Naloxone Postconditioning Alleviates Rat Myocardial Ischemia Reperfusion Injury by Inhibiting JNK Activity

Neohesperidin alleviated pathological damage and immunological imbalance in rat myocardial ischemia-reperfusion injury via inactivation of JNK and NF-κB p65

Neohesperidin (NEO) exerts antiviral, antioxidant, anti-inflammation, and antitumor effects in some diseases. The purpose of this study was to investigate the effect and mechanism of NEO on myocardial ischemia-reperfusion (I/R) injury. Results indicated that NEO suppressed the levels of serum inflammatory cytokines, myocardial damage markers, and oxidative stress markers, and increased the levels of antioxidant in myocardial I/R rats. NEO also inhibited cell apoptosis. Besides, NEO also inhibited the phosphorylation of c-Jun N-terminal kinases (JNK) and nuclear factor kappa B (NF-κB) p65. Furthermore, the protective effects of NEO on myocardial tissue damage, inflammatory cytokines, myocardial injury markers, oxidative stress markers, cell apoptosis, spleen, thymus and liver indices, and phagocytic indices were reversed by JNK activator and NF-κB activator, respectively. In conclusion, NEO alleviates myocardial damage, oxidative stress, cell apoptosis, and immunological imbalance in I/R injury via the inactivation of JNK and NF-κB, making NEO a potential agent for myocardial I/R therapy.

A review of myocardial ischaemia/reperfusion injury: Pathophysiology, experimental models, biomarkers, genetics and pharmacological treatment

Cardiovascular diseases are known to be the most fatal diseases worldwide. Ischaemia/reperfusion (I/R) injury is at the centre of the pathology of the most common cardiovascular diseases. According to the World Health Organization estimates, ischaemic heart disease is the leading global cause of death, causing more than 9 million deaths in 2016. After cardiovascular events, thrombolysis, percutaneous transluminal coronary angioplasty or coronary bypass surgery are applied as treatment. However, after restoring coronary blood flow, myocardial I/R injury may occur. It is known that this damage occurs due to many pathophysiological mechanisms, especially increasing reactive oxygen types. Besides causing cardiomyocyte death through multiple mechanisms, it may be an important reason for affecting other cell types such as platelets, fibroblasts, endothelial and smooth muscle cells and immune cells. Also, polymorphonuclear leukocytes are associated with myocardial I/R damage during reperfusion. This damage may be insufficient in patients with co-morbidity, as it is demonstrated that it can be prevented by various endogenous antioxidant systems. In this context, the resulting data suggest that optimal cardioprotection may require a combination of additional or synergistic multi-target treatments. In this review, we discussed the pathophysiology, experimental models, biomarkers, treatment and its relationship with genetics in myocardial I/R injury. SIGNIFICANCE OF THE STUDY: This review summarized current information on myocardial ischaemia/reperfusion injury (pathophysiology, experimental models, biomarkers, genetics and pharmacological therapy) for researchers and reveals guiding data for researchers, especially in the field of cardiovascular system and pharmacology.

Pharmacological postconditioning: a molecular aspect in ischemic injury

OBJECTIVE

Ischaemia/reperfusion (I/R) injury is defined as the damage to the tissue which is caused when blood supply returns to tissue after ischaemia. To protect the ischaemic tissue from irreversible injury, various protective agents have been studied but the benefits have not been clinically applicable due to monotargeting, low potency, late delivery or poor tolerability.

KEY FINDINGS

Strategies involving preconditioning or postconditioning can address the issues related to the failure of protective therapies. In principle, postconditioning (PoCo) is clinically more applicable in the conditions in which there is unannounced ischaemic event. Moreover, PoCo is an attractive beneficial strategy as it can be induced rapidly at the onset of reperfusion via series of brief I/R cycles following a major ischaemic event or it can be induced in a delayed manner. Various pharmacological postconditioning (pPoCo) mechanisms have been investigated systematically. Using different animal models, most of the studies on pPoCo have been carried out preclinically.

SUMMARY

However, there is a need for the optimization of the clinical protocols to quicken pPoCo clinical translation for future studies. This review summarizes the involvement of various receptors and signalling pathways in the protective mechanisms of pPoCo.

