Pretreatment Of Animals Research Articles

Effect of oxytocin pretreatment on the development of morphine tolerance and dependence in rats

Increased opioid synthesis and release, and enhanced alpha-2 adrenoceptor signaling have been suggested to mediate repeated oxytocin-induced long-lasting effects including elevated pain threshold in rats. This study evaluated whether oxytocin pretreatment would influence development of dependence and tolerance to the nociceptive and body temperature responses to morphine and enhance effects of alpha-2 adrenergic agonist clonidine on nociceptive threshold, body temperature and morphine withdrawal signs. Rats injected subcutaneously with saline or 1 mg/kg oxytocin for 5 days were implanted with placebo or morphine pellets 24 h after the treatment period. Body temperature and nociception were assessed, with nociception determined via by hot plate and tail immersion tests, before and 4, 24 and 48 h after pellet implantation, and following a challenge dose of morphine. Withdrawal signs were determined after naloxone administration. Oxytocin produced analgesia, as evidenced by increased paw withdrawal latency in the hot plate test. Morphine increased body temperature and nociceptive threshold which declined over time. Morphine challenge could not demonstrate tolerance to the body temperature response. Analgesic tolerance was observed in the hot plate test in saline and in both tests in oxytocin pretreated rats. Naloxone-precipitated withdrawal appeared to be less severe in oxytocin pretreatment. Clonidine was ineffective on the withdrawal signs but decreased body temperature and increased tail flick latency in the tail immersion test in oxytocin pretreated animals. These results, while producing evidence for a hyperresponsiveness in alpha-2 adrenoceptors, provide contrasting effects on morphine tolerance and dependence, and their partial mediation by opioidergic and adrenergic activation in repeated oxytocin treatment.

Effect of Opuntia elatior on Alteration in Glutamic Oxaloacetic Transaminase activity induced by Gamma Radiation in Swiss Albino Mice

When mice are exposed to gamma radiation, all the body systems are affected adversely. Liver enzymes which are responsible for removal of toxicity created by irradiation increases in the body. Several herbs are known to reduce this toxicity. Opuntia elatior (OE) ,a cactus, was tested in this study for its activity to remove toxins induced by whole body exposure to Co60 gamma rays (6Gy).A moderate dose of OE (10 mg/kg body weight) was given orally to mice, before whole body irradiation and GOT activity was studied in their kidney at 1,3,5,10,15 and 30 post treatment days . Whole body gamma ray exposure increases GOT activity in the kidneys also. In OE pretreated animals this increase was significantly lesser and early recovery was observed. Two types of extracts were used in this study (ethanolic and acetonic). Both were able to reduce gamma radiation induced increase significantly and almost equally. As OE cladode extracts are quite cheap and produce no side effects(OE cladodes are used as food), it may be used to prevent unwanted toxic effects of gamma radiation exposure.

Vibrio splendidus infection induces dysbiosis in the blue mussel and favors pathobiontic bacteria

Studies on marine epizootics are often based on the identification of a single pathogen. However, the one-pathogen-one-disease paradigm is not always sufficient to explain the disease, especially since the evidences on the role of microbiota in health and disease. Vibrio splendidus strains have been associated with Mytilus edulis mortality in France. To assess the role of mussel microbiota in the infectious process, we performed experiments combining the investigation of total microflora dynamics during a realistic experimental infection by V. splendidus and the monitoring of mussel survival and the dominance of potential opportunistic bacteria after antibiotic treatment. We found that Vibrio exposure affected the structure and predictive function of the mussel microbiota. Dysbiosis was accompanied with the appearance of a pathobiont dominated by Bacteroidetes and Fusobacteria phyla. The injection of a homogenate of infected organisms increased Mytilus mortality compared to the direct injection of Vibrio while the antibiotic pretreatment reduced the effect of pathogen exposure and mortalities. The decrease of opportunistic bacteria abundance in antibiotic pretreated animals confirmed their implication in pathogenesis. Our findings suggest that mussel disease results from a collaboration between external pathogens and pathobiont bacteria. Therefore, an insight into microbiota functions is needed to a better understanding of pathosystems.

