STUDY OF THE HISTOLOGICAL OF MOUSE INTERVERTEBRAL DISC DEVELOPMENT

Background and At least two different elements can be detected in the structure of mature intervertebral disc. The central portion contains nucleus pulpous. Its few cells being embedded in gel form material. The outer protein, however, is called annulus fibroses, composed of concentric layers of intertwined annulus bands. Although the major anatomical structures of intervertebral disc are well known, there are little information on the development of its components such as cell type and extracellul matrix. Therefore, this study was conducted to study the histological changes in the development of intervertebral disc in mouse. Methods and Materials: In this study, collagen fiber appearance and cellular differentiation were studied using serial section and histological staining methods in the course of intervertebral disc development in mouse embryo. The findings indicated that from the 12th day of gestation, the notochord starts getting separated from the floor plate of neural tube. Gradually on the next days, as mesenchyme cells get condensed around, patterns of intervertebral disc differentiation can be observed, leading to disc development toward the end of gestation. Throughout this process, the notochord degenerates. Theses changes start from the middle portion of notochord and proceeds towards head and tail. Then vertebral bodies are forward in portions with degenerated notochord changes. During the development changes of intervertebral disc, remnants of notochord form nucleus pulpous in the intervertebral disc. However, the mesenchyme surrounding it (forthcoming annulus fibrosus) consist of structurally dissimilar regions. Under these circumstances, the outer portion is made up of highly-densed collagen material but in the inner portion, remnants of embryonic hyaline cartilage and collagen fibers can be detected.