Figure 4.
Continued.
Figure 4.
Effects of niacinamide on protein and mRNA expression of cyclin dependent kinase Inhibitors in hDPCs with and without H2O2 treatment. (A) Cells (5.0 × 105 cells/well) were seeded in 60 mm dishes. After 24 h, cells were treated with niacinamide (1, 2, and 4 mM) and 10 µM of MNX in complete medium for 24 h. Western bot analysis was performed using 40 μg of total protein. GAPDH was used as a loading control (B) The band intensity was quantitated. Data represent mean ± SD (n = 4) (C) Cells (5.0 × 105 cells/well) were seeded in 60 mm dishes and cultured for 24 h, then medium was replaced with serum limitation medium. After serum limitation for 24 h, cells were treated with various concentrations of niacinamide (1, 2 and 4 mM) and 10 µM of MNX in the presence of 500 µM of H2O2 for 24 h. Western bot analysis was performed using 40 μg of total protein. GAPDH was used as a loading control (D) The band intensity was quantitated. Data represent mean ± SD (n = 4) (E) Cells (1.5 × 105 cells/well) were seeded in 6-well plates and incubated for 24 h. After serum limitation for 24 h, niacinamide was treated at concentrations of 1, 2, and 4 mM for 24 h in the presence of H2O2. The mRNA expression levels of p21 (CDKN1A) and p16 (CDKN2A) were measured by RT-PCR. Data represent mean ± SD (n = 3). #p < 0.05 and ##p < 0.01 compared to non-treated control. *p < 0.05 and **p < 0.01 compared to H2O2-treated control.
Abbreviations: N.S, not significant; N.T, non-treated control; NIA, niacinamide; MNX, minoxidil.