Establishment of new mouse embryonic stem cell lines is improved by physiological glucose and oxygen.

Embryonic stem cell lines are routinely selected and cultured in glucose and oxygen concentrations that are well above those of the intrauterine environment. Supraphysiological glucose and hyperoxia each increase oxidative stress, which could be detrimental to survival in vitro by inhibiting proliferation and/or inducing cell death. The aim of this study was to test whether isolation of new embryonic stem cell lines from murine blastocysts is improved by culture in physiological (5%) oxygen instead of approximately 20%, the concentration of oxygen in room air, or in media containing physiological (100 mg/dL) instead of 450 mg/dL glucose. We found that culturing in either physiological oxygen or physiological glucose improved the success of establishing new murine embryonic stem cell lines, and that culture when concentrations of both oxygen and glucose were physiological improved the success of establishing new lines more than culture in either alone. Physiological oxygen and glucose reduce oxidative stress, as determined by 2',7'-dichloro-dihydrofluorescein fluorescence. BrdU incorporation suggests that physiological oxygen and glucose increase the pool of proliferating cells. Cells isolated in physiological oxygen and glucose are capable of self-renewal and differentiation into all three germ layers in vitro. However, none of the culture conditions prevents cytogenetic instability with prolonged passage. These results suggest that culture of cells derived from murine blastocysts in physiological oxygen and glucose reduces oxidant stress, which increases the success of establishing new embryonic stem cell lines.