Facial vein collection and ibuprofen administration in mouse serial blood collections reduce pain and inflammation

Blood collection is essential for assessing the physiological status of laboratory animals, however, it inflicts pain, stress, tissue damage, and behavioral disorder to the animal. The administration of analgesics is one way to reduce the distress of animals suffering after experiments. Here we compared efficacious blood collection methods from the facial vein (FV), retroorbital plexus (RP), and lateral tail vein (TV) and the effects of ibuprofen administration based on animal welfare aspects. We evaluated body condition, behavioral activity, stress, pain, immunological profiles, and genetic changes in serial blood collections with or without ibuprofen administration for 8 weeks. We found that RP method reduced body weight, food intake, and water intake. RP method increased the grimace scales of orbital tightening and ear position. RP and TV methods reduced nest-building behaviors. RP and TV methods increased the concentrations of corticosterone, prostaglandin E2, and pro-inflammatory cytokines in peripheral blood. Infiltration of effector immune cells was increased in RP methods. Gene expressions associated with stress, pain, and immune system regulation were upregulated in all RP groups and ibuprofen non-administrated TV group. In contrast, the changed features were restored in FV method and ibuprofen administration. These data indicate that the FV blood collection and ibuprofen administration are suitable methods to mitigate physiologically harmful factors for mice depending on animal welfare considerations.