Herbal root extracts in Ben-Cha-Moon-Yai remedy attenuated pain-like behaviors and inflammation through the opioid and prostaglandin systems

Ethnopharmacological relevanceBen-Cha-Moon-Yai (BMY) remedy used in Thai traditional medicine as an anti-inflammatory, analgesic, and antipyretic agent compromises five herbal root extracts of equal weights: Aegle marmelos (L.) Corrêa (AM), Oroxylum indicum (L.) Kurz (OI), Dimocarpus longan Lour. (DL), Dolichandrone serrulata (Wall. ex DC.) Seem. (DS), and Walsura trichostemon Miq. (WT). Aim of the studyTo assess the anti-nociceptive and anti-inflammatory effects of the root extracts of all five species of BMY in experimental animal (mouse) models to ensure the rational use of herbal products in Thai traditional medicine. Materials and methodsRoot extracts prepared by ethanol and water extraction were used for the biological assays in animal models at five dose levels: 25, 50,100,200 & 400 mg/kg. The anti-nociceptive activity was evaluated based on hot-plate latency, duration of paw licking induced by formalin, and abdominal writhing induced by acetic acid. Carrageenan- and prostaglandin-induced paw oedema models were used to determine the anti-inflammatory activity. ResultsThe oral administration of AM, DS and WT root extracts displayed significant analgesic effects in the hot-plate test, both phases (early and late) of formalin test and acetic-acid induced writhing test at different dose levels. OI and DL only produced significant analgesia in the late phase of the formalin test and writhing test. The pretreatment of animals with the non-selective opioid receptor antagonist naloxone, reverse AM, DS and WT induced-antinociceptive activity. In both carrageenan and prostaglandin-induced paw oedema tests, all five herbal plant root extracts significantly reduced paw oedema at 3 h or more at different dose levels. Rotarod test results showed no effects of five herbal plant root extracts on the balance and the motor coordination at the highest dose level evaluated (400 mg/kg). ConclusionThe root extracts of AM, DS, and WT possess both central and peripheral anti-nociceptive properties, while OI and DL possess only peripheral analgesic properties. All five root extracts own anti-inflammatory properties, which might be due to their activity on the prostaglandin system. Altogether these findings ensure the rational use of BMY remedy in Thai traditional medicine.

Evaluation of Antiepileptic Activity of Flowers of Cocos nucifera L. Against Experimentally Induced Convulsions in Rats

The report used to be planned to analyze the antiepileptic activity of Cocos nucifera flowers against special experimentally induced convulsions in rats. In the present study, antiepileptic activity was assessed by following experimental models. Anti-convulsant in vivo models: Maximal electroshocks (MES) induced models in rats, Pentylenetetrazole (PTZ) induced in rats. Pretreatment of animals with Cocos nucifera flowers extract has reduced by half the general continuance of tonic hind leg extension, the most commonly used endpoint in assessing clonic convulsions. MES provokes repetitive neuronal firing indicates epileptic neurons. MES is the widely accepted model to demonstrate the antiepileptic property of a drug. This property is antagonistic of the plant extract could flow from to blockade of voltage-gated sodium channel or due to effect on NMDA receptors. The Cocos nucifera flowers extract was also demonstrated potential anticonvulsant activity in PTZ induced convulsions and this may be due to its agonistic activity on the GABAA receptor. This is further supported by an elevated level of GABA by the plant extract in the PTZ model. Methanolic extract of Cocos nucifera flowers has shown significant anticonvulsant activity against MES and Pentlylenetetrazole induced convulsion models. This observed activity could also be the referable presence of flavonoids and other phytochemical constituents found in the powerful extract.
 Keywords: Cocos nucifera, antiepileptic activity, Maximal electroshock, Pentlylenetetrazole, Flavonoids,

Therapeutic Potential of Selected Medicinal Plants Against Carrageenan Induced Inflammation in Rats.

The current study was aimed to analyze the therapeutic effect of selected medicinal plants, that is, Curcuma longa, Zingiber officinale, Trigonella graceum-foenum, Nigella sativa, and Syzygium aromaticum against carrageenan-induced oxidative stress and inflammation in rats. Phytochemical analysis revealed the presence of diverse range of bioactives. IC50 values for antioxidant assays including DPPH (2,2-diphenyl-1-picrylhydrazyl), metal chelating, ABTS scavenging (2, 2′-Azino-Bis-3-Ethylbenzothiazoline-6-Sulfonic Acid), β-carotene bleaching, and H2O2 (hydrogen peroxide) scavenging ranged from 37-294, 71-243.4, 69.66-191.8, 98.92-228.5, and 82-234.9 μg/mL, respectively. All tested plants extract were found active against tested pathogenic microorganisms with lowest minimum inhibitory concentrations. Oral administration of tested plants extracts in different doses (250, 500, and 1000 mg/kg b. w) did not exhibit any toxicological effects on hemato-biochemical profile of treated rats in comparison to control group rats. Further, plants extract exhibited considerable anti-inflammatory activity in rats paw inflammation and decreased cellular infiltration to inflammatory site in dose dependent manner. Pretreatment of animals with tested plants extract (100, 200, and 400 mg/kg b. w.) caused significant alteration in total antioxidants, oxidants, and enzymes activities in paw tissue homogenate and the effect was more pronounced at higher concentration (400 mg/kg b. w.). Results showed that tested plants extract are rich source of diverse classes of phenolics and have therapeutic potential against oxidative stress and inflammation.

