title: Quantification of the rat spinal microglial response to peripheral nerve injury as revealed by immunohistochemical image analysis and flow cytometry.
abstract: Microgliosis is implicated in the pathophysiology of several neurological disorders, including neuropathic pain. Consequently, perturbation of microgliosis is a mechanistic and drug development target in neuropathic pain, which highlights the requirement for specific, sensitive and reproducible methods of microgliosis measurement. In this study, we used the spinal microgliosis associated with L5 spinal nerve transection and minocycline-induced attenuation thereof to: (1) evaluate novel software based semi-quantitative image analysis paradigms for the assessment of immunohistochemical images. Microgliosis was revealed by immunoreactivity to OX42. Several image analysis paradigms were assessed and compared to a previously validated subjective categorical rating scale. This comparison revealed that grey scale measurement of the proportion of a defined area of spinal cord occupied by OX42 immunoreactive cells is a robust image analysis paradigm. (2) Develop and validate a flow cytometric approach for quantification of spinal microgliosis. The flow cytometric technique reliably quantified microgliosis in spinal cord cell suspensions, using OX42 and ED9 immunoreactivity to identify microglia. The results suggest that image analysis of immunohistochemical revelation of microgliosis reliably detects the spinal microgliosis in response to peripheral nerve injury and pharmacological attenuation thereof. In addition, flow cytometry provides an alternative approach for quantitative analysis of spinal microgliosis elicited by nerve injury.
authors.affiliation: Department of Anaesthetics, Pain Medicine and Intensive Care, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital Campus, 369 Fulham Road, London SW10 9NH, UK. j.blackbeard@imperial.ac.uk
authors.forename: J
authors.initials: J
authors.lastname: Blackbeard
authors.forename: K P
authors.initials: KP
authors.lastname: O'Dea
authors.forename: V C J
authors.initials: VC
authors.lastname: Wallace
authors.forename: A
authors.initials: A
authors.lastname: Segerdahl
authors.forename: T
authors.initials: T
authors.lastname: Pheby
authors.forename: M
authors.initials: M
authors.lastname: Takata
authors.forename: M J
authors.initials: MJ
authors.lastname: Field
authors.forename: A S C
authors.initials: AS
authors.lastname: Rice
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D000943:Antigens, Differentiation / Q000378:metabolism; D039481:CD11b Antigen / Q000378:metabolism; D003952:Diagnostic Imaging / Q000379:methods*; D005434:Flow Cytometry / Q000379:methods*; D007839:Functional Laterality; D007150:Immunohistochemistry / Q000379:methods*; D008297:Male; D017628:Microglia / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D008911:Minocycline / Q000627:therapeutic use; D010523:Peripheral Nervous System Diseases / Q000188:drug therapy / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012984:Software; D013116:Spinal Cord / Q000187:drug effects / Q000473:pathology*; D018709:Statistics, Nonparametric
chemical_list: D000900:Anti-Bacterial Agents; D000943:Antigens, Differentiation; D039481:CD11b Antigen; D008911:Minocycline