Effects Of Space Radiation And Microgravity On Cellular Genome Stability

Space environment seriously affects astronauts'health in space,in which microgravity and radiation are the two main factors that cause biological effects in space enviroument.The effects of microgravity and radiation on astronauts' and space travelers' health,normal physiological functions and the future generations' health have attracted extensive attention from the scientific communities in many countries,and have gradually become one of the biggest problems in the development of the aerospace industry.However,the effects of microgravity and space radiation on cellular genome stability have not been studied systematically.This study concentrated on exploring the effects and changes of cell genomic damage,as well as the possible mechanisms with microgravity and space radiation.In this study,we investigated the effeects of space environment on the cellular genomic stability using DNA darage response deficient(mRad9-/-)mouse embryonic stem(mES)cells and the corresponding wild type(mRad9+/+)mES cells as the models in both ground simulation experiments and real space experiments.In the ground simulation experiments,we studied the effects of stimulated microgravity(SMG),regulare radiation and heavy ion radiation on the intracellular ROS production,DNA damage and apoptosis.The changes of gene expression profile in mES cells cultured under SMG were also examined using RNA deep-sequence.In the real space experiment,we investigated the effects of real space environment onboard the SJ-10 recoverable scientific satellite.As a result,SMG treatment led to increased DNA damage in DNA damage response deficient mES cells while not in the corresponding wild type mES cells,indicating that SMG was a weak genotoxic tress.We also observed the additive effects of SMG and H2O2 in intracellular ROS production,DNA damage and apoptosis,which further confirmed the hypothesis that SMG was a weak genotoxic tress.Furthermore,NAC inversed the additive effects of SMG and H2O2 on ROS production and protected the cells from DNA damage and apoptosis.We also found that radiation could cause serious DNA damage and pretreatment with SMG for 23 hr could promote the DNA damage repairing capacity of mES cells.RN A deep-sequence analyses revealed novel differential gene expressions in the DNA damage response deficient mES cells and the corresponding wild type mES cells cultured under SMG or 1G.These data will be compared with the data obtained from the real space experiments onboard the SJ-10 recoverable scientific satellite,which will provide valuable information on the effects of real space environment on cellular genomic stability.