Saline Research Articles

Myoblast Transfer in Ischemic Heart Failure: Effects on Rhythm Stability

Skeletal myoblast (SM) implantation promotes recovery of myocardial function after ischemic injury. Clinical observations suggest an association of SM implantation and ventricular arrhythmias. Support for this link has been sought in animal studies, but none employing models of congestive heart failure. In a canine model of postinfarction congestive heart failure (CHF) we compared the frequency of rhythm disturbances using ambulatory electrocardiography monitoring following skeletal myoblast or saline (SAL) implantation. In 19 mongrel dogs ischemic injury and CHF were induced by intracoronary microsphere infusions. Direct intramyocardial injection of autologous skeletal myoblasts (ASM) (2.7-8.3 x 10(8) cells) or SAL controls was administered to 11 and 8 dogs, respectively. Serial echocardiography and 24-h ambulatory electrocardiography were recorded at baseline (after CHF induction) and at 4 weeks and at 8-10 weeks after injection. Comparisons between groups of left ventricular ejection fraction (LVEF) and the frequency of ventricular arrhythmias, supraventricular arrhythmias, and measures of heart rate variability (HRV) were made at each of the three time points. LVEF increased from 41 +/- 6% to 47 +/- 2% (p < 0.03) in the ASM group, and did not change (42 +/- 6% to 40 +/- 2%, p = ns) in SAL. After injection, no differences were seen in the number of dogs demonstrating ventricular tachycardia (n = 3 vs. n = 2, p = ns) or frequent PVCs (n = 3 vs. n = 3, p = ns) in the ASM versus SAL groups, respectively. Significant changes were observed in a time-domain measure of HRV, standard deviation of normal-to-normal RR interval (in ms: 4 weeks 174 +/- 95 vs. 242 +/- 19; 8 weeks 174 +/- 78 vs. 276 +/- 78, ASM vs. SAL), but not in other time domain parameters. In this canine model of ischemic CHF, ASM implantation did not result in a significant increase in ventricular arrhythmias compared to controls animals. The potential for ASM implantation to affect time-domain parameters of HRV merits further study.

Chronic citalopram treatment elevates serotonin synthesis in flinders sensitive and flinders resistant lines of rats, with no significant effect on Sprague–Dawley rats

The influence of citalopram on regional 5-hydroxytryptamine (serotonin, 5-HT) synthesis, one of the most important presynaptic parameters of serotonergic neurotransmission, was studied. Sprague–Dawley (SPD) rats were used as the controls, and Flinders Resistant Line (FRL) rats were used as auxiliary controls, to hopefully obtain a better understanding of the effects of citalopram on Flinders Sensitive Line (FSL; “depressed”) rats. Regional 5-HT synthesis was evaluated using a radiographic method with a labelled tryptophan analog tracer. In each strain of rats, the animals were treated with citalopram (10 mg/(kg day)) or saline for 14 days. The groups consisted of between fourteen and twenty rats. There were six groups of rats with citalopram (CIT) and saline (SAL) groups in each of the strains (SPD–SAL, SPD–CIT, FRL–SAL, FRL–CIT, FSL–SAL and FSL–CIT). A two-factor analysis of variance was used to evaluate the effect of the treatment c ., SPD-SAL relative to SPD-CIT) followed by planned comparisons to evaluate the effect in each brain region. In addition, the planned comparison with appropriate contrast was used to evaluate a relative effects in SPD relative to FSL and FRL, and FSL relative to FRL groups. A statistical analysis was first performed in the a priori selected regions, because we had learned, from previous work, that it was possible to select the brain regions in which neurochemical variables had been altered by the disorder and subsequent antidepressant treatments. The results clearly show that citalopram treatment does not have an overall effect on synthesis in the control SPD rats; there was no significant ( p > 0.05) difference between the SPD–SAL and SPD–CIT rats. In “depressed” FSL rats, citalopram produced a significant ( p < 0.05) elevation of synthesis in seventeen out of thirty-four regions, with a significant ( p < 0.05) reduction in the dorsal and median raphe. In the FRL rats, there was a significant ( p < 0.05) elevation in the synthesis in twenty-two out of thirty-four brain regions, with a reduction in the dorsal raphe. In addition to these regions magnus raphe was different in the SPD and FSL groups, but it was on the statistical grounds identified as an outlier. There were significant changes produced in the FSL and FRL rats in thirteen out of seventeen a priori selected brain regions, while in the SPD rats, citalopram produced significant changes in only four out of seventeen a priori selected regions. The statistical evaluation also revealed that changes produced by citalopram in the FSL and FRL rats were significantly greater than those in the SPD rats and that there was no significant difference between the effect produced in the FSL and FRL rats. The presented results suggest that in “depressed” FSL rats, the antidepressant citalopram elevates 5-HT synthesis, which probably in part relates to the reported improved in behaviour with citalopram.

