Chlorella vulgaris restores bone marrow cellularity and cytokine production in lead-exposed mice

► We evaluated the immunoprotective effects of CV in lead-exposed mice. ► c-Kit+Lin− and Gr1+Mac+ hematopoietic cells, and total cellularity were examined. ► NK cell activity and production of IL-1α, TNF-α, IFN-γ, IL-10, IL-6 were evaluated. ► CV recovered the reduced numbers of hematopoietic cell populations in Pb-exposed mice. ► CV modulated NK cells activity and the production of IFN-γ, IL-1α, TNF-α, IL-10 and IL-6. Chlorella vulgaris (CV) was examined for its modulating effects on the reduction induced by lead (Pb) on the numbers of marrow hematopoietic stem cells (HSCs) (c-Kit+Lin−), granulocyte–macrophage progenitors (Gr1+Mac1+) and total bone marrow cellularity. In mice gavage-treated daily with 50mg/kg dose of CV for 10days, concomitant to a continuous offering of 1300ppm lead acetate in drinking water, the treatment with the algae recovered the significantly reduced numbers of these cell populations to control values. As CV may have a myelostimulating effect through the induction of cytokines, we evaluated its modulating effects on the production of IL-1α, TNF-α, IFN-γ, IL-10 and IL-6. Our results demonstrated that lead significantly impairs the production of IFN-γ, IL-1α and TNF-α and increases the production of IL-10 and IL-6 and that these effects are successfully modulated by the CV treatment. The activity of NK cells, reduced in Pb-exposed animals, was raised to levels higher than those of controls in the exposed group treated with CV. Treatment with the algae also stimulated the production of IFN-γ, IL-1α, TNF-α and NK cells activity in normal mice. In addition, zinc bone concentrations, reduced in lead-exposed mice, were partially, but significantly, reversed by the treatment with CV.