Concomitant administration of resveratrol and resistance training ameliorates acrylamide-induced spatial learning impairment in rats.

Objective: The present study examined effects of resistance training (RT) and resveratrol (RES) alone and together on acrylamide (AC)-induced memory impairment in rats. Materials and Methods: Animals were divided into 6 groups: (1) Control group which received normal saline intraperitoneally (ip) daily for 8 weeks; (2) Scopolamine (SCO) group which received SCO (1 mg/kg/day, ip) for 8 weeks; (3) AC group which received AC (5 mg/kg/day, ip) for 8 weeks; (4) AC + RT group which received AC (5 mg/kg/day, ip) for 8 weeks and performed RT (5 days a week for 8 weeks); (5) AC + RES group which received AC (5 mg/kg/day, ip) and RES (1 mg/kg/day, ip) for 8 weeks; and (6) AC + RT + RES group which received AC (5 mg/kg/day, ip) and RES (1 mg/kg/day, ip) for 8 weeks and performed RT (5 days a week for 8 weeks). On day 53, animal training began in the Morris Water Maze (MWM) and 24 hr after the last training, the probe test was performed. Results: RT and RES alone did not significantly affect escape latency or traveled distance increased by AC. However, concomitant RES and RT treatment significantly reduced these parameters compared to the AC group. Co-treatment with RES and RT also significantly increased the time spent in the target quadrant compared to the AC group. Lipid peroxidation was reduced in the AC+RES and AC+RT+RES groups compared to the AC group. Conclusion: It seems that daily co-treatment with RES and RT for 8 weeks ameliorates the memory-impairing effects of AC.

Hesperidin neuroprotective effects against carbon monoxide-induced toxicity in male rats.

Carbon monoxide (CO) is produced via incomplete combustion of fossil fuels and it may cause long-term neurological sequel upon exposure. Hesperidin (HES), a flavanone glycoside found in citrus plants, exerts diverse beneficial health effects. The present study mechanistically examined the neuroprotective effects of HES in CO-poisoned rats. Thirty male Wistar rats (five groups of six animals) were exposed to 3000 ppm CO for 1 h. Immediately after the exposure and on the next 4 consecutive days (totally five doses), rats intraperitoneally received either normal saline (the control group) or different doses of HES (25, 50, and 100 mg/kg). A sham group that was not exposed to CO was also considered. After evaluation of spatial learning and memory using a Morris water maze (MWM), animals were sacrificed and oxidative stress status in blood samples, and Akt, Bax, Bcl2, and brain-derived neurotrophic factor (BDNF) expression in brain samples were assessed. Western blot analysis indicated increased Akt but decreased Bax/Bcl2 levels in the HES 100 mg/kg, and induced BDNF levels in all HES-treated groups. MWM results showed that HES significantly decreased memory loss. The current findings indicate that HES could alleviate neurological impairments induced by CO in rats.

Hormetic effects of curcumin on oxidative stress injury induced by trivalent arsenic in isolated rat hepatocytes.

Objective: Arsenic (As) poisoning is a worldwide public health problem. Arsenic can cause cancer, diabetes, hepatic problems, etc. Hence, we investigated possible hepatoprotective properties of curcumin against As3+-induced liver damages in freshly isolated rat hepatocytes. Materials and Methods: Isolation of hepatocytes was done by the two-step liver perfusion method using collagenase. The EC50 concentration of As3+ was used in toxicity assessments and curcumin (2, 5, and 10 µM) was added 15 min before As3+ addition to isolated hepatocytes. Curcumin impact was assessed in terms of cytotoxicity, lipid peroxidation induction, reactive oxygen species (ROS) levels, and mitochondrial membrane potential. Results: As3+ significantly increased cytotoxicity, malondialdehyde and ROS levels and induced mitochondrial membrane damage and hepatocyte membrane lysis after 3 hr incubation. Curcumin 2 µM significantly prevented lipid peroxidation induction, ROS formation, and mitochondrial membrane damage; while curcumin 5 µM had no apparent effect on these parameters, curcumin 10 µM potentiated them. Conclusion: Curcumin only at low doses could ameliorate oxidative stress injury induced by As3+ in isolated rat hepatocytes.

