Fig. 4

Effects of protease inhibitors on the induction of matrix metalloproteinases (MMPs) mRNA levels. a–d Beas2B cells (a–d) were treated with medium (C), dust extract (DE) (0.25 %), α1-antitrypsin (10 ug/ml) (α1-AT) alone, soybean trypsin inhibitor (10 μg/ml) (SBTI) alone or dust extract in the presence of α1-antitrypsin (10 μg/ml) or soybean trypsin inhibitor (10 μg/ml) for 3 h. SAE cells (e) were treated similarly with SBTI (10 ug/ml) and levels of MMP mRNAs were determined by qRT-PCR. The levels of each mRNA in control cells were arbitrarily considered as 100 and relative levels in other treatments are shown. Data shown for Beas2B cells are means ± SE (n = 3–4) for C, DE, α1-AT + DE samples and means ± SD (n = 2) for α1-AT, SBTI, SBTI + DE and for SAE cells are means ± SE (n = 3). *P < 0.05