Fig. 2.

Stretch influences collagen fibril formation in an embryonic tendon model. Transmission electron microscopy images of fibrin gel tendon constructs seeded with embryonic chick metatarsal tendon cells at day 0 (T0), and after 4 days (T4) with and without stretching. Slow stretching (2 mm/day) increased collagen organization and collagen fibril packing volume in this in vitro model of embryonic tendon formation. Scale bar = 250 nm. Figure reprinted with permission by Wiley Periodicals, Inc. from Kalson et al. 2011 [56]