Strain-induced integrin β1 and β3 expression in periodontal ligament (PDL) cells after 6 hours. (A) PDL cells were seeded on flexible bottom cell culture dishes and strained with averaged 2.5% for 6 hours. For indirect immunofluorescence (IIF), the flexible membrane was divided into pieces derived from the inner and outer part of the membrane, and fixed for staining procedure. In IIF integrin subunit β1 (A, B) and subunit β3 (E, F) were visualized in controls and after 6 hours of strain-application (β1 C, D and β3 G, H) by using an anti-integrin β1 and β3-specific antibody. The green fluorescent signal illustrates the integrin β1 and β3 expression, while the blue fluorescence visualises the nuclear DAPI-staining. Scale bar, 50 μm.