Establishment and significance of an in vitro model of degeneration of human cervical endplate chondrocytes

Abstract

To establish an in vitro model of degeneration of human cervical endplate chondrocytes and observe the morphology and phenotypes of endplate chondrocytes in normal and degenerative cervical vertebral endplates. Cartilage endplates of 49 patients were divided into control group (n = 19) with cervical vertebral fracture or dislocation and experiment group (n = 30) with cervical spondylotic myelopathy. Endplate chondrocytes were isolated by enzyme digestion and cultured in vitro. The morphological appearances, growth curve and biological characteristics of endplate chondrocytes from normal and degenerative cartilage endplate were observed by inverted phase contrast microscope, HE staining, MTT, toluidine blue staining and reverse transcription-polymerase chain reaction (RT-PCR) respectively. RT-PCR was used to detect the mRNA expression of aggrecan, type II collagen and type I collagen. The endplate chondrocytes expressed aggrecan, type II collagen and type I collagen. The phenotypes and biological characteristics were similar to those of articular chondrocytes. The morphological appearance of primary endplate chondrocytes in the control group were mostly polygons, nucleus with round or ellipse, sometimes nuclei, vacuoles in intra cytoplasm, expressing a high proliferating rate. The cells of the experiment group were fusiform and their proliferating rates decreased. Compared with the control group, the mRNA expression of aggrecan (0.695 ± 0.052 vs 0.950 ± 0.032, t = 7.263, P = 0.002) and type II collagen (0.726 ± 0.035, 0.907 ± 0.078, t = 3.681, P = 0.021) markedly decreased. And the mRNA expression of type I collagen (0.795 ± 0.028 vs 0.552 ± 0.070, t = -5.560, P = 0.005) increased in the experiment group. A degenerative cell model of human cervical endplate chondrocytes has been established successfully in vitro. It may offer the cytological rationales for exploring the mechanism of intervertebral disc degeneration. And the previous restrictions of studying only the model of animal cells shall be resolved.