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. 2016 Oct;55(4):542–553. doi: 10.1165/rcmb.2015-0254OC

Figure 5.

Figure 5.

Formaldehyde elicits nuclear factor erythroid-derived 2, like 2 (Nrf-2)–dependent antioxidant response in HASM cells. Whole-cell lysates from HASM cells exposed to PBS or formaldehyde were immune blotted for the markers of antioxidant (thioredoxin [Trx] 1) and cytoprotective (quinone oxido-reductase [NQO] 1) responses, as surrogate measures of Nrf-2 activation. (A) In response to formaldehyde exposure (0.2 and 0.8 ppm), NQO1 and Trx1 were elevated compared with the PBS-treated cells. NQO1 and Trx1 increases were noticed as early as 2 hours after exposure and remained elevated 18 hours after exposure (representative immune blot, n = 2). (B–D) At 18 hours after exposure, the lowest concentration of formaldehyde (0.2 ppm) caused a significant increase in NQO1 (*P = 0.017, n = 4) and Trx1 (*P = 0.0054, n = 4 donors), whereas a higher level of formaldehyde (2 ppm) caused relatively subdued induction of NQO1 and Trx1 (**P = 0.012, n = 4 donors). (B) Representative immune blot for n = 4 donors; (C and D) densitometry ratio; black lines show the mean for n = 4 donors. NS, not significant.