Paraquat (PQ)-induced pulmonary fibrosis increases exercise metabolic cost, reducing aerobic performance in rats

Rats exposed to the quaternary herbicide paraquat (PQ) exhibit oxidative stress and lung injury. In the present study, we investigated the effect of multiple exposures to PQ on aerobic performance during progressive exercise on a treadmill in rats. PQ was dissolved in saline (SAL) (10 mg/ml) and administered intraperitoneally 7 mg/kg body wt to Wistar rats (n = 5) once a week for one month. Control rats received SAL (0.7 ml/kg body wt., intraperitoneally, n = 5) over the same time period. The animals were submitted to aerobic evaluation on a treadmill using a progressive protocol until fatigue prior to the administration of the first dose of PQ or SAL and repeated at 1 week and 40 days following the last dose of the herbicide. Twenty-four hours after the last performance tests, the animals were sacrificed, lungs removed and divided in two groups: PQ and SAL for histopathological analysis. The animals exposed to PQ exhibited decrease in aerobic performance and mechanical efficiency (ME) as well as increase in oxygen consumption during exercise in comparison to the controls forty days after the last dose of PQ. Lung histologic changes included atelectasis, interstitial edema, and inflammation cells in PQ group. The collagen system fibers, fraction area of alveolar collapse and influx of polymorphonuclear (PMN) cells in lung parenchyma were higher in PQ compared to SAL. In conclusion, multiple exposures to PQ induce pulmonary fibrosis, reduce the aerobic performance and mechanical efficiency and increase the metabolic cost of exercise in rats.

Neonatal Exposure to Fenoterol and Betamethasone: Effects on the Behavioral Development in the Rat

We investigated longitudinally the behavioral development in the rat following exposure to β-agonists and glucocorticoids (GC). Neonatal rats received either 1 mg/kg fenoterol (FEN), 0.3 mg/kg betamethasone (BET), or saline (SAL). Weanling and young adult rats were tested in the open field, the elevated-plus maze, and the water maze. FEN-treated as well as BET-treated animals displayed increased anxiety-like behavior. Furthermore, BET-treated adult animals showed a reduced locomotor activity. An enhanced 24-h memory in the water maze in both treatment groups may be facilitated by emotional arousal due to the increased anxiety levels. The possible neurobiological underpinnings are discussed in detail.

Extracellular-signal regulated kinases expression is altered in brainstem nuclei during neuropathic pain and antidepressants treatment

