Study on Irradiated Injury of Human Pancreatic Carcinoma Cell Line MIA PaCa-2 Induced by High Dose per Fraction

Abstract

Objective:To initially observe the cellular irradiated injury by high dose per fraction.Methods:We cultivated human pancreatic carcinoma MIA PaCa-2 cells and and divided them into 0,2,5,10,and 17 Gy groups.Cultivated cells were radiated by 6MV-X ray in one fraction with medical processing accelerator.We observed cellular morphous by histological technology after 24 hours.The degree of injury of DNA detected by comet assay instantly after radiation and by DNA ladder test at 6 and 12 hours after radiation.Changes in cell cycle were explored by flow cytometry at 0,6,12,24, and 36 hours after radiation.Results:After X-ray radiation,human pancreatic carcinoma cell line (MIA PaCa-2) were swelling. With the increase of radiation dose (less than 10 Gy),apoptotic necrosis and G2/M blockage of cell cycle was more obvious. When radiation dose was more than 10 Gy,the peak of apoptotic necrosis appeared early and obvious.The degree of DNA injury was most obvious when radiation dose was 10 Gyand was decreased when radiation dose was 17 Gy.When radiation dose was less than 10Gy,DNA ladder was single electrophoresis band.When radiation dose was 10Gy group, DNA ladder detection showed multiple typical ladder band.When radiation dose was more than 10Gy,vague irregular bands were observed.Conclusion:Different from conventional dose-fraction radiation,high dose per fraction causes oncotic necrosis as the main cell death type.