Mechanisms of cinnamic aldehyde against myocardial ischemia/hypoxia injury in vivo and in vitro: Involvement of regulating PI3K/AKT signaling pathway.

To investigate the protection of cinnamic aldehyde (CA) against myocardial ischemia/hypoxia (I/H) injury and its potential mechanisms in vivo and in vitro. Mice were pretreated with CA for 7 days, and then isoproterenol (85 mg/kg) was administered for 2 consecutive days to assess its cardioprotection. Furthermore, an in vitro myocardial I/H model was established by administering CoCl2 (600 µM) to H9c2 cells for 24 h. H9c2 cells were pretreated with CA for 12 h to assess its protection. We observed that CA improved electrocardiogram and histopathological changes and decreased creatine kinase and lactate dehydrogenase activities and oxidative stress levels. The TUNEL results showed that CA reduced the degree of apoptosis. Furthermore, CA could lead to a down-regulation of the Caspase-3 and Bax protein expressions, but an up-regulation of the Bcl-2 protein expressions. Importantly, CA increased p-PI3K and p-AKT protein expressions, indicating the activation of the PI3K/AKT signaling pathway. Moreover, treatment with CA improved the cell viability rate and mitochondrial membrane potential while markedly decreasing apoptosis and oxidative stress levels in vitro. Our results suggested that CA exerts cardioprotection on myocardial I/H injury, which possibly occurred in connection with inhibition of oxidative stress and apoptosis via activation of the PI3K/AKT signaling pathway.

Differential toxicity of abrin in human cell lines of different organ origin.

Abrus precatorius is a highly toxic seed containing the poison abrin. Similar in properties to ricin, this toxin binds to ribosomes causing cessation of protein synthesis and cell death. With an estimated human lethal dose of 0.1-1 µg/kg, it has been the cause of fatalities due to accidental and intentional ingestion. In present study, we profiled seven human cell lines of different organ origin, for their sensitivity against abrin toxicity. These cell lines are, A549, COLO 205, HEK 293, HeLa, Hep G2, Jurkat, SH-SY5Y and derived from lung, intestine, kidney, cervix, liver, immune and nervous system respectively. MTT, NR, CVDE and LDH assays have been used to determine their response against abrin toxin. Among these cell lines A549 was the most sensitive cell line while Hep G2 was found least sensitive cell lines. Hep G2 cells are shown to have mitochondrial resistance and delayed generation of oxidative stress compared to A549 cells. Remarkable variation in sensitivity against abrin toxicity prompted the evaluation of Bcl2, Bax and downstream caspases in both cells. Difference in Bcl2 level has been shown to play important role in variable sensitivity. Findings of present study are helpful for selection of suitable cellular model for toxicity assessment and antidote screening.

Impact of metal nanoparticles on the structure and function of metabolic enzymes.

The widespread use of nanoparticles raises many serious concerns about the safety and environmental impact of nanoparticles. Therefore, risk assessments of specific nanoparticles in occupational and environmental exposure are essential before their large-scale production and applications, especially in medicine and for usage in household items. In this study, the effects of five different metal nanoparticles on the structure, stability, and function of four metabolic enzymes were evaluated using various biophysical techniques. Our results show that Cu nanoparticles exhibited the most significant adverse effects on the structures, stability, and activities of all the metabolic enzymes. Zn nanoparticles caused moderate adverse effects on these enzymes. The rest of the metal (Al, Fe, and Ni) nanoparticles had a relatively lower impact on the metabolic enzymes. Our data indicated that Cu nanoparticles promote metal-catalyzed disulfide bond formation in these proteins. In summary, some metal nanoparticles can cause adverse effects on the structure, function, and stability of metabolic enzymes. In addition, metal nanoparticles may affect protein homeostasis in the cytosol or extracellular fluids.

Protective effects of chitosan and chitosan oligosaccharide against oxidative damage in liver tissue of rats with fluorine poisoning.

