title: Characterization of nociceptive behavioural responses in the awake pig following UV-B-induced inflammation.
abstract: BACKGROUND
  Among the current translational inflammatory pain models, the ultraviolet (UV) irradiation is of rapidly growing interest. The development of primary thermal and mechanical hyperalgesia has been observed in humans and rodents. The pig as a translational animal model might be advantageous due to its great homology with humans.
  
  
  METHODS
  The skin in the flank of awake pigs was irradiated by a UV-B light source (1 J/cm(2) ) and changes in thermal and mechanical sensitivity 24 and 48 h following irradiation were measured via assessment of nociceptive behaviours.
  
  
  RESULTS
  Thermal sensitivity increased significantly within the inflamed site 24 h after irradiation as indicated by the reduction of latency to respond to thermal stimulation from baseline to 24 h (P < 0.05). At 48 h, the response latency had not decreased any further (P = 0.414). Thermal sensitivity was also higher at the inflamed skin site than at the control site 24 and 48 h following irradiation (P < 0.05). An overall decrease of 50% of the baseline mechanical threshold was observed 24 and 48 h following UV-B irradiation (P = 0.092). Following the inflammatory challenge, the mechanical sensitivity was higher at the site of irradiation compared with the control skin at both 24 and 48 h (P < 0.05).
  
  
  CONCLUSIONS
  Our study shows that behavioural recordings are a valid tool for the assessment of thermal hyperalgesia following UV-B inflammation in porcine skin, but they were not capable of providing a clear indication of the development of mechanical hyperalgesia.
authors.affiliation: Department of Animal Science, Aarhus University, Tjele, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Di Giminiani
authors.forename: L J
authors.initials: LJ
authors.lastname: Petersen
authors.forename: M S
authors.initials: MS
authors.lastname: Herskin
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D018592:Cross-Over Studies; D003627:Data Interpretation, Statistical; D006358:Hot Temperature; D007249:Inflammation / Q000209:etiology / Q000523:psychology*; D008297:Male; D010146:Pain / Q000209:etiology / Q000523:psychology*; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology; D010812:Physical Stimulation; D011833:Radiation Injuries, Experimental / Q000150:complications / Q000523:psychology*; D015203:Reproducibility of Results; D012867:Skin / Q000528:radiation effects; D013552:Swine; D014466:Ultraviolet Rays