Histochemical demonstration of nitric oxide in herniated lumbar discs. A clinical and animal model study.
METHODS
This study was designed to localize the cells that produce nitric oxide in a lumbar disc herniation by histochemical method, including in situ hybridization.


OBJECTIVE
To clarify which cells in herniated lumbar discs produce nitric oxide.


BACKGROUND
It was reported that herniated lumbar intervertebral disc specimens in culture are capable of producing nitric oxide.


METHODS
Surgical specimens from lumbar disc herniation were examined to determine nitric oxide synthase histologically using nicotinamide adenine dinucleotide phosphate diaphorase histochemistry. Allografts of intervertebral disc materials were placed on the epidural space at L6 level in the rat. Nitric oxide synthase was examined in the applied tissues using nicotinamide adenine dinucleotide phosphate diaphorase histochemistry and in situ hybridization histochemistry.


RESULTS
Nicotinamide adenine dinucleotide phosphate diaphorase (nitric oxide synthase) positive cells were observed in 2 (40%) of 5 herniated disc materials in patients. The positive cells were mainly in granulation tissue around intervertebral disc materials. In animal models, nitric oxide synthase-positive cells were observed in all specimens at 1 and 2 weeks postoperatively. Newly formed vessels and small round cells in granulation tissue around the grafted intervertebral disc showed positive reaction. In situ hybridization demonstrated the expression of inducible isoform of nitric oxide synthase messenger RNA (mRNA) identical to small round cells around the applied intervertebral disc.


CONCLUSIONS
Nitric oxide in a lumbar disc herniation is mainly produced by cells in granulation tissue around the herniated intervertebral disc.
Hashizume
H
H
Department of Orthopedic Surgery, Wakayama Medical College, Japan.
Kawakami
M
M
Nishi
H
H
Tamaki
T
T
D000328:Adult; D000818:Animals; D005260:Female; D006097:Granulation Tissue / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D017403:In Situ Hybridization; D007403:Intervertebral Disc / Q000166:cytology / Q000378:metabolism* / Q000637:transplantation; D007405:Intervertebral Disc Displacement / Q000378:metabolism*; D008159:Lumbar Vertebrae / Q000378:metabolism*; D008297:Male; D009569:Nitric Oxide / Q000032:analysis* / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley
D009569:Nitric Oxide; D019001:Nitric Oxide Synthase