Effects of gallic acid on intraperitoneal adhesion bands in rats.

Objective: Gallic acid (GA) is an organic acid that possesses anti-inflammatory effects as it inhibits the production of metalloproteinases, tissue plasminogen activator, growth factors and adhesion molecules. Since formation of abdominal surgery-induced adhesion bands is accompanied by inflammation, angiogenesis and cell proliferation, in the current study, we assessed potential beneficial properties of GA against adhesion bands formation in rats. Materials and Methods: Thirty-six adult male rats were assigned into six groups of six animals. After induction of anesthesia, peritoneal injury was induced using a standard method and animals received either GA (10, 25, 50 and 100 mg/kg), or normal saline, while a group of rats remained intact. Seven days after the surgery, animals were decapitated and samples were collected for pathology evaluations. Also, lipid peroxidation (TBARS) and tumor necrosis factor alpha (TNF-α) levels were determined in serum samples. Results: Our results showed that GA significantly reduced lipid peroxidation in serum samples but had no effect on TNF-α levels. Furthermore, microscopic and macroscopic injuries reduced significantly in GA-treated animals. Conclusion: Since GA reduced adhesion bands formation at microscopic and macroscopic levels, it could be considered a treatment against adhesion bands formation.

Intrahippocampal co-administration of nicotine and O-acetyl-L-carnitine prevents the H-89-induced spatial learning deficits in Morris water maze.

OBJECTIVES: H-89 (a protein kinase AII [PKA II] inhibitor) impairs the spatial memory in the Morris water maze task in rats. In the present study, we aimed to study the protective effects of nicotine and O-acetyl-L-carnitine against H-89-induced spatial memory deficits. METHODS: Spatial memory impairment was induced by the bilateral intrahippocampal administration of 10 µM H-89 (dissolved in dimethyl sulfoxide, DMSO) to rats. The rats then received bilateral administrations of either nicotine (1 µg/µL, dissolved in saline) or O-acetyl-L-carnitine (100 µM/side, dissolved in deionized water) alone and in combination. Control groups received either saline, deionized water, or DMSO. RESULTS: The H-89-treated animals showed significant increases in the time and distance travelled to find hidden platforms, and there was also a significant decrease in the time spent in the target quadrant compared to DMSO-treated animals. Nicotine and O-acetyl-L-carnitine had no significant effects on H-89-induced spatial learning impairments alone, but the bilateral intrahippocampal co-administration of nicotine and O-acetyl-L-carnitine prevented H-89-induced spatial learning deficits and increased the time spent in the target quadrant in comparison with H-89-treated animals. CONCLUSIONS: Our results indicated the potential synergistic effects of nicotine and O-acetyl-L-carnitine in preventing protein kinase AII inhibitor (H-89)-induced spatial learning impairments.

Convalescent Blood: Current Perspective on the Efficacy of a Legacy Approach in COVID-19 Treatment.

Since early 2020, COVID-19 has wreaked havoc in many societies around the world. As of the present, the SARS-CoV-2-borne disease is propagating in almost all countries, affecting hundreds of thousands of people in an unprecedented way. As the name suggests, the novel coronavirus, widely known as SARS-CoV-2, is a new emerging human pathogen. A novel disease of relatively unknown origin, COVID-19 does not seem to be amenable to the currently available medicines since there is no specific cure for the disease. In the absence of any vaccine or effective antiviral medication, we have no tools at our disposal, but the method of quarantine, be it domestic or institutional, to hinder any further progression of this outbreak. However, there is a record of physicians in the past who practiced convalescent blood transfusion. To their awe, the method seemed to be useful. It is anticipated that these contemporary methods will outdo any other vaccination process in the time being, as blood transfusion is instead a cost-effective and time-friendly technique. Following a successful trial, this new approach of contemporary nature to a viral disease may serve as an emergency intervention to intercept infectious outbreaks and prevent an impending epidemic/pandemic. In this review, we document the most recent evidence regarding the efficiency of convalescent plasma and serum therapy on SARS, MERS, and particularly COVID-19, while discussing potential advantages and possible risks of such practice.

