Effect of a low-frequency pulsed electromagnetic field on expression and secretion of IL-1β and TNF-α in nucleus pulposus cells

OBJECTIVE: To investigate changes in nucleus pulposus cell expression and secretion of interleukin (IL)-1β and tumour necrosis factor (TNF)-α following stimulation with a low-frequency (LF) pulsed electromagnetic field (PEMF). METHODS: Primary rat nucleus pulposus cells were isolated and cultured in vitro, followed by stimulation with LF-PEMFs at a frequency of 2 Hz and different intensities, ranging from 0.5–3.0 A/m. Cells were observed for morphological changes, and proliferation rates were measured by cell viability counts. Expression of IL-1β and TNF-α within the nucleus pulposus cells was measured using western blotting, and levels of IL-1β and TNF-α secreted in the culture media were measured using enzyme-linked immunosorbent assay. RESULTS: Stimulation of nucleus pulposus cells with LF-PEMFs did not appear to affect cell morphology or nucleus pulposus cell IL-1β and TNF-α expression levels. LF-PEMFs did not significantly affect cell proliferation, however, levels of IL-1β and TNF-α secreted into the culture media were found to be significantly reduced in an intensity-dependent manner. CONCLUSION: Low-frequency PEMF stimulation may inhibit secretion of IL-1β and TNF-α in cultured nucleus pulposus cells.