Chlorella vulgaris Modulates Immunomyelopoietic Activity and Enhances the Resistance of Tumor-Bearing Mice

Abstract

We studied the effects of Chlorella vulgaris (CV) on the interaction between stromal and hematopoietic stem cells in normal and Ehrlich ascites tumor (EAT)-bearing mice. Long-term bone marrow culture (LTBMC), cytokine production, spleen mononuclear cells (SMC) proliferation (SCP), colony stimulating activity (CSA), and NK cells activity were evaluated. In tumor bearers, reduced capacity of stromal cell layer to support the growth and differentiation of granulocyte-macrophage progenitor cells (CFU-GM), concomitantly to decreased numbers of total nonadherent cells in LTBMC and reduced local production of IL-6 and IL-1α, were observed. Presence of the tumor has not altered the number of stromal adherent cells. CV treatment restored the ability of stromal cells from EAT-bearing mice to produce IL-6 and IL-1α, which was consistent with increased number of nonadherent cells and higher ability to display CFU-GM in vitro. EAT growth increased SCP, serum CSA, and IL-10 production and concurrently depressed NK cell activity and the secretion of IL-2, IFN-γ, and TNF-α. Treatment of tumor-bearing mice with CV augmented CSA, SMC proliferation, NK cell activity, and the production of IL-2, IFN-γ, and TNF-α, whereas IL-10 levels where reduced. Our results suggest that CV modulates immunehematopoietic cell activity and disengages tumor-induced suppression of these responses.

ACKNOWLEDGMENTS

This research, which is part of the PhD dissertation presented by A. Lisie Ramos to the Pharmacology Post-Graduate Program of the Faculty of Medical Sciences of the State University of Campinas (UNICAMP), was supported by grants from FAPESP (04/03639-3) and CNPq (300575/2008-4). The authors would like to acknowledge the technical contribution of Sueli C. Oliveira and Raphael M. Pereira.