ANALGESIC REFINEMENT OF PAINFUL EXPERIMENTS IN LABORATORYANIMALS

Suffering in laboratory animals undergoing painful or stressing experiments is a major concern for scientists as much for the community. To gain scientific value and community approval, the design of animal experiments must take into account individual suffering, aim of the experiment and public opinion. Physical pain is an heterogeneous symptom varying with stimulus nature, location and intensity. Pain perception changes with the Individual and with psychic conditions such as thrill or competition decreasing and stress, fear or anxiety increasing it. As a consequence, pain assessment poses an heavy drawback to effective treatment of pain in animals. Non painful experiments must also take into account individual fear, stress and anxiety to effectively prevent suffering. Preemptive, intra-operative, post-operative and multimodal analgesia, in addition to sedation, anxiolysis, pain assessment, proper analgesic regimen and tender loving care are crucial components of a refined animal experiment, to be taken into account by the research team and by the ethical committee before an experiment takes place. The analgesic protocol must be tailored for the specific experiment adjusting it to each individual to guarantee time fitting, effective anesthetic and analgesic treatments. Postoperative pain depends on a precise multimodal analgesic strategy to be commenced before inflicting pain to the patient. Multimodal analgesia, founded on inhibiting different pain mechanisms, is a mandatory requisite of any invasive procedure. NSAIDs, opioids, α-2 agonists, NMDA / AMPA receptors blocking drugs and local anaesthetics should skilfully be combined to act on reception, transduction, transmission and perception of painful stimuli, preventing unnecessary suffering of the patient. Intrathecal administration of local anaesthetics and/or systemic analgesics, where appropriate, should be encouraged. Individual response to pain and stress is often an understated component of an experimental design in live animals. Analgesic refinement of animal experiments requires experienced anesthetists, able to measure and treat pain in single species.