Basic Research
Copyright ©The Author(s) 2005. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Aug 21, 2005; 11(31): 4827-4832
Published online Aug 21, 2005. doi: 10.3748/wjg.v11.i31.4827
GFAP and Fos immunoreactivity in lumbo-sacral spinal cord and medulla oblongata after chronic colonic inflammation in rats
Yi-Ning Sun, Jin-Yan Luo, Zhi-Ren Rao, Li Lan, Li Duan
Yi-Ning Sun, Jin-Yan Luo, Department of Gastroenterology, The Second Hospital of Xi抋n Jiaotong University, Xi’an 710004, Shaanxi Province, China
Zhi-Ren Rao, Li Lan, Li Duan, Department of Neurosciences, the Fourth Military Medical University, Xi’an 710032, Shaanxi Province, China
Author contributions: All authors contributed equally to the work.
Correspondence to: Professor Jin-Yan Luo, Department of Gastroenterology, The Second Hospital of Xi’an Jiaotong University, Xi’an 710004, Shaanxi Province, China. ljy18272@163.com
Telephone: +86-29-87678758
Received: August 26, 2004
Revised: December 3, 2004
Accepted: December 8, 2004
Published online: August 21, 2005
Abstract

AIM: To investigate the response of astrocytes and neurons in rat lumbo-sacral spinal cord and medulla oblongata induced by chronic colonic inflammation, and the relationship between them.

METHODS: Thirty-three male Sprague-Dawley rats were randomly divided into two groups: experimental group (n = 17), colonic inflammation was induced by intra-luminal administration of trinitrobenzenesulfonic acid (TNBS); control group (n = 16), saline was administered intra-luminally. After 3, 7, 14, and 28 d of administration, the lumbo-sacral spinal cord and medulla oblongata were removed and processed for anti-glial fibrillary acidic protein (GFAP), Fos and GFAP/Fos immunohistochemistry.

RESULTS: Activated astrocytes positive for GFAP were mainly distributed in the superficial laminae (laminae I-II) of dorsal horn, intermediolateral nucleus (laminae V), posterior commissural nucleus (laminae X) and anterolateral nucleus (laminae IX). Fos-IR (Fos-immunoreactive) neurons were mainly distributed in the deeper laminae of the spinal cord (laminae III-IV, V-VI). In the medulla oblongata, both GFAP-IR astrocytes and Fos-IR neurons were mainly distributed in the medullary visceral zone (MVZ). The density of GFAP in the spinal cord of experimental rats was significantly higher after 3, 7, and 14 d of TNBS administration compared with the controls (50.4±16.8, 29.2±6.5, 24.1±5.6, P<0.05). The density of GFAP in MVZ was significantly higher after 3 d of TNBS administration (34.3±2.5, P<0.05). After 28 d of TNBS administration, the density of GFAP in the spinal cord and MVZ decreased and became comparable to that of the controls (18.0±4.9, 14.6±6.4, P>0.05).

CONCLUSION: Astrocytes in spinal cord and medulla oblongata can be activated by colonic inflammation. The activated astrocytes are closely related to Fos-IR neurons. With the recovery of colonic inflammation, the activity of astrocytes in the spinal cord and medulla oblongata is reduced.

Keywords: Astrocytes; Neurons; Glial fibrillary acidic protein; Fos; Spinal cord; Medulla oblongata; Colonic inflammation