scholarly journals Estrogen Replacement Reduces Oxidative Stress in the Rostral Ventrolateral Medulla of Ovariectomized Rats

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Fan Hao ◽  
Ying Gu ◽  
Xing Tan ◽  
Yu Deng ◽  
Zhao-Tang Wu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Protein Expression ◽  
Rostral Ventrolateral Medulla ◽  
Sympathetic Tone ◽  
Ovariectomized Rats ◽  
Ventrolateral Medulla ◽  
Sympathetic Outflow ◽  
Protective Effects ◽  
Estrogen Replacement ◽  
Ovx Rats

Cardiovascular disease prevalence rises rapidly after menopause, which is believed to be derived from the loss of estrogen. It is reported that sympathetic tone is increased in postmenopause. The high level of oxidative stress in the rostral ventrolateral medulla (RVLM) contributes to increased sympathetic outflow. The focus of this study was to determine if estrogen replacement reduces oxidative stress in the RVLM and sympathetic outflow in the ovariectomized (OVX) rats. The data of this study showed that OVX rat increased oxidative stress in the RVLM and sympathetic tone; estrogen replacement improved cardiovascular functions but also reduced the level of oxidative stress in the RVLM. These findings suggest that estrogen replacement decreases blood pressure and sympathoexcitation in the OVX rats, which may be associated with suppression in oxidative stress in the RVLM through downregulation of protein expression of NADPHase (NOX4) and upregulation of protein expression of SOD1. The data from this study is beneficial for our understanding of the mechanism of estrogen exerting cardiovascular protective effects on postmenopause.

scholarly journals The Cardiovascular Effect of Systemic Homocysteine Is Associated with Oxidative Stress in the Rostral Ventrolateral Medulla

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Mei-Fang Zhong ◽  
Yu-Hong Zhao ◽  
Hua Xu ◽  
Xing Tan ◽  
Yang-Kai Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Protein Expression ◽  
Significant Risk ◽  
Significant Risk Factor ◽  
Current Data ◽  
Rostral Ventrolateral Medulla ◽  
Sympathetic Tone ◽  
Ventrolateral Medulla ◽  
Vehicle Group ◽  
Renal Sympathetic Nerve Activity

It has been demonstrated that homocysteine (HCY) is a significant risk factor of hypertension, which is characterized by overactivity of sympathetic tone. Excessive oxidative stress in the rostral ventrolateral medulla (RVLM), a key region for control of sympathetic outflow, contributes to sympathetic hyperactivity in hypertension. Therefore, the goal of the present study is to determine the effect of systemic HCY on production of reactive oxygen species (ROS) in the RVLM. In the rat model of the diet-induced hyperhomocysteinemia (L-methionine, 1 g/kg/day, 8 weeks), we found that the HCY resulted in a significant increase (≈3.7-fold, P<0.05) in ROS production in the RVLM, which was paralleled with enhanced sympathetic tone and blood pressure (BP). Compared to the vehicle group, levels of BP and basal renal sympathetic nerve activity in the HCY group were significantly (P<0.05, n=5) increased by an average of 27 mmHg and 31%, respectively. Furthermore, the rats treated with L-methionine (1 g/kg/day, 8 weeks) showed an upregulation of NADPHase (NOX4) protein expression and a downregulation of superoxide dismutase protein expression in the RVLM. The current data suggest that central oxidative stress induced by systemic HCY plays an important role in hypertension-associated sympathetic overactivity.

scholarly journals Protective Effects of Tualang Honey against Oxidative Stress and Anxiety-Like Behaviour in Stressed Ovariectomized Rats

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Badriya Al-Rahbi ◽  
Rahimah Zakaria ◽  
Zahiruddin Othman ◽  
Asma’ Hassan ◽  
Asma Hayati Ahmad
Keyword(s):  
Oxidative Stress ◽  
Protein Carbonyl ◽  
Ovariectomized Rats ◽  
Protective Effects ◽  
Ovx Rats ◽  
Anxiolytic Agent ◽  
Glutathione S Transferases ◽  
Brain Oxidative Stress ◽  
The Brain ◽  
Tualang Honey

The present study aims to evaluate the antioxidant and anxiolytic-like effect of Tualang honey in stressed ovariectomized (OVX) rats. The animals were divided into; (i) nonstressed sham-operated control rats, (ii) sham-operated control rats exposed to stress, (iii) nonstressed OVX rats, (iv) OVX rats exposed to stress, (v) OVX rats exposed to stress and treated with 17 β-oestradiol (E2) (20 μg daily, sc), and (vi) OVX rats exposed to stress and treated with Tualang honey (0.2 g/kg body weight, orally). The open field test was used to evaluate the anxiety-like behaviour and ELISA kits were used to measure oxidant/antioxidant status of the brain homogenates. The result showed that anxiety-like behavior was significantly increased in stressed OVX compared to other groups, and administering either E2 or Tualang honey significantly decreased anxiety-like behaviour in stressed OVX rats. The levels of malondialdehyde (MDA) and protein carbonyl (PCO) were significantly decreased while the levels/activities of superoxide dismutase (SOD), glutathione S-transferases (GST), glutathione peroxidase (GPx), and glutathione reductase (GR) were significantly increased in the brain homogenates of treated stressed OVX groups compared to untreated stressed OVX. In conclusion, Tualang honey has protective effects against brain oxidative stress and may be useful alternative anxiolytic agent especially for postmenopausal women.

