Journal List > Yonsei Med J > v.42(1) > 1029253

TOOLS
Lee, Sohn, Park, Ahn, Lee, and Park: Studies on the changes of c-fos protein in spinal cord and neurotransmitter in dorsal root ganglion of the rat with an experimental peripheral neuropathy
Original Article
Yonsei Medical Journal

Yonsei Medical Journal 2001; 42(1): 30-40.

Published online: 3 April 2009

DOI: https://doi.org/10.3349/ymj.2001.42.1.30

Studies on the changes of c-fos protein in spinal cord and neurotransmitter in dorsal root ganglion of the rat with an experimental peripheral neuropathy

Won Taek Lee1, Min Kyun Sohn2, Seung Hwa Park3, Soo Kyung Ahn1, Jong Eun Lee1, Kyung Ah Park1

1Brain Research Institute and Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea.

2Department of Rehabilitation, Choongnam University College of Medicine, Daejon, Korea.

3Department of Anatomy, Konkuk University College of Medicine, Choongju, Korea.

Kyung Ah Park, M.D. Department of Anatomy, Yonsei University College of Medicine, C.P.O. Box 8044, Seoul 120-752, Korea. Tel: 82-2-361-5167, Fax: 82-2-365-0700, kapark@yumc.yonsei.ac.kr

Received 2 September 2000       Accepted 9 October 2000

Copyright © 2001 The Yonsei University College of Medicine

Abstract

Animal models for human chronic pain syndromes have been developed and widely used for pain research. One of these neuropathic pain models by Kim and Chung (1992) has many advantages for operation and pain elicitation. In this neuropathic model we have examined the c-fos protein, substance P, CGRP immunoreactivity in dorsal root ganglia and dorsal horn. 50 Sprague-Dawley rats were used for this study. L5 and L6 spinal nerves were ligated tightly to produce the neuropathic pain model. After 2, 4, 8, 16, and 24 hours and 1 week of surgery, rats were anesthetized and sacrificed by perfusion. After confirmation of the roots transected by the surgery, the L5 and L6 dorsal root ganglions and spinal cord were removed and processed for immunohistochemistry. All tissue sections were immunohistochemically stained for substance P, CGRP and c-fos using the peroxidase-antiperoxidase (PAP) method. The number of immunostained substance P and CGRP dorsal root ganglion cells and c-fos immunoreactive dorsal horn cells were counted and analyzed statistically with Mann-Whitney U test.
The results are as follows. The number of c-fos protein immunoreactive neurons in the superficial layer of dorsal horn were increased markedly 2 hours after operation, and gradually decreased to normal level 1 week after operation. The number of c-fos protein immunoreactive neurons in the deep layer of the dorsal horn gradually increased to a peak 24 hours after operation, then decreased to the normal level 1 week after operation. The number of substance P and CGRP immunoreactive L5 and L6 dorsal root ganglion neurons were decreased markedly 1 week after the pain model operation.
In conclusion, after neuropathic pain model operation, c-fos proteins were immediately expressed in the superficial layer of spinal dorsal horn, thereafter c-fos proteins in the deep layer of spinal dorsal horn were expressed. CGRP and substance P immunoreactive neurons in DRG were decreased markedly 1 week after neuropathic pain model operation. These decrements do not coincide with the other chronic pain models, which show great increases in these pain transmitting substances. Therefore, the relationship between pain and c-fos, SP and CGRP should be investigated further.

Keywords: Pain, neuropathy, c-fos, substance p, CGRP, immunohistochemistry

TOOLS
Similar articles