Expression of hypoxia-inducible factor 1 alpha and its relationship to apoptosis in human lumbar nucleus pulposus / 中国组织工程研究

ABSTRACT

BACKGROUND:Under hypoxic environment, hypoxia-inducible factor 1α plays a dualregulatory role in cel apoptosis. Severity of hypoxia is the key to determine whether cels appear to have apoptosis or adapt to survive. When the cels are exposed to chronic or extreme hypoxia, a lack of protection mechanisms from hypoxia-inducible factor-1α can induce cel apoptosis. OBJECTIVE: To research the expression of hypoxia-inducible factor 1α in human lumbar nucleus pulposus of different herniated types and its relationships with cel apoptosis. METHODS: The nucleus pulposus was harvested from 60 cases of herniation of lumbar intervertebral discs, L4-5 in 41 cases and L5-S1 in 19 cases. The nucleus pulposus tissues were equaly divided into protruded and sequestered groups. Meanwhile, the nucleus pulposus tissues from another 10 cases of lumbar spine fracture were taken as control group. Expression of hypoxia-inducible factor 1α and apoptosis of lumbar nucleus pulposus cels were observed and detected with immunohistochemical technique and TUNEL method. Correlation of hypoxia-inducible factor 1α and apoptosis in human lumbar nucleus pulposus of different herniated types was analyzed. RESULTS AND CONCLUSION: The expression of hypoxia-inducible factor 1α was visualized in each case, but it was significantly higher in the sequestered group than in the protruded group and control group (P < 0.01). Apoptosis of nucleus pulposus cels were found in al the three groups, but the apoptotic rate was also higher in the sequestered group than in the protruded group and control group (P < 0.01). Expression of hypoxia-inducible factor 1α was positively correlated with cel apoptosis in human lumbar nucleus pulposus (P < 0.01). Overal, the expression of hypoxia-inducible factor1α in degenerative human lumbar nucleus pulposus is associated with herniated types, which is the highest in the sequestered type. The relationship between hypoxia-inducible factor 1α and apoptosis is positive.