Molecular Hydrogen Attenuated N-methyl-N-Nitrosourea Induced Corneal Endothelial Injury by Upregulating Anti-Apoptotic Pathway

PURPOSE. Previous work by our group has demonstrated the value of N-methyl-Nnitrosourea (MNU)-induced corneal endothelial decompensation in animal models. The aim of this study was to investigate the effect of molecular hydrogen (H-2) on MNU-induced corneal endothelial cell (CEC) injury and the underlying mechanism. METHODS. MNU-induced animal models of CEC injury were washed with hydrogen-rich saline (HRS) for 14 days. Immunofluorescence staining, immunohistochemical staining, and corneal endothelial assessment were applied to determine architectural and cellular changes on the corneal endothelium following HRS treatment. MNU-induced cell models of CEC injury were co-cultured with H-2. The effect of H-2 was examined using morphological and functional assays. RESULTS. It was shown that MNU could inhibit the proliferation and specific physiological functions of CECs by increasing apoptosis and decreasing the expression of ZO-1 and Na+/K+-ATPase, whereas H-2 improved the proliferation and physiological function of CECs by anti-apoptosis. Cell experiments further confirmed that H-2 could reverse MNU damage to CECs by decreasing oxidative stress injury, interfering with the NF-kappa B/NLRP3 pathway and the FOXO3a/p53/p21 pathway. CONCLUSIONS. This study suggests that topical application of H-2 could protect CECs against corneal damage factors through anti-apoptotic effect, reduce the incidence and severity of corneal endothelial decompensation, and maintain corneal transparency.

Automated summary

The study demonstrated that MNU inhibited the proliferation and specific physiological functions of CECs by increasing apoptosis and decreasing expression of ZO-1 and Na+/K+-ATPase, while H-2 improved CECs' proliferation and physiological function through anti-apoptotic effects. H-2 was also shown to reverse MNU damage by decreasing oxidative stress injury and interfering with the NF-kappa B/NLRP3 pathway and the FOXO3a/p53/p21 pathway.