Antiulcerogenic activity of Anogeissus pendula hydroalcoholic extract on pylorus ligated induced gastric ulcers in Albino Wistar rats

BackgroundAnogeissus pendula Edgew (Combretacae) is a traditional Indian medicinal plant with antiulcer, anti-inflammatory, anti-hepatoprotective and other pharmacological effects. A. pendula is commonly used by tribal groups to treat gastric disorders, and this may be due to phenolic compounds. PurposeThe aim of this study is to determine the antiulcer activity of Anogeissus pendula in pylorus ligated albino Wistar rats, and the biochemical function in ulcer protection via various biochemical studies. Study DesignThe study was conducted on albino Wistar rats using a pylorus ligation ulcer model. Ranitidine (20 mg/kg b.w) and APHAE (200 and 400 mg/kg b.w) were given orally to different groups of rats (n = 6), 1 h before pylorus ligation. The studied parameters were the amount of gastric juice, pH, total and free acidity, and ulcer index. The antioxidant parameters like LPO, GSH, CAT, SOD, and total protein were also studied. ResultsAt doses of 200 and 400 mg/kg, Anogeissus pendula stem hydroalcoholic extract (APHAE) demonstrated substantial inhibition of gastric lesions. In the pretreated animals, there was a decrease in ulcer index (P < 0.001) and a decrease in gastric volume, free and total acidity (P <0.001). The pH of the gastric juice, on the other hand, increased significantly. In the animals given APHAE medications, the protein content was found to be significantly lower (P< 0.001). In the gastric juice of pylorus ligated rats, APHAE pretreatment substantially reduced the rise in SOD, GSH, and CAT accompanied by a decrease in LPO (P< 0.001). ConclusionThe study revealed that Anogeissus pendula hydroalcoholic extract has considerable antioxidant potential. As a result, additional research into the separation and elucidation of individual phytochemicals and their action mechanisms is required.

Discovery and development of brain-penetrant 18F-labeled radioligands for neuroimaging of the sigma-2 receptors

We have discovered and synthesized a series of indole-based derivatives as novel sigma-2 (σ2) receptor ligands. Two ligands with high σ2 receptor affinity and subtype selectivity were then radiolabeled with F-18 in good radiochemical yields and purities, and evaluated in rodents. In biodistribution studies in male ICR mice, radioligand [18F]9, or 1-(4-(5,6-dimethoxyisoindolin-2-yl)butyl)-4-(2-[18F]fluoroethoxy)-1H-indole, was found to display high brain uptake and high brain-to-blood ratio. Pretreatment of animals with the selective σ2 receptor ligand CM398 led to significant reductions in both brain uptake (29%–54%) and brain-to-blood ratio (60%–88%) of the radioligand in a dose-dependent manner, indicating high and saturable specific binding of [18F]9 to σ2 receptors in the brain. Further, ex vivo autoradiography in male ICR mice demonstrated regionally heterogeneous specific binding of [18F]9 in the brain that is consistent with the distribution pattern of σ2 receptors. Dynamic positron emission tomography imaging confirmed regionally distinct distribution and high levels of specific binding for [18F]9 in the rat brain, along with appropriate tissue kinetics. Taken together, results from our current study indicated the novel radioligand [18F]9 as the first highly specific and promising imaging agent for σ2 receptors in the brain.

