Abstract: Abstract Objective:To explore the effect on the proliferation of cultured human degenerate nucleus pulposus and annular fibrosus cell under the cyclic stretch micro-strain.Methods:The human degenerate intervertebral disc come from a case of 29 years old patient with lumbar disc herniation, and assessing the degree of degeneration through the pathological diagnosis. under the sterile conditions，respectively culturing nucleus pulposus and annular fibrosus cell using enzymatic digestion and cell lines were identified. The third generation cells were seeded on the silicone rubber membrane carrier, using the EF3200 mechanical tester equipped with BioDynamic bioreactor system, imposed a frequency of 0.25Hz, strain 0με, 50000με, 100000με and 150000με loaded 3h, and then detecting the proliferation activity in different strain environment using flow cytometry. Results:The degenerated nucleus pulposus and annulus fibrosus cells grew well after the stress load. With the micro-strain increases, the percentage of degenerative nucleus pulposus cells in S phase were higher than annulus fibrosus cells in 100000 με and 150000 με，and the difference was statistically significant (P<0.01); The PI value of degenerative annulus fibrosus cells were higher than nucleus pulposus cells in every micro-strain value，and the difference was statistically significant (P<0.05).Conclusion:The overall effect of micro-strain loading to human degenerated nucleus pulposus and annulus fibrosus cells is consistent, at the same of micro-strain stimulation, the proliferation promoting effect to the annulus fibrosus cells was significantly higher than nucleus pulposus cells. Key words intervertebral disk displacement flow cytometry intervertebral discs degeneration nucleus pulposus cells annulus fibrosus cells stretch micro-strain proliferation index

Key words: Intervertebral discs degeneration, Nucleus pulposus cells, Annulus fibrosus cells, Stretch micro-strain, Proliferation index.