## 4 Discussion  
We investigated the effect of PEMF treatment on growth of the tibial growth plate through anatomical observations and blood tests after raising eight rats in the experimental group exposed to a pulsed magnetic field of 28 Hz and 20 Gauss for 10 h for 10 days, in comparison to the normal group. As for the size of the growth plate, the experimental group exposed to the pulsed magnetic field showed a higher growth rate with a highly significant difference, and the circulating IGF-1 hormone levels also showed a higher serum concentration in the experimental group exposed to a pulsed magnetic field. Bone elongation is a complex process driven by multiple intrinsic (hormones, growth factors) and extrinsic (nutrition, environment) variables [18]. Because the growth of biological tissues, including bones and growth plates, is closely associated with nutrient supply, it is necessary to determine whether the growth of the growth plate is due to the pulsed magnetic field or the amount of food consumed, if the experimental group is given more food than the normal group. However, as a result of daily tracking of dietary amount and weight, the experimental group had a lower dietary intake than the normal group. Thus,  
Figure 8: Effect of PEMF treatment on creatinine, AST, ALT, LDH, and NO levels in the serum. (**A**) Creatinine, (**B**) AST and ALT, (**C**) LDH, and (**D**) NO levels. Effects of PEMF treatment on kidney and liver function, circulating cell damage, and inhibiting inflammation were evaluated by ELISA and biochemical analysis. the difference in the growth rate of the growth plate can be inferred as an effect of the pulsed magnetic field. Dietary efficiency was 2% higher in the experimental group, which showed a lower food intake and body weight than the normal group. Considering that the difference between the growth plates between the two groups was 25.6%, it is difficult to say that dietary efficiency also contributed to the difference in the growth rate of the growth plate. Because growth during childhood is closely regulated by various systemic factors, such as insulin, growth hormone, and IGF-1 [19], the correlation between growth plate growth rate and IGF-1 is also an important basis for judgment. IGF-1, a 70-amino acid peptide biosynthesized mainly in the liver as an endocrine hormone, is both the main mediator of growth hormone action and a growth hormone-independent growth factor that stimulates cell proliferation and differentiation and protects cells from apoptosis [19]. IGF-1 is also expressed in growth plates, where it works in a paracrine/autocrine manner to contribute to longitudinal bone growth [20; 21]. Thus, in this study, we evaluated whether PEMFs stimulate circulatory IGF-1, which plays a major role in stimulating bone growth. From the growth plate size comparison result, the serum IGF-1 levels in the PEMF-stimulated experimental group were higher than those in the normal group; thus, it can be inferred that PEMF contributed to growth plate size by promoting the secretion of IGF-1, and a correlation was confirmed. IGF-1 levels increased after stimulation with PEMF despite no dietary changes, enabling growth of the growth plate. Even if the growth plate, by PEMF stimulation, shows a significant difference and the growth rate is higher, if the pulsed magnetic field damages the living tissue of the rat or causes side effects that cause toxicity, it cannot be concluded that there is a direct effect. Blood analysis revealed that there were no toxic side effects due to PEMF, with creatinine, AST, and ALT values within the normal range. In addition, no side effects from inflammatory reactions, such as cell damage and destruction, by pulsed magnetic fields were observed. NO is a free radical involved in the regulation of many physiological processes, such as vascular relaxation, platelet aggregation, immune response, and bone cell function [22].