L-citrulline: A preclinical safety biomarker for the small intestine in rats and dogs in repeat dose toxicity studies

IntroductionGastrointestinal (GI) toxicity is still an issue within drug development, especially for novel oncology drugs. The identification of GI mucosal damage at an early stage with high sensitivity and specificity across preclinical species and humans remains difficult. To date, in preclinical studies, no qualified mechanistic, diagnostic or prognostic biomarkers exist for GI mucosal toxicity. L-citrulline is one of the most promising biomarker candidates used in clinical settings to quantify enterocyte integrity in various small intestinal diseases. L-citrulline is an intermediate metabolic amino acid produced mainly by functional enterocytes of the small intestine, whereby enterocyte loss will cause a drop in circulating L-citrulline. MethodsIn several repeat-dose toxicity studies, plasma L-citrulline has been evaluated as a potential safety biomarker for intestinal toxicity in beagle dogs and Wistar (Han) rats treated with different oncological drug candidates in drug development. Clinical observations and body weight determinations were performed during the pretreatment, treatment and treatment-free recovery period as well as toxicokinetic, gross and histopathology examinations. The quantitative determination of plasma L-citrulline levels during the pretreatment (only dogs), treatment and treatment-free recovery period were performed using an HPLC MS/MS assay. In cynomolgus monkeys, the first investigations on baseline L-citrulline levels were performed. ResultsIn dogs, a dose- and exposure-dependent decrease of up to 50% in plasma L-citrulline was seen without histopathological alterations. However, a decrease of more than 50% in comparison to the individual animal pretreatment value of L-citrulline correlated very well with histopathological findings (intestinal crypt necrosis, villus atrophy, enterocyte loss) and clinical signs (bloody faeces and diarrhoea). During a treatment-free recovery period, a trend of increasing levels was observed in dogs. In rats, absolute L-citrulline plasma levels of treated animals decreased compared to the values of the concurrent control group. This decrease also correlated with the histopathological findings in the small intestine (single cell necrosis and mucosa atrophy). Because of a large physiological variation in L-citrulline plasma levels in dogs and rats, a clear cut-off value for absolute L-citrulline levels predictive of intestinal mucosal toxicity was difficult to establish. However, a > 50% decrease in L-citrulline plasma levels during the treatment period strongly correlated with histopathological findings. DiscussionBased on the performed analysis, a longitudinal investigation of L-citrulline plasma levels for individual animals in the control and treatment groups is essential and pretreatment values of L-citrulline levels in rodents would be highly informative. Overall, further cross-species comparison (Cynomolgus monkey, mouse) and implementation in clinical trials as exploratory biomarker is essential to foster the hypothesis and to understand completely the clinical relevance of L-citrulline as a small intestine biomarker.

Prebiotic Mannan Oligosaccharide Pretreatment Improves Mice Survival Against Lethal Effects of Gamma Radiation by Protecting GI Tract and Hematopoietic Systems.

Total body irradiation (TBI) results in critical injuries in a dose dependent manner that primarily damages highly proliferating tissues including hematopoietic stem cells (HSCs) and intestinal crypt stem cells etc. This may result in hematopoietic syndrome leading to bone marrow failure and gastrointestinal syndrome leading to chronic intestinal functional alterations. Death results from the gastrointestinal syndrome due to sepsis, bleeding, dehydration, and multi-system organ failure. We demonstrate that the prebiotic mannan oligosaccharide (MOS) pretreatment substantially prolongs survival in both male and female mice when administered 2 h prior to radiation either through oral or intraperitoneal route. The radioprotective efficacy of MOS was found to be age dependent and improves survival even in aged mice (12–13 months old). MOS pretreatment effectively abrogates radiation-induced hematopoietic injury and accelerates recovery of lymphocytes and WBCs and alleviates depletion of circulatory blood cells. Results also illustrate that MOS pretreatment abolishes crypt cell death and denudation of villi in comparison to the respective irradiated animals and ameliorates the overall radiation-induced damage to the GI system. MOS pretreatment facilitates intestinal recovery leading to enhanced animal survival demonstrating its protection efficacy against TBI induced mortality. Moreover, MOS pretreated animals show signs of accelerated recovery in terms of severity of radiation sickness symptoms including weight loss and completely abolish TBI associated mortality.

Sodium R-lipoate and enzymatically-modified isoquercitrin suppressed IgE-independent anaphylactic reactions and stress-induced gastric ulceration in mice

