The roles of apoptosis and proliferation in human cervical disc degeneration

Abstract

Objective To detect the cell densities,apoptosis rate as well as the expression of PCNA,bax and Caspase-3 in human cervical discs,and analyze their relationships to study the roles that apoptosis and proliferation play in the development of human cervical disc degeneration and the signal transduction pathway of disc cells' apoptosis.Methods Thirty-three herniated human cervical discs were surgically collected from 27 patients undergoing anterior cervical discoidectomy and fusion.The control group consisted of 21 human cervical discs harvested from 6 young men without spine.related eonditiorib immediately after their deaths.Apoptotic disc cells were detected by TUNEL and histomorphology and immunohistoehemical staining was performed to examine the expression of PCNA.bax and Capase-3 in all specimcns.Results The cell densities in experimental group were less than those in control group(In nucleus pulposus:6.30±1.54 vs 8.96±1.14;In cartilaginous end plate:17.27±1.82 vs 25.41±1.89).The number of TUNEL-positive cells in experimental group was more than that in control grouP(In nucleus pulposus:11.73±1.36 vs 7.02±1.26;In cartilaginous end plate:13.04±1.75 vs 6.86±1.42).The number of PCNA positive cells in nucleus pulposus in experimental group was more than that in control group(8.38±1.98 vs 4.55±1.54).The number of cells positive for bax-and Caspase-3 in nucleus pulposus in experimental group was more than t11at in control group(For bax:19.32±1.95 vs 10.94±1.72:For Caspase-3:15.05±1.74 vs 8.92 4-1.48).The number of TUNEL-positive cell8 showed a significandy inverse eorrelation with cell densities(P＜0.01).In nucleus pulposus of experimental group,the number of PCNA-positive cells showed a significant positive correlation with cell densities(P＜0.01).The numher of cells positive for bax-and Caspase-3-showed significant positive correlations with that of TUNEL-positive cells(P＜0.01).Condusion The imbalance between apoptosis and proliferation could contribute to the decrease of cell density in degenerative human cervical disc.The upregulation of expression of bax and Caspase-3 miSht play a role in disc cells' apoptosis in nucleus pulposus of human cervical discs. Key words: Cervical spine; Disc degeneration; Apeptosis:Proliferation