Evaluation of the possible in vitro effects of mobile phone type radiation on the hematopoietic system of rats

The project described in this thesis was designed to evaluate the effects of mobile phone type radiation on the hematopoietic system/blood forming system of rats. The project includes a computational study, which was performed to mathematically determine the Specific energy Absorption Rate (SAR) levels in the bone marrow samples followed by three independent experimental studies on animal samples, which were performed to observe the possible changes in function of the hematopoietic system of rats under different exposure conditions. In the first experimental study on the animal samples, the rat bones were extracted and divided into three groups: sham exposed, radiofrequency (RF) exposed group, and positive control group. The bones from each group were exposed to 900 MHz continuous wave (CW) RF radiation for 30 minutes at room temperature. The root mean square (rms) forward power into a Transverse Electromagnetic (TEM) cell to produce 2 W/kg averaged SAR levels in the bone marrow was set at 16.7 W (determined using finite-difference-time-domain (FDTD) method). After exposure, the bone marrow cells were extracted and the following end points were tested: (a) proliferation rate of whole bone marrow cells, (b) maturation rate of erythroblasts, (c) proliferation rate of lymphoblasts, and (d) DNA damage (strand breaks/ alkali labile sites) of lymphoblasts. No significant changes in the above stated end points in the RF exposed group were observed when compared to the sham exposed group. In the second experimental study, the rat long bones in media in a Petri dish were divided into the four following groups: sham exposed group, RF exposed group (2W/kg), RF exposed group (10 W/kg), and positive control group. The bones were exposed to 900 MHz CW RF radiation for 90 minutes in a TEM cell at physiological temperature (37 °C +/- 1 °C). As before, the rms forward power into a TEM cell to produce 2 W/kg and 10 W/kg averaged SAR levels in the bone marrow was determined using FDTD numerical analysis. After exposure, the lymphoblasts were extracted and the following end points were tested (a) proliferation rate of lymphoblasts, and (b) DNA damage (strand breaks/ alkali labile sites) of lymphoblasts. The data did not indicate any significant change in the proliferation rate or DNA damage of lymphoblasts in RF exposed group when compared to sham exposed group. In the third experimental study, a dose response effect of an in vitro 1800 MHz CW and pulse modulated (PM) wave RF radiation exposure at 2 W/kg and 10 W/kg for 120 minutes on the hematopoietic system of rats was observed. As before, the rms forward power into a waveguide to produce 2 W/kg and 10 W/kg averaged SAR levels in the bone marrow was determined using FDTD numerical analysis. The rat long bones were divided into six groups: Sham-exposed, CW RF exposed (2 W/kg), CW RF exposed (10 W/kg), PM RF exposed (2 W/kg), PM RF exposed (10 W/kg), and positive control group. After the exposure, the lymphoblasts were extracted and the following end points were tested (a) proliferation rate of lymphoblasts and (b) DNA damage (strand breaks/ alkali labile sites) of lymphoblasts. We did not find any significant difference in the examined end points in the RF exposed group when compared to the sham exposed group. Thus, the findings revealed no significant effect on the hematopoietic system in rats after 900 MHz CW/1800 MHz CW and PM wave RF exposure at the 2 W/kg and 10 W/kg localized SAR limit value recommended by the International Commission for Non-Ionizing Radiation Protection (ICNIRP) for public and occupational exposure.