Effects of Bifidobacterium bifidum on adaptive immune senescence in aging mice

Abstract

Bifidobacteria are a natural component of the bacterial flora of the human body and have a symbiotic bacteria-host relationship with human beings. Aging is associated with reduced numbers of beneficial colonic Bifidobacteria and impaired immunity. The possible anti-senescence effects of Bifidobacteria are presently unknown. The aims of the present study were to investigate possible anti-senescence effects of B. bifidum on naturally senescent mice and to explore their mechanisms. After treatment with B. bifidum, mice were killed and samples collected. Cytokine production in serum and lymphocyte culture supernatant, anti-oxidation activity and gene expressionwere measured. B. bifidum significantly increased cytokine IL-2 and IFN-γ levels but decreased proinflammatory cytokines IL-6 and TNF-α concentrations. Moreover, B. bifidum improved anti-oxidation activity and reduced lipid peroxidation in thymusandspleen. Inaddition, B. bifidum down-regulatedp16expression in thymusandspleen. Taken together, the results indicate, for the first time, that B. bifidum delays senescence by severalmechanisms, including enhancement of anti-oxidation activity in thymus and spleen, alteration of gene expression and improvement in immune function. © 2010 The Societies and Blackwell Publishing Asia Pty Ltd.