Bcl-2蛋白表达与人类不同年龄段椎间盘组织细胞凋亡的相关性研究

摘要

目的:探讨凋亡相关蛋白Bcl-2在人类不同年龄段椎间盘组织细胞凋亡的作用.方法:采用脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(terminal deoxynucleotidyl transferase mediated dUTP nick end labeling,TUNEL)、免疫组织化学方法以及HE染色法对人类不同年龄段正常人腰椎间盘髓核细胞对比.结果:①HE染色:在胚胎和儿童时期髓核内以脊索细胞为主,到成年后以软骨样细胞为主.从胚胎后期开始,椎间盘髓核细胞数量随年龄增长而逐渐减少,到老年阶段髓核细胞的数量已经很少(P＜0.05).②TUNEL检测:胚胎后期即可见髓核细胞TUNEL反应阳性,而且在各年龄段均可见TUNEL反应阳性细胞,阳性颗粒的平均光密度值逐年增高(P＜0.05).从胚胎后期到成年,TUNEL阳性细胞率随年龄增长而逐渐降低,并降到整个生命过程中的最低点;继之,TUNEL阳性细胞率又逐年升高(P＜0.05).③Bcl-2蛋白免疫组织化学染色:自胚胎后期开始,Bcl-2蛋白就开始有较高水平的表达,但呈现逐年下降的趋势(P<0.05).Bcl-2蛋白阳性细胞表达率亦呈同样趋势(P<0.05).结论:在整个生命过程中,随年龄增长大量腰椎间盘髓核细胞发生凋亡,细胞数量明显减少.细胞凋亡是椎间盘细胞减少的原因之一.Bcl-2蛋白可能参与了椎间盘细胞凋亡的调节,但表达水平较低,不能阻止细胞凋亡的发生.%Objective: To explore the expression of Bcl-2 protein in apoptosis of intervertebral disc cells and gene regulation in different ages of human body. Method: The apoptotie status and the expression of Bcl-2 protein in the intervertebral disc ceils in different ages of human body were detected with TdT-mediated dUTP-biotin nick end labeling (TUNEL) and immunohistochemistry methods. Result: ①Hematoxylin and eosin staining: In embryonal and infantile stages, notochordal cells are the mainly kind of cells in different ages of human intervertebral disc, but cartilaginoid cells are the mainly kind of cells in adults. From the later stage of embryo, the number of nucleus pulposus cells reduce gradually with the age, arrive the old -age stage nucleus pulposus cells already few（ P＜0.05 ); ②TUNEL: The TUNEL positive cells of nucleus pulposus cells can be seen immediately after child bearing, and in each age. The average optical density of the stained granules of TUNEL increases year by year （ P＜0.05 ). From the later stage of embryo to adulthood, the rate of TUNEL positive cells reduce to the lowest gradually in the whole life, then increase with the age （ P＜O. 05 ) ; ③Bcl-2 protein immunohistochemical labeling: A higher expression of Bcl-2 protein could be seen in the later stage of embryo, but reduce gradually with the age ( P＜0.05 ）. The rate of Bcl-2 protein positive cells also be reported the same trend ( P＜O. 05 ）. Conclusion: During the life span, a lot of nucleus pulposus cells of intervertebral disc died with the increasing age. Bcl-2 protein may involve apoptosis of nucleus pulposus cells, but due to the lower expressions Bcl-2 can' t obstruct the occurrence of apoptosis.