Resveratrol, curcumin and gallic acid attenuate glyoxal-induced damage to rat renal cells.

Glyoxal (GO), a by-product of glucose auto-oxidation, is involved in the glycation of proteins/ lipids and formation of advanced glycation (AGE) and lipoxidation (ALE) end products. AGE/ALE were shown to contribute to diabetic complications development/progression such as nephropathy. Diabetic nephropathy progression has an oxidative nature. Given the antioxidant effects of polyphenols, potential protective effects of resveratrol, curcumin and gallic acid, in rat renal cells treated with GO, were evaluated in the present work. According to our results, incubation of GO with the cells reduced their viability and led to membrane lysis, reactive oxygen species (ROS) formation, lipid peroxidation, mitochondrial membrane potential collapse, and lysosomal membrane leakage. These findings were prevented by pre-treatment with resveratrol, curcumin and gallic acid. Mitochondrial and lysosomal toxic interactions appear to worsen oxidative stress/cytotoxicity produced by GO. Resveratrol, curcumin and gallic acid inhibited ROS formation and attenuated GO-induced renal cell death.

A binuclear iron(III) complex of 5,5'-dimethyl-2,2'-bipyridine as cytotoxic agent.

The binuclear iron(III) complex (1), namely, {[Fe(5,5'-dmbpy)2(OH2)]2(µ-O)}(NO3)4 with a distorted octahedral coordination, formed by four nitrogen and two oxygen atoms, was previously reported by our team. In this study the DNA-binding and cytotoxicity evaluation for target complex were studied. The results indicated strong cytotoxicity activity against A549 cells comparable to cisplatin values. The binding interaction between complex 1 and FS-DNA was investigated by UV-Vis, fluorescence spectroscopy, and gel electrophoresis at physiological pH (7.2). The DNA binding investigation has shown groove binding interactions with complex 1, therefore the hydrogen binding plays an important role in the interaction of DNA with complex 1. The calculated thermodynamic parameters (ΔH°, ΔS° and ΔG°) show that hydrogen bonding and Vander-Waals forces have an important function in Fe(III) complex-DNA interaction. Moreover, DNA cleavage was studied using agarose gel electrophoresis. Viscosity measurements illustrated that relative viscosity of DNA was unchanged with the adding concentrations of Fe(III) complex. Molecular docking simulation results confirmed the spectroscopic and viscosity titration outcomes.

Umbelliprenin relieves paclitaxel-induced neuropathy.

OBJECTIVES: Umbelliprenin (UMB) is a prenylated coumarin that acts as an in vitro antioxidant and inhibits lipoxygenase managing the inflammation pathways, while in vivo it exerts anti-inflammatory activities. METHODS: In this study, neuropathic pain was induced by four intraperitoneal doses of 2 mg/kg per day of paclitaxel (PTX) on days 1, 3, 5 and 7. Here, 49 male mice were randomly divided in the following groups: sham (not treated animals), negative control (PTX-treated receiving normal saline), single-dose UMB 6.25, 12.5 and 25 mg/kg groups (PTX-treated receiving UMB 6.25, 12.5 and 25 mg/kg, respectively), prevention (PTX-treated receiving PTX along with UMB 12.5 mg/kg on days 1, 3, 5 and 7) and positive control group (PTX-treated receiving imipramine 10 mg/kg as acute treatment). Hot-plate test was done to assess response to heat. Finally, interleukin (IL)-6 levels in the sciatic nerve and lipid peroxidation in sera were assessed. KEY FINDINGS: Umbelliprenin was found equally effective for acute treatment with imipramine, when comparing the prevention group and the positive control group. Single, 25 mg/kg UMB effectively attenuated hyperalgesia, lipid peroxidation and IL-6 levels. CONCLUSIONS: Umbelliprenin alleviated neuropathic pain, and decreased serum IL-6 levels and oxidative stress. UMB deserves further investigations, especially in clinical settings.

Anti-hypertensive effect of crocin and hesperidin combination in high-fat diet treated rats.