Prdx1 alleviates cardiomyocyte apoptosis through ROS-activated MAPK pathway during myocardial ischemia/reperfusion injury

Apoptosis induced by oxidative stress blocks the recovery of heart function in myocardial ischemia reperfusion injury (MIRI). Peroxiredoxin 1 (Prdx1) inhibits oxidative stress. However, the expression and function of Prdx1 in MIRI are unclear. In present study, Prdx1 protein level increased in rat MIRI model, associated with cardiomyocyte apoptosis. Cultured rat embryonic ventricular myocardial H9c2 cells with hypoxia/reoxygenation (H/R) treatment was utilized to mimic MIRI in vitro, showing that H/R treatment increased the ratio of p-p38/p38, p-JNK/JNK and apoptosis index. But Prdx1 ameliorate the up-regulation of p-p38/p38 ratio and p-JNK/JNK ratio, as well as decreased H9c2 cell apoptosis. SB203580 (p38 inhibitor) and SP600125 (JNK inhibitor) inhibited H9c2 cell apoptosis, and at the same time Prdx1 down-regulated the activation of p38 MAPK and JNK during H/R treatment. In addition, a ROS scavenger N-acetyl-l-cysteine (NAC) down-regulated the protein level of p-p38, p-JNK and Prdx1, and H9c2 cell apoptosis. In summary, these findings indicated that Prdx1 inhibited MAPK pathway induced cells apoptosis, and ROS is the upstream regulator of H/R induced apoptosis.

Protective effect of sevoflurane on myocardial ischemia-reperfusion injury in rat hearts and its impact on HIF-1α and caspase-3 expression

This study was designed to investigate possible protective effects of sevoflurane on myocardial ischemia-reperfusion injury (MIRI) and its impact on expression of HIF-1α and caspase-3 in rats, so as to provide new insights for the treatment of MIRI. Forty SD rats were randomly divided into four groups (n=10) including Sham operation (Sham), ischemia-reperfusion (IR), sevoflurane preconditioning group (Sevo-Pre) and sevoflurane post-conditioning (Sevo-Post) groups. Perfusion was performed using ex vivo heart perfusion. The baseline values of cardiac function were recorded in each group at the end of balanced perfusion and after 60 min of reperfusion. Myocardial infarct size (MIS) was calculated at the end of perfusion using TTC staining. Levels of HIF-1α and caspase-3 protein and HIF-1α (western blotting) and Bcl-2 mRNA (RT-qPCR) were detected at the end of reperfusion. Our results showed no significant differences in cardiac function between the groups at the end of the balanced perfusion. After reperfusion for 60 min, however, the cardiac functions of the Sevo-Pre and Sevo-Post groups were significantly better than those in the IR group, and the MIS at the end of reperfusion was significantly decreased. Western blotting and RT-qPCR showed that expression of HIF-1α protein was significantly increased, expression of caspase-3 protein was significantly decreased and expression of HIF-1α and Bcl-2 mRNA were significantly increased in Sevo-Pre and Sevo-Post groups compared with the levels in the IR group at the end of reperfusion. There were no significant differences in experimental results between Sevo-Pre and Sevo-Post groups. Our data support the idea that sevoflurane can improve MIRI in rats by improving cardiac function and reducing MIS. This protective effect seems to be achieved by activation of HIF-1α and inhibition of caspase-3.

Cardioprotective effects of Achillea wilhelmsii on the isolated rat heart in ischemia-reperfusion

Context

There are some reports about protective effects of Achillea on the heart.

Objective

We investigated the effect of Achillea wilhelmsii extract on cardiac function during ischemia–reperfusion (I/R) injury in the isolated rat heart.

Materials and methods

60 male Wistar rats were randomly divided into 6 groups; 1: Control group, 2: Control-ischemia (CI) 3: vitamin C (10 mg/kg), 4–6: Extract groups (E 100, E 200 and E 400 mg/kg). The animals received normal saline, vitamin C or A. wilhelmsii extract orally for 4 weeks. At the end of the treatment, the hearts were subjected to in vitro I/R Injury (20 min of global ischemia, followed by 40 min of reperfusion, Langendorff's mode). Heart rate (HR) and left ventricular pressure (LVP) were measured using a pressure transducer connected to a data acquisition system. Lactate dehydrogenase (LDH) and creatine kinase (CK) activities in the effluent were measured to determine the myocardial injury degree. The malondialdehyde (MDA), total thiol groups (-SH), superoxide anion dismutase (SOD) and catalase (CAT) in myocardial tissue were detected to determine the oxidative stress degree.

Results

Pretreatment with Achillea wilhlemsii significantly decreased the LDH, CK activities, and MDA level, while it increased the LVDP, ±dp/dt_max, rate-pressure product (RPP), SH groups, SOD and CAT activities, and also the coronary artery flow.

