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Son, Park, and Kim: Effect of Valproic Acid on Nitric Oxide and Nitric Oxide Synthase in Trabecular Meshwork Cell
Original Article

Journal of the Korean Ophthalmological Society 2018; 59(6): 543-548.

Published online: 15 June 2018

DOI: https://doi.org/10.3341/jkos.2018.59.6.543

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

Myung Seo Son, MD1, Cheul Ho Park, MD2, Jae Woo Kim, MD, PhD1

1Department of Ophthalmology, Catholic University of Daegu School of Medicine, Daegu, Korea.

2Hyundai Eye Clinic, Kumi, Korea.

Address reprint requests to Jae Woo Kim, MD, PhD. Department of Ophthalmology, Daegu Catholic University School of Medicine, #33 Duryugongwon-ro 17-gil, Nam-gu, Daegu 42472, Korea. Tel: 82-53-650-4728, Fax: 82-53-627-0133, jwkim@cu.ac.kr

Received 6 July 2017       Revised 16 August 2017       Accepted 31 May 2018

©2018 The Korean Ophthalmological Society

The Korean Ophthalmological Society

(open-access):

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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.

Keywords: Endothelial nitric oxide synthase (eNOS), Nitric oxide, Trabecular meshwork, Valproic acid

Figures and Tables

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).

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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).

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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).

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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).

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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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Notes

This work was supported by the grant of purpose of donation, department of Ophthalmology, Daegu Catholic University School of Medicine.

Conflicts of Interest The authors have no conflicts to disclose.

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