α-Ketoglutarate stimulates cell growth through the improvement of glucose and glutamine metabolism in C2C12 cell culture

IntroductionCellular adaptation to physical training and energy metabolism play an important role during physical exercise. This study sought to investigate the effects of α-KG on cell growth and energy metabolism in C2C12 cell culture.MethodsC2C12 cells were cultured in media pretreated without (control) or with α-KG at different concentrations, and cells and media were harvested every 24 h for 8 days. From cell counts, specific cell growth rate (SGR) and doubling time were calculated. The content of glucose, glutamine, lactate, and ammonia in media was determined, and the specific consumption rate (SCR) or production rate (SPR) was calculated. Additionally, cell colony-forming efficiency (CFE) was determined.ResultsThe control cells showed a CFE at 50%, a typical cell growth curve in the first 5 days with a mean SGR at 0.86/day, and a mean cell count doubling time at 19.4 h. In the group with α-KG at 100 mM, the cells underwent rapid cell death, and thus no further analysis was made. The treatment with α-KG at lower concentrations (0.1 mM and 1.0 mM) led to a higher CFE at 68 and 55%, respectively, whereas those in groups with higher α-KG concentration decreased (10 and 6% for 20 mM and 30 mM α-KG, respectively). The mean SGR was 0.95/day, 0.94/day, 0.77/day, 0.71/day, and 0.65/day for groups treated with α-KG at 0.1, 1.0, 10.0, 20.0, and 30.0 mM, respectively, and the corresponding cell count doubling time was 17.6, 17.8, 20.9, 24.6, and 24.7 h, respectively. In comparison with that of the control group, the mean glucose SCR decreased in all the groups treated with α-KG, while the mean glutamine SCR remained unchanged; the mean lactate SPR increased in the groups treated with α-KG ≥ 20.0 mM. Finally, the mean SPR of ammonia was lower in all α-KG groups than that in the control.Discussion and conclusionThe treatment with α-KG at lower concentrations increased cell growth whereas at higher concentrations decreased cell growth, and α-KG reduced glucose consumption and ammonia production. Therefore, α-KG stimulates cell growth in a dose-dependent manner, which is likely through the improvement of glucose and glutamine metabolism in a C2C12 culture setting.