1995 Fiscal Year Final Research Report Summary
Pathomechanism of radicular pain in lumbar radiculopathy.
| Project/Area Number |
06671473
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Orthopaedic surgery
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| Research Institution | Wakayama Medical College, School of Medicine |
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Principal Investigator |
KAWAKAMI Mamoru Wakayama Medical College, Orthop.Surg., Assistante, 医学部, 助手 (20195051)
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| Co-Investigator(Kenkyū-buntansha) |
TAMAKI Tetsuya Wakayama Medical College, Orthop.Surg., Professor, 医学部, 教授 (30009592)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Nucleus Pulposus / Anulus Fibrosus / Pain / Hyperalgesia / Phospholipase A2 / Nitric Oxide / Mepacrine / L-NAME |
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| Research Abstract |
Fat, nucleus pulposus (NP) and anulus fibrosus (AF) were allografted into the epidural space at L_6 level in the rat. Withdrawal response thresholds to mechanical stimuli and withdrawal response latencies to thermal stimuli on the tail postoperatively. Interleukin-1, PLA_2 and NOS were examined in the applied tissues using immunohistochemistry, NADPH-diaphorase histochemistry and in situ hybridization. In results, allografted fat did not produce hyperalgesia. Allografts of NP and NP+AF showed evidence of mechanical and thermal hyperalgesia, respectively. Although interleukin-1 was demonstrated in all applied tissues, PLA_2 was only observed around the applied NP and NP+AF.NOS was only markedly increased around the applied. The NP group (allografted NP placed on the sciatic nerve) and NP+AF group (NP+AF,respectively) were mede to evaluate the sensitivities to noxious stimuli following local sciatic nerve administration of L-NAME or mepacrine into the operated site. Only rats in the NP group showed evidence of mechanical hyperalgesia. Injection of L-NAME resulted in evidence of mechanical hyperalgesia in the NP+AF group. Mechanical hyperalgesia, which was produced in the NP group and after injection of L-NAME in the NP+AF group, both of which returned to normal after mepacrine injection. In conclusion, it appears that PLA_2 and NO play important but different roles in pathomechanisms of radicular pain in lumbar disc herniation.
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