Acute cardiac injury induces glial cell response and activates extracellular signaling-regulated kinase-1 and -2 in the spinal cord of Wistar rats.
We have examined the activation of glial cells and the upregulation of phosphorylated extracellular signaling-regulated kinase (ERK)-1 and -2 in upper thoracic segments of the spinal cord in rats following acute cardiac injury (ACI). ACI was established by intramyocardial injection of formalin and confirmed by hematoxylin and eosin (H&E) and terminal transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) staining. Following ACI, the astrocytes (determined by glial fibrillary acidic protein (GFAP) immunoreactivity (-IR)) and microglia (determined by OX-42-IR) were activated within the thoracic spinal cord. Phosphorylated (phospho-) ERK-IR was also activated in response to ACI. The upregulation of phospho-ERK was observed at 1h and became very obvious at 6h following ACI. The upregulated phospho-ERK was evidently expressed in the superficial and deep dorsal horn of the thoracic spinal cord. The activated ERK was also expressed in the intermediolateral nucleus (IML), nucleus intercalatus (IC) and the long processes projecting to the central canal, regions closely associated with autonomic outflow. Thus, the present study suggested that ACI could induce the activation of spinal ERK, which might link the nociceptive processing with the spinal sympathetic reflexes in myocardial injury in clinics.
Ping Dai
Ru
R
Department of Anatomy, Faculty of Medicine, National University of Singapore, Lower Kent Ridge Road, Singapore 117597, Singapore.
Ping He
Bei
B
Thameem Dheen
S
S
Tay
Samuel Sam Wah
SS
D000208:Acute Disease; D000818:Animals; D004789:Enzyme Activation; D045604:Extracellular Fluid / Q000378:metabolism; D005557:Formaldehyde; D006331:Heart Diseases / Q000139:chemically induced / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009457:Neuroglia / Q000502:physiology*; D010146:Pain / Q000139:chemically induced / Q000378:metabolism; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D013116:Spinal Cord / Q000378:metabolism* / Q000473:pathology*; D013909:Thorax; D015854:Up-Regulation
D005557:Formaldehyde; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases