The expression of hypoxia inducible factor-1alpha and apoptosis in herniated discs.
METHODS
Human intervertebral disc was obtained for the study of hypoxia inducible factor (HIF)-1alpha and apoptosis using immunohistochemical staining.


OBJECTIVE
To study the expression of HIF-1alpha and apoptosis in herniated lumbar discs.


BACKGROUND
The presence of HIF-1alpha in human chondrocytes and rat intervertebral discs has been proven; however, to our knowledge, its expression in human intervertebral disc cells has not been reported. Apoptosis of the human intervertebral disc appears as a degenerative change caused by the aging of the intervertebral disc. To our knowledge, there is no reported study showing the correlation between apoptosis and HIF-1alpha in the human intervertebral disc.


METHODS
There were 15 human intervertebral discs stained for HIF-1alpha immunohistochemically, and apoptosis was detected using the terminal deoxynucleotidyl transferase mediated-dUTP nick end labeling method. On average, the patients were 32.9 years old. The intervertebral discs were divided into noncontained (9 patients) and contained (6) groups. For the control group, 5 disc samples were used.


RESULTS
The expression of HIF-1alpha was visualized in every case, with an average of 62.2% +/- 9.5% in the noncontained group, 30.5% +/- 3.6% in the contained group, and 11.4% +/- 9.3% in the control group. Apoptosis occurred in 74.3% +/- 7.3% of the cells in the noncontained group, 42.8% +/- 5.5% of the cells in the contained group, and 28% +/- 8.4% of the cells in the control group. HIF-1alpha and apoptosis expressions were both observed more frequently in the noncontained disc herniation group (P < 0.001). The correlation analysis between the degree of HIF-1alpha expression and apoptosis was also statistically significant.


CONCLUSIONS
HIF-1alpha and apoptosis physiologically occur in human beings. Their expression was the highest in the noncontained group. HIF-1alpha may play a crucial role for the survival of disc cells and resorption of the herniated disc in human intervertebral discs.
Ha
Kee-Yong
KY
Department of Orthopedic Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Koh
In-Jun
IJ
Kirpalani
Papni Arjandas
PA
Kim
Young-Yul
YY
Cho
Yun-Kyoung
YK
Khang
Gil-Son
GS
Han
Chang Whan
CW
D000328:Adult; D017209:Apoptosis; D005260:Female; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007403:Intervertebral Disc / Q000378:metabolism / Q000503:physiopathology*; D007405:Intervertebral Disc Displacement / Q000378:metabolism / Q000503:physiopathology*; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged
D051795:Hypoxia-Inducible Factor 1, alpha Subunit