Activation of autophagy in the retina after optic nerve crush injury in rats

Abstract

AIM: To investigate the activation of autophagy in rat retina after optic nerve crush (ONC) and evaluate its relationship with apoptosis of retinal ganglion cells (RGCs). METHODS: The ONC model was established. Western blots were performed to investigate expression of p62, LC3 and Beclin-1. Transmission electron microscopy was performed to discover the autophagosomes in the retina after ONC. Immunohistochemistry was used to confirm the distribution of LC3. TUNEL was performed to confirm the relationship between autophagy and RGC apoptosis. RESULTS: p62/Beclin-1 ratio was declined shortly after ONC until to day 7 after ONC and then restored to a normal level at day 21. There was an opposite change in the LC3-II/LC3I ratio in the retina compared to the p62/Beclin-1 ratio. Increased autophagosomes were found after ONC using transmission electron microscopy, and most of the LC3-stained cells were colocalized with RGCs and Müller cells. More LC3-immunoreactive cells and apoptotic RGCs were found on day 7 following ONC. CONCLUSION: Possible activation of autophagy in RGCs after ONC; autophagy mainly occurred in RGCs and Müller cells, and the apoptosis of RGCs after ONC may be partly associated with autophagic activation.

Keywords

• autophagy
• optic nerve crush
• apoptosis
• retinal ganglion cells
• rat