Discussion and conclusion

Our findings indicated that Achillea wilhelmsii could provide protection for heart against the I/R injury which may be related to the improvement of myocardial oxidative stress states.

NecroX-5 protects mitochondrial oxidative phosphorylation capacity and preserves PGC1α expression levels during hypoxia/reoxygenation injury

Although the antioxidant and cardioprotective effects of NecroX-5 on various in vitro and in vivo models have been demonstrated, the action of this compound on the mitochondrial oxidative phosphorylation system remains unclear. Here we verify the role of NecroX-5 in protecting mitochondrial oxidative phosphorylation capacity during hypoxia-reoxygenation (HR). Necrox-5 treatment (10 µM) and non-treatment were employed on isolated rat hearts during hypoxia/reoxygenation treatment using an ex vivo Langendorff system. Proteomic analysis was performed using liquid chromatography-mass spectrometry (LC-MS) and non-labeling peptide count protein quantification. Real-time PCR, western blot, citrate synthases and mitochondrial complex activity assays were then performed to assess heart function. Treatment with NecroX-5 during hypoxia significantly preserved electron transport chain proteins involved in oxidative phosphorylation and metabolic functions. NecroX-5 also improved mitochondrial complex I, II, and V function. Additionally, markedly higher peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC1α) expression levels were observed in NecroX-5-treated rat hearts. These novel results provide convincing evidence for the role of NecroX-5 in protecting mitochondrial oxidative phosphorylation capacity and in preserving PGC1α during cardiac HR injuries.

Endogenous opiates and behavior: 2014

This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants). This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants).

Sevoflurane post-conditioning reduces rat myocardial ischemia reperfusion injury through an increase in NOS and a decrease in phopshorylated NHE1 levels

The protective effects of sevoflurane post-conditioning against myocardial ischemia/reperfusion (I/R) injury (MIRI) have been previously reported. However, the mechanisms responsible for these protective effects remain elusive. In this study, in order to investigate the molecular mechanisms responsible for the protective effects of sevoflurane post-conditioning on isolated rat hearts subjected to MIRI, Sprague-Dawley rat hearts were randomly divided into the following 6 groups: i) the sham-operated control; ii) 2.5% sevoflurane; iii) ischemia/reperfusion (I/R); iv) 2.5% sevoflurane post-conditioning plus I/R; v) 2.5% sevoflurane post-conditioning + NG-nitro-L-arginine methyl ester (L-NAME) plus I/R; and vi) L-NAME plus I/R. The infarct size was measured using 2,3,5-triphenyl tetrazolium chloride (TTC) staining. Additionally, the myocardial nitric oxide (NO), NO synthase (NOS) and nicotinamide adenine dinucleotide (NAD⁺) levels were determined. Autophagosomes and apoptosomes in the myocardium were detected by transmission electron microscopy. The levels of Bcl-2, cleaved caspase-3, Beclin-1, microtubule-associated protein light chain 3 (LC3)-I/II, Na⁺/H⁺ exchanger 1 (NHE1) and phosphorylated NHE1 protein were measured by western blot analysis. NHE1 mRNA levels were measured by reverse transcription-quantitative polymerase chain reaction. Compared with the I/R group, 15 min of exposure to 2.5% sevoflurane during early reperfusion significantly decreased the myocardial infarct size, the autophagic vacuole numbers, the NHE1 mRNA and protein expression of cleaved caspase-3, Beclin-1 and LC3-I/II. Post-conditioning with 2.5% sevoflurane also increased the NO and NOS levels and Bcl-2 protein expression (P<0.05 or P<0.01). Notably, the cardioprotective effects of sevoflurane were partly abolished by the NOS inhibitor, L-NAME. The findings of the present study suggest that sevoflurane post-conditioning protects the myocardium against I/R injury and reduces the myocardial infarct size. The underlying protective mechanisms are associated with the inhibition of mitochondrial permeability transition pore opening, and with the attenuation of cardiomyoctye apoptosis and excessive autophagy. These effects are mediated through an increase in NOS and a decrease in phopshorylated NHE1 levels.

