Characterization of cyclophosphamide cystitis, a model of visceral and referred pain, in the mouse: Species and strain differences

ABSTRACTPurpose: Existing animal models of visceral pain in the mouse are of limited practical usefulness since they are labor intensive or not visceral specific. Recently a rat model of cyclophosphamide (CP) cystitis was developed that requires only intraperitoneal injection and features inflammation confined to the bladder. We adapted this model for use in multiple mouse strains to investigate the genetic basis of variability in visceral nociception.Materials and Methods: Outbred CD-1 mice and 12 inbred mouse strains were tested for behavioral changes induced by CP (0 to 300 mg/kg intraperitoneally).Results: We noted that despite the absence of postural changes or abdominal crises in CD-1 mice, CP produced dose dependent decreases in voluntary locomotor activity unaccompanied by ataxia measured on the rotarod test; referred hyperalgesia of the tail base region but not of the hind paw, which was inhibited in dose dependent fashion by morphine (0 to 20 mg/kg); and bladder inflammation corresponding to the...