[Characterization of cultured Sertoli cells under high-temperature and hypoxic conditions]

Sertoli cells (SCs) isolated from adult C57Bl/6 mice were characterized under four different cell culture conditions: standard conditions (34 degrees C, 21% O2 - 34_21), high-temperature conditions (37 degrees C, 21% O2 - 37_21), hypoxic conditions (34 degrees C, 5% O2 - 34_5), and combination of these conditions (37 degrees C, 5% O2 - 37_5). Proliferation and viability were promoted when SCs were grown under hypoxia: 28.5 and 24.6% of SCs were BrdU-positive at the peak of proliferation, 92.7 and 92.7% of SCs were viable after 15 days in culture at 34_5 and 37_5, respectively, versus 20.2 and 88.9% at 34_21, respectively. In SCs grown under high-temperature conditions proliferation was slightly increased, but viability was decreased: 23.1% of SCs were BrdU-positive, and only 74.9% of SCs were viable at 37_21. At the same time cultivation of SCs at 37 degrees C promoted their dedifferentiation: after 15 days in culture 98.8 and 98.6% of cells at 37_5 and 37_21, respectively, expressed a marker of immature SCs--cytokeratin-18, compared to 26.5% at 34_5 and 6.6% at 34_21. Expression of Wt1, a transcription factor controlling cell-cell junction formation and germ cell development, disappeared in most cells after 3 days in culture under all culture conditions. However, SCs forming colonies restored Wt1 expression at day 15 in culture under high-temperature conditions: 59.1 and 29.5% of SCs were Wt1-positive at 37_21 and 37_5, respectively, versus 11.1 and 3.6% at 34_21 and 34_5, respectively. Cultured SCs expressed other SC markers (vimentin, clusterin, Gata-4) under all culture conditions. Our results show that cultured SCs may be useful for reproductive biology and regenerative medicine.