Analgesia in mice with experimental meningitis reduces pain without altering immune parameters.

Intracranial lymphocytic choriomeningitis virus (LCMV) infection is a widely used animal model to study virus-induced cytotoxic T cell (CTL) mediated meningitis and immunopathology. Nevertheless, this model causes severe pain and distress in mice, especially at later stages of the disease. Therefore, new treatment regimens to improve animal welfare have to be developed. In this study, we subcutaneously implanted ALZET® osmotic pumps continuously releasing buprenorphine to reduce pain in mice with LCMV-induced meningitis. Thereby, mice treated with buprenorphine demonstrated strongly reduced symptoms of pain. However, the LCMV-specific cytotoxic T cell response and the immune cell infiltration into the central nervous system (CNS) were unchanged in analgesia treated mice indicating that the LCMV-induced immune response was not altered in these mice. Taken together, we demonstrate that in this animal model for meningitis continuous buprenorphine treatment improves animal welfare without affecting the immune response.