Cardiovascular diseases are the leading cause of death worldwide. Hypertension is the most important cause of such conditions. The use of medicinal herbs is of particular importance due to their lower cost and side effects. The aim of the present study was to compare the effect of hesperidin (HES) and crocin (CRO) alone and in combination, on blood pressure in a rat model of high-fat diet (HFD)-induced hypertension, using invasive carotid artery measurements. Animals were randomly assigned to the following groups: control group (received standard chow diet), HFD control group (received HFD containing 32% kcal of fat and 0.1% cholesterol), and three groups of HFD-treated animals that were treated with a single dose of CRO (20 mg/kg), HES (20 mg/kg), or CRO + HES (20 + 20 mg/kg). Except for the control group, rats received HFD for 7 weeks. On day 50, CRO, HES and normal saline were administered intraperitoneally and carotid arteries of the rats were cannulated. Three hours after the carotid artery cannulation, mean arterial blood pressure (MAP), systolic and diastolic blood pressure (SBP and DBP), and heart rate (HR) were measured using an intra-arterial catheter with the use of a Power Lab system. Data was analyzed using SPSS software. Rats that received HFD for 49 days presented a significant increase in SBP, HR and MAP compared to the control group (P<0.001). Whereas, HFD-treated rats of the CRO + HES group showed lower levels of SBP, HR and MAP; however, DBP remained unaffected. HES administration in HFD treated rats resulted in a significant decrease in SBP compared to the HFD control group with no significant differences in MAP. The hypotensive effects of the simultaneous administration of CRO and HES in HFD-hypertensive rats suggest the need for further study of these two natural products as a potential preventive measure against hypertension development, especially in patients with high normal blood pressure.

Magnesium sulfate ameliorates carbon monoxide­induced cerebral injury in male rats.

Carbon monoxide (CO) has been shown to induce several cardiovascular abnormalities, as well as necrosis, apoptosis and oxidative stress in the brain. Magnesium sulfate (MS) has been shown to have beneficial activities against hypoxia in the brain. In the present study, the possible protective effects of MS against CO­induced cerebral ischemia were investigated. For this purpose, 25 male Wistar rats were exposed to 3,000 ppm CO for 1 h. The animals were divided into 5 groups (n=5 in each group) as follows: The negative control group (not exposed to CO), the positive control group (CO exposed and treated with normal saline), and 3 groups of CO­exposed rats treated with MS (75, 150 and 300 mg/kg/day) administered intraperitoneally for 5 consecutive days. On the 5th day, the animals were sacrificed and the brains were harvested for the evaluation of necrosis, apoptosis and oxidative stress. Histopathological evaluation revealed that MS reduced the number and intensity of necrotic insults. The Bax/Bcl2 ratio and malondialdehyde (MDA) levels were significantly decreased in a dose­dependent manner in the MS­treated rats compared to the positive control group, while a significant dose­dependent increase in Akt expression, a pro­survival protein, was observed. In addition, MS administration reduced pro­apoptotic indice levels, ameliorated histological insults, favorably modulated oxidative status and increased Akt expression levels, indicating a possible neuroprotective effect in the case of CO poisoning. On the whole, the findings of this study indicate that MS may prove to be useful in protecting against CO­induced cerebral injury.

Flavonoids as potent allosteric inhibitors of protein tyrosine phosphatase 1B: molecular dynamics simulation and free energy calculation.

Protein tyrosine phosphatase 1B (PTP1B) is a member of the PTP superfamily which is considered to be a negative regulator of insulin receptor (IR) signaling pathway. PTP1B is a promising drug target for the treatment of type 2 diabetes, obesity, and cancer. The existence of allosteric site in PTP1B has turned the researcher's attention to an alternate strategy for inhibition of this enzyme. Herein, the molecular interactions between the allosteric site of PTP1B with three non-competitive flavonoids, (MOR), (MOK), and (DPO) have been investigated. Three ligands were docked into allosteric site of the enzyme. The resulting protein-ligand complexes were used for molecular dynamics studies. Principal component and free-energy landscape (FEL) as well as cluster analyses were used to investigate the conformational and dynamical properties of the protein and identify representative enzyme substrates bounded to the inhibitors. Per residue energy decomposition analysis attributed dissimilar affinities of three inhibitors to the several hydrogen bonds and non-bonded interactions. In conclusion, our results exhibited an inhibitory pattern of the ligands against PTP1B.