Anaphylaxis is a life-threatening allergic reaction, for which the worldwide prevalence is rapidly increasing. The currently used synthetic antiallergic drugs have a high tendency to cause adverse effects, like gastric ulcers, in long-term use. Therefore, a great deal of attention has been given to develop new safer and more effective antiallergic agents from natural compounds that are chemically/enzymatically-modified. Here, we evaluated/compared the efficacy of two different doses (50 and 100 mg/kg body weight “b.w”, given orally) of sodium R-lipoate (NaRLA) and enzymatically-modified isoquercitrin (EMIQ) in alleviating both local/systemic non-immunological anaphylactic reactions and stress-induced gastric ulceration in mice, in comparison with sulfasalazine (SSZ) as a reference drug. The results indicated that the pre-treatment of animals with NaRLA or EMIQ (especially at 100 mg/kg b.w) completely succeeded, as SSZ, in alleviating the hind paw edema induced by either histamine or compound 48/80 (Cpd 48/80). Furthermore, NaRLA and EMIQ prevented the mast cell degranulation and anaphylactic shock caused by Cpd 48/80 (in a dose-dependent manner) and reduced significantly (P < 0.001) the histamine release from the mouse peritoneal mast cells, like SSZ. Moreover, their use was associated with alleviating both gastric histopathological and biochemical alterations in the water-restraint stress (WRS) mice model towards the control values. They also decreased the percentage of degranulated mesenteric mast cells in the WRS mice model. In conclusion, our findings provide possibility that both NaRLA and EMIQ may serve as an effective therapeutic agents for mast cells-dependent anaphylactic reactions without risks of inducing gastric ulcers.

L-citrulline: A preclinical safety biomarker for the small intestine in rats and dogs in repeat dose toxicity studies

IntroductionGastrointestinal (GI) toxicity is still an issue within drug development, especially for novel oncology drugs. The identification of GI mucosal damage at an early stage with high sensitivity and specificity across preclinical species and humans remains difficult. To date, in preclinical studies, no qualified mechanistic, diagnostic or prognostic biomarkers exist for GI mucosal toxicity. l-citrulline is one of the most promising biomarker candidates used in clinical settings to quantify enterocyte integrity in various small intestinal diseases. l-citrulline is an intermediate metabolic amino acid produced mainly by functional enterocytes of the small intestine, whereby enterocyte loss will cause a drop in circulating l-citrulline. MethodsIn several repeat-dose toxicity studies, plasma l-citrulline has been evaluated as a potential safety biomarker for intestinal toxicity in beagle dogs and Wistar (Han) rats treated with different oncological drug candidates in drug development. Clinical observations and body weight determinations were performed during the pretreatment, treatment and treatment-free recovery period as well as toxicokinetic, gross and histopathology examinations. The quantitative determination of plasma l-citrulline levels during the pretreatment (only dogs), treatment and treatment-free recovery period were performed using an HPLC MS/MS assay. In cynomolgus monkeys, the first investigations on baseline l-citrulline levels were performed. ResultsIn dogs, a dose- and exposure-dependent decrease of up to 50% in plasma l-citrulline was seen without histopathological alterations. However, a decrease of more than 50% in comparison to the individual animal pretreatment value of l-citrulline correlated very well with histopathological findings (intestinal crypt necrosis, villus atrophy, enterocyte loss) and clinical signs (bloody faeces and diarrhoea). During a treatment-free recovery period, a trend of increasing levels was observed in dogs. In rats, absolute l-citrulline plasma levels of treated animals decreased compared to the values of the concurrent control group. This decrease also correlated with the histopathological findings in the small intestine (single cell necrosis and mucosa atrophy). Because of a large physiological variation in l-citrulline plasma levels in dogs and rats, a clear cut-off value for absolute l-citrulline levels predictive of intestinal mucosal toxicity was difficult to establish. However, a > 50% decrease in l-citrulline plasma levels during the treatment period strongly correlated with histopathological findings. DiscussionBased on the performed analysis, a longitudinal investigation of l-citrulline plasma levels for individual animals in the control and treatment groups is essential and pretreatment values of l-citrulline levels in rodents would be highly informative. Overall, further cross-species comparison (Cynomolgus monkey, mouse) and implementation in clinical trials as exploratory biomarker is essential to foster the hypothesis and to understand completely the clinical relevance of l-citrulline as a small intestine biomarker.

Potential of an aqueous extract of Lippia multiflora Moldenke (Verbenaceae) in the treatment of anxiety disorders: Possible involvement of serotoninergic transmission

