Abstract:

In order to study the effect of low oxygen on cell proliferation in vitro by culturing bovine somatic cells under the normoxic (20%) and hypoxic (5%) conditions, three types of bovine donor cells commonly used for nuclear transfer (fetal fibroblasts, fetal oviduct epithelial cells, cumulus granulosa cells) were cultured in 20% and 5% oxygen content of the culture environment for continuous subculture and cell colony formation, at the same time, cell proliferation lifespan (be determined by Population doubling level) and colony formation efficiency. The results indicated that 5% oxygen environment promoted the three kinds of cells proliferation in vitro, and proliferation lifespan of cells in hypoxic group extended significantly (50.61±2.47, 16.35±0.43, 43.38±0.84 vs 27.42±0.23, 12.14±0.83, 32.76±1.53, P<0.01). In the case of culture at 500 cells·dish^-1 (diameter 100 mm), the cell colony formation efficiency of fetal oviduct epithelial cells cultured in low oxygen was much higher than that cultured in normal oxygen ((53.05±4.62)% vs (36.68±5.68)%, P<0.01), however, fetal fibroblasts and cumulus granulosa cells in hypoxic group displayed only a litter more cell colonies than the normoxic group, the difference was not significant (P>0.05). When seeding at one cell·well^-1 in 96-well plates, single-cell colony formation efficiency of hypoxic group was significantly higher than that of the normoxia group ( (21.60±2.37)%, (22.29±5.42)%, (27.92±3.69)% vs (12.01±1.42)%, (7.92±2.86)%, (10.49±3.07)%, P<0.01 or P＜0.05). The result indicate that reducing the oxygen content(20%) of in vitro culture conditions to low oxygen (5%), which better approximate to the physiologic situation, can extend cell proliferation lifespan and improve the efficiency of single-cell colony formation, low oxygen has a good role in promoting cell growth.