TEM revealed the ultrastructure change of chondrocytes.

<p>(A) The ultrastructure change of chondrocytes under various compressive stresses after injecting Salubrinal at days 1, 3 and 7.ER dilation is indicated by an arrow, condensed chromatin is indicated by an asterisk, vesicles are indicated by triangles, and decreasing collagen deposition indicated by a pentagram. Scale bars, 1 μm. (B) Higher magnification in the day-3 light compressive stress subgroup. ER dilation is indicated by an arrow, vesicles are indicated by triangle. Scale bars, 0.5 μm. (C) Higher magnification in the day-7 light compressive stress subgroup after injecting Salubrinal. (D) Higher magnification in the day-7 heavy compressive stress subgroup. ER dilation is indicated by an arrow, condensed chromatin is indicated by an asterisk,and decreasing collagen deposition indicated by a pentagram.