Fluorine toxicity has negative effects on soft tissue besides skeletal and dental tissues. In the present study, we have investigated the protective effect of chitosan (CS) and chitosan oligosaccharide (COS) on liver tissue of fluorine-intoxicated rats taking the antioxidant characteristics of chitosan and its derivatives into consideration. In this study, 42 male Wistar albino rats were randomly selected to determine the control and experimental fluorosis groups. Our study lasted for 12 weeks. As a consequence of the study, MDA significantly increased in the liver tissue of NaF group while some antioxidant values significantly decreased. It was detected that serum AST and LDH levels increased significantly while ALB and TP values significantly decreased in NaF group. The degenerations were identified in the liver histopathology of all fluoride-treated groups. We have concluded according to the results that chitosan oligosaccharide can be more effective compared with chitosan.

Protective effect of 5,6,7,8-trtrahydroxyflavone against acute hypobaric hypoxia induced-oxidative stress in mice.

Severe oxidative stress triggered by acute hypobaric hypoxia (AHH) is harmful for lots of organs in body, especial brain and heart. Flavonoids with antioxidant properties can protect organs from oxidative stress. Our previous study found that 5,6,7,8-trtrahydroxyflavone (5,6,7,8-THF), a flavones with four consecutive hydrogen group on ring A, showed excellent antioxidant properties in vitro. In the present study, the protective of 5,6,7,8-THF against oxidative stress caused by AHH was investigated. Mice were administered with 5,6,7,8-THF(500mg/kg) for 5 consecutive days before HH exposure. The heart rate (HR) and blood pressure (BP) was measured. The activity of SOD, CAT, GSH-Px, LDH, Na+-K+-ATPase and Ca2+-Mg2+-ATPase and the content of H2O2, MDA, LD and ATP in brain and heart tissue was evaluated using commercial kit. AHH led to a significant increase in HR and decrease in BP. Pretreatment of 5,6,7,8-THF could reversed these changes. In addition, administration of 5,6,7,8-THF could significantly increase the activity of SOD, CAT and GSH-Px and decrease the content of H2O2 and MDA in the brain and heart of mice under AHH. Furthermore, 5,6,7,8-THF inhibited the activity of LDH, decreased the level of LD and improved ATPase activity. These results indicate that 5,6,7,8-THF may protect the mice against AHH injury via scavenging free radical, inhibiting lipid peroxidation, enhancing antioxidant enzyme activity, preserving energy metabolism and can be further explored as an excellent anti-hypoxia agent for preventing acute mountain sickness.

Cardioprotective effect of boswellic acids against doxorubicin induced myocardial infarction in rats.

The aim of the present study was to evaluate the cardioprotective activity of boswellic acids in doxorubicin (DOX) induced cardiotoxicity. DOX (2.5mg/kg) was used intraperitoneally in rats to induce cardiotoxicity in six divided doses every alternate day over a period of two weeks. Dexrazoxane (10:1) was used as a standard drug. Boswellic acids (250, 500 and 750 mg/kg) were orally administered to rats for 14 days. After 14 days, rats were sacrificed, and blood was withdrawn through cardiac puncture. The blood lipid profile and cardiac biomarkers including LDH, CK-MB, CPK, SGOT and troponin T were measured. The heart of rats was isolated for histopathological studies. Graphpad Prism was used for statistical analysis. There was a significant increase in the level of cardiac enzymes and complete lipid profile parameters in diseased group as compared to control group. Pre-treatment with boswellic acids decreased level of all the measured parameters and decreased the severity of myocardial damage as supported by histopathological studies. It was concluded that boswellic acids possess cardioprotective potential by lowering cardiac biomarkers and blood lipid profile. Thus, boswellic acids might act as cardioprotective agent against doxorubicin induced cardiotoxicity.

An inhibitory and beneficial effect of chlorpromazine and promethazine (C + P) on hyperglycolysis through HIF-1α regulation in ischemic stroke.