Event Abstract Back to Event Extracellular-signal regulated kinases expression is altered in brainstem nuclei during neuropathic pain and antidepressants treatment Gisela Borges1, Esther Berrocoso2, Antonio Ortega-Alvaro2, Juan Antonio-Mico2 and Fani L. Neto1* 1 Universidade do Porto, Instituto de Histologia e Embriologia, Faculdade de Medicina do Porto e Instituto de Biologia Molecular e Celular (IBMC), Portugal 2 Universitad de Cadiz, Departamento de Neurociencias,Facultad de Medicina, Spain Antidepressants are prescribed for neuropathic pain relief but the underlying mechanisms are not understood. Extracellular-signal regulated kinases (ERKs) have been implicated both in antidepressants effects and in pain processing. Here, we evaluated the effect of noxious stimulation or antidepressants administration on ERKs’ activation in the chronic constriction injury (CCI) model of neuropathic pain in rats.CCI was surgically induced by loose ligation of the sciatic nerve. Control rats were sham-operated. To evaluate the effect of noxious stimulation on ERKs activation, SHAM and CCI anaesthetised rats received mechanical stimulation in the ipsilateral hindpaw (SHAM or CCI stimulated, SS and CCI-S, respectively). Other rats did not receive stimulation (SHAM or CCI not stimulated, SNS and CCI-NS, respectively). To study the influence of two antidepressants, separate groups of CCI or SHAM rats were treated for 21 days with saline (SA), amitrityline (AMI, a tricyclic antidepressant) or duloxetine (DLX, a serotonin and norepinephrine reuptake inhibitor). The amount of antidepressant diluted in water/day was evaluated for each rat. Hyperalgesia was analysed by the plantar and the paw pinch nociceptive tests. Immunoreactive cells against pERKs1/2 were counted in monoaminergic brainstem nuclei.Baseline ERKs1/2 activation was observed in monoaminergic brainstem areas of SNS and SHAM-SA animals, like the A5, Locus Coeruleus (LC), Lateral Paragigantocellular (LPGi) and Lateral Reticular (LRt) nuclei. CCI-S or CCI-NS rats showed increased pERKs expression in the A5, LPGi and LRt, but in LC labelling intensity decreased. No changes were detected between stimulated and non-stimulated either in SHAM or CCI groups of rats. AMI and either AMI or DLX induced increases in pERKs expression in A5 and LPGI, respectively, of SHAM rats. Contrarily, among CCI rats antidepressants had no effect on ERKs activation in any region studied, but significant decreases were detected in CCI-AMI when compared to SHAM-AMI rats, in A5 and in Dorsal Raphe. No differences were detected for DLX.Neuropathic pain changed ERKs1/2 activation pattern on some brainstem regions while noxious stimulation had no effects. Additionally antidepressants seem to act on ERKs pathway in serotonergic and/or noradrenergic regions under normal conditions. However, under chronic painful input these mechanisms seem altered.Grant: PI070687, HP2006-0062, Spain; E-42/07, CRUP, Portugal. Conference: 11th Meeting of the Portuguese Society for Neuroscience, Braga, Portugal, 4 Jun - 6 Jun, 2009. Presentation Type: Oral Presentation Topic: Symposium 5 – Pain Citation: Borges G, Berrocoso E, Ortega-Alvaro A, Antonio-Mico J and Neto FL (2009). Extracellular-signal regulated kinases expression is altered in brainstem nuclei during neuropathic pain and antidepressants treatment. Front. Neurosci. Conference Abstract: 11th Meeting of the Portuguese Society for Neuroscience. doi: 10.3389/conf.neuro.01.2009.11.024 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Aug 2009; Published Online: 05 Aug 2009. * Correspondence: Fani L Neto, Universidade do Porto, Instituto de Histologia e Embriologia, Faculdade de Medicina do Porto e Instituto de Biologia Molecular e Celular (IBMC), Porto, Portugal, fanineto@med.up.pt Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Gisela Borges Esther Berrocoso Antonio Ortega-Alvaro Juan Antonio-Mico Fani L Neto Google Gisela Borges Esther Berrocoso Antonio Ortega-Alvaro Juan Antonio-Mico Fani L Neto Google Scholar Gisela Borges Esther Berrocoso Antonio Ortega-Alvaro Juan Antonio-Mico Fani L Neto PubMed Gisela Borges Esther Berrocoso Antonio Ortega-Alvaro Juan Antonio-Mico Fani L Neto Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Neonatal hyperleptinaemia programmes anxiety-like and novelty seeking behaviours but not memory/learning in adult rats

