Evaluation of the antiapoptotic effect of Coenzyme Q10 as a countermeasure against eye lesions endured during long duration space flight

Understanding human space exploration-related damages, whose main causes are microgravity and cosmic irradiations, is an essential goal for mission design and risk assessment. One main target of space related damaging agents is the retina, which cells are known to undergo apoptosis in the response to space irradiation and microgravity. This review summarizes the most relevant results we have achieved by developing the project RA (“Radiation, microgravity and Apoptosis”) funded by Agenzia Spaziale Italiana (ASI), in which we proposed a peculiar countermeasure aimed to inhibit retinal cell apoptosis: the Coenzyme Q10 (CoQ10). We have previously recognized CoQ10, the well-known free radical scavenger, as a potent, general antiapoptotic molecule, being a gatekeeper of the mitochondrial permeability transition pore whose opening is the main trigger of apoptosis. We have carried out studies on retina cultured cells subjected to a plethora of damaging stimuli, including radiations and microgravity (by using a Rotator Wall Vessel Bioreactor), and on animal models of radiation- or excitotoxicity-induced retinal damage. Our results clearly indicated that CoQ10 significantly counteracted apoptosis in response to all tested damaging stimuli, both in vitro and in vivo. This supports the possibility that CoQ10 treatment could be evaluated as an optimal countermeasure against retinal lesions during space explorations. Furthermore, our observation that CoQ10 administered as eye drops reaches the choroid/retina area strongly suggests that it could be simply and efficiently administered in this form.