BACKGROUND: After ischemic stroke, the increased catabolism of glucose (hyperglycolysis) results in the production of reactive oxygen species (ROS) via nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX). A depressive or hibernation-like effect of C + P on brain activity was reported to induce neuroprotection. The current study assesses the effect of C + P on hyperglycolysis and NOX activation. METHODS: Adult male Sprague-Dawley rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) followed by 6 or 24 h of reperfusion. At the onset of reperfusion, rats received C + P with or without temperature control, or phloretin [glucose transporter (GLUT)-1 inhibitor], or cytochalasin B (GLUT-3 inhibitor). We detected brain ROS, apoptotic cell death, and ATP levels along with HIF-1α expression. Cerebral hyperglycolysis was measured by glucose, protein expression of GLUT-1/3, and phosphofructokinase-1 (PFK-1), as well as lactate and lactate dehydrogenase (LDH) at 6 and 24 h of reperfusion. The enzymatic activity of NOX and protein expression of its subunits (gp91phox) were detected. Neural SHSY5Y cells were placed under 2 h of oxygen-glucose deprivation (OGD) followed by reoxygenation for 6 and 24 h with C + P treatment. Cell viability and protein levels of HIF-1α, GLUT-1/3, PFK-1, LDH, and gp91phox were measured. A HIF-1α overexpression vector was transfected into the cells, and then protein levels of HIF-1α, GLUT-1/3, PFK-1, and LDH were quantitated. In sham-operated rats and control cells, the protein levels of HIF-1α, GLUT-1/3, PFK-1, LDH, and gp91phox were measured at 6 and 24 h after C + P administration. RESULTS: C + P reduced the protein elevations after stroke in HIF-1α, glycolytic enzymes, as well as in ROS, cell death, glucose and lactate, but raised ATP levels in the brain. In ischemic rats exposed to GLUT-1/3 inhibitors, ROS, cell death, glucose, and lactate were all decreased, as well as GLUT-1, GLUT-3, LDH, and PFK-1 protein levels. C + P decreased ischemia-induced NOX activation by reducing the enzymatic activity and protein expression of the NOX subunit gp91phox, as was observed in the presence of GLUT-1/3 inhibitors. These markers were significantly decreased following C + P administration with the induced hypothermia, while C + P administration with temperature control at 37 °C induced lesser protection after ischemia stroke. In the OGD/reoxygenation model, C + P treatment increased cell viability and diminished protein levels of HIF-1α, GLUT-1, GLUT-3, PFK-1, LDH, and gp91phox. However, in OGD with HIF-1α overexpression, C + P was unable to effectively reduce the upregulated GLUT-1, GLUT-3, and LDH. In normal conditions, C + P reduced HIF-1α and the levels of key glycolytic enzymes depending on its pharmacological effect. CONCLUSION: C + P, partially depending on hypothermia, attenuates hyperglycolysis and NOX activation through HIF-1α regulation.

Effects of Co-Ingestion of ß-Hydroxy-ß-Methylbutyrate and L-Arginine α-Ketoglutarate on Jump Performance in Young Track and Field Athletes.

The aim of the study was to determine the effect of simultaneous supplementation of ß-hydroxy-ß-methylbutyrate and L-Arginine α-ketoglutarate on lower limb power and muscle damage in medium distance runners aged 15.3 (±0.9) years old. METHODS: The study group consisted of 40 volunteers aged 14-17 years practicing medium distance running for at least two years. The study lasted 12 days and followed a randomized, double-blind, placebo-controlled, parallel design. All subjects attended a familiarization session on day 0 before the test. The subjects were randomly divided into two groups: supplements and placebo group. The same training cycle protocol was used in both groups during the 12-day training period. Morning warm-up involved 10 min jogging at 60-75% of maximal heart rate and countermovement jump height measurement. Main training units were carried out for both groups with the same volume. Training load assessment (the daily session Rating of Perceived Exertion (s-RPE) method) method takes into consideration the intensity and the duration of the training session to calculate the "training load" (TL). RESULTS: At the end of the training cycle, a significant (p = 0.002) decrease in the countermovement jump (CMJ) height was found in the placebo group when compared to the baseline. In the supplement group, there was no decrease in the countermovement jump height. Creatine kinase and lactate dehydrogenase concentration increased during the training days similarly in both groups and decreased on rest days. There were no differences between groups in enzymes concentration. The research results indicate that the supplement combination used in the supplements group prevented a reduction in the CMJ values. In contrast to the supplements group, in the placebo group, the CMJ changes were statistically significant: a noticeable (p = 0.002) decrease in CMJ was noted between the baseline measurement and the 6th measurement. The well-being of the subjects from both groups changed significantly during the training period, and the intergroup differences in the mood level were similar and not statistically significant. CONCLUSIONS: The results of this study indicate that the daily co-supplementation with calcium salt of ß-hydroxy-ß-methylbutyrate (7.5 g) and L-Arginine α-ketoglutarate (10 g) during training might help to prevent decline in jump performance. No influence on muscle damage markers or mood was shown.

