Fig. 2.

Ionizing radiation induces LDHA expression, lactate production, and extracellular acidification in lung fibroblasts. Primary human lung fibroblasts were exposed to 0, 3-, 7-, and 10-Gy radiation from a ¹³⁷Cs γ-ray source and cell lysates, and supernatants were collected at 5 days postradiation. A: cell viability was measured using an Alamar blue assay of mitochondrial activity (n = 3). B: LDHA protein expression was analyzed by Western blot. One representative experiment is shown (n = 3). C: LDHA expression relative to GAPDH was determined by densitometry and normalized to 0-Gy control. D: extracellular acidification rates (ECAR) were measured using a Seahorse Bioscience XF96 Flux Analyzer (n = 10–12). E: lactate levels were measured in the supernatants using a Nova BioProfile Automated Analyzer (n = 3). *P ≤ 0.05, compared with 0-Gy control by ANOVA. #P ≤ 0.05, compared with 3 and 7 Gy; ns = no statistical significance.