Leptin treatment during lactation programmes for leptin resistance at adulthood, evidenced by hyperleptinaemia, hyperphagia and overweight. Since leptin is known to affect stress response, emotional behaviour and memory/learning performance, the objective of the present study was to evaluate whether neonatal hyperleptinaemia programmes anxiety-like and novelty-seeking behaviours as well as memory/learning in adult male rats. During the first 10 days of lactation (from PN1 to PN10), pups were s.c. injected once per day with either 50 μL of saline (SAL) or murine leptin (LEP — 8 μg/100 g of body mass, saline diluted). Serum leptin was assessed at PN10 and at PN150. Two separate experiments were carried out: 1) experiment one: at PN137, 29 SAL and 30 LEP rats were tested in the elevated plus-maze (EPM) and, at PN142, their behaviour was assessed in the hole board (HB) arena; 2) experiment two: at PN140, a different group of rats consisting of 53 SAL and 56 LEP animals were tested in the radial arm water maze (RAWM). Serum leptin concentration was higher in the LEP group at PN10 and at PN150. LEP animals spent significantly less time in the open arms of the EPM. Furthermore, the number of nose-pokes in the HB arena was higher in LEP rats. There were no differences between groups regarding latency to find the hidden platform in the RAWM. Our results suggests that a central mechanism of leptin resistance at adulthood, caused by neonatal hyperleptinaemia, is associated with an increased level of anxiety and also that it intensifies novelty seeking-behaviour.

Toll-like Receptor 4 Relates to Lipopolysaccharide-induced Mucus Hypersecretion in Rat Airway

Toll-like receptor 4 (TLR4) is a transmembrane protein that participates in the recognition of lipopolysaccharide (LPS), a potentially important source of inflammation. To investigate the role of TLR4 in LPS-induced airway mucus hypersecretion (AMH), we used a LPS-induced rat model treated with dexamethasone (DEX). Rats were randomly divided into four experimental groups: 1) saline (SA)-treated with distilled water (DW) (control group); 2) LPS-treated with DW (LPS group); 3) LPS-treated with DEX (LPS plus DEX group); 4) SA-treated with DEX (DEX group). DEX (5 mg/kg) was intraperitoneally injected 1 h before being administered intratracheally with LPS. Expressions of TLR4 and MUC5AC were evaluated with RT-PCR, in situ hybridization, immunohistochemistry and Alcian blue/Periodic acid-schiff (AB/PAS) staining. Increased expressions of TLR4 protein and mRNA were found in rat airway treated with LPS and peaked on day 2 after LPS administration. Following this, LPS increased MUC5AC expression and AB/PAS-stained goblet cells in rat airway. Correlation analysis showed TLR4 correlated well with the expression of MUC5AC (r = 0.684, p <0.01) and AB/PAS-stained area (r = 0.781, p <0.01). In addition, DEX pretreatment significantly reduced LPS-induced overexpression of TLR4 (p <0.05) in rat airway. These results suggest TLR4 relates to LPS-induced AMH and support a role of TLR4 in DEX inhibition of LPS-induced AMH.

Preemptive Morphine Analgesia Attenuates the Long-Term Consequences of Neonatal Inflammation in Male and Female Rats

Despite mounting evidence on the importance of pain management in preterm infants, clinical use of analgesics in this population is limited. Our previous studies have shown that neonatal inflammation results in long-term alterations in adult somatosensory thresholds, characterized by decreased baseline nociceptive sensitivity, and enhanced hyperalgesia after a subsequent inflammatory insult. The present studies were conducted to determine whether preemptive morphine attenuates these negative consequences. At P0, pups received an injection of morphine sulfate before an intraplantar injection of 1% carrageenan. Control pups received either saline (SAL) followed by intraplantar carrageenan, morphine sulfate followed by intraplantar SAL, or SAL followed by intraplantar SAL. Preemptive morphine significantly attenuated neonatal injury-induced hypoalgesia in adolescence and adulthood. Similarly, morphine pretreated animals displayed significantly less hyperalgesia and recovered faster from a subsequent inflammatory insult compared with controls. Neonatal morphine had no significant effect on morphine analgesia in adulthood. Interestingly, neonatally injured animals that did not receive morphine displayed a significant rightward shift in the morphine dose-response curve in the absence of peripheral inflammation. Together, these results demonstrate that preemptive morphine significantly attenuates the long-term behavioral impact of neonatal inflammatory injury.

