Objectives: This study concerns: (1) the long-term effects of peripheral lipopolysaccharide (LPS) in neonatal rats on inflammation and antioxidant parameters in brain and (2) the effects of a Spirulina-enriched diet given to lactating mothers on protective and inflammatory parameters in brains of suckling pups subjected to peripheral inflammation.
Methods: Five-day old rat pups were treated with LPS (i.p. 2 mg/kg). After 3, 7, 30, and 65 days, mRNA, miRNA, and protein levels of pro-inflammatory cytokines and the Nuclear factor E2-related factor 2 (Nrf2)-system were examined. In a sub-group, a Spirulina-enriched diet was given to the mothers 24 hours before the pups were treated with LPS, then the effects on antioxidant and inflammatory parameters were evaluated.
Results: The main findings were: (1) interleukin 1 beta (IL-1β) was upregulated in cortex 3, 7, and 30 days after LPS treatment, (2) Nrf2 and the catalytic subunit of γ-glutamylcysteinyl ligase were decreased in cortex 7 days after LPS in parallel with increased levels of phosphorylated p38 and decreased levels of histone H3 acetylation, and (3) a Spirulina-enriched diet to lactating mothers normalized both the increased IL-1β expression and the decreased antioxidant parameters after LPS. The protective effects of Spirulina were correlated with decreased levels of phosphorylated p38 and high levels of the antioxidant miRNA-146a.
Discussion: A Spirulina diet given to lactating mothers can protect against neuroinflammation and decreased antioxidant defence in brain of suckling pups subjected to peripheral inflammation, possibly via decreased activation of p38 and high levels of the antioxidant miRNA-146a.
Keywords: Antioxidant system; Neuroinflammation; Nrf2; Spirulina; miRNA.