Figure 4.

Effect of TNF-α and IL-6 on the levels of MMP-1. Cells were cultured with 1 ng/mL TNF-α or 25 ng/mL IL-6 individually and jointly for 12 h. Total RNA and cell-culture supernatants were then collected. (a) The mRNA levels of MMP-1 determined by real-time PCR from total RNA. (b) Representative Western blot for MMP-1 protein in cell-culture supernatants. (c) Quantitative analysis of MMP-1 protein levels by Image-Pro Plus. Values are expressed as mean ± standard deviation of three independent experiments. KC: keratoconus (n = 3), NC: normal cornea (n = 3). *P < 0.05, compared with cells stimulated by TNF-α or IL-6 individually