Neurotrophic Factors Secreted by Induced Pluripotent Stem Cell-Derived Retinal Progenitors Promote Retinal Survival and Preservation in an Adult Porcine Neuroretina Model.

Purpose: Paracrine factors released by pluripotent stem cells have shown great potential as therapeutic agents in regenerative medicine. The purpose of this study was to characterize trophic factor secretion of retinal progenitor cells (RPCs) derived from human induced pluripotent stem cells (iPSCs) and to assess its impact on retinal survival ex vivo. Methods: RPCs were generated from human 3D1 iPSCs following previously established protocols with modifications. Conditioned medium (CM) was harvested from iPSC-derived retinal progenitors and analyzed for trophic factor composition through multiplex enzyme-linked immunosorbent assay. Retina-preserving capability of the collected CM was examined using a degenerative porcine neuroretina model. Viability of the CM-treated retina explants was evaluated using the resazurin-based PrestoBlue reagent, whereas the lactate dehydrogenase (LDH) assay was used to assess retinal cytotoxicity. Retina explants were also analyzed morphologically through immunohistochemistry for glial cell activation and apoptosis. Results: We have successfully generated and characterized iPSC-derived RPCs that secreted an array of neuroprotective factors, including osteopontin, hepatocyte growth factor, stromal cell-derived factor 1, and insulin-like growth factor-1. Retina explants cultured in CM derived from iPSC-RPCs (iPSC-RPC-CM) showed better preservation of the retinal microarchitecture and fewer terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)+ nuclei, and reduced reactive gliosis. Furthermore, we saw a reduction in extracellular LDH levels in CM-treated retina explants, which also exhibited higher metabolic activity than the untreated controls. Conclusions: iPSC-derived RPCs secrete many trophic factors that have been shown to promote neuroprotection, tissue repair, and regeneration in the retina. Overall, we have demonstrated the neuroprotective effects of iPSC-RPC-CM through a degenerative neuroretina model ex vivo.

Recognition of Potential COVID-19 Drug Treatments through the Study of Existing Protein-Drug and Protein-Protein Structures: An Analysis of Kinetically Active Residues.

We report the results of our in silico study of approved drugs as potential treatments for COVID-19. The study is based on the analysis of normal modes of proteins. The drugs studied include chloroquine, ivermectin, remdesivir, sofosbuvir, boceprevir, and α-difluoromethylornithine (DMFO). We applied the tools we developed and standard tools used in the structural biology community. Our results indicate that small molecules selectively bind to stable, kinetically active residues and residues adjoining them on the surface of proteins and inside protein pockets, and that some prefer hydrophobic sites over other active sites. Our approach is not restricted to viruses and can facilitate rational drug design, as well as improve our understanding of molecular interactions, in general.

Luteolin protects microglia against rotenone-induced toxicity in a hormetic manner through targeting oxidative stress response, genes associated with Parkinson's disease and inflammatory pathways.

