कैंसर विज्ञान एवं चिकित्सा

Non-thermal Effects of Far-Infrared Ray(FIR) on Human Hepatocellular Carcinoma Cells HepG2 and their Tumors

Abstract

Tatsuo Ishikawa, Jun Ishibashi, Kikuji Yamashita, Shine-Od Dalkhsuren, Kaori Sumida, Takahumi Masui and Seiichiro Kitamura

Background: We developed a cell culture CO2 incubatorand a mice rack that can continuously irradiate cells ormurine with FIR. Our goal is to make clear the non-thermaleffect of FIR on HepG2 with these instrumentsmorphologically.

Methods: By using them, in vitro , we examined theproliferation of cultured HepG2 cells with hematocytometer,BrdU assay, WST-1 assay, HE staining, Toluidine bluestaining and microarray studies. And in vivo, we measuredthe tumors, observed the sections by IHC, DAPI stainingwith light microscopes and performed microarray studies.

Results: Proliferation of HepG2 cells were suppressed(e.g., cell count declined by 34% after 10 days of FIRirradiation), tumor volumes reduced by 86% after 30 daysof FIR irradiation, mRNA of Vascular Endothelial GrowthFactor (VEGF) decreased by 48%, vascular area in crosssections from the tumors decreased 60% compared withthe control. More frequent properties in apoptosis wereobserved by TUNEL and DAPI staining in FIR-treatedgroups. Body weight of mice increased compared with thecontrol. Oxydation and Reduction (Redox) reactions byH+ (proton and electron)/O2- (a kind of Reactive OxygenSpecies (ROS)) were induced by FIR.

Conclusions: These results clarified that FIR inhibitedthe proliferation of HepG2 at non-thermal circumstances(at 25±0.5, 37±0.5°C). FIR will serve as a tool againstdiseases induced by HepG2.