Degenerative and regenerative signaling pathways in restoration injured RGCs and melatonin future prospect for their survival

Background & Objectives: Optic neuropathies are related to the conditions in which optic nerve fibers are degenerated by any reasons including inflammation, trauma, ischemia, mitochondrial dysfunction, etc. The neurons of the retina including retinal ganglion cells (RGCs) inherently face a limited ability regenerate axons after either disease or trauma, thereby resulting in irreversible vision loss. In this review, we discussed the detailed cellular and molecular mechanisms affecting axonal regeneration in the visual system after optic neuropathy and then we demonstrated that how melatonin might physiologically and pharmacologically play an important role in the management of optic neuropathy.Materials & Methods: In November ۲۰۱۸, we searched literature in PubMed, google scholar, web of sciences, Scopus, and other databases for published studies. The key terms included "retinal ganglion cell survival/death", "inflammation", "oxidative stress", "apoptosis", "melatonin", "excitotoxic damage", and "hypoxia".Results: Melatonin as a wide-spectrum antioxidant and powerful free radical scavenger is able to defend RGCs against a variety of harmful circumstances including inflammation (attenuating the production of proinflammatory cytokines such as IL-۱β and TNF-α), oxidative/nitrosative stress (decrease in the electron leakage from the mitochondrial electron transport chain), glutamate-mediated neurotoxicity, apoptosis, and HIF-۱α expression in the retina. Furthermore, we found that melatonin may have a protective effect on RGCs via its effects on neurotrophic factors such as BDNF. Therefore, melatonin may be a new therapeutic medication that will assist scientists to mitigate RGC death.Conclusions: According to the key information provided in this examination, melatonin may act as a promising medication to diminish RGC death in numerous retinal pathologic circumstances.

کلیدواژه ها:

Regeneration ، Degeneration ، Melatonin ، RGCs ، Inflammation ، Oxidative/nitrosative