Rotenone, an environmental toxin, triggers Parkinson's disease (PD)-like pathology through microglia-mediated neuronal death. The effects and molecular mechanisms of flavonoid luteolin against rotenone-induced toxicity was assessed in microglial BV2 cells. Cells were pretreated with luteolin (1-50 µM) for 12 h and then was co-treated with 20 µM of rotenone for an additional 12 h in the presence of luteolin. The viability (MTT), IL-1ß and TNF-α levels and lactate dehydrogenase (LDH) release (ELISA), and Park2, Lrrk2, Pink1, Nrf2 and Trx1 mRNA levels (qRT-PCR) were measured. In rotenone exposed microglia, luteolin increased viability significantly at lower concentrations (1-5 µM) compared to higher concentrations (25-50 µM). Rotenone increased LDH release and IL-1ß levels in a dose-dependent manner (1-20 µM). Luteolin inhibited rotenone-induced LDH release, however the activity decreased in concentration-dependent manner Neither rotenone nor luteolin altered TNF-α levels, but luteolin reduced IL-1ß levels in a concentration dependent manner in rotenone exposed cells. The mRNA levels of Nrf2 and Trx1, which are the master regulators of redox state, were increased by rotenone, as well as by luteolin, which exhibited an inverse relationship between its concentration and effect (1-20 µM). Park2 mRNA levels increased by luteolin, but decreased by rotenone. Pink1 mRNA levels was not altered by rotenone or luteolin. Lrrk2 mRNA levels reduced by luteolin, while it was increased by rotenone. Results suggest that luteolin have favorable effects on regulation of oxidative stress response, genes associated with PD and inflammatory pathways, hence protects microglia against rotenone toxicity in a hormetic manner.

The effects of chronic oxytocin administration on body weight and food intake in DHT-induced PCOS model rats.

Polycystic ovary syndrome (PCOS) is commonly associated with metabolic disorders, which are exacerbated by obesity. Recent studies have revealed that oxytocin contributes to metabolic, appetite, and body weight regulation. In the present study, we evaluated the effects of chronic administration of oxytocin on body weight, food intake, and fat mass in a dihydrotestosterone-induced rat model of PCOS. Body weight, body weight change, and relative cumulative food intake were significantly lower in the oxytocin-treated PCOS rats than in the vehicle-treated control PCOS rats. Similarly, visceral adipocyte size was significantly smaller in the oxytocin-treated PCOS rats than in the vehicle-treated control PCOS rats. On the other hand, the numbers of cystic follicles in the ovary did not differ between the two groups. The chronic administration of oxytocin did not affect the rats' serum aspartate aminotransferase, alanine aminotransferase, or lactate dehydrogenase levels, indicating that it does not have adverse effects on hepatic function. These findings suggest that oxytocin could be a candidate drug for preventing the onset of obesity-related metabolic disorders in PCOS patients.

Local and systemic effects caused by Crotalus durissus terrificus, Crotalus durissus collilineatus, and Crotalus durissus cascavella snake venoms in swiss mice.

INTRODUCTION: Crotalus envenomations cause serious complications and can be fatal without appropriate treatment. Venom isoforms present and inter/intraspecific variations in the venom composition can result in different symptoms presented by bites by snakes from the same species but from different geographical regions. We comparatively evaluated the local and systemic effects caused by Crotalus durissus terrificus (Cdt), C.d. collilineatus (Cdcolli), and C.d. cascavella (Cdcasc) envenomation. METHODS: Venom chromatography was performed. Proteolytic, phospholipase, and LAAO activities were analyzed. Edema, myotoxicity, hepatotoxicity, nephrotoxicity, and coagulation alterations were evaluated. RESULTS: The venom SDS-PAGE analyses found the presence of convulxin, gyroxin, crotoxin, and crotamine in Cdt and Cdcolli venoms. Crotamine was not present in the Cdcasc venom. Cdt, Cdcollli, and Cdcasc venoms had no proteolytic activity. Only Cdcasc and Cdt venoms had phospholipase activity. LAAO activity was observed in Cdcolli and Cdcasc venoms. Cdcolli and Cdcasc venoms caused 36.7% and 13.3% edema increases, respectively. Cdt venom caused a 10% edema induction compared to those by other venoms. All venoms increased TOTAL-CK, MB-CK, and LDH levels (indicating muscle injury) and ALT, AST, GGT, and ALP levels (markers of liver damage) and were able to induce a neuromuscular blockade. Urea and creatinine levels were also altered in both plasma and urine, indicating kidney damage. Only Cdcolli and Cdcasc venoms increased TAPP and TAP. CONCLUSIONS: Together, these results allow us to draw a distinction between local and systemic effects caused by Crotalus subspecies, highlighting the clinical and biochemical effects produced by their respective venoms.