Ethnopharmacological relevance: The leaves and stems of Lippia multiflora Moldenke (Verbenaceae) are used in traditional medicine to treat depression, anxiety and epilepsy. Aim of the study: The present study investigated the anxiolytic-like effects of Lippia multiflora aqueous extracts in experimental models of anxiety. Materials and methods: Elevated plus maze and open field tests were used to evaluate anxiety and exploratory behaviour. The possible mechanism of action of Lippia multiflora were investigated after pretreatment of animal with agonist and antagonist of serotonin receptors, such as: mCPP, a partial agonist at the 5-HT2C receptors; Way-100635, a selective 5-HT1A receptors antagonist; and DOI, the 5-HT2A/2C receptors agonist. The levels of monoamine neurotransmitters were evaluated in the brain. Results: In the elevated plus maze, Lippia multiflora increased the number of entries into and percentage of time in open arms, and reduced rearing, head dipping, and percentage of time in closed arms. These effects were blocked with the agonist and antagonist of serotonin receptors. In the open field, Lippia multiflora increased crossing and reduced rearing and defecation. The endogenous levels of noradrenaline, dopamine and serotonin in the brain homogenates remain comparable to that distilled water-treated animals. Conclusion: It could be concluded that Lippia multiflora aqueous extracts, used in traditional medicine in Cameroon for the treatment of depression, anxiety and epilepsy seemed to possess anxiolytic properties in mice. These effects might be mediated by serotonin receptors, but not by modulation of the levels of monoamine neurotransmitters when the extract is administered once after one hour.

Behavioural and neurochemical characterisation of the anxiolytic properties of an aqueous extract of Dysphania ambrosioides (L.) Mosyakin and Clemants (Chenopodiaceae) in experimental mice

Ethnopharmacological relevance: Dysphania ambrosioides (L.) Mosyakin &amp; Clemants (Chenopodiaceae) is a medicinal plant known for its anxiolytic, antidepressant and anticonvulsant activities in Cameroonian folk medicine. Aim of the study: The aim of this work is to evaluate the anxiolytic effects of Dysphania ambrosioides aqueous extracts and investigate its mechanism of action. Materials and methods: Elevated plus maze test and open field test were used for detecting it anxiolytic properties. The possible mechanism of action of the aqueous extracts were investigated after pretreatment of animals with different antagonists of GABAA complex receptors (5 mg/kg N-methyl-β-carboline-3-carboxamide, 4 mg/kg flumazenil or 2 mg/kg bicuculline) 30 minutes prior to the oral administration of 370 mg/kg Dysphania ambrosioides aqueous extract. Results: Dysphania ambrosioides increased the percentage of entries into and percentage of time in open arms, and reduced rearing, head dipping, and percentage of time in closed arms, in the elevated plus maze. It reduced rearing and defecation, and increased crossing, in the open field. In addition, anxiolytic-like properties of Dysphania ambrosioides were blocked by different antagonists of GABAA complex receptors (N-methyl-β-carboline-3-carboxamide, flumazenil or bicuculline) as examined in elevated plus maze test. Finally, the activity of GABA-T activity was inhibited and the brain GABA concentration was increased by the extracts, respectively. Conclusion: These results suggest that Dysphania ambrosioides possess anxiolytic-like properties in mice that might involve an action on benzodiazepine and/or GABA sites in the GABAA receptor complex or by modulating brain GABA concentration in the central nervous system.

Evaluation of the high affinity [18F]fluoropyridine-candesartan in rats for PET imaging of renal AT1 receptors

IntroductionAlterations in the expression of the Angiotensin II type 1 receptors (AT1R) have been demonstrated in the development of several heart and renal diseases. The aim of this study was to evaluate the novel compound [18F]fluoropyridine-candesartan as a PET imaging tracer of AT1R in rat kidneys. MethodsCompetition binding assays were carried out with membranes from CHO-K1 cells expressing human AT1R. Binding to plasma proteins was assessed by ultrafiltration. Radiolabeled metabolites in rat plasma and kidneys of control and pretreated animals (candesartan 10 mg/kg or losartan 30 mg/kg) were analyzed by column-switch HPLC. Dynamic PET/CT images of [18F]fluoropyridine-candesartan in male Sprague-Dawley rats were acquired for 60 min at baseline, pre-treatment with the AT1R antagonist losartan (30 mg/kg) or the AT2R antagonist PD123,319 (5 mg/kg). ResultsFluoropyridine-candesartan bound with a high affinity for AT1R (Ki = 5.9 ± 1.1 nM), comparable to fluoropyridine-losartan but lower than the parent compound candesartan (Ki = 0.4 ± 0.1 nM). [18F]Fluoropyridine-candesartan bound strongly to plasma proteins (99.3%) and was mainly metabolized to radiolabeled hydrophilic compounds, displaying minimal interference on renal AT1R binding with 82% of unchanged tracer in the kidneys at 20 min post-injection. PET imaging displayed high renal and liver accumulations and slow clearances, with maximum tissue-to-blood ratios of 14 ± 3 and 54 ± 12 in kidney cortex and liver, respectively, at 10 min post-injection. Binding specificity for AT1R was demonstrated with marked reductions in kidney cortex (−84%) and liver (−93%) tissue-to-blood ratios at 20 min post-injection, when blocking with AT1R antagonist losartan (30 mg/kg). No change was observed in kidney cortex of rats pre-treated with AT2R antagonist PD 123,319 (5 mg/kg), confirming binding selectivity for AT1 over AT2 receptors. ConclusionHigh kidney-to-blood ratios and binding selectivity to renal AT1R combined with tracer in vivo stability displaying minimal interference from labeled metabolites support further PET imaging studies with [18F]fluoropyridine-candesartan.

