Detection of MMP-1 Activity by Collagen Zymography

The conditioned media collected at 24 h after UVA exposure was used to detect MMP-1 activity using collagen zymography as previously described (Flament et al., 2013). Culture supernatant was subjected to electrophoresis on 10% polyacrylamide gels containing 1% collagen substrate. Following electrophoresis, the gel was washed twice with 2.5% Triton X-100 to remove SDS and allow MMP-1 to renature and was incubated in the developing buffer overnight at 37°C. The gel was then stained with 0.006% Coomassie brilliant blue G-250 and destained using a destaining solution as previously described in Chaiprasongsuk et al., 2017. Determination of MMP-1 activity observed as colorless (unstained) bands was performed using a CAMAG TLC scanner (Muttenz, Switzerland) and analyzed with the ImageMaster software (Hoefer Pharmacia Biotech). Data were expressed as a percentage of control (100%, sham treatment in non-irradiated cells).