Status of Stat3 in an Ovalbumin-Induced Mouse Model of Asthma: Analysis of the Role of Socs3 and IL-6

Background: Stat3, Socs3 and cytokines play an integral role in the coordination and persistence of inflammation. However, a clear understanding of the role played by the Stat3/IL-6 and Socs3 pathway in airway inflammation is lacking. We report the alteration in the status of expression and activation of Stat3 by ovalbumin (OVA), and establish its relationship with Socs3 and IL-6 in the lungs of mice with eosinophilic pulmonary inflammation and airway hyperresponsiveness. Methods: Alterations in the expression of Stat3, Socs3 and IL-6 were determined in a murine model of asthma, where Balb/c mice were sensitized and challenged with OVA (OVA/OVA) and compared with control mice sensitized and challenged with saline (SAL) (SAL/SAL) mice. The OVA/OVA mice were characterized by a moderate increase in methacholine-induced specific airway resistance, the presence of 150 μg/ml of OVA-specific IgG and 8.93 μg/ml OVA-specific IgE antibody and elevated levels of eosinophils and Th2 cytokines (IL-4 and IL-5) in the bronchoalveolar lavage fluid. In contrast SAL/SAL mice had low eosinophils, IL-4 and IL-5 and no OVA-specific IgG and IgE antibodies in the BALF. Stat3 and Socs3 expression profiles were monitored in OVA/OVA and Stat3- and Socs3-silenced OVA/OVA mice. Furthermore, expression of IL-6 in Stat3- and Socs3-silenced mice and the exogenous effect of IL-6 on Stat3 were studied. Results: The results show that expression and activation of Stat3 mRNA and proteins are significantly low in lung of OVA/OVA mice in comparison to SAL/SAL mice following OVA challenge. An increased pool of Socs3 mRNA is observed in OVA/OVA mice with or without OVA challenge and in SAL/SAL mice 24 h after OVA challenge. Transient in vivo blocking of Socs3 gene by Socs3 siRNA restores the expression of IL-6 mRNA and protein in OVA/OVA mice, and nasal administration of recombinant IL-6 to OVA/OVA mice enhanced Stat3 mRNA expression. Conclusions: Our data suggest that airway inflammation is associated with low expression of Stat3 and IL-6 and overexpression of Socs3 genes in a mouse model of asthma. Furthermore, IL-6 is under the influence of the Socs3 gene and may contribute to the negative regulation of Stat3 via IL-6 following a challenge with an allergen during the development of asthma.

Acute Exercise Protects Against Doxorubicin Cardiotoxicity

Numerous methods have been used to minimize the cardiotoxic effects of the chemotherapeutic agent doxorubicin (DOX), and most have had limited success. Chronic endurance exercise has been shown to protect against DOX cardiotoxicity, but little is known regarding the effects of acute exercise on DOX-induced cardiac dysfunction. The purpose of this study was to determine the effects of a single bout of acute endurance exercise on the cardiac dysfunction associated with DOX treatment. Male Sprague-Dawley rats either performed an acute exercise bout on a motorized treadmill for 60 minutes at a maximal speed of 25 m/min with a 5% grade (EX) or remained sedentary (SED) 24 hours before receiving either a 15-mg/kg DOX bolus dose or saline (SAL). Cardiac function was then analyzed 5 days post injection using a Langendorff isolated perfused heart model. In addition, myocardial lipid peroxidation was analyzed as an indicator of oxidative stress. Doxorubicin treatment alone (SED+DOX) promoted a significant decline in end-systolic pressure (-35%), left ventricular developed pressure (-59%), and the maximal rate of left ventricular pressure development (-43%) as well as a 45% increase in lipid peroxidation products when compared with SED+SAL (P<.05). Acute exercise 24 hours before DOX treatment, however, had a cardioprotective effect, as end-systolic pressure, left ventricular developed pressure, and the maximal rate of left ventricular pressure development were significantly higher in EX+DOX compared with SED+DOX (P<.05) and EX+DOX had similar levels of lipid peroxidation products as SED+SAL CONCLUSIONS: An acute exercise bout performed 24 hours before DOX treatment protected against cardiac dysfunction, and this exercise-induced cardioprotection may partly be explained by a reduction in the generation of reactive oxygen species.

