title: Dexmedetomidine reduces neuropathic pain in a rat model of skin/muscle incision and retraction.
abstract: BACKGROUND
  Dexmedetomidine has been proposed as a novel anesthetic adjuvant. However, it remains unclear whether peripheral administration of dexmedetomidine is safe and effective to reduce acute postoperative pain. This study aimed to examine the effects of dexmedetomidine on neuropathic pain.
  
  
  METHODS
  Adult male Sprague-Dawley rats were anaesthetized and randomly allocated into four groups (n = 8): Groups S, R, RD1, and RD5were injected with saline, 0.5% ropivacaine, 0.5% ropivacaine combined with 1 μg dexmedetomidine, and 0.5% ropivacaine combined with 5 μg dexmedetomidine, respectively, around the saphenous nerve. Then, the rats were subjected to skin/muscle incision and retraction (SMIR) surgery in the medial thigh. Mechanical and heat sensitivity was evaluated and morphology of the dorsal root ganglion (DRG) neurons was observed by electron microscopy.
  
  
  RESULTS
  Some 62.5%, 50%, 12.5%, and 25% of rats developed mechanical hypersensitivity in Groups S, R, RD1, and RD5, respectively. The number of swollen mitochondria in DRG neurons was significantly more in Group S (257.2 ± 60.9) and Group R (291.6 ± 82.1) than in Group RD1(97.2 ± 33.3) and Group RD5(13.6 ± 17.9). In addition, the edema in endoplasmic reticulum and Golgi apparatus was decreased in Group RD1and Group RD5compared with Group S and Group R.
  
  
  CONCLUSIONS
  Peripheral administration of dexmedetomidine improves mechanical and heat hyperalgesia and mitigates postoperative pain.
authors.affiliation: Department of Anesthesiology, Guangdong Women and Children's Hospital, Guangzhou, China; Department of Anesthesiology, General Hospital of Guangzhou Military Region Affiliated to Southern Medical University, Southern Medical University, Guangzhou, China.
authors.forename: Xizhao
authors.initials: X
authors.lastname: Huang
authors.affiliation: Department of Anesthesiology, General Hospital of Guangzhou Military Region Affiliated to Southern Medical University, Southern Medical University, Guangzhou, China.
authors.forename: Rongfang
authors.initials: R
authors.lastname: Deng
authors.affiliation: Department of Anesthesiology, General Hospital of Guangzhou Military Region Affiliated to Southern Medical University, Southern Medical University, Guangzhou, China.
authors.forename: Weifeng
authors.initials: W
authors.lastname: Tu
authors.affiliation: Department of Anesthesiology, Guangdong Women and Children's Hospital, Guangzhou, China. Electronic address: hzrong136@163.com.
authors.forename: Zurong
authors.initials: Z
authors.lastname: Hu
mesh_terms: D000577:Amides / Q000627:therapeutic use; D018712:Analgesics, Non-Narcotic / Q000627:therapeutic use*; D000779:Anesthetics, Local / Q000627:therapeutic use; D000818:Animals; D062109:Dermatologic Surgical Procedures; D020927:Dexmedetomidine / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D007267:Injections; D008297:Male; D018482:Muscle, Skeletal / Q000601:surgery*; D009437:Neuralgia / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000175:diagnosis / Q000517:prevention & control*; D011300:Preoperative Care; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077212:Ropivacaine; D013848:Thigh; D016896:Treatment Outcome
chemical_list: D000577:Amides; D018712:Analgesics, Non-Narcotic; D000779:Anesthetics, Local; D020927:Dexmedetomidine; D000077212:Ropivacaine
keywords: dexmedetomidine; dorsal root ganglion neuron; postoperative pain; ropivacaine; skin/muscle incision and retraction