Protective Effects of Ginsenosides on 17α-Ethynyelstradiol-Induced Intrahepatic Cholestasis via Anti-Oxidative and Anti-Inflammatory Mechanisms in Rats

2017 ◽  
Vol 45 (08) ◽  
pp. 1613-1629 ◽  
Author(s):  
Yan-Jiao Xu ◽  
Zao-Qin Yu ◽  
Cheng-Liang Zhang ◽  
Xi-Ping Li ◽  
Cheng-Yang Feng ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Alkaline Phosphatase ◽  
Superoxide Dismutase ◽  
Protein Expression ◽  
Intrahepatic Cholestasis ◽  
Serum Levels ◽  
Total Bile Acid ◽  
Protective Effects ◽  
Sod Activity ◽  
Mda Content

The present study was designed to assess the effects and potential mechanisms of ginsenosides on 17[Formula: see text]-ethynyelstradiol (EE)-induced intrahepatic cholestasis (IC). Ginsenoside at doses of 30, 100, 300[Formula: see text]mg/kg body weight was intragastrically (i.g.) given to rats for 5 days to examine the effect on EE-induced IC. Serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and total bile acid (TBA) were measured. Hepatic malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were determined. Protein expression of proinflammatory cytokines TNF-[Formula: see text], IL-6 and IL-1[Formula: see text] was analyzed by immunohistochemistry and Western blot. Results indicated that ginsenosides remarkably prevented EE-induced increase in the serum levels of AST, ALT, ALP and TBA. Moreover, the elevation of hepatic MDA content induced by EE was significantly reduced, while hepatic SOD activities were significantly increased when treated with ginsenosides. Histopathology of the liver tissue showed that pathological injuries were relieved after treatment with ginsenosides. In addition, treatment with ginsenosides could significantly downregulate the protein expression of TNF-[Formula: see text], IL-6 and IL-1[Formula: see text] compared with EE group. These findings indicate that ginsenosides exert the hepatoprotective effect on EE-induced intrahepatic cholestasis in rats, and this protection might be attributed to the attenuation of oxidative stress and inflammation.

scholarly journals Hypertension in Patients with Neurovascular Compression Is Associated with Increased Central Sympathetic Outflow

2002 ◽  
Vol 13 (1) ◽  
pp. 35-41
Author(s):  
Hans P. Schobel ◽  
Helga Frank ◽  
Ramin Naraghi ◽  
Helmut Geiger ◽  
Elmar Titz ◽  
...  
Keyword(s):  
Essential Hypertension ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Cold Pressor Test ◽  
Rostral Ventrolateral Medulla ◽  
Ventrolateral Medulla ◽  
Neurovascular Compression ◽  
Sympathetic Outflow ◽  
Nerve Activity ◽  
Central Sympathetic Outflow

ABSTRACT. Recent data suggest a causal relationship between essential hypertension and neurovascular compression (NVC) at the rostral ventrolateral medulla. An increase of central sympathetic outflow might be an underlying pathomechanism. The sympathetic nerve activity to muscle was recorded in 21 patients with hypertension with NVC (NVC+ group) and in 12 patients with hypertension without NVC (NVC− group). Heart rate variability, respiratory activity, BP, and central venous pressure at rest and during unloading of cardiopulmonary baroreceptors with lower-body negative pressure and during a cold pressor test were also measured. Resting sympathetic nerve activity to muscle was twice as high in the NVC+ group compared with the NVC− group (34 ± 22 versus 18 ± 6 bursts/min; P < 0.05). Resting heart rate (P = 0.06) and low- to high-frequency power ratio values (P = NS) (as indicators of cardiac sympathovagal balance) tended to be augmented as well in the NVC+ group. The sympathetic nerve activity to muscle response to the cold pressor test was increased in the NVC+ group versus the NVC− group (+15 ± 11 versus 6 ± 12 bursts/min; P = 0.05), but hemodynamic and sympathetic nerve responses to lower-body negative pressure did not differ between the two groups. It is concluded that NVC of the rostral ventrolateral medulla in patients with essential hypertension is accompanied by increased central sympathetic outflow. Therefore, these data support the hypothesis described in the literature: in a subgroup of patients, essential hypertension might be causally related to NVC of the rostral ventrolateral medulla, at least in part, via an increase in central sympathetic outflow.

