Hyperbaric oxygenation modulates vascular reactivity to angiotensin-(1-7) in diabetic rats: Potential role of epoxyeicosatrienoic acids

Abstract

Previously, a facilitating effect of hyperbaric oxygenation (HBO₂) on aortic ring responses to angiotensin-(1-7) in healthy rats was reported, with epoxyeicosatrienoic acids (EETs) possibly playing an important role. The aim of this study was to assess whether HBO₂ exerts similar effects in diabetic rats and to further explore the role of specific cytochrome P450 (CYP) enzymes in changes induced by HBO₂. Aortic relaxation to angiotensin-(1-7) was significantly higher in HBO₂ diabetic rats compared to control diabetic rats, while HBO₂ had no effect on angiotensin II contraction. N-methylsulphonyl-6-(2-propargyloxyphenyl/hexanamide inhibited the facilitation of angiotensin-(1-7) responses in HBO₂ rats, suggesting an important role of EETs in this modulation. mRNA expression of CYP2J3 and protein expression of CYP2C11 were significantly upregulated in HBO₂ diabetic rats, whereas CYP4A1, CYP4A2 and CYP4A3 mRNA and CYP2J3 protein expression was similar between groups. Mean arterial pressure, ferric reducing ability of plasma and Thiobarbituric Acid Reactive Substances levels and serum angiotensin-(1-7) concentrations were not significantly changed.

Hyperbaric oxygenation and 20‐hydroxyeicosatetreanoic acid inhibition reduce stroke volume in female diabetic Sprague–Dawley rats

“…Throughout 15 min, 100% oxygen pressure was increased to 2 ATA (2 atmospheres, 2 bars), and animals were treated for 2 h. Decompression was also done over 15 min (Kibel et al . ). The second HBO 2 in group (iii) was performed according to the same protocol, 12 h later (Zhang, ).…”

“…After surgery, animals were put into a hermetically closed hyperbaric chamber (Đuro Đaković Holding d.d., Slavonski Brod, Croatia). Throughout 15 min, 100% oxygen pressure was increased to 2 ATA (2 atmospheres, 2 bars), and animals were treated for 2 h. Decompression was also done over 15 min (Kibel et al 2015). The second HBO 2 in group (iii) was performed according to the same protocol, 12 h later (Zhang, 2007).…”

“…Other metabolites of arachidonic acid, such as epoxyeicosatrienoic acids (EETs), have the potential to alleviate the impairment of tissue perfusion and detrimental outcome of stroke (Kibel et al . ; Zuloaga et al . ).…”

“…The inhibitors of 20-HETE, such as N-hydroxy-N -(4-butyl-2methylphenyl)-formamidine (HET0016), reduce stroke volume and improve neurological outcome after stroke in animal models (Renic et al 2009;Crago et al 2011). Other metabolites of arachidonic acid, such as epoxyeicosatrienoic acids (EETs), have the potential to alleviate the impairment of tissue perfusion and detrimental outcome of stroke (Kibel et al 2015;Zuloaga et al 2015).…”

Reduced Dietary Selenium Impairs Vascular Function by Increasing Oxidative Stress in Sprague-Dawley Rat Aortas

“…The aortic ring experiments were done according to the protocol already described in our laboratory [32]. Short segments from each end of the isolated aorta were severed and discarded, whereas the rest of the vessel was cut into rings (of about 3–4 mm in length).…”