程序性死亡分子5在退变腰椎间盘中的表达

Expression of programmed cell death 5 in degenerated lumbar intervertebral disc

背景:细胞凋亡在腰椎间盘退变中起重要作用。程序性死亡分子5是一个促细胞凋亡的蛋白,在骨关节炎的软骨细胞中表达增高,但是至今未见在退变椎间盘中表达的报道。目的:观察程序性死亡分子5在正常、突出和脱出腰椎间盘髓核细胞中的表达规律,分析其在腰椎间盘退变中的作用。方法:用SP免疫组织化学方法、免疫荧光方法检测程序性死亡分子5在2例正常、23例突出和17例脱出腰椎间盘髓核细胞中的表达,用脱氧核苷酸转移酶末端标记法和透射电镜检测髓核细胞凋亡情况;用天狼星红染色观察髓核组织细胞外基质Ⅰ,Ⅱ型胶原纤维的变化。结果与结论:脱出组髓核细胞表达程序性死亡分子5的阳性率高于突出组(P<0.05),脱出组髓核细胞脱氧核苷酸转移酶末端标记阳性率高于突出组(P<0.05)。荧光显微镜和激光共聚焦显微镜观察结果显示程序性死亡分子5表达定位于退变椎间盘的髓核细胞的细胞核;用透射电镜检测到凋亡的髓核细胞;天狼星红染色结果显示,随着年龄增长,髓核中Ⅱ型胶原纤维减少,Ⅰ型胶原纤维增多。结果提示退变椎间盘髓核细胞表达程序性死亡分子5上调,细胞凋亡增加,程序性死亡分子5介导的细胞凋亡在椎间盘退变中起到重要作用。

BACKGROUND:Cell apoptosis plays an important role in intervertebral disc degeneration.Programmed cell death 5(PDCD5) is a protein which promotes cell apoptosis and upgrade expressed in osteoarthritic cartilage.But the study of expression of PDCD5 on degenerated lumbar intervertebral disc has not been reported until now.OBJECTIVE:To investigate the expression of PDCD5 in nucleus pulposus cells from normal,protruded and extruded lumbar intervertebral disc and to analyze the relationship between PDCD5 and lumbar intervertebral disc degeneration.METHODS:Samples from 2 normal,23 protruded and 17 extruded lumbar intervertebral discs were collected.The expression of PDCD5 was detected with immunohistochemical staining and immunofluorescence detection.Nucleus pulposus cell apoptosis was identified by TUNEL and transmission electronic microscope.The extracellular matrix degeneration was detected with sirius red staining.RESULTS AND CONCLUSION:PDCD5 positive rate of nucleus pulposus cells from extruded intervertebral disc was higher than that from protruded intervertebral disc(P < 0.05).TUNEL detection positive rate of nucleus pulposus cells from extruded intervertebral disc was higher than that from protruded intervertebral disc(P < 0.05).PDCD5 was observed to be located in cell nucleus with confocal laser scanning microscopy.Cell apoptosis can be observed with transmission electronic microscope.With age increased,type Ⅰ collagen increased and typeⅡcollagen decreased in nucleus pulposus.In degenerated intervertebral disc,the expression of PDCD5 and nucleus pulposus cells apoptosis increased with age increased and disc degeneration scale increased.Nucleus pulposus cells apoptosis through PDCD5 pathway plays an important role in lumbar intervertebral disc degeneration.