scholarly journals Overexpression of Central ACE2 (Angiotensin-Converting Enzyme 2) Attenuates the Pressor Response to Chronic Central Infusion of Ang II (Angiotensin II)

Hypertension ◽  
2020 ◽  
Vol 76 (5) ◽  
pp. 1514-1525
Author(s):  
Anyun Ma ◽  
Lie Gao ◽  
Ahmed M. Wafi ◽  
Li Yu ◽  
Tara Rudebush ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Angiotensin Converting Enzyme ◽  
Pressor Response ◽  
Rostral Ventrolateral Medulla ◽  
Ventrolateral Medulla ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
Intracerebroventricular Infusion

We investigated the mechanism by which ACE2 (angiotensin-converting enzyme 2) overexpression alters neurohumoral outflow and central oxidative stress. Nrf2 (nuclear factor [erythroid-derived 2]-like 2) is a master antioxidant transcription factor that regulates cytoprotective and antioxidant genes. We hypothesized that upregulation of central ACE2 inhibits the pressor response to Ang II (angiotensin II) by reducing reactive oxygen species through a Nrf2/antioxidant enzyme–mediated mechanism in the rostral ventrolateral medulla. Synapsin human Angiotensin Converting Enzyme 2 positive (SynhACE2 +/+ ) mice and their littermate controls synhACE2 −/− were used to evaluate the consequence of intracerebroventricular infusion of Ang II. In control mice, Ang II infusion evoked a significant increase in blood pressure and norepinephrine excretion, along with polydipsia and polyuria. The pressor effect of central Ang II was completely blocked in synhACE2 +/+ mice. Polydipsia, norepinephrine excretion, and markers of oxidative stress in response to central Ang II were also reduced in synhACE2 +/+ mice. The MasR (Mas receptor) agonist Ang 1–7 and blocker A779 had no effects on blood pressure. synhACE2 +/+ mice showed enhanced expression of Nrf2 in the rostral ventrolateral medulla which was blunted following Ang II infusion. Ang II evoked nuclear translocation of Nrf2 in cultured Neuro 2A (N2A) cells. In synhACE2 −/− mice, the central Ang II pressor response was attenuated by simultaneous intracerebroventricular infusion of the Nrf2 activator sulforaphane; blood pressure was enhanced by knockdown of Nrf2 in the rostral ventrolateral medulla in Nrf2 floxed (Nrf2 f/f ) mice. These data suggest that the hypertensive effects of intracerebroventricular Ang II are attenuated by selective overexpression of brain synhACE2 and may be mediated by Nrf2-upregulated antioxidant enzymes in the rostral ventrolateral medulla.

scholarly journals Valsartan Reduces Left Ventricular Hypertrophy in Ovariectomized Spontaneous Hypertensive Rats

2020 ◽  
Vol 33 (4) ◽  
pp. 371-371
Author(s):  
Hong Ding ◽  
Ning-ying Li ◽  
Xiang Zhang ◽  
Pan-pan Zhang ◽  
Jing Yu
Keyword(s):  
Oxidative Stress ◽  
Wall Thickness ◽  
Interventricular Septum ◽  
Posterior Wall ◽  
Left Ventricular ◽  
Ovariectomized Rats ◽  
Control Group ◽  
Hypertensive Rats ◽  
Sham Control ◽  
Ovx Rats

Abstract Objective To investigate the effects of valsartan on left ventricular mass, function, and oxidative stress in ovariectomized spontaneous hypertensive rats (SHR). Methods Twelve-week-old female SHRs were randomly divided into ovariectomy (OVX) control (n = 12), OVX + valsartan (n = 12), sham control (Sham, n = 13), and Sham + valsartan (n = 14) groups. Valsartan (30 mg/kg/day) or double-distilled water was given by oral gavage. After 12 weeks of valsartan or water treatment, left ventricular wall thickness and function, superoxide dismutase (SOD), glutathione peroxidase (GSH), and 8-hydroxydeoxyguanosine (8-OHdG) were assessed. Results There was a significant interaction between ovariectomy and valsartan on interventricular end-diastolic septum thickness (IVSTd), end-systolic interventricular septum thickness (IVSTs), left ventricular end-diastolic posterior wall thickness (LVPWTd), and left ventricular end diastolic diameter (LVEDD) (P &lt; 0.05). Valsartan treatment in OVX rats decreased IVSTd, IVSTs, LVPWTd, and LVPWTs compared to OVX control (P &lt; 0.05). Compared with Sham + control group, LVESP and ±dP/dt of LV were decreased while LVEDP was increased in OVX + control group (all P &lt; 0.05). After valsartan treatment, LVESP and ±dP/dt of LV were increased and LVEDP was decreased in ovariectomized rats (all P &lt; 0.05). Ovariectomy decreased GSH and SOD levels and increased 8-OHdG levels, which were reversed by valsartan treatment (all P &lt; 0.05). Conclusion Valsartan treatment decreases oxidative stress, reduces LV hypertrophy, and improves cardiac function in overiectomized SHR.