The hepatoprotective effects of aquatic extract of Levisticum officinale against paraquat hepatocyte toxicity.

Paraquat is extensively used as a strong nitrogen-based herbicide for controlling weeds in agriculture. This herbicide is extremely toxic to humans and induces multiorgan failure due to accumulation in the cells. So far, many instances of fatal poisoning have been reported. Paraquat is metabolized primarily in the liver. Accordingly, the effects of aquatic Levisticum officinale extract on biochemical factors and oxidative status were evaluated in hepatocytes exposed to paraquat in this study. The results showed that paraquat-induced hepatocyte destruction is mediated by reactive oxygen species (ROS) production. The aquatic extracts of Levisticum officinale (100, 200, and 300µg/mL) could prevent lipid peroxidation and reduction in the potential of mitochondrial membranes (P<0.05). The antioxidants, ROS scavengers (mannitol, dimethyl sulfoxide, and α-tocopherol), and mitochondrial permeability transition pore-sealing agent (carnitine) inhibited the effects of paraquat. The pore-sealing compound inhibited hepatotoxicity, indicating that paraquat induces cell death via mitochondrial pathways. Hepatic cell death due to paraquat could be prevented by hepatocyte pretreatment with aquatic Levisticum officinale extracts, antioxidants, and ROS scavengers; therefore, oxidative stress might directly reduce the mitochondrial membrane potential. In conclusion, paraquat hepatotoxicity may be associated with oxidative stress and maintained by the disruption of mitochondrial membrane potential. Levisticum officinale aquatic extract, presumably due to its strong antioxidant properties, could protect against the destructive effects of paraquat on rat hepatocytes.

Neuro-Protective Effects of Resveratrol on Carbon Monoxide-Induced Toxicity in Male Rats.

Acute carbon monoxide (CO) poisoning causes neurotoxicity through induction of necrosis, apoptosis, lipid peroxidation and oxidative stress. Resveratrol (RES) is a natural polyphenolic phytoalexin that exhibits neuroprotective effects in ischemia/reperfusion due to its anti-apoptotic, anti-necrotic and strong anti-oxidant properties as well as its ability to activate pro-survival pathways. In this study, rats were exposed to CO 3000 ppm for 1 h. Immediately after poisoning and on the next four consecutive days, RES (1, 5 and 10 mg/kg) was administered intraperitoneally. On the fifth day, animals' brains were excised, and necrosis, lipid peroxidation level and the level of Akt, BAX and BCL2 expression were evaluated. The results showed that RES 10 mg/kg significantly reduced lipid peroxidation, but RES 1 and 5 mg/kg had no significant effect on this parameter. Furthermore, RES 5 and 10 mg/kg significantly increased Akt expression level, while BAX/BCL2 ratio was reduced by RES 1, 5 and 10 mg/kg. Moreover, RES reduced necrotic foci in the brain, but the best results were seen following treatment with RES 10 mg/kg. In summary, RES showed neuroprotective effect in CO-poisoned rats as it decreased necrosis and BAX/BCL2 ratio and increased Akt expression levels. Copyright © 2017 John Wiley & Sons, Ltd.

Protective effects of Sesamum indicum extract against oxidative stress induced by vanadium on isolated rat hepatocytes.

Vanadium toxicity is a challenging problem to human and animal health with no entirely understanding cytotoxic mechanisms. Previous studies in vanadium toxicity showed involvement of oxidative stress in isolated liver hepatocytes and mitochondria via increasing of ROS formation, release of cytochrome c and ATP depletion after incubation with different concentrations (25-200 µM). Therefore, we aimed to investigate the protective effects of Sesamum indicum seed extract (100-300 µg/mL) against oxidative stress induced by vanadium on isolated rat hepatocytes. Our results showed that quite similar to Alpha-tocopherol (100 µM), different concentrations of extract (100-300 µg/mL) protected the isolated hepatocyte against all oxidative stress/cytotoxicity markers induced by vanadium in including cell lysis, ROS generation, mitochondrial membrane potential decrease and lysosomal membrane damage. Besides, vanadium induced mitochondrial/lysosomal toxic interaction and vanadium reductive activation mediated by glutathione in vanadium toxicity was significantly (P < 0.05) ameliorated by Sesamum indicum extracts. These findings suggested a hepato-protective role for extracts against liver injury resulted from vanadium toxicity. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 979-985, 2016.

