Antibiotics reduce the growth rate and differentiation of embryonic stem cell cultures.

Embryonic stem cells (ESCs) are being investigated increasingly for their potential as a cell source for tissue engineering. Antibiotics are regularly used in ESC culture media to control contamination, although they can be cytotoxic and interfere with protein synthesis. Our aim was to examine the effects of the frequently used antibiotics gentamicin and combined penicillin and streptomycin on ESC culture using differentiation of murine ESC into type II pneumocytes as a model. Antibiotics reduced the expression of the specific marker for type II pneumocytes, SPC mRNA, by up to 60%. We also identified an adverse effect on the growth rate of differentiating embryoid bodies, causing a significant ( p < 0.05) reduction of up to 40%, and an increase in population doubling time of up to 48%. No contamination was seen in any of the cultures. Our findings suggest that the routine use of antibiotics in ESC culture should be avoided as it may reduce the efficiency of the culture system.