Science and Education Publishing International Journal of Clinical and Experimental Neurology 3 2 2015 05 19 Cyclooxygenase Expression in Canines Following Peripheral Nerve Injury 26 31 EN Shigeru Kobayashi Department of Orthopedics and Rehabilitation Medicine, Faculty of Medical Sciences, The University of Fukui, Fukui, Japan Yoshihiko Suzuki Syuichi Yamada Naji Al-Khudairi Adam Meir IJCEN2015321 10.12691/ijcen-3-2-1 2015 04 20 2015 05 11 2015 05 19 In order to investigate the mechanism of neurogenic pain, this study used a median nerve compression model in dogs. The nerve was compressed with a clip for three weeks. Immunohistochemistry was done by the avidin-biotin-peroxidase complex method to observe the changes of T cells (CD45) and macrophages (Mac-1) after compression. Antibodies against cyclooxygenase (COX)-1 and 2 were used to examine the localization and changes of these mediators caused by nerve compression. In control animals, resident T cells were detected, but there were no macrophages. COX-2 was positive in the Schwann cells and vascular endothelial cells, while COX-1 was detected in the vascular endothelial cells. After nerve compression, numerous T cells and macrophages appeared among the demyelinized nerve fibers. The macrophages were positive for COX-2. COX-2 may be deeply involved in neuritis arising from mechanical compression, and this mediator seems to be important in the manifestation of neurogenic pain.