Exposure to 900 MHz Radiofrequency Radiation Induces Caspase 3 Activation in Proliferating Human Lymphocytes

Abstract

In this study, the induction of apoptosis after exposure to 900 MHz radiofrequency radiation (GSM signal) was investigated by assessing caspase 3 activation in exponentially growing Jurkat cells and in quiescent and proliferating human peripheral blood lymphocytes (PBLs). The exposure was carried out at an average specific absorption rate of 1.35 W/kg in a dual wire patch cell exposure system where the temperature of cell cultures was accurately controlled. After 1 h exposure to the radiofrequency field, a slight but statistically significant increase in caspase 3 activity, measured 6 h after exposure, was observed in Jurkat cells (32.4%) and in proliferating human PBLs (22%). In contrast, no effect was detected in quiescent human PBLs. In the same experimental conditions, apoptosis was also evaluated in Jurkat cells by Western blot analysis and in both cell types by flow cytometry. To evaluate late effects due to caspase 3 activity, flow cytometry was also employed to assess apoptosis and viability 24 h after radiofrequency-radiation exposure in both cell types. Neither the former nor the latter was affected. Since in recent years it has been reported that caspases are also involved in processes other than apoptosis, additional cell cycle studies were carried out on proliferating T cells exposed to radiofrequency radiation; however, we found no differences between sham-exposed and exposed cultures. Further studies are warranted to investigate the biological significance of our findings of a dose-response increase in caspase 3 activity after exposure to radiofrequency radiation.

Mobile Phone Radiation Does Not Induce Pro-apoptosis Effects in Human Spermatozoa

“…PS exposure to the outer leaflet of the plasma membrane has previously been observed in human spermatozoa (40)(41)(42)(43). Consistent with results from previous studies showing a lack of PS externalization in various cell types after in vitro exposure to RF EMFs (16,44,45), no evidence of a change in PS externalization was found after a 1-h exposure of human spermatozoa to 900 MHz GSM radiation. The percentage of PS-externalizing living cells (Annexin V z PI 2 ) observed in the present study is in close agreement with the observations of Ricci et al (46) but differs from those of other studies (47,48).…”

“…This may suggest an independence of the mechanisms of PS translocation and caspase activation in the physiology of spermatozoa. In some studies an increase in caspase activity after RF EMF exposure was observed that did not correlate with expression of markers of apoptosis (16,39).…”

“…Also, it is not known whether apoptosis can be initiated in fully differentiated human spermatozoa (15). It has recently been reported that RF EMF exposure causes a dose-responsive increase in caspase 3 activity, a pro-apoptosis event, but does not cause apoptosis (16). Activation of caspase 3 is considered as an indicator of a cell's commitment to apoptosis (17), and activated caspases, in particular caspase 3, have previously been identified in human spermatozoa (18)(19)(20).…”

Enhancement of Apoptosis by Titanium Alloy Internal Fixations During Microwave Treatments for Fractures: An Animal Study

“…There might be other ones, such as the reactive oxygen species or other non-thermal effects of microwave. Several studies demonstrated that microwave could cause cells apoptosis and the temperature was under 41°C [19][20][21]. The mechanism of muscle cell apoptosis in this study was complicated, and not exactly the same as that of tumor cell apoptosis in hyperthermia condition [22].…”

Pulse modulated 900 MHz radiation induces hypothyroidism and apoptosis in thyroid cells: A light, electron microscopy and immunohistochemical study

“…There are studies reporting controversial results on the activation of caspases and apoptotic responses due to continuouswave or modulated RF radiation exposure in different cell types. Palumbo et al (2008) reported increased caspase-3 activation in proliferating human lympochytes that were exposed to a 900 MHz RFR. On the contrary, Merola et al (2006) and Joubert et al (2006) found no significant effects on caspase-3 activity in human LAN-5 neuroblastoma and SH-SY5Y neuroblastoma cells after RFR exposure.…”