Effect of intermittent cyclic equibiaxial stretch on MMP-1 promoter activity. HIG-82 cells were transfected with 1G or 2G promoter-luciferase reporter plasmids and exposed to 8 h of intermittent cyclic 2%–9% 0.5 Hz equibiaxial stretch. Cells were grown on collagen I coated cell culture plates and a subset of plates was subjected to stretch in a Flexcell 4000 system. Unloaded controls were concurrently placed in the stretch apparatus but were not subjected to stretch. MMP-1 promoter activity reported relative to unloaded control 1G promoter activity. (n = 9, †p < 0.05 wrt matching 1G variant).