups 1 and 2. Males of groups 3 and 4 were used as controls. Euthanasia of rats was performed 30 and 60 days after the start of the experiment by bloodletting under thiopental anesthesia. Histological sections of the temporomandibular joints were prepared according to conventional methods, placed on slides, stained with hematoxylin-eosin and examined with microscopes.

Results. The thickness of the perichondrium was somewhat thinned mainly in the cell layer. Blood supply grew in the surrounding vessels. Some of the large cells with eccentrically located clearer nuclei, localized mainly on the periphery, synthesizing a matrix around them. A moderate number of osteoblasts were visualized along the edge of the trabeculae. Moderate mucoid edema was observed in the intra-articular disc. Its fibers thickened slightly, the amount of cellular infiltrate between them increased, with a predominance of fibroblasts, macrophages and mast cells. Focal hyperplasia of cells and the synthesis of synovial fluid increased. Among the thick fibers of the ligament, the number of thin collagen fibers with swelling and moderate cellular response increased.

Bundles of collagen fibers were visualized in the surrounding tissue, between which fibrocytes accumulated, as well as signs of ossification. An increase in the number of osteoblasts in the fibrous structure and destructive changes of chondrocytes were indicative of signs of cartilage destruction. Focal hyperplasia of hematopoietic cells was observed among bone trabeculae fibers. A large number of capillary loops were visualized in the trabeculae. Blood supply to the blood vessels decreased. Maturation of chondrocytes, their transformation from cells of the first to cells of the second type, led to growth of basophilia of intercellular substance. Osteoblasts were visualized in the inner surface of the joint between the cells of the fibroblastic row.

Conclusions. Experimental streptozotocin-induced diabetes mellitus led to severe destructive processes in the temporomandibular joints. The revealed morphological changes of structural elements in this joint testify to disturbance of processes of osteotherapy and chondrosynthesis in 2 months from the beginning of experimental modeling of a hyperglycemia.