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Abstract
Purpose
To investigate the role of L-ascorbic acid (LAA) on the survival and its association with nitric oxide (NO) production against hydrogen peroxide-induced oxidative stress in trabecular meshwork (TM) cells.
Methods
Primarily cultured human TM cells were exposed to hydrogen peroxide; 10, 100 µM for 2 days, or 1 mM single exposure with or without co-exposure of LAA. Cellular survival and nitrite production were assessed with MTT and Griess assays, respectively. Flow cytometry using annexin/PI double staining was performed to evaluate apoptosis.
Results
Hydrogen peroxide decreased cellular survival significantly in a dose-dependent manner accompanied with decreased NO production. However cellular survival and NO production were increased significantly with co-exposure of LAA. Cellular survival and NO were highly correlated. Flow cytometric analysis revealed that LAA inhibited hydrogen peroxide-induced apoptosis.
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 | Figure 1. Effect of L-ascorbic acid on the survival of cultured trabecular meshwork cells. L-ascorbic acid increased cellular survival in a dose-dependent manner. (* p<0.05) |
 | Figure 2. Effect of hydrogen peroxide on the survival of cultured TM cells exposed to 10, 100 µM for 2 days, or 1 mM single exposure. Hydrogen peroxide decreased cellular survival significantly in both conditions. (* p<0.05) |
 | Figure 3. L-ascorbic acid increased survival of cultured trabecular meshwork cells exposed to 10, or 100 µM hydrogen peroxide. (* p<0.05) |
 | Figure 4. Comparison of the effects of 0.5 mM L-NAME, 100 µM L-ascorbic acid (LAA), or 100 µM hydrogen peroxide on the survival of cultured trabecular meshwork cells. (* p<0.05) |
 | Figure 5. Effect of L-ascorbic acid (LAA) on the production of nitric oxide in cultured trabecular meshwork cells. LAA increased nitric oxide production in a dose-dependent manner. (* p<0.05) |
 | Figure 6. Effect of hydrogen peroxide on the production of nitric oxide in cultured trabecular meshwork cells. Hydrogen peroxide decreased nitric oxide production significantly. (* p<0.05) |
 | Figure 7. Effect of L-NAME, 100 µM L-ascorbic acid (LAA), or 100 µM hydrogen peroxide on the production of nitric oxide. (* p<0.05) |
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