Figure 3.

Graph showing the number of activated (BrdU⁺) satellite cells/fiber plated either in collagen-coated FlexCell dishes (as supplied) or in the same dishes with an additional layer of Vitrogen gel. Fibers were plated on flexible or rigid wells and allowed to adhere overnight (16 hr). BrdU was added and cultures were subject to stretching for 2 hr (plates with rigid-bottomed wells were placed in vacuum mats but not stretched). There was no difference in activation between fibers plated on collagen-coated or Vitrogen-covered dishes in the absence of stretch for either flexible- or rigid-bottomed wells. However, stretching for 2 hr induced a significant increase in activation (BrdU⁺ cells/fiber) when fibers were plated into Vitrogen-covered dishes !(∗p<0.05). There was no change in activation induced by stretching fibers that were plated onto collagen-coated wells.