A Preliminary Study on the Mechanism of Early Lesions in the Subchondral Bone of a Rat Model of Intevertebral Disc Degeneration.

To observe the lesion characteristics of vertebral subchondral bone by establishing a rat model of intervertebral disc degeneration. Thirty-two Sprague--Dawley rats were randomly divided into four groups of eight rats each, and one group served as the control group without any treatment. The rats in the experimental group were injected with 30 μl of anhydrous alcohol under the endplate (sub-endplate) above the Co6 vertebrae and 30 μl of phosphate buffered saline buffer under the endplate above the Co8 vertebrae. Eight rats were randomly taken for follow-up testing at 2, 4, and 8 w after establishment of models. The rats underwent imaging X-rays and magnetic resonance imaging to assess vertebral subchondral bone and intervertebral disc degeneration grades; then serum enzyme-linked immunosorbent assay was performed to measure tumor necrosis factoralpha, interleukin-1 beta, type I procollagen amino-terminal peptide, type I collagen carboxy-terminal peptide, vascular endothelial growth factor A and endostatin. The Co5/Co6 and Co7/Co8 motion segments (including the adjacent vertebrae and intervertebral disc) were used to perform micro-computed tomography, histological staining with hematoxylin and eosin, sapphire green, and toluidine blue, as well as for detecting the expression of collagen type II, and vascular endothelial growth factor A expression. Collagen type II, aggregated proteoglycan (aggrecan), sox-9, vascular endothelial growth factor A by immunohistochemical tests. Imaging, histologic staining and immunohistochemistry confirmed the successful establishment of intervertebral disc degeneration model. Histological observations and immunohistochemical analysis showed progressive degeneration of major intervertebral disc structures. Blocking the intervertebral disc trophic pathway in the vertebral subchondral bone region can successfully establish intervertebral disc degeneration rat model, and the possible main lesion characteristics of the vertebral subchondral bone during this process include abnormal bone remodeling, destruction of blood vessels and enhanced inflammatory response. [ABSTRACT FROM AUTHOR]