Abstract
Purpose :
Sulfur mustard is a chemical weapon threat, and its exposure to the eye causes severe eye pain, photophobia, excessive lacrimation, anterior segment defects and blindness. This study aims to evaluate the possible effects of mustard gas toxicity on retinal Muller glial cells.
Methods :
Muller glial cells (MIO-M1) were cultured in DMEM and exposed to nitrogen mustard at different concentrations (50-1000µM) for 3h, 24h and 72h. Real-time cellular integrity and morphological evaluation were done using the xCELLigence system. Cellular toxicity and viability were performed using TUNEL and Prestoblue assays. The intracellular oxidative stress was measured by DCFDA, and DHE staining and antioxidant gene expression was determined by qPCR. The effect of nitrogen mustard on glial cell activation was determined by GFAP and vimentin antibody staining and by qPCR of inflammatory markers. AO/PI and DAPI staining further evaluated cell death, apoptosis, necrosis, and DNA damage. We assessed the pyroptosis mechanism by measuring caspase-1, caspase-3, and ASC and NLRP3 inflammasome using immunoassays.
Results :
The cellular and morphological evaluation revealed hyperactivation of Muller glial cells after nitrogen mustard exposure in a dose- and time-dependent manner. Nitrogen mustard significantly increased oxidative stress up to 24h with enhanced cell death in 72 h. We found a significant increase in antioxidant enzymes at lower concentrations of nitrogen mustard. Increased oxidative stress and inflammatory milieu caused activation of NLRP3 inflammsome resulting in Muller cell gliosis. NM-induced cell death was mainly driven by caspase-1 and NLRP-3 pyroptosis and was less dependent on caspase-3.
Conclusions :
In conclusion, the nitrogen mustard caused retinal Muller glial cell gliosis with increased oxidative stress, inflammation, and cell death primarily driven by caspase-1/NLRP3 pyroptosis.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.