Fig. 1

a Vascular endothelial growth factor-A (VEGF-A) mRNA levels in Normal (NF) and Fibrotic (FF) fibroblast total RNA lysates in response to 24 h exposure to hypoxia and hyperoxia. Using quantitative reverse transcriptase polymerase chain reactions (qRT-PCR) of total RNA cell lysates, panVEGF-A mRNA levels significantly increased in response to hypoxia in NF (****p < 0.0001) and FF (***p < 0.001). The response of FF to hypoxia was significantly attenuated compared to the NF response (****p < 0.0001). FF panVEGF-A mRNA levels also significantly increased in response to hyperoxia (p < 0.01), (NF and FF n = 6). Changes in VEGF-A_xxxa mRNA levels reflected those seen for panVEGF-A with increased mRNA levels in response to hypoxia in total RNA lysates of NF (****p < 0.0001) and FF (p < 0.01), an attenuated response of FF to hypoxia compared to NF (***p < 0.001) and increased FF VEGF-A_xxxa mRNA levels in response to hyperoxia (*p < 0.05), (NF and FF n = 6). In contrast, VEGF-A_xxxb mRNA levels did not change in response to hypoxia or hyperoxia (NF and FF n = 6) (data not shown). Data are presented as mean fold change in expression (2^△△CT) with SEM, data analysis performed on △△CT values. Statistical analysis: analysis of variance with post hoc Holm-Sidak multiple comparisons analysis used throughout. b VEGF-A isoform protein expression in Normal (NF) and Fibrotic (FF) fibroblast cell lysates in response to 24 h exposure to hypoxia and hyperoxia. By ELISA, panVEGF-A protein expression in NF and FF cell lysates were significantly up-regulated in response to hypoxia (****p < 0.0001). The response of FF to hypoxia was significantly attenuated compared to the NF response (****p < 0.0001). Hyperoxia had no significant effect on panVEGF-A protein expression in NF and FF (NF n = 7, FF n = 7). Using a specific VEGF-A₁₆₅b ELISA, there was no significant effect of either hypoxia and hyperoxia on VEGF-A₁₆₅b expression in both NF and FF (NF and FF n = 6). Data presented as means with SEM, ANOVA with Holm’s Sidak multiple comparisons statistical analysis