Table 1.

Neuritic accumulation of autophagosomes and autolysosomes in diverse experimental models of neurite injuries.

Insult	In vivo/ in vitro	Tissues/cell type/cell line	Effects	Phenotype	Refs
Mechanical injury
Root avulsion/distal axotomy	In vivo	Motor neuron	Undetermined.	Autophagy is initiated independently of the distance and severity of the lesion.	[13]
Anterior/posterior axotomy	In vivo	DA	Harmful.	Conditional deletion of Atg7 in adult mice offers axon protection.	[69]
Axotomy	In vivo	RGC	Harmful.	Autophagy inhibition prevents axonal degeneration.	[12]
Posterior transection	In vitro	SCG	Harmful.	Autophagy inhibition prevents neuritic degeneration.	[68]
Pharmacological toxin exposure
METH	In vitro	DA	Undetermined.	Degradative autophagic vacuoles accumulate in neuritic varicosities.	[5]
Zinc depletion	In vitro	SCG	Harmful.	Autophagy inhibition prevents terminal neurites from degeneration.	[50]
NMDA	In vitro	CGN	Harmful.	Autophagy inhibition prevents neuritic degeneration.	[6]
Nutrition withdrawal
NGF deprivation	In vitro	SCG, PC12	Harmful.	Autophagy inhibition prevents neuritic degeneration.	[68]
Serum deprivation	In vitro	PC12	Undetermined.	Autophagosomes and autolysosomes accumulate in degenerating neurites.	[34, 70]
Lysosome inhibitors or inactivation of degradation
Vinblastine	In vitro	Cortical neurons, SCG	Harmful.	Autophagosomes and autolysosomes accumulate in degenerating neurites. Autophagy inhibition prevents neuritic degeneration.	[7, 68]
Cathepsins deletion	In vivo	Brain tissues	Undetermined.	Autophagosomes accumulate in degenerating neurites.	[71]
Cysteine protease inhibitors	In vivo	Hippocampus	Beneficial.	Activated caspase-3 and autophagic vacuoles colocalize in degenerating neurites, which accelerates apoptosis.	[72]
Cathepsins inhibitors	In vitro	Hippocampal neurons	Undetermined.	Lysosomes and fused dense bodies (FDBs) composed of secondary lysosomes, postlysosomal compartments, and autophagic vacuoles accumulate selectively in the axon hillock and initial segment of the axon.	[73]

3-MA, 3-methyladenine; CGN, rat cerebellar granule neuron; DA, Dopamine neurons; METH, methamphetamine; NGF, nerve growth factor; NMDA, N-methyl-D-aspartate; RGC, retinal ganglion cell; SCG, superior cervical ganglion.