The effects of ischemic postconditioning on myocardial function and nitric oxide metabolites following ischemia-reperfusion in hyperthyroid rats

Ischemic postconditioning (IPost) could decrease ischemia-reperfusion (IR) injury. It has not yet reported whether IPost is useful when ischemic heart disease is accompanied with co-morbidities like hyperthyroidism. The aim of this study was to examine the effect of IPost on myocardial IR injury in hyperthyroid male rats. Hyperthyroidism was induced with administration of thyroxine in drinking water (12 mg/L) over a period of 21 days. After thoracotomy, the hearts of control and hyperthyroid rats were perfused in the Langendorff apparatus and subjected to 30 minutes global ischemia, followed by 120 minutes reperfusion; IPost, intermittent early reperfusion, was induced instantly following ischemia. In control rats, IPost significantly improved the left ventricular developed pressure (LVDP) and ±dp/dt during reperfusion (p<0.05); however it had no effect in hyperthyroid rats. In addition, hyperthyroidism significantly increased basal NO_x (nitrate+nitrite) content in serum (125.5±5.4 µmol/L vs. 102.8±3.7 µmol/L; p< 0.05) and heart (34.9±4.1 µmol/L vs. 19.9±1.94 µmol/L; p<0.05). In hyperthyroid groups, heart NO_x concentration significantly increased after IR and IPost, whereas in the control groups, heart NO_x were significantly higher after IR and lower after IPost (p< 0.05). IPost reduced infarct size (p<0.05) only in control groups. In hyperthyroid group subjected to IPost, aminoguanidine, an inducible nitric oxide (NO) inhibitor, significantly reduced both the infarct size and heart NO_x concentrations. In conclusion, unlike normal rats, IPost cycles following reperfusion does not provide cardioprotection against IR injury in hyperthyroid rats; an effect that may be due to NO overproduction because it is restored by iNOS inhibition.

Preventive Effect of Polysaccharide of Larimichthys crocea Swim Bladder on Reserpine Induced Gastric Ulcer in ICR Mice

This project's aim was to determine the reserpine-induced gastric ulcer preventive effect of polysaccharide of Larimichthys crocea swim bladder (PLCSB) in ICR mice. The anti-gastric ulcer effects of polysaccharide of Larimichthys crocea swim bladder was evaluated in mice model using morphological test, serum levels assay, cytokine levels assay, tissue contents analysis, reverse transcription-polymerase chain reaction (RT-PCR) analysis and western bolt assay. High concentration (50 mg/kg dose) of PLCSB reduced IFN-γ as compared to low concentration (25 mg/kg dose) and control mice. SS and VIP serum levels of PLCSB treated mice were higher than those of control mice, and MOT and SP serum levels were lower than control mice. Gastric ulcer inhibitory index of PLCSB treatment groups mice were much lower than control mice, and the high concentration treated mice were similar to the ranitidine treated mice. The SOD and GSH-Px activities of PLCSB treated mice were higher than control mice, close to normal mice and ranitidine treated mice. PLCSB treated mice also showed the similar contents of NO and MDA to normal group. By RT-PCR and western blot assay, PLCSB significantly induced inflammation in tissues of mice by downregulating NF-κB, iNOS, and COX-2, and upregulating IκB-α. These results suggest that PLCSB showed a good gastric ulcer preventive effect as the gastric ulcer drug of ranitidine. Polysaccharide of Larimichthys crocea swim bladder may be used as a drug material from marine products.

Cardioprotective Effect of the Aqueous Extract of Lavender Flower against Myocardial Ischemia/Reperfusion Injury

This study was conducted to evaluate the cardioprotective property of the aqueous extract of lavender flower (LFAE). The myocardial ischemia/reperfusion (I/R) injury of rat was prepared by Langendorff retrograde perfusion technology. The heart was preperfused with K-H solution containing LFAE for 10 min before 20 minutes global ischemia, and then the reperfusion with K-H solution was conducted for 45 min. The left ventricular developed pressure (LVDP) and the maximum up/downrate of left ventricular pressure (±dp/dtmax) were recorded by physiological recorder as the myocardial function and the myocardial infarct size was detected by TTC staining. Lactate dehydrogenase (LDH) and creatine kinase (CK) activities in the effluent were measured to determine the myocardial injury degree. The superoxide anion dismutase (SOD) and malondialdehyde (MDA) in myocardial tissue were detected to determine the oxidative stress degree. The results showed that the pretreatment with LFAE significantly decreased the myocardial infarct size and also decreased the LDH, CK activities, and MDA level, while it increased the LVDP, ±dp/dtmax, SOD activities, and the coronary artery flow. Our findings indicated that LFAE could provide protection for heart against the I/R injury which may be related to the improvement of myocardial oxidative stress states.