Induction of Anti-inflammatory Functions in Peripheral Blood Monocytes by Dopamine in Vitro

Abstract

Introduction: Nowadays, some aspects of neuroendocrine and immune systems intercalation are already known. Accordingly, it has been shown that certain immune cells, such as monocytes, can produce and store dopamine in their secretory vesicles. This study was conducted to investigate the effects of dopamine on some immunological functions of the rat peripheral blood monocytes. Material & Methods: In this experimental study, peripheral blood mononuclear cells of rats were isolated by a ficoll-hypaque gradient. Afterward, the plastic adherent fractions were used as monocytes. Monocytes in the treatment group cocultured for 24 h with 5×10-7 M dopamine, and then their phagocytosis performance, respiratory burst, killing ability, nitric oxide production, neutral red harvest, vital ability, and NF-κB gene expression were investigated. Results: The results of this study showed that both control or treatment monocytes showed no significant difference in phagocytosis after the challenge with opsonized yeast. Nevertheless, the neutral red uptake, respiratory burst, and nitric oxide production after the challenge with opsonized yeast, and also the expression of NF-κB, were decreased in dopamine-treated monocytes compared to monocytes in the control group (P<0.05). The monocyte vitality of the treatment group did not show any significant effects compared to the monocytes of the control group. Discussion & Conclusion: It seems that dopamine dynamically creates an anti-inflammatory phenotype in the monocyte. Therefore, alongside a decrease in the lysosomal compartment activity, the monocytes produce lower levels of free oxygen and nitrogen radicals.

Keywords

• dopamine
• monocytes
• rat