Beyond inflammation: Centrally mediated antinociceptive properties of Spirulina platensis LEB-18 biomass via the opioid system

[Display omitted] •Spirulina platensis biomass exhibits antinociceptive properties in animal models.•Anti-inflammatory properties of Spirulina platensis are mediated by IL-10.•Spirulina platensis biomass promotes centrally mediated antinociception.•Spirulina platensis has intrinsic analgesic properties mediated by opioid system. The management of pain is a world health issue. Available painkillers induce undesired side effects and are sometimes inefficient. Spirulina biomass has promoted anti-inflammatory activity in preclinical and clinical trials. This work characterizes the antinociceptive properties of Spirulina platensis LEB-18 biomass (SP-LEB18) and their mechanisms of action. In the CFA model in mice, SP-LEB18 reduced paw edema and mechanical allodynia, confirming its anti-inflammatory action and showing its antinociceptive activity. Cytokines levels were evaluated by ELISA; SP-LEB18 promoted an increase of IL-10 levels and a reduction of TNF-α and IL-1β levels. SP-LEB18 promoted centrally mediated antinociception, as indicated by the tail flick test. When the same set of experiments was conducted with IL-10 knockout mice, the antinociception was still detected in the tail flick test, but not in the CFA model. Pretreatment with naloxone abolished the effect of SP-LEB18, demonstrating a pure antinociceptive action of Spirulina biomass via the opioid system.