Radio-adaptive doses effect on HT29 and MRC5 cell lines: comparison in hypo and hyper fractionation regime
Background: The exposure of cell lines to low-dose irradiaon leads to changes at molecular level, which may induce adapve response. We examined radio-adapve doses effect on human colorectal adenocarcinoma cell line (HT29) and human fetal fibroblasts (MRC5) cell line followed by hyper and hypo fraconaon regimes, with main purpose to decrease cell viability in HT29, and at the sameme to spare MRC5 cells. Material and Methods: The cell lines were pre-irradiated with 0.03Gy, 0.05Gy and 0.07Gy. Two hours later, control and pre-irradiated cells were irradiated in hyper and hypo fraconaon regimes. Cell viability and the total c ell number were measured. Results: Comparing the response between two cell lines in the same regime, it was found that pre-irradiaon dose of 0.05Gy increased cell viability in MRC5 cell line, accompanied with decrease of cell viability in HT29 cell line, which gave a major contribuon to the main goal of the present research, i.e. to determine the dose that might spare the normalssue. Conclusion: To our best knowledge, fraconaon in several consecuve d ays in two designed regimes is described for the firstme. These are the first reported results using low-doses pre-irradiaon followed by hyper and hypo fraconaon regimes, with approximately same biological effecve dose.