Areca nut potentiates TGF-β action on hGF cells.

Human gingival fibroblast (hGF) cells were serum deprived by replenishing with medium containing 0.2% serum for 24 h. Subsequently, hGF cells were treated for 72 hours with areca nut water extract (5H− 5 µg/ml) and or TGF-β (5 ng/ml). Real time PCR was used to examine the expression of genes regulated by TGF-β or areca nut extracts (A, B, C, D, E, F, G and H). I] Direct Red 80 stained hGF cells showing the presence of total collagens following treatment with Areca nut water extract and/or TGF-β for 5 days (Figure 5I, 10× magnification images, i-Untreated, ii-5H (5 µg/ml) Areca nut water extract, iii- TGF-β, iv- 5H+TGF-β). Figure 5J shows the quantitation of the Direct Red staining as measured at 550 nm.