Background:
Glaucoma is a multifactorial optic neuropathy progressive characterized by structural loss of retinal
ganglion cells (RGCs) and irreversible loss of vision. High intraocular pressure (HIOP) is a high risk factor for glaucoma. It
has been reported that the manners of RGCs’ loss are in-depth explored after acute HIOP injury, such as, apoptosis, autophagy and necrosis. However, pyroptosis, a novel type of pro-inflammatory cell programmed necrosis, rarely reported after
acute HIOP injury. Researches also showed that melatonin (MT) possesses substantial anti-inflammatory properties. However, whether melatonin could alleviate retinal neurons death, especially pyroptosis, by acute HIOP injury is unclear.
Objective:
This study explored pyroptosis of retinal neurons and the effects of MT preventing retinal neurons form pyroptosis after acute HIOP injury.
Method:
Establish acute HIOP model in rat by increasing the IOP and then reperfusion. Western Blot (WB) was adopted to
detect molecules related to pyroptosis at the protein level, such as GasderminD (GSDMD), GasderminDp32 (GSDMDp32),
Caspase-1 (Casp-1) and Caspase-1p20 (Casp-1p20), and the products of inflammatory reactions, as interleukin-18 (IL-18)
and interleukin-1β (IL-1β) as well. At the same time, Immunofluorescence (IF) was used to co-localize Casp-1with retinal
neurons to determine the position of Casp-1 expression. Morphologically, Ethidium homodimer-III staining, a method
commonly used for judging cell death, was carried out to stain dead cells. Subsequently, Lactate Dehydrogenase (LDH) cytotoxicity assay kit was used to quantitative analysis the LDH released after cell disruption.
Results:
The results suggested that pyroptosis played a vital role in retinal neurons death, especially in the ganglion cell layer, by acute HIOP injury and peaked at 6h after acute HIOP injury. Furthermore, it was found that MT might prevent retinal
neurons from pyroptosis via NF-κB/NLRP3 axis after acute HIOP injury in rats.
Conclusion:
MT treatment might be considered a new strategy for protecting retinal neurons against pyroptosis following
acute HIOP injury.