Intra-arterial Instillation of a Nociceptive Agent Modulates Cardiorespiratory Parameters Involving 5-HT3 and TRPV1 Receptors in Anesthetized Rats.

Since long back, it has been a matter of discussion regarding the role of peripheral blood vessels in the regulation of cardiorespiratory (CVR) system. The role of 5-HT3 and TRPV1 receptors present on perivascular nerves in elicitation of CVR reflexes was examined after intra-arterial instillation of bradykinin in urethane anesthetized rats. Femoral artery was cannulated retrogradely and was utilized for the instillation of saline/agonist/antagonist and recording of blood pressure (BP), using a double ported 24G cannula. BP, respiration and ECG were recorded for 30 min after bradykinin (1 μM) in the absence or presence of antagonists. Instillation of bradykinin produced immediate hypotensive (40%), bradycardiac (17%), tachypnoeic (45%) and hyperventilatory (96%) responses of shorter latencies (5-8 s) favoring the neural mechanisms in producing the responses. In lignocaine (2%) pretreated animals, bradykinin- induced hypotensive (10%), bradycardiac (1.7%), tachypnoeic (13%) and hyperventilatory (13%) responses attenuated significantly. Pretreatment with ondansetron (100 μg/kg), 5-HT3-antagonist attenuated the hypotensive (10%), bradycardiac (1.7%), tachypnoeic (11%) and hyperventilatory (11%) responses significantly. Pretreatment with capsazepine (1 mg/kg), transient receptor potential vanilloid 1- antagonist blocked the hypotensive (5%), bradycardiac (1.2%), tachypnoeic (6%) and hyperventilatory (6%) responses significantly. In conclusion, presence of a nociceptive agent in the local segment of an artery evokes vasosensory reflex responses modulating CVR parameters involving TRPV1 and 5-HT3 receptors present on the perivascular sensory nerve terminals in anesthetized rats.

Quercetin: a savior of alveolar barrier integrity under hypoxic microenvironment

ABSTRACT High altitude pulmonary edema (HAPE) is generally characterized by the loss of alveolar epithelial barrier integrity. The current study was undertaken to assess the noninvasive approaches of HAPE diagnosis and to evaluate the prophylactic potential of quercetin in preventing alveolar junction impairments. Male SD rats fed with quercetin 1 h prior to hypoxia (7,620 m, for 6 h) were selected. PET/CT imaging was performed to visualize the lung uptake of 18F-FDG in animals under hypoxia. Further, oxidant status, catalase activity, hematological & blood gas parameters were evaluated. Moreover, tight junction (TJ) proteins (ZO-1, JAM-C, Claudin-4, and occludin) expression analysis was accomplished using immune-blotting. The structural differences in lung epithelia were noted by TEM imaging. Quercetin prophylaxis has significantly reduced the FDG uptake in rat lungs under hypoxia. It has also dramatically alleviated the protein oxidation followed by an elevation in catalase activity in the lungs under hypoxia. The TJ protein expression in the lungs has also been restored to normal upon quercetin pre-treatment. Concomitantly, the quercetin preconditioning has elicited the stable blood gas and hematological parameters under hypoxia. The observations from TEM imaging have also implicated the normal lung epithelial structures in the quercetin pretreated animals under hypoxia. Quercetin prophylaxis has significantly restored alveolar epithelium integrity by abating oxidative stress in the lungs under hypoxia. Abbreviations: CT- Computed Tomography 18F-FDG- Fluorodeoxyglucose (18FHAPE- High Altitude Pulmonary EdemaHb- HemoglobinHCT- HematocritHCO3 – BicarbonateJAM- Junctional Adhesion MoleculeKBq- Killo BecquerelPaO2 - Partial pressure of arterial oxygenPaCO2 - Partial pressure of arterial carbon di-oxidePET- Positron Emission TomographyRBC- Red Blood CorpusclesSD- Sprague DawleyTJ- Tight JunctionsTEM- Transmission Electron MicroscopyWBC- White Blood CorpusclesZO- Zona Occludin.

