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Fig. 1 | Acta Neuropathologica Communications

Fig. 1

From: Genetic inactivation of SARM1 axon degeneration pathway improves outcome trajectory after experimental traumatic brain injury based on pathological, radiological, and functional measures

Fig. 1

Sarm1 knockout reduces corpus callosum atrophy and axon pathology at 10 weeks post-TBI. a Sarm1 knockout attenuates CC atrophy that develops after TBI. b Sarm1 knockout preserves intact, myelinated axons after TBI. c–f Representative images of pathological features from high resolution electron microscopy in CC sagittal sections. c Example from a Sarm1 WT sham mouse to show the cytoskeleton, mitochondria and surrounding myelin sheath of intact axons in contrast with a rare damaged axon with a densely compacted cytoskeleton (blue arrow). d Sarm1 WT TBI mouse example of an axon with an abnormally large mitochondrion (red arrow) and an axon with a typical mitochondrion (red asterisk). Mitochondria were considered abnormal when swollen to > 50% of the axon area. e Demyelinated axon (yellow arrow) lacking ensheathing myelin but with otherwise intact cytoskeleton in a Sarm1 WT TBI mouse. f Damaged axon (blue arrow) with vesicle accumulation and cytoskeletal breakdown in a Sarm1 KO TBI mouse. g–j Representative electron microscopy images from CC sagittal sections for Sarm1 WT sham (g) and TBI (h) mice in comparison with Sarm1 KO sham (i) and TBI (j) mice. Arrows identify examples of damaged axons with accumulated vesicles and/or compacted cytoskeleton (blue), abnormal mitochondria (red), or demyelination (yellow). k–m Quantification of axon and myelin pathology at 10 weeks after TBI or sham procedure. Sarm1 knockout reduces chronic stage axon damage (k), normalizes mitochondria morphology (l), and eliminates TBI-induced demyelinated component of de/unmyelinated axons (M). Sarm1 WT: n = 9 sham, n = 8 TBI. Sarm1 KO: n = 7 sham, n = 9 TBI. ns = not significant. Further statistical details are provided in Additional File 1: Table S1. c–f scale bars = 0.5 µm. g–j, scale bars = 1 µm

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