title: Intraprostatic capsaicin injection as a novel model for nonbacterial prostatitis and effects of botulinum toxin A.
abstract: OBJECTIVE
  An animal model for nonbacterial prostatitis in rats was developed with the use of intraprostatic injection of capsaicin, an agent thought to excite C-afferent fibers and cause neurogenic inflammation. The analgesic and anti-inflammatory properties of botulinum toxin type A (BoNT-A) was tested in this model.
  
  
  METHODS
  Adult male Spraque-Dawley rats were injected with varying doses of capsaicin into the prostate. The nociceptive effects of capsaicin were evaluated for 30min by using a behavior approach; then the prostate was removed for histology and cyclooxygenase (COX) 2 protein concentration measurement. Evans blue (50mg/kg) was also injected intravenously to assess for plasma protein extravasation. A second set of animals were injected with up to 20U of BoNT-A into the prostates 1 wk prior to intraprostatic injection of 1000micromol/l capsaicin.
  
  
  RESULTS
  Capsaicin dose dependently induced modifications in pain behavior: closing of the eyes, hypolocomotion, and inflammatory changes: increase of inflammatory cell accumulation, COX2 expression, and plasma extravasation at the acute stage, but completely recovered at 1 wk. BoNT-A pretreatment dose dependently reversed pain behavior and inflammation. BoNT-A 20U significantly decreased inflammatory cell accumulation, COX2 expression, and Evans blue extraction (82.1%, 83.0%, and 50.4%, respectively), and reduced pain behavior (66.7% for eye score and 46.5% for locomotion score).
  
  
  CONCLUSIONS
  Intraprostatic capsaicin injection induced neurogenic prostatitis and prostatic pain, and may be a useful research model. BoNT-A produced anti-inflammatory and analgesic effects, and support clinical evaluation in prostatitis.
authors.affiliation: Department of Urology, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Yao-Chi
authors.initials: YC
authors.lastname: Chuang
authors.forename: Naoki
authors.initials: N
authors.lastname: Yoshimura
authors.forename: Moya
authors.initials: M
authors.lastname: Wu
authors.forename: Chao-Cheng
authors.initials: CC
authors.lastname: Huang
authors.forename: Po-Hui
authors.initials: PH
authors.lastname: Chiang
authors.forename: Pradeep
authors.initials: P
authors.lastname: Tyagi
authors.forename: Michael B
authors.initials: MB
authors.lastname: Chancellor
mesh_terms: D000818:Animals; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D002211:Capsaicin / Q000008:administration & dosage*; D004195:Disease Models, Animal; D007267:Injections; D008297:Male; D009498:Neurotoxins / Q000627:therapeutic use*; D011472:Prostatitis / Q000139:chemically induced / Q000188:drug therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D009498:Neurotoxins; D019274:Botulinum Toxins, Type A; D002211:Capsaicin