Cell phone effects: Testicular proteome modified
Ezine
- Published: Sep 1, 2014
- Author: Steve Down
- Channels: Proteomics & Genomics / Proteomics
Electromagnetic radiation from cell phones
The controversy over the potential health effects of electromagnetic radiation associated with cell phones has been fuelled by new research originating in Iran. A team of scientists from Shiraz University has found that electromagnetic fields change the proteome of rat testes, with implications for fertility.
There has been conflicting evidence over the last decade on the harmful nature of these EMFs. For instance, some studies have suggested that they do not affect the brain whereas others have found the opposite. Most notably, a recent study from Greece revealed that 143 proteins in the mouse brain were affected, including some from the regions dealing with learning and memory. The same type of radiation is emitted by wireless transmitters and wireless computer equipment, so the effects might be more widespread than first anticipated.
Now, Masood Sepehrimanesh, Nasrin Kazemipour, Mehdi Saeb and Saeed Nazifi have turned their attention to the testis, comparing the protein expressions from animals exposed to an EMF with those that were not exposed. Their main focus was on proteins that were induced or completely inhibited, rather than those which underwent a partial change in expression.
Lab rats exposed to EMF
Over 30 days, ten rats were exposed daily to 900 MHz radiation for 1, 2 or 4 hours and ten others were sham exposed under the same conditions in the cage. After this period, they were sacrificed and the proteins extracted from the testes.
The protein components in the extracts were separated by 2D SDS-PAGE under a protocol designed to minimise technical variations. Each testis sample was analysed in triplicate and all of the samples were prepared at the same time by a single technician using the same apparatus.
The separated proteins on the gel were visualised with a silver stain and those that were present only in the irradiated group or the sham group were marked as candidates for identification by mass spectrometry following digestion with trypsin.
Protein oxidation induced
The total number of protein spots on the gels ranged from 365 to 439 but there was little difference between the protein patterns for all three exposure groups. The overall protein concentrations and weights of the testes were not affected by the EMF treatment but there were some differences in individual proteins.
Significantly, 18 proteins were found only in the exposed group and 16 in the sham exposed group. They were not a result of thermal damage to the testes because the temperatures were maintained at 23°C during the whole program. The strongest and best separated spots, numbering 7 and 6 in the exposed and sham exposed groups, respectively, were analysed.
One of the proteins that disappeared following irradiation is Cu-Zn superoxide dismutase which offers major protection against oxygen toxicity in the testis. Its absence was attributed to the lack of viable spermatogonia, immature stem cells that form spermatocytes, where it is normally found in large quantities. If validated in further research, this effect alone is a serious consequence of EMFs.
The appearance of type II peroxiredoxin 1 in the testis after exposure to the EMF was due to over-oxidation of its cysteine residues. The occurrence of oxidative stress was supported by the appearance of heat shock proteins, possibly induced to combat the formation of free radicals, and the loss of valosin-containing protein due to the oxidative S-thiolation of cysteine residues.
Other affected proteins were related to metabolism and cytoskeletal processes within the testis. So, several different processes within the testis appear to be affected by the impact of EMFs.
The research team acknowledge that their findings will have to be confirmed by complementary studies using other methods like Western blotting and immunohistochemical procedures. However, if the protein alterations can be repeated, then exposure to EMFs from cell phones and wifi equipment will have to be reconsidered by national and international health organisations as they could have a bearing on male fertility.
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