Buprenorphine extended-release (Ethiqa XR) impacts the immunological response in mice exposed to aerosolized Burkholderia pseudomallei or Yersinia pestis

IntroductionEthiqa XR is an extended-release formulation of the potent partial opioid buprenorphine and has been FDA-indexed for mice and other laboratory animal species to relieve pain. Unfortunately, the use of analgesia may produce confounding effects that distort physiological and pathophysiological responses during laboratory animal studies.

Since various reports have indicated that Ethiqa XR can affect the inflammatory response in several in vivo models, we sought to evaluate the effects of Ethiqa XR treatment on the immune response to and disease pathogenesis associated with bacterial biothreat agents.MethodsBALB/c and C57BL/6 mouse strains were treated or not with Ethiqa XR before and 48 h after challenge with aerosolized Burkholderia pseudomallei K96243 or Yersinia pestis CO92. Control mice were similarly treated with Ethiqa XR but were not challenged.

Mice were euthanized 60-72 hours post-treatment/challenge to harvest blood, serum, lung, brain and spleen for bacterial burden and immunological profiling.ResultsBoth C57BL/6 and BALB/c mouse strains showed higher bacterial dissemination to the spleen 60-72 h after B. pseudomallei challenge when treated with Ethiqa XR.