title: Preventive Treatment with Ketamine Attenuates the Ischaemia-Reperfusion Response in a Chronic Postischaemia Pain Model.
abstract: Ischemia and inflammation may be pathophysiological mechanisms of complex regional pain syndrome (CRPS). Ketamine has proposed anti-inflammatory effects and has been used for treating CRPS. This study aimed to evaluate anti-inflammatory and analgesic effects of ketamine after ischaemia-reperfusion injury in a chronic postischaemia pain (CPIP) model of CRPS-I. Using this model, ischemia was induced in the hindlimbs of male Sprague-Dawley rats. Ketamine, methylprednisolone, or saline was administered immediately after reperfusion. Physical effects, (oedema, temperature, and mechanical and cold allodynia) in the bilateral hindpaws, were assessed from 48 hours after reperfusion. Fewer (56%) rats in the ketamine group developed CPIP at the 48th hour after reperfusion (nonsignificant). Ketamine treated rats showed a significantly lower temperature in the ischaemic hindpaw compared to saline (P < 0.01) and methylprednisolone (P < 0.05) groups. Mechanical and cold allodynia were significantly lower in the ischaemic side in the ketamine group (P < 0.05). Proinflammatory cytokines TNF-α and IL-2 were significantly lower at the 48th hour after reperfusion in ketamine and methylprednisolone groups, compared to saline (all P < 0.05). In conclusion, immediate administration of ketamine after an ischaemia-reperfusion injury can alleviate pain and inflammation in the CPIP model and has potential to treat postischaemic pain.
authors.affiliation: Department of Anaesthesiology, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Suryamin
authors.initials: S
authors.lastname: Liman
authors.affiliation: Department of Anaesthesiology, The University of Hong Kong, Pokfulam, Hong Kong ; Laboratory and Clinical Research Institute for Pain, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Chi Wai
authors.initials: CW
authors.lastname: Cheung
authors.affiliation: Department of Anaesthesiology, The University of Hong Kong, Pokfulam, Hong Kong ; Laboratory and Clinical Research Institute for Pain, The University of Hong Kong, Pokfulam, Hong Kong ; Department of Anaesthesiology, China Medical University and Hospital, Taichung 40402, Taiwan.
authors.forename: Kar Lok
authors.initials: KL
authors.lastname: Wong
authors.affiliation: Department of Anaesthesiology, The University of Hong Kong, Pokfulam, Hong Kong ; Laboratory and Clinical Research Institute for Pain, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Wai
authors.initials: W
authors.lastname: Tai
authors.affiliation: Department of Anaesthesiology, The University of Hong Kong, Pokfulam, Hong Kong ; Laboratory and Clinical Research Institute for Pain, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Qiu
authors.initials: Q
authors.lastname: Qiu
authors.affiliation: Department of Anaesthesiology, The University of Hong Kong, Pokfulam, Hong Kong ; Laboratory and Clinical Research Institute for Pain, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Kwok Fu
authors.initials: KF
authors.lastname: Ng
authors.affiliation: Department of Anaesthesiology, The University of Hong Kong, Pokfulam, Hong Kong ; Laboratory and Clinical Research Institute for Pain, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Siu Wai
authors.initials: SW
authors.lastname: Choi
authors.affiliation: Department of Anaesthesiology, The University of Hong Kong, Pokfulam, Hong Kong ; Laboratory and Clinical Research Institute for Pain, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Michael
authors.initials: M
authors.lastname: Irwin
mesh_terms: D000700:Analgesics / Q000627:therapeutic use*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002908:Chronic Disease; D020918:Complex Regional Pain Syndromes / Q000188:drug therapy*; D004195:Disease Models, Animal; D006614:Hindlimb / Q000503:physiopathology; D006930:Hyperalgesia; D007376:Interleukin-2 / Q000378:metabolism; D007511:Ischemia / Q000209:etiology; D007649:Ketamine / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D008775:Methylprednisolone / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000503:physiopathology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000700:Analgesics; D007376:Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D007649:Ketamine; D008775:Methylprednisolone