Changes in brain orexin levels in a rat model of depression induced by neonatal administration of clomipramine

Depression is associated with a deficiency of serotonergic neurons that have been found to suppress orexinergic neurons, which in turn activate these neurons in a feedback loop. This evidence suggests that orexins may be involved in the pathology of depression. Long Evans rats were treated with clomipramine (CLI) and saline (SAL) from postnatal days 8 through 21. One set of rats from both groups was sacrificed at 35 days of age for quantification of orexins in multiple brain regions. At 3-4 months of age a second set of rats was tested for immobility in a forced swim procedure, a common test for depressive signs in rats, and a third set was sacrificed for the quantification of orexins. Compared with the control rats, adult rats with neonatal CLI treatment had (1) increased forced swim immobility and (2) increased orexins A and B in the hypothalamus. However, both orexins A and B levels were decreased in multiple brain regions in the juvenile CLI rats compared with same-age controls. We concluded that although orexin levels were decreased in juvenile CLI rats, adult CLI rats with features of depression had significantly higher levels of hypothalamic orexins compared with adult controls. These results imply that orexins are likely to be involved in the pathological regulation of depression.

Prenatal Dexamethasone Impairs Behavior and the Activation of the BDNF Exon IV Promoter in the Paraventricular Nucleus in Adult Offspring

Prenatal manipulations to the hypothalamic-pituitary-adrenal axis are shown to affect auditory responses to an acoustic challenge as well as behavior in adult life. To achieve these results, we examined the effect of prenatal dexamethasone (DEX) treatment in male and female adult rat offspring by assessing body and adrenal weight, anxiety using the elevated plus maze (EPM), and acoustic startle responses as well as the effects of acoustic challenge in the paraventricular nucleus (PVN). DEX male offspring had reduced adrenal gland weight in adult life and demonstrated anxiolytic-like behavior when tested on the EPM. The acoustic startle amplitude in naive DEX-treated male offspring was significantly higher compared with saline (SAL)-treated males and females and DEX-treated females. When challenged with either a glucocorticoid agonist or antagonist, the startle response of the SAL-treated males and females significantly increased or decreased in the presence of agonist and antagonist treatment, respectively, whereas DEX males and females were not affected. Acoustic challenge caused an increase in c-fos mRNA and glucocorticoid receptor nuclear translocation in the PVN of all groups. BDNF and TrkB mRNA increased in the PVN after acoustic challenge in the SAL-treated males and females but not in the DEX males or females. These findings exemplify the differential sensitivity of the developing nervous and endocrine systems to prenatal hormonal stress and demonstrate that prenatal DEX treatment elicits long-term behavioral alterations related to anxiety and auditory processing.

Neonatal manipulation of oxytocin influences the partner preference in mandarin voles (Microtus mandarinus)

