Anti-proliferative effect of extremely low frequency electromagnetic field on preneoplastic lesions formation in the rat liver.
BACKGROUND
Recently, extremely low frequency electromagnetic fields (ELF-EMF) have been studied with great interest due to their possible effects on human health. In this study, we evaluated the effect of 4.5 mT-120 Hz ELF-EMF on the development of preneoplastic lesions in experimental hepatocarcinogenesis.


METHODS
Male Fischer-344 rats were subjected to the modified resistant hepatocyte model and were exposed to 4.5 mT - 120 Hz ELF-EMF. The effects of the ELF-EMF on hepatocarcinogenesis, apoptosis, proliferation and cell cycle progression were evaluated by histochemical, TUNEL assay, caspase 3 levels, immunohistochemical and western blot analyses.


RESULTS
The application of the ELF-EMF resulted in a decrease of more than 50% of the number and the area of gamma-glutamyl transpeptidase-positive preneoplastic lesions (P = 0.01 and P = 0.03, respectively) and glutathione S-transferase placental expression (P = 0.01). The number of TUNEL-positive cells and the cleaved caspase 3 levels were unaffected; however, the proliferating cell nuclear antigen, Ki-67, and cyclin D1 expression decreased significantly (P < or = 0.03), as compared to the sham-exposure group.


CONCLUSIONS
The application of 4.5 mT-120 Hz ELF-EMF inhibits preneoplastic lesions chemically induced in the rat liver through the reduction of cell proliferation, without altering the apoptosis process.
Jiménez-García
Mónica Noemí
MN
Department of Physics Center of Research and Advanced Studies of the National Polytechnic Institute, Mexico City, Mexico. jj@fis.cinvestav.mx
Arellanes-Robledo
Jaime
J
Aparicio-Bautista
Diana Ivette
DI
Rodríguez-Segura
Miguel Angel
MA
Villa-Treviño
Saúl
S
Godina-Nava
Juan José
JJ
D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D002453:Cell Cycle / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects*; D019938:Cyclin D1 / Q000378:metabolism; D004574:Electromagnetic Fields; D051549:Glutathione S-Transferase pi / Q000378:metabolism; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D019394:Ki-67 Antigen / Q000378:metabolism; D008099:Liver / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D008113:Liver Neoplasms / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D011230:Precancerous Conditions / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D051381:Rats; D011916:Rats, Inbred F344; D013997:Time Factors; D005723:gamma-Glutamyltransferase / Q000378:metabolism
C530106:Ccnd1 protein, rat; D019394:Ki-67 Antigen; D019938:Cyclin D1; D005723:gamma-Glutamyltransferase; D051549:Glutathione S-Transferase pi; C496558:Gstp1 protein, rat; C505410:Casp3 protein, rat; D053148:Caspase 3