Local and systemic effects caused by Crotalus durissus terrificus, Crotalus durissus collilineatus, and Crotalus durissus cascavella snake venoms in swiss mice

Abstract INTRODUCTION: Crotalus envenomations cause serious complications and can be fatal without appropriate treatment. Venom isoforms present and inter/intraspecific variations in the venom composition can result in different symptoms presented by bites by snakes from the same species but from different geographical regions. We comparatively evaluated the local and systemic effects caused by Crotalus durissus terrificus (Cdt), C.d. collilineatus (Cdcolli), and C.d. cascavella (Cdcasc) envenomation. METHODS: Venom chromatography was performed. Proteolytic, phospholipase, and LAAO activities were analyzed. Edema, myotoxicity, hepatotoxicity, nephrotoxicity, and coagulation alterations were evaluated. RESULTS: The venom SDS-PAGE analyses found the presence of convulxin, gyroxin, crotoxin, and crotamine in Cdt and Cdcolli venoms. Crotamine was not present in the Cdcasc venom. Cdt, Cdcollli, and Cdcasc venoms had no proteolytic activity. Only Cdcasc and Cdt venoms had phospholipase activity. LAAO activity was observed in Cdcolli and Cdcasc venoms. Cdcolli and Cdcasc venoms caused 36.7% and 13.3% edema increases, respectively. Cdt venom caused a 10% edema induction compared to those by other venoms. All venoms increased TOTAL-CK, MB-CK, and LDH levels (indicating muscle injury) and ALT, AST, GGT, and ALP levels (markers of liver damage) and were able to induce a neuromuscular blockade. Urea and creatinine levels were also altered in both plasma and urine, indicating kidney damage. Only Cdcolli and Cdcasc venoms increased TAPP and TAP. CONCLUSIONS: Together, these results allow us to draw a distinction between local and systemic effects caused by Crotalus subspecies, highlighting the clinical and biochemical effects produced by their respective venoms.

Alprostadil attenuates myocardial ischemia/reperfusion injury by promoting antioxidant activity and eNOS activation in rats

Abstract Purpose: To investigate the effect of alprostadil on myocardial ischemia/reperfusion (I/R) in rats. Methods: Rats were subjected to myocardial ischemia for 30 min followed by 24h reperfusion. Alprostadil (4 or 8 μg/kg) was intravenously administered at the time of reperfusion and myocardial infarct size, levels of troponin T, and the activity of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) in the serum were measured. Antioxidative parameters, nitric oxide (NO) content and phosphorylated endothelial nitric oxide synthase 3 (p-eNOS) expression in the left ventricles were also measured. Histopathological examinations of the left ventricles were also performed. Results: Alprostadil treatment significantly reduced myocardial infarct size, serum troponin T levels, and CK-MB and LDH activity (P<0.05). Furthermore, treatment with alprostadil significantly decreased malondialdehyde (MDA) content (P<0.05) and markedly reduced myonecrosis, edema and infiltration of inflammatory cells. Superoxide dismutase and catalase activities (P<0.05), NO level (P<0.01) and p-eNOS (P<0.05) were significantly increased in rats treated with alprostadil compared with control rats. Conclusion: These results indicate that alprostadil protects against myocardial I/R injury and that these protective effects are achieved, at least in part, via the promotion of antioxidant activity and activation of eNOS.

