The aim of this study was to use the "modified resistant hepatocyte model", which induces a rapid proliferation of altered hepatocytes to form preneoplastic lesions in the rat liver, to seek information concerning the effects of extremely low frequency electromagnetic fields on hepatocarcinogenesis (carcinogenesis in the liver).
The authors hypothesized that the development of preneoplastic lesions chemically induced in rat livers could be affected by extremely low frequency electromagnetic field exposure (4.5 mT, 120 Hz). The extremely low frequency electromagnetic field was applied from 7 days before starting the carcinogenic treatment, because the initial approach of the experiment was to assess the electromagnetic field effect on the inhibition of preneoplastic lesions development in rat liver (to prevent the disease in the early stages of its development).
Carcinogenesis was initiated by diethylnitrosamine. Seven days later the animals were treated by 2-acetylaminofluorene for three consecutive days (before a partial hepatectomy). Three groups of 6 rats each were used: 1) control group (no treatment), 2) sham exposed positive control group (carcinogenic treatment and sham exposure), 3) exposed group (carcinogenic treatment and exposure). The animals were sacrificed on day 25 after carcinogenesis initiation.
Exposure duration: continuous for 50 min/day on 32 days
|Exposure duration||continuous for 50 min/day on 32 days|
|magnetic flux density||4.5 mT||-||measured||-||-|
The application of the extremely low frequency electromagnetic field resulted in a decrease of more than 50% of the number and the area of gamma-glutamyltransferase-positive preneoplastic lesions and glutathione S-transferase-p expression. The number of positive cells in the TUNEL assay and the caspase 3 levels were unaffected. However, the expressions of PCNA, Ki-67, and cyclin D1 expression decreased significantly, as compared to the sham exposed group.
The authors conclude that the application of 120 Hz extremely low frequency electromagnetic field (4.5 mT) inhibits preneoplastic lesions chemically induced in the rat liver through the reduction of cell proliferation, without altering the apoptosis process. This finding could be the basis for the design of strategies and clinical applications of extremely low frequency electromagnetic fields to treat hepatocellular carcinoma.