J Korean Ophthalmol Soc.  2018 Jun;59(6):543-548. 10.3341/jkos.2018.59.6.543.

Effect of Valproic Acid on Nitric Oxide and Nitric Oxide Synthase in Trabecular Meshwork Cell

• Son MS
• Park CH
• Kim JW

• KMID: 2413817
• DOI: http://doi.org/10.3341/jkos.2018.59.6.543

Abstract

PURPOSE
To investigate the effects of valproic acid on the production of nitric oxide (NO) and expression of endothelial nitric oxide synthase (eNOS) in cultured human trabecular meshwork cells (HTMC).
METHODS
Primarily cultured HTMC were exposed to 0.25, 0.5, and 1.0 mM valproic acid for 6, 12, and 24 hours. Expression of eNOS mRNA was assessed with Reverse transcription-polymerase chain reaction, and production of NO was assessed with Griess assay. Cellular survival was assessed with the 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay.
RESULTS
Valproic acid at concentrations of 0.25, 0.5, 1.0 mM did not affect the cellular survival of HTMC significantly after exposure for 24 hours. Valproic acid increased NO production in a dose- and time-dependent manner. Also, valproic acid increased the degree of eNOS mRNA expression in a dose-dependent manner in HTMC.
CONCLUSIONS
Valproic acid increases production of NO and expression of eNOS mRNA in HTMC. Thus, valproic acid might increase aqueous outflow through the trabecular meshwork.

Keyword

Endothelial nitric oxide synthase (eNOS); Nitric oxide; Trabecular meshwork; Valproic acid

MeSH Terms

Humans
Nitric Oxide Synthase Type III
Nitric Oxide Synthase*
Nitric Oxide*
RNA, Messenger
Trabecular Meshwork*
Valproic Acid*
Nitric Oxide
Nitric Oxide Synthase
Nitric Oxide Synthase Type III
RNA, Messenger
Valproic Acid

Figure

• 

  Figure 1 Effects of valproic acid (VPA) on the survival of trabecular meshwork cells. VPA did not affect the survival significantly compared to non-exposed control (p>0.05).

• 

  Figure 2 Effects of valproic acid on the production of nitric oxide in trabecular meshwork cells after exposure for 6 hours. Valproic acid did not affect the production of nitric oxide significantly (p>0.005).

• 

  Figure 3 Effects of valproic acid on the production of nitric oxide in trabecular meshwork cells after exposure for 12 hours. Exposure to 0.5 and 1.0 mM valproic acid increased the production of nitric oxide significantly (*p<0.05).

• 

  Figure 4 Effects of valproic acid on the production of nitric oxide in trabecular meshwork cells after exposure for 24 hours. Exposure to 0.5 and 1.0 mM valproic acid increased the production of nitric oxide significantly (*p<0.05).

• 

  Figure 5 Expression of endothelial nitric oxide synthase (eNOS) mRNA after exposed to valproic acid (VPA) in trabecular meshwork cells. Exposure to 0.25, 0.5, 1.0 mM for 6, 12, 24 hours increased the degree of eNOS mRNA expression in a dose- and time-dependent manners. (A) After 6 hours. (B) After 12 hours. (C) After 24 hours of exposure. β-actin was used as internal standard.

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