Evaluation of coenzyme Q10 combined with or without N-acetyl cysteine or atorvastatin for preventing contrast-induced kidney injury in diabetic rats.

Combined antioxidants effect for prevention of contrast-induced nephropathy (CIN) remains unclear. This study assessed the potential protective effects of coenzyme Q10 (CoQ10) alone or combined with N-acetyl cysteine (NAC) or atorvastatin against CIN in diabetic rats. Animals were randomly divided into five groups, including control and four disease groups with CIN and diabetes. Group 2 included diabetic rats with CIN. Groups 3-5 included diabetic rats that received CoQ10, CoQ10 and NAC, or CoQ10 and atorvastatin, respectively, before CIN induction. Serum, urine, and tissue were collected to evaluate renal protective effects of tested agents. Renal biomarkers, oxidative stress, and histopathological alterations were investigated. Rats with CIN showed significant renal impairment as revealed by the deleterious effects on kidney function and histology. While induction of CIN did not affect the renal levels of catalase, glutathione peroxidase (GPx), and thiobarbituric acid reactive substances, pretreatment of animals with CoQ10/NAC showed significant increase in GPx and catalase levels versus controls. Lastly, pretreatment with CoQ10/atorvastatin showed regenerative effect on distal tubules with mild kidney histology alterations relative to CIN rats. The combined use of CoQ10/atorvastatin could be a potential strategy to prevent CIN. However, future studies are warranted to test different combinations for longer prophylactic periods.

Dabigatran mitigates cisplatin-mediated nephrotoxicity through down regulation of thrombin pathway

IntroductionCisplatin (CDDP) nephrotoxicity is one of the most significant complications limiting its use in cancer therapy. ObjectivesThis study investigated the pivotal role played by thrombin in CDDP-mediated nephrotoxicity. This work also aimed to clarify the possible preventive effect of Dabigatran (Dab), a direct thrombin inhibitor, on CDDP nephrotoxicity. MethodsAnimals were grouped as follow; normal control group, CDDP nephrotoxicity group, CDDP + Dab 15, and CDDP + Dab 25 groups. Four days following CDDP administration, blood and urine samples were collected to evaluate renal function. Moreover, tissue samples were collected from the kidney to determine apoptosis markers, oxidative stress and histopathological evaluation. An immunofluorescence analysis of tissue factor (TF), thrombin, protease-activated receptor-2 (PAR2), fibrin, pERK1/2 and P53 proteins expression was also performed. ResultsThrombin, pERK, cleaved caspase-3, and oxidative stress markers were significantly elevated in CDDP-treated group. However, pretreatment of animals with either low or high doses of Dab significantly improved kidney function and decreased oxidative stress and apoptotic markers. ConclusionWe conclude that thrombin is an important factor in the pathogenesis of CDDP kidney toxicity via activation of ERK1/2, P53 and caspase-3 pathway, which can be effectively blocked by Dab.

Activity Of Amomum Tasao-Ko Fruits Essential Oil Against Methicillin-Resistant Staphylococcus Aureus In Vivo

Methicillin-Resistant Staphylococcus Aureus (MRSA) is one of the most serious health concerns bacterial owing to its incidence and the severity of the associated infections. It is necessary to find new chemical compounds with anti-MRSA activity. A model of MRSA infection was prepared by intraperitoneal injection of MRSA. A. tasao-ko essential oil was used for pretreatment and treatment of MRSA-infected animals and the 50% effective dose (ED50) was calculated according to improved Karber’s method respectively. The levels of serum interleukin (IL)-1β, IL-6, Tumor Necrosis Factor alpha (TNF-α), Malondialdehyde (MDA), Glutathione Peroxidase (GSH-Px) and Hydroxyl Radical (·OH) were measured using dedicated assay kits. The statistical analysis of inflammatory factors and oxidative stress factors was tested using one-way ANOVA computed by SPSS software. The ED50 values for the prevention and treatment of MRSA infection in A. tasao-ko essential oil were 0.15 g/kg and 0.18 g/kg, respectively. A. tasao-ko essential oil significantly reduced the inflammatory factors (IL-1β, IL-6, TNF-α), oxidative stress factors (MDA, ·OH) and increased the GSH-Px content in mice infected with MRSA. In the high-dose group, 7 days after treatment, the cytokine contents have no difference with control group (P &gt; 0.05). A. tasao-ko essential oil exhibited anti-MRSA effect in vivo and can also ameliorate the abnormal changes in inflammatory factors and oxidative stress that arise from MRSA.