Effect of Gamma Irradiation on Proliferation and Survival of Sf9 cells: Radio resistance in a Lepidopteran Insect Cell Line

摘要

Sf9 cells of Spodopterafntgiperda, when exposed to gamma-irradiation from a ~(60)Co source, were found markedly less sensitive to ionising radiation than mammalian cells in terms of both growth kinetics and survival. Following irradiation at 1.2 Gy s~(-1), there was a dose dependent delay in Sf9 cell proliferation and plateau cell density was reduced. These effects were dependent on close rate too, In the range 0.3 - 1.2 Gy s~(-1), growth was delayed longer and reached a lower plateau with increasing dose rate. Exposure to radiation caused a decrease In adherence of cells to the substrate, and an increase in number of enlarged ("giant") cells. Analysis of colony formation after irradiation at 1.2 Gy s~(-1) gave a survival curve of conventional shape but with a very large Do value of 24 Gy. Extrapolation number (N) was 2.9, a value within the normal range for mammalian cells. At 0.12 Gy s~(-1) N had a similar value of 3.2, but Do was higher (30 Gy) than at the higher dose rate. This study indicates that the relative insensltivity of lepidopteran insects may be attributed to some extent to the intrinsic properties of their constituent cells.