3H-1,2-dithiole-3-thione protects PC12 cells against amyloid beta 1-42 (Aß1-42) induced apoptosis via activation of the ERK1/2 pathway.

AIMS: Increasing evidence displays that deposition of aggregated ß-amyloid (Aß) leads to neuronal cell apoptosis, thus aggravates the pathological progression of Alzheimer's disease (AD). 3H-1,2-dithiole-3-thione (D3T) has been proved to exert neuroprotective effects. However, the effect of D3T on protecting against Aß-induced apoptosis and the underlying mechanism are unknown. MAIN METHODS: MTT, DCFH-DA assay, LDH release assay, Fluo-3 AM assay, Flow cytometry and Western blot were used to examine cell viability, ROS level, LDH release, intracellular Ca2+ concentration, cell apoptosis and related proteins level respectively. KEY FINDINGS: In the present study, we found that D3T pretreatment significantly increased cell viability and decreased reactive oxygen species (ROS) levels, lactate dehydrogenase (LDH) levels and the intracellular calcium concentration of rat pheochromocytoma (PC12) cells after Aß1-42 exposure. In addition, D3T pretreatment inhibited Aß1-42 induced cell apoptosis as well as protein levels of Bax and Caspase-3 in PC12 cells. Further, D3T markedly activated extracellular regulated protein kinase 1/2 (p-ERK1/2) but not PI3K/Akt signaling. Moreover, the protective effect of D3T against Aß1-42 induced apoptosis was abolished by the ERK1/2 pathway inhibitor PD98059 while PI3K inhibitor LY294002 had no significant effect. SIGNIFICANCE: Taken together, these findings suggest that D3T protects PC12 cells against Aß1-42 induced apoptosis through activation of the ERK1/2 pathway.

Total flavones of Rhododendron simsii Planch flower protect isolated rat heart from ischaemia-reperfusion injury and its mechanism of UTR-RhoA-ROCK pathway inhibition.

OBJECTIVES: Total flavones of Rhododendron simsii Planch flower (TFR) are an effective part extracted from the flower. The present study was designed to investigate the protective effect of TFR in isolated rat heart following global ischaemia-reperfusion and the possible underlying mechanisms. METHODS: Langendorff perfusion apparatus was used to perfuse isolated rat heart which was subjected to global ischaemia-reperfusion. The hemodynamic parameters were continuously monitored. Coronary flow as well as lactate dehydrogenase (LDH), creatine phosphokinase-MB (CK-MB) and cardiac troponin I (cTnI) in coronary effluents was measured. RhoA activity and urotensin receptor (UTR) and Rho-related coiled-coil-forming protein kinase (ROCK) protein expressions in rat myocardium were examined, respectively. Cardiac dysfunction was indicated by the alterations of hemodynamic parameters and the reduced coronary flow. KEY FINDINGS: Total flavones of Rhododendron simsii Planch flower significantly improved ischaemia-reperfusion-induced cardiac dysfunction and leakages of LDH, CK-MB and cTnI, and inhibited myocardial ischaemia-reperfusion-increased RhoA activity and UTR, ROCK1 and ROCK2 protein expressions. The improvement of TFR in the cardiac dysfunction and the leakage of LDH, CK-MB and cTnI were markedly attenuated under the UTR blockade and ROCK inhibition. TFR-inhibited RhoA activity was decreased under the UTR blockade. CONCLUSIONS: Total flavones of Rhododendron simsii Planch flower had a protective effect on ischaemia-reperfusion injury in isolated rat heart, which may be attributed to the blocking of UTR and subsequent inhibition of the RhoA-ROCK pathway.

Effect of Caffeine on Serum Tumour Necrosis Factor Alpha and Lactate Dehydrogenase in Wistar Rats Exposed to Cerebral Ischaemia-reperfusion Injury.

