Effects of pulsed electromagnetic fields on the A2A adenosine receptor in human degenerative nucleus pulposus cells

Abstract

Objective \nTo explore the expression of the A2A adenosine receptor and the inflammatory cytokines interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) in human degenerative nucleus pulposus (NP) cells after they have been treated with a pulsed electromagnetic field (PEMF). \n \n \nMethods \nHuman degenerative NP cells were cultured in vitro and treated using an 0.8mT PEMF with a pulse frequency of 50Hz. The pulse width was 150μs and the exposure time was 30min, repeated 5 times at 12 hour intervals. The expression of the A2A adenosine receptor in NP cells was determined using western blotting and reverse transcription polymerase chain reactions. The expression of the inflammatory cytokines IL-1β and TNF-α were detected using enzyme-linked immunosorbent assays (ELISA). The human degenerative NP cells were also treated with an antagonist and agonist of the A2A adenosine receptor, and the expression of IL-1β and TNF-α were also determined using ELISA. \n \n \nResults \nAfter the PEMF treatment the expression of the A2A adenosine receptor increased significantly, while the expression of IL-1β and TNF-α decreased significantly. However, the A2A adenosine receptor antagonist reversed the inhibitory effect of the PEMF on the expression of IL-1β and TNF-α, while the agonist played an opposite role. \n \n \nConclusion \nA PEMF can significantly inhibit the expression of IL-1β and TNF-α in human degenerative NP cells, which could be related to up-regulation of the expression of the A2A adenosine receptor in those cells. \n \n \nKey words: \nPulsed electromagnetic fields;\xa0Adenosine receptors;\xa0Nucleus pulposus cells;\xa0Inflammatory cytokines