The therapeutic effect of PEMF on reproduction Kumar S et al. CLINICS 2011;66(7):1237-1245 Figure 6 - The five columns represent the CK activity distribution in the sperm fractions of the various groups. The results are expressed as IU/108 spermatozoa ¡ standard deviation. All of the determinations were performed in triplicate. The thermal energy inside the body at room temperature is random, whereas the thermal energy from an external source is coherent (over a period of time exceeding 10 sec). It may be possible that a coherent signal interferes with the rhythmicity of the physiological process inside the body. ROS generation in the testes was responsible for the possible toxic effects on the physiology of reproduction. However, cells have a defense mechanism [i.e., antioxidants (reduced glutathione, catalase, superoxide dismutase)] to fight against increased ROS production. Furthermore, melatonin stimulates the activity of several important endogenous antioxidants (GSH-Px, SOD) to combat the effect of reactive oxygen species.37 Melatonin is exclusively synthesized and secreted at night and is an efficient endogenous free radical scavenger. Decreased serum testosterone levels and increased crea- tine kinase activity were associated with reduced male fertility. Our data reflect an appreciable increase in sperm creatine kinase activity and a decline in the activities of antioxidants and melatonin. In spermatozoa, CK-BB is localized to the mitochondria of the midpiece region.38 Creatine phosphate serves as a donor for the re-phosphor- ylation of adenosine diphosphate (ADP) into ATP, which supports flagellar dynein/adenosine triphosphate and sperm quality. The CK activity differences were reflected in the sperm ATP concentrations and ATP/ADP ratios.39 CK was associated with increased ROS and served as an indicator for oxidative stress. Genotoxic stresses induced by irradiation trigger an arrest or delay in the G2 phase of the cell cycle to permit the repair of damaged DNA.40 Cell cycle analysis by flow cytometry with propidium iodide has confirmed these results because EMF exposure induces the appearance of a sub-G1 apoptotic peak, which is characteristic of DNA fragmenta- tion in spermatozoa.7 Activated caspases commit the cells with defective repair machinery to an apoptotic death by cleaving a number of substrates. The results of the caspase assay suggest that the apoptotic cell counts are significantly Figure 7 - The responses of the sperm caspase activities to an electromagnetic field. Caspase 3 activity was measured after overnight incubation (expressed as mmol of released pNA per min per ml of sperm lysate). The values are means¡SEMs. *, significantly (p,0.05, Fisher’s test) different from its respective sham group. 1242