Caffeine is known to confer neuro-protection via A1 and A2A adenosine receptor antagonism in which adenosine neuro-modulates excitotoxic release of glutamate. Currently, it is unclear whether caffeine modulates inflammation in ischaemic stroke model. The present study examined effects of caffeine following ischaemia-reperfusion injury on neuro-inflammatory tumour necrosis alpha (TNF-α), lactate dehydrogenase (LDH), as well as effect of caffeine against brain ischaemic damage on histology. Thirty three adult male Wistar rats (180-300 g) were used in this study. They were randomly divided into four groups (n=5 each): Group I (Control) that received neither the operation nor any treatment; Group II (Sham/Water) received a pseudo-ischaemic-reperfusion and 1ml water for injection; Group III (BCCO/Water) that received complete bilateral common carotid occlusion (BCCO) and 1ml water for injection; Group IV (BCCO/Caffeine) that received complete BCCO and caffeine solution intraperitoneally at a dose of 50% LD50 value (144mg/kg); and thirteen rats were used for LD50 assessment. Sensory and motor functions significantly (p<0.05) decreased in the rat following ischaemia-reperfusion injury when compared to pre-injury state on Garcia neurological score. Caffeine reduced brain ischaemic injury and significantly reduced (p<0.05) TNF-α activity. While no significant effects (p>0.05) of caffeine was observed on LDH activity. This study has shown neuro-protective roles of caffeine against ischaemia-reperfusion damage to brain tissue, inflammatory TNF-α activity, but not on LDH activity.

Alprostadil attenuates myocardial ischemia/reperfusion injury by promoting antioxidant activity and eNOS activation in rats.

PURPOSE: To investigate the effect of alprostadil on myocardial ischemia/reperfusion (I/R) in rats. METHODS: Rats were subjected to myocardial ischemia for 30 min followed by 24h reperfusion. Alprostadil (4 or 8 µg/kg) was intravenously administered at the time of reperfusion and myocardial infarct size, levels of troponin T, and the activity of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) in the serum were measured. Antioxidative parameters, nitric oxide (NO) content and phosphorylated endothelial nitric oxide synthase 3 (p-eNOS) expression in the left ventricles were also measured. Histopathological examinations of the left ventricles were also performed. RESULTS: Alprostadil treatment significantly reduced myocardial infarct size, serum troponin T levels, and CK-MB and LDH activity (P<0.05). Furthermore, treatment with alprostadil significantly decreased malondialdehyde (MDA) content (P<0.05) and markedly reduced myonecrosis, edema and infiltration of inflammatory cells. Superoxide dismutase and catalase activities (P<0.05), NO level (P<0.01) and p-eNOS (P<0.05) were significantly increased in rats treated with alprostadil compared with control rats. CONCLUSION: These results indicate that alprostadil protects against myocardial I/R injury and that these protective effects are achieved, at least in part, via the promotion of antioxidant activity and activation of eNOS.

Silver nanoparticles increase connexin43-mediated gap junctional intercellular communication in HaCaT cells through activation of reactive oxygen species and mitogen-activated protein kinase signal pathway.

Silver nanoparticles (AgNPs) are widely used in health and consumer products that routinely contact skin. However, the biological effects and possible mechanisms of AgNPs on skin remain unclear. Gap junctional intercellular communication (GJIC) plays a critical role in multicellular organisms to maintain tissue homeostasis. The aim of this study is to examine if non-coated AgNPs affect GJIC in human keratinocytes (HaCaT cells), and to identify the possible molecular mechanisms responsible for the effects. GJIC, connexin (Cx)43 protein and mRNA expression, and the effect of siRNA-mediated knockdown of Cx43 on GJIC were assessed. HaCaT cells exposed to non-coated AgNPs at different doses after a 24 hour exposure. To explore further the underlying mechanism, reactive oxygen species and mitogen-activated protein kinase pathway were evaluated after 2, 6, 12 and 24 hours. Our results revealed that non-coated AgNP exposure at subcytotoxic doses increase GJIC partially via Cx43 upregulation. Reactive oxygen species and extracellular signal-regulated kinase and activation of c-Jun N-terminal kinase were involved in the AgNP-induced upregulation of Cx43. This study provides new insight into the potential mechanism of AgNP biological activity.