To study whether exposure to 50 Hz extremely low frequency sinusoidal electromagnetic field affects the expression and production of inducible nitric oxide synthase (iNOS) and monocyte chemotactic protein-1 (MCP-1, a chemokine) in human monocytes.
Chemokines and iNOS play a central role in various immunological and inflammatory processes. NO and MCP-1 reciprocally modulate their expression and play an important, but not fully defined role, in the development and progression of many diseases.
Cells from each subject (n=10) were divided into four groups: 1) control cells, 2) cells stimulated with LPS, 3) control cells exposed to electromagnetic fields, 4) cells stimulated with LPS and exposed to electromagnetic fields.
The data showed that the electromagnetic field exposure affects the expression of iNOS and MCP-1 in human monocytes in vitro at the mRNA level and protein synthesis. The effects of exposure clearly differed with respect to the potentiation and inhibition of iNOS and MCP-1 expression: Whereas iNOS was down-regulated both at the mRNA level and at the protein level, MCP-1 was up-regulated.
In conclusion, electromagnetic fields may represent a non-pharmacological inhibitor of NO and an inducer of MCP-1, which activate one of theses molecules and lead to inhibition of the other or vice versa, establishing a mechanism that protects cells from excess stimulation and contributes to the regulation of cell homeostasis. These findings provide helpful information regarding the electromagnetic field-mediated modulation of the inflammatory response in vivo.