Chronic arsenic exposure impairs macrophage functions in the exposed individuals

Abstract

Introduction: Owing to the established roles of human macrophages in immune defense, we investigated the effect of chronic arsenic exposure upon these major hematopoietic cells in 70 arsenic-exposed individuals with skin lesions and 64 unexposed individuals. Methods: Human monocyte-derived macrophages were prepared from peripheral blood mononuclear cells, by culture of the adherent cells for 6 days in medium supplemented with granulocyte–monocyte colony stimulating factor. Parameters studied included cell adhesion capacity, expression of CD₅₄ and F-actin, nitric oxide production, phagocytic capacity, and effect of arsenic on Rho A-ROCK pathway. Results: In macrophages of exposed individuals when compared to unexposed group, there was cell rounding accompanied with a significant (p < 0.001) loss of cell adhesion capacity, decrease in nitric oxide production, impaired phagocytic capacity, and decreased CD ₅₄ and F-actin expression. Additionally, chronic arsenic exposure affected Rho A-ROCK pathway which in turn impaired macrophage functions. Discussion and Conclusion: These altogether could contribute significantly to arsenic-induced immunosuppression observed in the arsenic-exposed individuals.