Virgin rice bran oil alleviates hypertension through the upregulation of eNOS and reduction of oxidative stress and inflammation in L-NAME-induced hypertensive rats

Gulladawan Jan-On; Weerapon Sangartit; Poungrat Pakdeechote; Veerapol Kukongviriyapan; Jintana Sattayasai; Ketmanee Senaphan; Upa Kukongviriyapan

doi:10.1016/j.nut.2019.110575

Virgin rice bran oil alleviates hypertension through the upregulation of eNOS and reduction of oxidative stress and inflammation in L-NAME-induced hypertensive rats

Nutrition. 2020 Jan:69:110575. doi: 10.1016/j.nut.2019.110575. Epub 2019 Aug 26.

Authors

Gulladawan Jan-On¹, Weerapon Sangartit¹, Poungrat Pakdeechote¹, Veerapol Kukongviriyapan², Jintana Sattayasai², Ketmanee Senaphan³, Upa Kukongviriyapan⁴

Affiliations

¹ Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Cardiovascular Research Group, Khon Kaen University, Khon Kaen, Thailand.
² Department of Pharmacology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
³ Division of Physiology, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, Thailand.
⁴ Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Cardiovascular Research Group, Khon Kaen University, Khon Kaen, Thailand. Electronic address: Upa_ku@kku.ac.th.

PMID: 31585258
DOI: 10.1016/j.nut.2019.110575

Abstract

Objective: Endothelial dysfunction associated with reduction in nitric oxide (NO) bioavailability plays an important role in development of hypertension. Consumption of a diet rich in antioxidants appears to lower the risk for hypertension. Virgin rice bran oil (VRBO) possesses antioxidant, anti-inflammatory, and hypocholesterolemic activities. However, to our knowledge, the antihypertensive effect of VRBO has not been investigated. The aim of this study was to examine the antihypertensive effect of VRBO in N^ω-nitro-l-arginine methyl ester (L-NAME)-induced hypertensive rats and its underlying mechanisms.

Methods: Hypertension was induced in rats by administration of L-NAME, after which VRBO, lisinopril (Lis), or VRBO + Lis was administered. Studies were then conducted on the hemodynamics of vascular responses to vasoactive substances, plasma angiotensin-converting enzyme (ACE), plasma nitrate/nitrite, oxidative stress, and inflammatory markers.

Results: L-NAME administration induced hemodynamic changes including elevation of blood pressure, increased peripheral vascular resistance, and endothelial dysfunction. Reduction in plasma nitrate/nitrite, overproduction of vascular superoxide, and increases in plasma ACE, malondialdehyde, protein carbonyl, and plasma tumor necrosis factor-α were observed in L-NAME hypertensive rats. The changes were associated with a marked decrease in endothelial NO synthase expression, increased expression of gp91^phoxand vascular cell adhesion molecule-1, and activation of nuclear factor-κB in aortic tissues. Administration of either VRBO or Lis significantly mitigated all of these deleterious effects. The combination of VRBO and Lis was more effective than either treatment alone.

Conclusions: The antihypertensive effect of VRBO may be mediated by restoration of hemodynamics, increased NO bioavailability, and alleviation of oxidative stress and inflammation. VRBO has an additive effect on antihypertensive medication.

Keywords: Endothelial dysfunction; Hypertension; Inflammation; Oxidative stress; Virgin rice bran oil.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Antihypertensive Agents / pharmacology*
Antioxidants / pharmacology*
Disease Models, Animal
Hypertension / chemically induced
Hypertension / drug therapy*
Inflammation
Male
NG-Nitroarginine Methyl Ester
Nitric Oxide Synthase Type III / metabolism
Oxidation-Reduction / drug effects
Oxidative Stress / drug effects*
Rats
Rats, Sprague-Dawley
Rice Bran Oil / pharmacology*
Up-Regulation / drug effects

Substances

Antihypertensive Agents
Antioxidants
Nitric Oxide Synthase Type III
Rice Bran Oil
NG-Nitroarginine Methyl Ester