title: Does inflammation induced by ultraviolet B and heat rekindling alter pain-related behaviour in rats?
abstract: OBJECTIVE
  To investigate whether induction of the ultraviolet B and heat rekindling (UVB/HR) model alters burrowing behaviour in rats.
  
  
  METHODS
  Randomized, blinded, prospective experimental study.
  
  
  METHODS
  Sixteen adult male Wistar rats weighing 250-300 g.
  
  
  METHODS
  In the UVB/HR group (n = 8), UV irradiation was delivered to the heel area of the right plantar pelvic limb paw at a dose of 1000 mJ cm(-2) , using a narrow-band UVB light source. Twenty-four hours later, heat rekindling was performed by placement of a feedback-controlled thermode set at a constant temperature of 45 °C over the area of UVB irradiation for 5 minutes. Both interventions were carried out under pentobarbital anaesthesia. The 'sham' group (n = 8) was anaesthetized only. In the burrowing test, rats were housed singly for 2 hours in cages furnished with a burrow filled with sand. The amount of sand remaining in the burrow after 2 hours was weighed and the amount displaced from the burrow calculated. The burrowing test was carried out for two consecutive days prior to UVB irradiation (day 0), on day 1 prior to HR, on days 2 and 3 after UVB exposure and at equivalent time points in the sham group.
  
  
  RESULTS
  Rats in the sham group burrowed means (SD) of 2429 (73) g and 2358 (124) g of sand on days -2 and 3, respectively, while those in the UVB/HR group burrowed 2460 (26) and 2419 (58) g on days -2 and 3, respectively. There was no significant effect of treatment on the amount of sand burrowed at any time point.
  
  
  CONCLUSIONS
  Pain associated with UVB/HR model induction is below the threshold required to affect rat burrowing behaviour and therefore questions the face validity of UVB/HR as a translational model of inflammatory pain.
authors: School of Veterinary Sciences, University of Bristol, Langford, North Somerset, UK.
authors: Melissa
authors: M
authors: Smith
authors: School of Veterinary Sciences, University of Bristol, Langford, North Somerset, UK.
authors: Collette
authors: C
authors: Taylor
authors: School of Physiology and Pharmacology, University of Bristol, Bristol, UK.
authors: Nirosha
authors: N
authors: Weerasinghe
authors: School of Biological Sciences, University of Bristol, Bristol, UK.
authors: Stella
authors: S
authors: Koutsikou
authors: School of Physiology and Pharmacology, University of Bristol, Bristol, UK.
authors: Bridget
authors: B
authors: Lumb
authors: School of Veterinary Sciences, University of Bristol, Langford, North Somerset, UK.
authors: Jo
authors: J
authors: Murrell
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000528:radiation effects; D006358:Hot Temperature; D007249:Inflammation / Q000523:psychology*; D008297:Male; D008954:Models, Biological; D010146:Pain / Q000209:etiology / Q000523:psychology*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D014466:Ultraviolet Rays
keywords: burrowing; heat rekindling; pain; rat; ultraviolet B