Proteoglycan and collagen type Ⅱ in the adjacent intervertebral disc of the cervical instability models / 中国组织工程研究

ABSTRACT

BACKGROUND:Cervical decompression and fusion internal fixation wil accelerate adjacent segment disc degeneration, and it is not clear whether single segment instaibility can increase the adjacent segment disc degeneration. OBJECTIVE:To study the changes of morphology, proteoglycan and col agen type Ⅱ in the adjacent intervertebral disc of the cervical instability models. METHODS:Sixteen New Zealand white rabbits were divided into two groups randomly, with eight rabbits in the control group and eight rabbits in the model group. The animal cervical instability models were made by destroyed partly annulus fibrosus and absorbed C 5/6 nucleus pulposus through anterior cervical puncture. After 12 weeks, the animal models were tested by X-ray film. Al rabbits were sacrificed and 10 mg nucleus pulposus of the intervertebral discs of C 4/5 cut from sagittal plane were harvested and stored under 0 ℃. The content of proteoglycan in nucleus pulposus was tested with phloroglucinol method. Then, the paraffin sections of intervertebral disc tissues were taken for hematoxylin-eosin staining and SABC immunohistochemical staining. RESULTS AND CONCLUSION:The notochord cells of C4/5 intervertebral discs in the experimental group was decreased, and being replaced by fibroblast-like cells. Round chondrocytes could be seen occasional y and intervertebral discs annulus fibrosus became rough and arranged disorderly, the hyaline degeneration and pigmentation were observed as wel as the fibrochondrocytes, and there was a gap between inner and outer annulus fibrosus. The content of proteoglycan was decreased in the nucleus pulposus, and there was significant difference between two groups. The col agen type Ⅱ in the degenerative disc nucleus pulposus and annulus fibrosus of the experimental group was lower than that of the control group. Cervical instability can lead to adjacent intervertebral disc degeneration with the morphological changes and decreased content of proteoglycan and col agen type Ⅱ.