ACUTE ALTERATIONS IN [CA2-15 CELLS SUBJECTED TO HIGH-STRAIN RATE DEFORMATION AND CHEMICAL HYPOXIA - AN IN-VITRO MODEL FOR NEURAL TRAUMA(]I IN NG108)

The short-term (less than 2 min) alterations in the intracellular free calcium concentration in differentiated NG108-15 (neuroblastoma cross glioma) cells exposed to dynamic mechanical deformation with and with out superimposed chemical hypoxia were determined, A previously develo ped device, modified for these studies, was used to apply deformations at a magnitude and rate representative of those experienced by neural tissue in Traumatic Brain Injury, Chemical hypoxia was imposed using a combination of 2-deoxy-D-glucose and salicylate, anaerobic and aerob ic metabolic blockers, respectively, Real time measurement of intracel lular free calcium concentration using Fura-2 and a custom epifluoresc ence microscopy system provided a quantitative index of cell response, At high rates of deformation (similar to 10 sec(-1)), increases in in tracellular free calcium concentration were exponentially related to t he magnitude of the applied deformation, Chemical hypoxia had no effec t on this acute response, At low rates of deformation, small increases in intracellular free calcium concentration were independent of the m agnitude of the deformation, These findings indicate that strategies f or seducing severity of TBI should focus on minimizing the rate of def ormation of neural cells, Together with data from animal, physical, an d finite element models, these data can be employed in the development of physiologic injury tolerance criteria for the whole head.