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Response to gravity vector changes in human NT2-N neurons. B.M. Uva1, F. Strollo2, F. Ricci3, M. Pastorino1, M. Cogoli-Greuter4, M.A. Masini1. 1Experimental Biology Department, Universitа di Genova, Italy, 2Unitа Endocrinologia INRCA & Universitа di Roma La Sapienza Italy, 3ENEA C.R. Roma Italy, 4Space Biology ETH Zurich Switzerland.

   The 3D RPM and the hyperfuge have been used to investigate on the effects of gravity vector changes on human NTera 2/D1 (NT2). The NT2—N cells are derived from the human teratocarcinoma cell line NT2 which is treated with retinoic acid. NT2-N cells have distinct neuronal morphology characterised by axons and dendrites, they are nearly identical to primary neurons in culture by numerous morphological, immunocytochemical, biochemical and electrophysiological criteria (Novak et al., 1999, J. of Neurochemistry). NT2-N  neurons express neuron specific proteins (neurofilaments) and are easily distinguishable from undifferentiated NT2 cells. The cells seeded onto "flasks on a slide" were submitted to: i) simulated µG for 5',15',30',1h and 23h, and ii) hypergravity (2.5xG) for the same period of time. Ground 1xG controls, kept in an identical equipment and treated in parallel were fixed onto the supporting frame of the machine in order to have their cells facing the same vibration stress as in simulated 0 x G. The cells were then fixed and submitted to immunohistochemistry using  antibodies to cytoskeletal proteins (б-tubulin, neurofilaments, F-actin), NGF and synaptic vesicles. Alterations were observed after only 5' of treatment. The cytoskeleton and the neural processes were damaged, expression of NGF was very weak in the NT2-N cells and absent in the undifferentiated NT2. Synaptic vesicles were not immunostainable. After 23h the cytoskeleton was again normal in NT2 and in NT2-N cells. NGF was again immunostainable and the nervous processes in the NT2-N cells were regenerated.

   We conclude that gravity vector changes induce only transient alterations in nervous cells as observed by us in C6 glioma cell lines (Uva et al., 2002 Brain Research).

 (Supported by a grant from the Italian Space Agency)