title: The effect of urinary trypsin inhibitor against neuropathic pain in rat models.
abstract: BACKGROUND
  Nerve injury sometimes leads to chronic neuropathic pain associated with neuroinflammation in the nervous system. In the case of chronic neuropathic pain, the inflammatory and algesic mediators become predominant and result in pain hypersensitivity following nervous system damage. It is well known that urinary trypsin inhibitor (ulinastatin, UTI) has an anti-inflammatory activity. Recently, the neuroprotective action of UTI on the nervous system after ischemic injury has been reported. Thus, we evaluated the neuroprotective effect of ulinastatin in a rat model of neuropathic pain.
  
  
  METHODS
  Neuropathic pain was induced with L5 spinal nerve ligation (SNL) in male Sprague-Dawley rats weighing 100-120 g. The rats were divided into 3 groups, with n = 8 in each group. The rats in the control group (group 1) were administered normal saline and those in group 2 were administered UTI (50,000 U/kg) intravenously through the tail vein for 3 days from the day of SNL. Rats in group 3 were administered UTI (50,000 U/kg) intravenously from the 5(th) day after SNL. The paw withdrawal threshold was measured using the von Frey test for 3 days starting from the 5(th) day after SNL.
  
  
  RESULTS
  The paw withdrawal thresholds were significantly increased in the rats of group 2 compared to the other groups (P < 0.05).
  
  
  CONCLUSIONS
  Ulinastatin, which was administered for 3 days after SNL, increased the paw withdrawal threshold and it could have a neuroprotective effect in the rat model of neuropathic pain.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Chosun University School of Medicine, Gwangju, Korea.
authors.forename: Ki Tae
authors.initials: KT
authors.lastname: Jung
authors.forename: Hyun Young
authors.initials: HY
authors.lastname: Lee
authors.forename: Myung Ha
authors.initials: MH
authors.lastname: Yoon
authors.forename: Kyung Joon
authors.initials: KJ
authors.lastname: Lim
keywords: neuropathic pain; rats; urinary trypsin inhibitor