DR5 and DcR2 are expressed in human lumbar intervertebral discs.
METHODS
To conform the 3 media way of the apoptosis for the degenerative lumbar disc with DR5 (TRAIL-R2) and DcR2 (TRAIL-R4), as one of the tumor necrosis factors family.


OBJECTIVE
To detect the expression of the DR5 (TRAIL-R2) and DcR2 (TRAIL-R4) protein and mRNA in human herniated and normal lumbar intervertebral discs (IVD).


BACKGROUND
The pathogenesis of lumber intervertebral disc herniation and degeneration is still unclear. A series of reports have suggested that apoptosis may play a key role in intervertebral disc degeneration. There are 3 apoptosis-inducing factors: FasL, TNF-alpha, and TRAIL, which trigger cell death by apoptosis-signaling pathways. These factors combined with the ligand to induce apoptosis. We have reported the expression of DR4 in IVD before. To our knowledge, there are still no studies the important role of the DR5 and DcR2 for apoptosis in IVD tissue.


METHODS
The expression and distribution of DR5 and DcR2 proteins were assessed using immunostaining in 60 herniated lumbar IVD and 22 normal lumbar IVD tissue samples. DR5 and DcR2 mRNA was also quantified using real time fluorescent reverse transcriptase-polymerase chain reaction (RT-PCR) in 30 herniated lumbar IVD and 9 normal lumbar IVD.


RESULTS
There were significant differences in the percentage of samples with DR5 expression between the herniated (41.60%) and normal IVD (26.09%) groups (P = 0.001). Similarly, DR5 mRNA levels differed between groups (P = 0.025). However, there were no differences in DcR2 protein or mRNA levels.


CONCLUSIONS
The current results indicate that disc cells, after herniation, undergo apoptotic cell death via the DR5/TRAIL pathway.
Chen
Bohua
B
Department of Orthopaedic Surgery, Affiliated Hospital of Qingdao University Medical College, Shandong, China. bhchen@hotmail.com
Ma
Bin
B
Yang
Shangyou
S
Xing
Xiuhua
X
Gu
Run
R
Hu
Yougu
Y
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D017209:Apoptosis; D016022:Case-Control Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007403:Intervertebral Disc / Q000737:chemistry* / Q000473:pathology; D007405:Intervertebral Disc Displacement / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008159:Lumbar Vertebrae / Q000737:chemistry* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000032:analysis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053319:Tumor Necrosis Factor Decoy Receptors / Q000032:analysis* / Q000235:genetics; D055815:Young Adult
D012333:RNA, Messenger; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; C505639:TNFRSF10B protein, human; C451501:TNFRSF10D protein, human; D053319:Tumor Necrosis Factor Decoy Receptors