Effects of non-contact electric fields on kidney and liver histology in tumour-induced rats

Abstract

Background: A novel modality of cancer treatment based on exposure to non-contact electric fields has been developed to reduce the cancer incidence. However, the safety of this electric field exposure on vital organs has not been fully investigated. Therefore, the purpose of this study was to observe the safety of the electric field exposure on kidney and liver structures. Methods: Female Sprague-Dawley rats were divided into one control group and three treatment groups. Animals were treated with 7,12-dimethylbenz[a]anthracene for mammary tumour induction and exposed to non-contact electric fields individually for 10 hours a day for three weeks. Fresh samples of kidney and liver were collected for observation of structural damage in both organs. Both organs were prepared for histopathological cross-sectioning using the paraffin method and Hematoxylin & Eosin staining followed by histological scoring using the post-examination masking method. Results: Damages found in the kidney were as follows: thickening of Bowman capsule, karyolysis, karyorrexhis, pyknosis, cloudy swelling, epithelial sloughing, inflammation, haemorrhage, and congestion. The thickening of Bowman’s capsule was significant, but other damages to the rest of kidney tissue were not significant. In addition, the number of inflammations and haemorrhages in the kidney structure of the placebo group was the lowest and significantly different compared to the other three groups. All damages to the kidneys were also found in the liver, but each showed a different degree of damage. The damages to the liver caused by exposure to the electric fields were not significant. Conclusions: Together with the effects of DMBA administration, exposure to non-contact electric fields can cause thickening of Bowman's capsule in the glomerulus of the kidney, however, in other kidney tissues and in the liver, exposure to this electric field was safe. It can even decrease the number of inflammations and haemorrhages in the organs.