title: Spinal cord injury-induced astrocyte migration and glial scar formation: effects of magnetic stimulation frequency.
abstract: The effects of magnetic stimulation on spinal cord injury-induced migration of white matter astrocytes were studied using an established animal model. Ethidium bromide was injected into the dorsal spinal cord funiculus of adult Sprague-Dawley rats on the left side at T10-11. Animals then received 1.52 Tesla-pulsed magnetic stimulation for 5 min at different frequencies (0-20 Hz) for 14 consecutive days. Selected animals received the non-competitive MEK1/2 inhibitor U0126 (10 microM), prior to stimulation at 10 Hz. Lesion volumes were measured in hematoxylin/eosin-stained sections. Expression of glial fibrillary acidic protein (GFAP), microtubule associated protein-2 (MAP-2) and extra-cellular signal-regulated kinasel/2 (ERK1/2) near the epicenter of injury was examined by Western blotting with quantification using an image analysis system. Lesion volumes decreased and GFAP and p-ERK1/2 expression increased with increasing magnetic stimulation frequency (0-10 Hz). MAP-2 expression was not affected at any frequency. Pretreatment with U0126 reduced GFAP and ERK1/2 expression and increased lesion volumes in response to stimulation at 10 Hz. It is concluded that magnetic stimulation increases the migration of astrocytes to spinal cord lesions. Activation of the ERK1/2 signaling pathway is proposed to mediate astrocyte migration and glial scar formation in response to spinal cord injury.
authors.affiliation: Department of Rehabilitation Medicine, WHO Collaborating Centre for Training and Research in Rehabilitaion (CHN-60) Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Li
authors.forename: Zheng-Yu
authors.initials: ZY
authors.lastname: Fang
authors.forename: Liang
authors.initials: L
authors.lastname: Xiong
authors.forename: Xiao-Lin
authors.initials: XL
authors.lastname: Huang
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000473:pathology; D002465:Cell Movement; D002921:Cicatrix / Q000473:pathology; D004195:Disease Models, Animal; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D020935:MAP Kinase Signaling System; D055909:Magnetic Field Therapy / Q000379:methods*; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009457:Neuroglia / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000378:metabolism / Q000473:pathology* / Q000628:therapy*
chemical_list: D005904:Glial Fibrillary Acidic Protein; C489787:MAP2 protein, rat; D008869:Microtubule-Associated Proteins