Effects of pulsed electromagnetic field on intervertebral disc cell apoptosis in rats

Despite numerous studies on pulsed electromagnetic field (PEMF) application, its effects of PEMF on intervertebral disc (IVD) have not yet been investigated in vivo. Accordingly, the effects of PEMF upon IVD in rats were evaluated through molecular surveys. Rats were divided into six groups: Group I and II were exposed to low and high frequency of PEMF (LF and HF, respectively). Group III and IV underwent induced disc degeneration and were exposed to low and high frequency of PEMF (LF/IDD and HF/IDD, respectively). Group V underwent induced disc degeneration (IDD), and group VI was control. The values of caspase 3, Bax, Bcl-2 and β-actin band density, as cell apoptotic markers, were obtained from band densitometry. Our results showed that the value of cleaved caspase-3 of cells and Bax/Bcl-2 ratio in IDD group increased significantly compared to the control group (p < 0.001). The value of cleaved caspase-3 and Bax/Bcl-2 ratio decreased significantly in LF/IDD and HF/IDD groups compared to IDD group (p < 0.05). No significant increase was seen in the cell apoptotic markers in the groups just exposed to PEMF compared to the control group. There was also no significant decrease in the Bax/Bcl-2 ratio in HF/IDD and LF/IDD groups compared to the control group. These data suggest that PEMF attenuates degenerative processes in rat's intervertebral discs and has no effect on normal discs. Regulations of the expression of apoptotic proteins may be one of the mechanisms by which PEMF is effective in reduce disc degeneration.