Figure 4. NAC alleviates TGF-β2-induced fibrosis in HConFs by improving cell antioxidant defense. HConFs were pretreated by TGF-β2 (4 ng/ml) with or without NAC (10 mM) for 24 h. (A) Protein levels of vimentin, α-SMA, fibronectin, and collagen-1. (B) mRNA levels of fibronectin, vimentin, C-TGF, N-cadherin and α-SMA determined by quantitative real-time PCR. (C) NAC effect on p-smad2/3 protein levels in TGF-β2-induced HConFs. (D) Relative antioxidant protein levels of γ-GCS, SOD1/2 and CAT determined using western blotting. (E) Relative antioxidant gene levels of γ-GCS, SOD1/2, NOX-1, and NOX-4 at specified times. (F) Representative images showing immunofluorescence staining for collagen-1 and (G) α-SMA in TGF-β2-induced HConFs at 24h (Nuclei = blue, α-SMA/collagen-1 = green/red). Data are mean ± S.D. n = 3. *p < 0.05, **p < 0.01, ***p < 0.001.