The cell membrane as a biosensor of oxidative stress induced by radiation exposure
6th international symposium on PREDICTIVE ONCOLOGY INTERVENTION STRATEGIES, Paris, Institut Pasteur, 02/2002
AIM: The role of biological membranes as a cellular target of radiation damage remains unclear. The present study investigates how biochemical and biophysical properties of biological membranes are altered after radiation exposure of relatively low doses. METHODS: Human blood sample were exposed to 60Cobalt gamma-rays at dose level ranged from 0 to 8 Gy. Characterization of the radio-induced oxidative stress and membrane biophysics consequences were performed until 72 hours post-radiation on human erythrocyte. RESULTS: Lipid peroxidation and protein oxidation increased in the hours following radiation exposure. An imbalance between the radiation-mediated oxidative damages and the global antioxidant capacity of the erythrocyte was observed following radiation exposure. Antioxidant enzyme activities and glutathione levels were found to decrease after radiation. The development of a radio-induced oxidative stress probably explains the reorganization of the fatty acid pattern 72 hours after radiation exposure. The PE-fatty acids of the (n-3) and (n-6) series decreased, while the PE saturated fatty acid content increased. All these modifications may participate in the variation of membrane micro-domain biophysical properties that we noted after radiation exposure. Finally, experiments performed on two in vivo models, i.e 8 Gy gamma-exposed monkey and TBI radiotherapy raised the possibility of using measurement of biophysical properties of biological membrane as potential bio-indicator of radiation exposure. CONCLUSIONS: Taken together, these findings reinforce our understanding of the pivotal role that the biological membrane may play in the expression and course of cellular damage after radiation exposure. (Poster presentation in the session on Carcinogenesis).