Figure 1

The application of cyclic tensile stress induced apoptotic cell death in spinal cord cells. Representative serial photomicrographs are shown of cells exposed to a tensile stress of 10% strain at 0.5 Hz at 0, 6, 24, and 48 hours (A, B). The number of green-stained living cells decreased (A: top row) while the number of red-strained dead cells increased (B: middle row) in a time-dependent manner during cyclic tensile stress application. Transmission electron microscopy (TEM) examination (C: bottom row) showed that all cells at 0 hour appeared viable, with large nuclei, and dotted with chromatin and abundant rough endoplasmic reticulum, while some cells at 6 hours showed deformity of nuclei and cytoplasm. TEM at 24 hours showed some cells with condensed and fragmented nuclei and condensed chromatin, and the change progressed at 48 hours (C: bottom row). Bar = 100 μm (A, B), 50 μm (C).