Detection of radiation-induced mutations in the liver after partial hepatectomy using HITEC transgenic mice

Abstract We investigate the dynamics of radiation-specific mutations in a mammalian differentiated cell of the liver in the transgenic mouse called Hypersensitive In vitro Test of Carcinogenecity (HITEC), carrying the rpsL gene as a reporter for mutation detection. In this study, we performed a partial hepatectomy (PH) to induce cell proliferation and increase the detection of mutation frequency. Prior to PH, the mice were exposed to 5 Gy gamma rays at 2 days, 10 days, 1 month or 2 months. The remnant liver was then resected at 3 or 10 days after PH, and the mutation frequencies (MFs) for both resected livers and remnant livers were analyzed. In mice where PH was done at 2 or 10 days after irradiation, the MF of the remnant livers of them increased approximately two times compared with that of the livers in which only irradiation was done. However, in mice where PH was done at 1 or 2 months after irradiation, the increase in MF was not seen. These results show that HP is effective in increasing the MF, and the repair system is clearly working even in mammalian differentiated cell.