scholarly journals Dehydroepiandrosterone Prevents H2O2-Induced BRL-3A Cell Oxidative Damage through Activation of PI3K/Akt Pathways rather than MAPK Pathways

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Longlong Li ◽  
Yao Yao ◽  
Zhihao Jiang ◽  
Jinlong Zhao ◽  
Ji Cao ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Protein Expression ◽  
Signaling Pathways ◽  
Hormone Receptors ◽  
Mapk Signaling ◽  
Ros Generation ◽  
Protective Effects ◽  
Pi3k Inhibitor Ly294002 ◽  
Beneficial Effects

Dehydroepiandrosterone (DHEA) is a popular dietary supplement that has well-known benefits in animals and humans, but there is not enough information about the mechanisms underlying its effects. The present study aimed at investigating these mechanisms through in vitro experiments on the effects of DHEA on rat liver BRL-3A cells exposed to oxidative stress through H2O2. The findings showed that DHEA increased the antioxidant enzyme activity, decreased ROS generation, and inhibited apoptosis in H2O2-treated cells. These effects of DHEA were not observed when the cells were pretreated with known antagonists of sex hormones (Trilostane, Flutamide, or Fulvestrant). Furthermore, treatment with estradiol and testosterone did not have the same protective effects as DHEA. Thus, the beneficial effects of DHEA were associated with mechanisms that were independent of steroid hormone pathways. With regard to the mechanism underlying the antiapoptotic effect of DHEA, pretreatment with DHEA was found to induce a significant decrease in the protein expression of Bax and caspase-3 and a significant increase in the protein expression of PI3K and p-Akt in H2O2-treated BRL-3A cells. These effects of DHEA were abolished when the cells were pretreated with the PI3K inhibitor LY294002. No changes were observed on the p-ERK1/2, p-p38, and p-JNK protein levels in H2O2-induced BRL-3A cells pretreated with DHEA. In conclusion, our data demonstrate that DHEA protects BRL-3A cells against H2O2-induced oxidative stress and apoptosis through mechanisms that do not involve its biotransformation into steroid hormones or the activation of sex hormone receptors. Importantly, the protective effect of DHEA on BRL-3A cells was mainly associated with PI3K/Akt signaling pathways, rather than MAPK signaling pathways.

Effects of resistance training and estrogen replacement on adipose tissue inflammation in ovariectomized rats

2017 ◽  
Vol 42 (6) ◽  
pp. 605-612 ◽  
Author(s):  
Maria Fernanda Cury Rodrigues ◽  
Fabiano Candido Ferreira ◽  
Natália Santanielo Silva-Magosso ◽  
Marina Rodrigues Barbosa ◽  
Markus Vinicius Campos Souza ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Resistance Training ◽  
Ovariectomized Rats ◽  
Low Grade ◽  
Estrogen Replacement ◽  
Expression Levels ◽  
Inflammatory Status ◽  
Ovx Rats ◽  
Tnf Α ◽  
Gene And Protein Expression

Estrogen deficiency is directly related to central obesity and low-grade inflammation. Hormonal replacement and exercise training are both able to decrease fat accumulation and inflammation in postmenopausal women. However, the efficiency of resistance training (RT) and estrogen replacement (ER) in minimizing adiposity and inflammation in the visceral adipose tissue (VAT) of ovariectomized (OVX) rats has not yet been elucidated. In this study, Sprague–Dawley rats were divided into the following 6 groups: sham-operated sedentary (Sham-Sed), OVX-Sed, Sham-RT, OVX-RT, OVX-Sed-ER, and OVX-RT-ER groups. ER was performed by implanting silastic capsules containing 17β-estradiol. For RT, the animals were required to climb a 1.1-m vertical ladder with conical flasks containing weights attached to their tails for 12 weeks. Histological analyses were used to evaluate morphological changes. Gene expression levels were determined by quantitative real-time reverse transcriptase polymerase chain reaction, and protein concentrations were determined using Multiplex/Luminex assays. Ovariectomy increased the body mass (BM), adipocyte area, and inflammation in the VAT, the latter of which was indicated by reduced interleukin-10 (48%) and increased tumor necrosis factor (TNF)-α concentration (∼3%). RT efficiently decreased BM, adipocyte area, and inflammation in the OVX groups. The combination of RT and ER decreased BM (19%) and the TNF-α concentration (18%) and increased the gene and protein expression levels of adiponectin (173% and 18%). These results indicate that RT and the combination of RT and ER are efficient strategies for reducing the BM and improving the inflammatory status of OVX rats.

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