Auraptene consolidates memory, reverses scopolamine-disrupted memory in passive avoidance task, and ameliorates retention deficits in mice.

OBJECTIVES: Auraptene (7-geranyloxycoumarin) (AUR), from Citrus species has shown anti-inflammatory, neuroprotective, and acetylcholinesterase (AChE) and beta-secretase inhibitory effects. Scopolamine is a nonselective muscarinic receptor antagonist which causes short-term memory impairments and is used for inducing animal model of Alzheimer's disease (AD). This research aimed to investigate the effect of AUR on scopolamine-induced avoidance memory retention deficits in step-through task in mice. MATERIALS AND METHODS: The effect of four-day pre-training injections of AUR (50, 75, and 100 mg/kg, subcutaneous (SC)) and scopolamine (1 mg/kg, IP), and their co-administration on avoidance memory retention in step-through passive avoidance task, was investigated by measuring the latency to enter to the dark chamber. RESULTS: Pre-training administration of AUR caused significant increase in step-through latency in comparison with control group, 48, 96, and 168 hr after training trial. The findings of this study showed that scopolamine (1 mg/kg, IP, for four consecutive days) impaired passive avoidance memory retention compared to saline-treated animals. Step-through passive avoidance task results showed that AUR markedly reversed scopolamine-induced avoidance memory retention impairments, 24 and 168 hr after training trial in step-through task. CONCLUSION: Results from co-administration of AUR and scopolamine showed that AUR reversed scopolamine-induced passive avoidance memory retention impairments.

A comparison of cardiomyocyte cytotoxic mechanisms for 5-fluorouracil and its pro-drug capecitabine.

1. 5-Fluorouracil (5-FU) and its prodrug capecitabine are key chemotherapeutic agents in the treatment of many gastrointestinal tract adenocarcinomas. In addition to their beneficial antitumor effects, they also possess undesired cardiac toxicity. In the present study, we investigated the cytotoxic mechanisms of 5-FU and capecitabine in freshly isolated rat cardiomyocytes. 2. 5-FU and capecitabine cytotoxicities were associated with reactive oxygen species (ROS) formation, lipid peroxidation and rapid glutathione depletion. Increased intracellular ROS could target mitochondria, and our findings confirmed that the cardiomyocytes mitochondrial membrane potential (ΔΨm) was rapidly decreased by 5-FU and capecitabine. Mitochondrial dysfunction subsequently initiates downstream events that trigger caspase-3 activation, and our results showed that 5-FU and capecitabine activated caspase-3 which leads to apoptosis or necrosis. However, 5-FU acted much more powerful than capecitabine at inducing several cytotoxicity markers in heart cardiomyocytes. In addition, 5-FU but not capecitabine caused lysosomal membrane leakiness when it was incubated with cardiomyocytes. All cytotoxicity markers were prevented by antioxidants, ROS scavengers, mitochondrial permeability transition (MPT) pore sealing agents and lysosomotropic agents. 3. Our findings showed that the cytotoxic action of 5-FU and capecitabine on cardiomyocytes are mediated by oxidative stress and subsequent mitochondrial dysfunction which causes caspase-3 activation and cell death.

Cytoprotective Effects of Hydrophilic and Lipophilic Extracts of Pistacia vera against Oxidative Versus Carbonyl Stress in Rat Hepatocytes.

