APOPTOSIS OF CELLS OF NUCLEUS PULPOSUS AND ACTIVATION MECHANISM OF INTERCELLULAR SIGNALING DURING DEGENERATION OF INTERVERTEBRAL DISC

我们先前进行了转化生长因子-β和骨形态发生蛋白在椎间盘退变后髓核细胞表达变化的免疫组织学研究。这些研究表明，转化生长因子-β表达的变化与细胞的凋亡有关。根据这一发现，本研究利用分子生物学方法，从细胞凋亡的角度阐明了衰老的机制。这项研究使用了加速衰老的小鼠品系(SAM-P/6)作为动物模型，可以在短时间内观察衰老。在过去的一年中，我们从4、8、12、16、20、24、28、32和50周龄的雄性加速衰老小鼠身上取出颈椎的间盘，并用免疫组织化学方法检测了转化生长因子-β1、-β2、-β3及其受体在髓核细胞中的表达。研究表明，随着年龄的增长，髓核细胞转化生长因子-β-1、-β-2、-β-3及其受体的表达减少，接近…在50周龄时更多为零，并伴随着髓核细胞数量的减少。今年，我们进行了一项实验，旨在证明髓核细胞的这种减少是由于细胞凋亡。在这项研究中，加速衰老的小鼠的核髓细胞用TUNEL法染色呈阳性，发现在32周龄时已经有caspase活性，表明细胞凋亡在这个年龄已经开始。电子显微镜下对细胞核的形态观察也显示了细胞凋亡的变化。2003年，我们进行了ASK1、JNK和p38的免疫组织学研究，旨在阐明椎间盘退变过程中细胞内信号转导与细胞凋亡相关的机制。随着椎间盘退变，ASK1、JNK和p38在髓核细胞中有表达，而对照组也有表达。因此，不可能阐明与细胞凋亡相关的细胞内信号转导的机制。较少

We previously conducted immunohistological studies of changes in TGF-β and BMP expression in nucleus pulposus cells following degeneration of the intervertebral disc. These studies suggested that changes in TGF-β expression are associated with apoptosis of cells. Following this finding, the present study was undertaken to clarify the mechanism of aging from the viewpoint of apoptosis, using molecular biological methods. The study involved a senescence-accelerated mouse strain (SAM-P/6) as the animal model, allowing observation of aging in a short time period. During last year, we removed the intervertebral discs of the cervical spine from male senescence-accelerated mice at ages 4, 8, 12, 16, 20, 24, 28, 32 and 50 weeks and examined immunohistologically the expression of TGF-β1, -β2, -β3 and their receptors in the discs' nucleus pulposus cells. The study revealed that as age advanced the expression of nucleus pulposus cell TGF-β1, -β2, -β3 and their receptors decreased, reaching almost … More zero at age 50 weeks and was accompanied by a decrease in the number of nucleus pulposus cells. This year, we conducted an experiment designed to demonstrate that such a decrease in nucleus pulposus cells is due to apoptosis. In this study, nucleus pulp cells of senescence-accelerated mice were stained positively using the TUNEL method and were found to already have caspase activity at age 32 weeks, suggesting that apoptosis had begun at this age. Morphological observation of the nuclei of the cells with an electron microscope also revealed apoptotic changes. The changes suggesting apoptosis were more marked at age 50 weeks.In 2003, we conducted immunohistological studies of ASK1, JNK and p38 aimed at clarifying the mechanism for intracellular signal transduction associated with apoptosis during degeneration of intervertebral discs. As the disc degenerated, the expression of ASK1, JNK and p38 in nucleus pulposus cells was noted, but it was also observed in the control group. Thus, it was not possible to clarify the mechanism for intracellular signal transduction associated with apoptosis. Less