Copaiba oil improves pulmonary nitric oxide bioavailability in monocrotaline-treated rats.

Oxidative stress is involved in increased pulmonary vascular resistance (PVR) and right ventricular (RV) hypertrophy, characteristics of pulmonary arterial hypertension (PAH). Copaiba oil, an antioxidant compound, could attenuate PAH damage. This study's aim was to determine the effects of copaiba oil on lung oxidative stress, PVR, and mean pulmonary arterial pressure (mPAP) in the monocrotaline (MCT) model of PAH. Male Wistar rats (170 g, n = 7/group) were divided into four groups: control, MCT, copaiba oil, and MCT + copaiba oil (MCT-O). PAH was induced by MCT (60 mg/kg i.p.) and, after 1 week, the treatment with copaiba oil (400 mg/kg/day gavage) was started for 14 days. Echocardiographic and hemodynamic measurements were performed. RV was collected for morphometric evaluations and lungs and the pulmonary artery were used for biochemical analysis. Copaiba oil significantly reduced RV hypertrophy, PVR, mPAP, and antioxidant enzyme activities in the MCT-O group. Moreover, increased nitric oxide synthase and decreased NADPH oxidase activities were observed in the MCT-O group. In conclusion, copaiba oil was able to improve the balance between nitric oxide and reactive oxygen species in lungs and the pulmonary artery and to reduce PVR, which could explain a decrease in RV hypertrophy in this PAH model.

Bucindolol Modulates Cardiac Remodeling by Attenuating Oxidative Stress in H9c2 Cardiac Cells Exposed to Norepinephrine.

The increased circulation of norepinephrine, found in the diseased heart as a result of sympathetic nervous system overactivation, is responsible for its cardiotoxic effects including pathological hypertrophy, cell death, and oxidative stress. Bucindolol is a third generation adrenergic blocker, which acts on the ß1 and ß2 receptors, and has additional α1 antagonist activity. Thus, the aim of this study was to investigate the action of bucindolol on oxidative stress, hypertrophy, cell survival, and cell death signaling pathways in H9c2 cardiac cells exposed to norepinephrine. H9c2 cells were incubated with 10 µM norepinephrine for 24 h in the presence or absence of bucindolol (10 µM) treatment for 8 h. Western blot was used to determine the expression of proteins for hypertrophy/survival and death signaling pathways. Flow cytometry was used to assess cell death via caspase-3/7 activity and propidium iodide and reactive oxygen species via measuring the fluorescence of CM-H2DCFDA. Norepinephrine exposure resulted in an increase in oxidative stress as well as cell death. This was accompanied by an increased protein expression of LC3B-II/I. The protein kinase B/mammalian target of the rapamycin (Akt/mTOR) pathway which is involved in cardiac remodeling process was activated in response to norepinephrine and was mitigated by bucindolol. In conclusion, bucindolol was able to modulate cardiac remodeling which is mediated by oxidative stress.

Decreased PGC1- α levels and increased apoptotic protein signaling are associated with the maladaptive cardiac hypertrophy in hyperthyroidism.

Hyperthyroidism can lead to the activation of proteins which are associated with inflammation, apoptosis, hypertrophy, and heart failure. This study aimed to explore the inflammatory and apoptotic proteins involved in the hyperthyroidism-induced cardiac hypertrophy establishment. Male Wistar rats were divided into control and hyperthyroid (12 mg/L L-thyroxine, in drinking water for 28 days) groups. The expression of inflammatory and apoptotic signaling proteins was quantified in the left ventricle by Western blot. Hyperthyroidism was confirmed by evaluation of T3 and T4 levels, as well as cardiac hypertrophy development. There was no change in the expression of HSP70, HIF1-α, TNF-α, MyD88, p-NFκB, NFκB, p-p38, and p38. Reduced expression of p53 and PGC1-α was associated with increased TLR4 and decreased IL-10 expression. Decreased Bcl-2 expression and increased Bax/Bcl-2 ratio were also observed. The results suggest that reduced PGC1-α and IL-10, and elevated TLR4 proteins expression could be involved with the diminished mitochondrial biogenesis and anti-inflammatory response, as well as cell death signaling, in the establishment of hyperthyroidism-induced maladaptive cardiac hypertrophy.

Copaiba Oil Attenuates Right Ventricular Remodeling by Decreasing Myocardial Apoptotic Signaling in Monocrotaline-Induced Rats.

There is an increase in oxidative stress and apoptosis signaling during the transition from hypertrophy to right ventricular (RV) failure caused by pulmonary arterial hypertension (PAH) induced by monocrotaline (MCT). In this study, it was evaluated the action of copaiba oil on the modulation of proteins involved in RV apoptosis signaling in rats with PAH. Male Wistar rats (±170 g, n = 7/group) were divided into 4 groups: control, MCT, copaiba oil, and MCT + copaiba oil. PAH was induced by MCT (60 mg/kg intraperitoneally) and, 7 days later, treatment with copaiba oil (400 mg/kg by gavage) was given for 14 days. Echocardiographic and hemodynamic measurements were performed, and the RV was collected for morphometric evaluations, oxidative stress, apoptosis, and cell survival signaling, and eNOS protein expression. Copaiba oil reduced RV hypertrophy (24%), improved RV systolic function, and reduced RV end-diastolic pressure, increased total sulfhydryl levels and eNOS protein expression, reduced lipid and protein oxidation, and the expression of proteins involved in apoptosis signaling in the RV of MCT + copaiba oil as compared to MCT group. In conclusion, copaiba oil reduced oxidative stress, and apoptosis signaling in RV of rats with PAH, which may be associated with an improvement in cardiac function caused by this compound.

Long-term T3 and T4 treatment as an alternative to aerobic exercise training in improving cardiac function post-myocardial infarction.

Here we aimed to compare the beneficial effects of T3 and T4 hormone treatment to those provided by aerobic exercise training in Wistar rats post-myocardial infarction (MI). Rats in one group were SHAM-operated and in the other group were subjected to MI surgery. One week after surgery, the MI group animals either received T3 and T4 hormones by gavage or underwent a low intensity aerobic exercise training protocol on a treadmill, and both treatments lasted until 10 weeks after MI. Untreated SHAM-operated and MI groups were also followed for the same duration. The cardiac function was assessed by echocardiography and catheterization, followed by blood collection (to measure T3, T4, and TSH hormones), and euthanasia. The lung, liver, heart, and tibia were collected (to assess hypertrophy and congestion indices). The left ventricle homogenate (without a scar) was used for the analyses of calcium handling proteins. Results showed that enhanced cardiac function was promoted by both interventions, with infarct size reduction, increased ejection fraction, and diastolic posterior wall thickness, but no alterations in heart rate, cardiac output, or T3, T4, and TSH levels. There was a positive force-frequency relationship accompanied by increased α-MHC, as well as decreased HSP70 protein expression. In conclusion, the effects of T3 and T4 hormone treatments were similar, and in some parameters superior, to those provided by the aerobic exercise training. Thus, lower doses of thyroid hormones could be more suitable as a coadjuvant treatment after MI, as a plausible alternative for patients who are intolerant to aerobic exercise training.