title: Therapeutic effect of epidurally administered lipo-prostaglandin e1 agonist in a rat spinal stenosis model.
abstract: BACKGROUND
  A lipo-prostaglandin E1 agonist is effective for the treatment of neurological symptoms of spinal stenosis when administered by an oral or intravenous route. we would like to reveal the therapeutic effect of an epidural injection of lipo-prostaglandin E1 on hyperalgesia in foraminal stenosis.
  
  
  METHODS
  A total of 40 male Sprague-Dawley rats were included. A small stainless steel rod was inserted into the L5/L6 intervertebral foramen to produce intervertebral foraminal stenosis and chronic compression of the dorsal root ganglia (DRG). The rats were divided into three groups: epidural PGE1 (EP) (n = 15), saline (n = 15), and control (n = 10). In the EP group, 0.15 µg.kg-1 of a lipo-PGE1 agonist was injected daily via an epidural catheter for 10 days from postoperative day 3. In the saline group, saline was injected. Behavioral tests for mechanical hyperalgesia were performed for 3 weeks. Then, the target DRG was analyzed for the degree of chromatolysis, chronic inflammation, and fibrosis in light microscopic images.
  
  
  RESULTS
  From the fifth day after lipo-PGE1 agonist injection, the EP group showed significant recovery from mechanical hyperalgesia, which was maintained for 3 weeks (P < 0.05). Microscopic analysis showed much less chromatolysis in the EP group than in the saline or control groups.
  
  
  CONCLUSIONS
  An epidurally administered lipo-PGE1 agonist relieved neuropathic pain, such as mechanical hyperalgesia, in a rat foraminal stenosis model, with decreasing chromatolysis in target DRG. We suggest that epidurally administered lipo-PGE1 may be a useful therapeutic candidate for patients with spinal stenosis.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Jeju National University Hospital, Jeju, Korea.
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Pyung Bok
authors.initials: PB
authors.lastname: Lee
authors.affiliation: Department of Pathology, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Ghee Young
authors.initials: GY
authors.lastname: Choe
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Jee Yeon
authors.initials: JY
authors.lastname: Moon
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Francis Sahngun
authors.initials: FS
authors.lastname: Nahm
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University School of Medicine, Seoul, Korea.
authors.forename: Yong Chul
authors.initials: YC
authors.lastname: Kim
keywords: epidural administration; hyperalgesia; spinal stenosis