Effect of Glutamine Stability on the Long-term Culture and Line Establishment of Chicken Primordial Germ Cells

Primordial germ cells (PGCs) are precursors of mature gametes, which transmit genetic information to the next generation. Due to the importance of PGCs in many fields, including developmental biology, genome editing, transgenesis, and conservation of avian genetic resources, various research aspects have focused on the cultivation of PGCs. Despite considerable progress in the establishment of specified culture media for the expansion of PGCs, a well-defined PGC culture medium has not yet been developed. This might be due to the complexity of the nutritional requirements of PGCs in the culture. Besides the nutritional needs, including vitamins, amino acids, salts, carbohydrates, and growth factors, a particular source of energy must be provided to sustain growth and viability. Glutamine is a major energy source for cultured cells, commonly added in cell culture media at higher concentrations than other amino acids. However, glutamine is very labile and rapidly degrades in solutions such as culture media. This generates ammonia as a by-product, which is toxic to the cultured cells and can affect cell viability and protein glycosylation. Therefore, the stability of glutamine in culture conditions is another concern for the long-term culture of PGCs. Here, we study the effect of glutamine stability on PGC culture using glutamine and GlutaMax (a commercial stabilized dipeptide form of glutamine). We found that the addition of GlutaMax in the medium promotes PGC proliferation. This effect might be exerted by minimizing production of toxic ammonia that results in maximizing cell performance and media stability.