J Korean Ophthalmol Soc.  2009 Aug;50(8):1254-1258. 10.3341/jkos.2009.50.8.1254.

Effect of Dexamethasone on the Production of Nitric Oxide in Trabecular Meshwork Cells

• Lee SY
• Kim JW

• KMID: 2212544
• DOI: http://doi.org/10.3341/jkos.2009.50.8.1254

Abstract

PURPOSE
To investigate the effects of dexamethasone (DEX) on the production of nitric oxide (NO) and its enzymatic synthetic pathway in cultured human trabecular meshwork (HTM) cells. METHODS: Primarily cultured HTM cells were exposed to 0, 10, 100, 1000 nM of DEX for 3 days. In addition, 100 micrometer sepiapterin, 100 micrometer ascorbic acid, and 10 micrometer methotrexate were co-exposed to DEX. The cellular survival and nitrite production rates were assessed by MTT assay and Griess assay, respectively. RESULTS: DEX did not significantly affect the survival of cultured HTM cells. DEX decreased the NO production in a dose-dependent manner. With co-exposure of DEX, ascorbic acid nullified the DEX-induced decrease of NO production. Sepiapterin and methotrexate did not affect DEX-induced decrease of NO production. CONCLUSIONS: DEX decreased NO production in HTM cells and the de novo pathway of tetrahydrobiopterin may be involved. This decrease may raise intraocular pressure by decreasing trabecular outflow.

Keyword

Dexamethasone; Nitric oxide; Tetrahydrobiopterin; Trabecular meshwork cells

MeSH Terms

Ascorbic Acid
Biopterin
Dexamethasone
Humans
Intraocular Pressure
Methotrexate
Nitric Oxide
Pterins
Trabecular Meshwork
Ascorbic Acid
Biopterin
Dexamethasone
Methotrexate
Nitric Oxide
Pterins

Figure

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  Figure 1. Effect of dexamethasone on the survival of cultured trabecular meshwork cells. Three-day exposure of dexamethasone did not significantly affect the survival of trabecular meshwork cells compared to non-exposed control (p>0.05).

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  Figure 2. Effect of dexamethasone on the production of nitric oxide in cultured trabecular meshwork cell exposed for 3 days. Dexamethasone decreased nitric oxide production (∗ p<0.05).

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  Figure 3. Effect of 100 μM sepiapterin on the production of nitric oxide after co-exposed to dexamethasone for 3 days. Sepiapterin further decreased nitric oxide production compared to non-exposed control (∗ p<0.05).

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  Figure 4. Effect of 100 μM ascorbic acid on the production of nitric oxide (NO) after co-exposed to dexame-thasone for 3 days. Ascorbic acid increased NO pro-duction and abolished dexamethasone-induced inhibition of NO production (p>0.05).

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  Figure 5. Effect of 10 μM methotrexate on the production of nitric oxide after co-exposed to dexamethasone for 3 days. Methotrexate did not affect the dexame-thasone-induced inhibition of nitric oxide production compared to non-exposed control (∗ p<0.05).

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