Fig. 2

TECs proliferate in low pH media in the presence of lactate. a TEC and NEC proliferation in sodium lactate-supplemented medium at indicated concentrations; the media pH (alkaline pH) was measured immediately before plates were placed in the incubator; cell proliferation was measured using the MTS assay after 72 h. Data represented as absorbances (b) TEC and NEC proliferation in lactic acid-supplemented medium at indicated concentrations; the media pH (decreasing pH) was measured immediately before plates were placed in the incubator; cell proliferation was measured using the MTS assay after 72 h. Data represented as fold change relative to 0 mM condition. c NEC proliferation in pH-adjusted, 20 mM lactic acid-supplemented medium; the media pH was adjusted to approximately 8 before application to the cells; cell proliferation was measured by the MTS assay after 72 h. Data represented as fold change relative to cells in media without pH adjustment. Results presented as mean ± SD. The experiment was independently repeated at least three times; *P < 0.05, **P < 0.001, ***P < 0.0001, by two-tailed unpaired Student’s t-test; N.S., not significant