Proliferation potential of human lumbar disc after herniation

To investigate the regenerative potential of human disc tissue, the disc sa mples were obtained during surgery from 24 adult patients with first lumbar prolapses and from 14 patients with recurrent lumbar prolapses. Preoperati ve magnetic resonance imaging (MRI) confirmed prolapse and disc degeneratio n in all cases. The proliferation activity of the sampled connective tissue cells was studied with the immunohistochemical expression of Ki-67(MIB-1) antigen. The antigen was positive in 6 of 24 (25%) specimens from first pro lapse and in none of the 14 specimens from the recurrent prolapse. The amou nt of proliferative cells did not correlate to the degree of disc degenerat ion in MRI. Our results indicate that connective tissue cells in adult dege nerative disc may show proliferation activity after the first herniation an d thus regenerative potential. The enhanced matrix proliferation may not be a significant reason for recurrent prolapses because none of the recurrent disc specimen showed proliferation activity.