Figure 6.

Microtubule breaking immediately after dynamic stretch injury. TEM (×2–9 × 10⁴) of 60-nm-thick longitudinal sections of axons demonstrate microtubule disruptions observed immediately after injury. A) In straight segments of axons, microtubules traversed the main axis of axons without regions of interruptions. Within undulations, microtubules demonstrated uniformly open spacing at the peak, displaying frayed free ends (asterisk). Remaining portions of microtubules were disorganized and twisted, with a curling configuration (arrow). B) Demonstration of progressive phases of undulation relaxation and acute formation of axonal swellings after stretch injury. C) Taxol (1 μM)-pretreated axons demonstrated similar microtubule disruptions in axons as control injured axons immediately after stretch injury (top). In contrast, nocodazole (Noc; 0.1 μM)-pretreated axons demonstrated almost complete loss of microtubules within the undulation (bottom). Scale bars = 500 nm.