This study was conducted to evaluate the cytoprotection of various extracts and bioactive compounds found in Pistacia vera againts cytotoxicity, ROS formation, lipid peroxidation, protein carbonylation, mitochondrial and lysosomal membrane damages in cell toxicity models of diabetes related carbonyl (glyoxal) and oxidative stress (hydroperoxide). Methanol, water and ethyl acetate were used to prepare crude pistachios extracts, which were then used to screen for in-vitro cytoprotection of freshly isolated rat hepatocytes against these toxins. The order of protection by Pistacia vera extracts against both hydroperoxide induced oxidative stress (ROS formation) and glyoxal induced protein carbonylation was: pistachio methanolic extract >pistachio water extract, gallic acid, catechin> α-tochoferol and pistachio ethyl acetate extract. Finally due to higher protection achieved by methanolic extract even compared to sole pretreatment of gallic acid, catechin or α-tochoferol, we suggest that cytoprotection depends on the variety of polar and non-polar compounds found in methanolic extract, it is likely that multiple cytoprotective mechanisms are acting against oxidative and carbonyl induced cytotoxicity. To our knowledge, we are the first to report the cytoprotective activity of Pistacia vera extracts against oxidative and carbonyl stress seen in type 2 diabetes hepatocytes model.

Oxidative mechanisms of fish hepatocyte toxicity by the harmful dinoflagellate Cochlodinium polykrikoides.

Harmful Algal Blooms caused by the marine ichthyotoxic dinoflagellate Cochlodinium polykrikoides are responsible for mass mortalities of wild and farmed fish worldwide. In this research, we investigated the cytotoxic mechanisms of aqueous extract of C. polykrikoides on isolated Rainbow trout (Oncorhynchus mykiss) liver hepatocytes. Algal extract exposure with isolated trout hepatocytes caused hepatocyte membrane lysis, reactive oxygen species (ROS) formation, glutathione depletion, lysosomal membrane rupture, collapse of mitochondrial membrane potential, ATP depletion and increase in ADP/ATP ratio, cytochrome C release into the hepatocyte cytosol, and activation of caspases cascade. Anti-oxidants, free radical scavengers, mitochondrial permeability transition (MPT) pore sealing agents, microsomal oxidases inhibitors, ATP generators and lysosomotropic agents protected fish hepatocytes against C. polykrikoides. Fish hepatocyte toxicity was also associated with mitochondrial and lysosomal membrane injury. These events caused cytochrome C release from the mitochondrial intra-membrane space into cytosol. The cytochrome C release could trigger activation of caspase-3 and apoptosis.

Ichthyotoxic Cochlodinium polykrikoides Induces Mitochondrial Mediated Oxidative Stress and Apoptosis in Rat Liver Hepatocytes.

In this research, we investigated the cytotoxic mechanisms of Cochlodinium polykrikoidescell lysate on isolated rat liver hepatocytes.This micro algae is responsible for a severe and widespread harmful algal bloom in the Persian Gulf and Gulf of Oman (2008-2009). Isolated hepatocytes were obtained by collagenase perfusion of Sprague-Dawley rat liver.According to our results, incubation of algal lysate with isolated rat hepatocytescaused hepatocyte membrane lysis, reactive oxygen species (ROS) formation, glutathione depletion, collapse of mitochondrial membrane potential,ATP depletion and increase in ADP/ATP ratio, cytochrome c release in to the hepatocyte cytosol,activation of caspase-3 (final mediator of apoptosis) and appearance of apoptosis phenotype. On the other hand, pre-treatment of antioxidants (α-tocopherol succinate and BHT), radical scavengers (mannitol and DMSO), mitochondrial permeability transition (MPT) pore sealing agents (cyclosporine A, carnitine and trifluoperazine), NADPH P450 reductase inhibitor (Diphenyliodonium chloride), CYP2E1 inhibitors (Phenylimidazole and 4-Methylpyrazole) and ATP generators (L-glutamine, Fructose and Xylitol)inhibitedcaspase-3 activation and cell death in algal lysate treated hepatocytes.Our data also confirmed that algal lysate activates apoptosis signaling via oxidative stress and mitochondrial pathway. Thus, ROS formation caused by the lysate exposure could directly be involved in mitochondrial MPT pore opening and activation of caspase-3 leading to C.polykrikoides lysateinduced apoptosis on rat hepatocytes. These findings contribute to a better understanding of C.polykrikoides-toxic effects on mammalian liver cells.