Neonatal manipulation of oxytocin (OT) has long-term effects on behavior and physiology. The objective of this research was to determine if neonatal exposure to OT can affect partner preferences and to characterize the mechanisms underlying social behavior such as neural activities of relevant brain regions in socially monogamous mandarin voles (Microtus mandarinus). After receiving a subcutaneous injection of isotonic saline (SAL) or OT within 24h of birth, mandarin vole at 60 days of age was paired with an unfamiliar opposite sex for 24h, followed immediately by an examination of their partner preference and 30 days later by the second examination of their partner preference and Fos expression in some brain regions. The results indicated that (1) while 24h cohabitation was insufficient for both female and male SAL-treated mandarin voles to form partner preference, neonatal exposure to OT significantly facilitate female, but not male mandarin voles to form partner preference within 24h of cohabitation; (2) the maintenance of partner preference in females was suppressed by neonatal OT treatment, while neonatal OT-treated males showed significant partner preference as neonatal SAL-treated males and females; in addition, the tendency of aggression to the strangers was impaired in both females and males, and neonatal OT-treated males showed significantly higher mounting behavior to the partner; (3) in comparison with saline-treated females, OT-treated females showed a significant decrease in Fos expression in all brain regions examined in response to partner preference. Relative to saline treatment, neonatal OT treatment induced to males a significant decrease of Fos expression in the bed nucleus of the stria terminalis (BNST), the hypothalamic paraventricular nucleus (PVN) and the mediodorsal thalamic nucleus (MD) as well as a significant increase in the medial preoptic area (MPOA), the dorsal part of the lateral septal nucleus (LSD) and the central amygdaloid nucleus (CeA). These results demonstrate that neonatal OT exposure has different effects on the formation and maintenance of partner preference in mandarin voles and the latter effects possibly via OT-induced changes of the neural activities of relevant brain regions.

Effectiveness of liposomal- N-acetylcysteine against LPS-induced lung injuries in rodents

Acute lung injury (ALI) and its most severe form, the acute respiratory distress syndrome (ARDS) are frequent complications in critically ill patients and are responsible for significant morbidity and mortality. So far, experimental evidence supports the role of oxidants and oxidative injury in the pathogenesis of ALI/ARDS. In this study, the antioxidant effects of conventional N-acetylcysteine (NAC) and liposomally entrapped N-acetylcysteine (L-NAC) were evaluated in experimental animals challenged with lipopolysaccharide (LPS). Rats were pretreated with empty liposomes, NAC, or L-NAC (25 mg/kg body weight, iv); 4 h later were challenged with LPS ( E. coli, LPS 0111:B4) and sacrificed 20 h later. Challenge of saline (SAL)-pretreated animals with LPS resulted in lung injury as evidenced by increases in wet lung weight (edema), increases in lipid peroxidation (marker of oxidative stress), decreases of lung angiotensin-converting enzyme (ACE) (injury marker for pulmonary endothelial cells) and increases in the pro-inflammatory eicosanoids, thromboxane B 2 and leukotriene B 4. The LPS challenge also increased pulmonary myeloperoxidase activity and chloramine concentrations indicative of neutrophil infiltration and activation of the inflammatory response. Pretreatment of animals with L-NAC resulted in significant increases in the levels of non-protein thiols and NAC levels in lung homogenates ( p <0.05) and bronchoalveolar lavage fluids ( p < 0.001), respectively. L-NAC was significantly ( p < 0.05) more effective than NAC or empty liposomes in attenuating the LPS-induced lung injuries as indicated by the aforementioned injury markers. Our results suggested that the delivery of NAC as a liposomal formulation improved its prophylactic effectiveness against LPS-induced lung injuries.

Oleic acid loading does not add to the nephrotoxic effect of albumin in an amphibian and chronic rat model of kidney injury

Under proteinuric conditions, ultrafiltrated albumin can induce an inflammatory and fibrotic response in proximal tubular cells. It is unclear whether albumin per se or compounds bound to albumin are nephrotoxic. Some studies have supported the toxicity of albumin-bound fatty acids; however, these compared untreated, fatty acid containing, albumin and delipidated albumin. To prevent confounding by the delipidation procedure, we compared delipidated albumin and oleic acid (OA)-loaded delipidated albumin in two models: the classical rat protein overload and the Axolotl. The latter had an amphibian kidney with a subset of nephrons that drained the peritoneal cavity, so that i.p. injection of albumin selectively targeted open but not closed nephrons and was used to prevent removal of fatty acids from albumin in the circulation. Protein overload was induced in Wistar rats (groups n = 8, for 12 weeks) and Axolotl (groups n = 10, for 10 days) by daily i.p. injections of 1 g (rat) or 50 mg (Axolotl) of fatty acid-free bovine serum albumin (BSA), fatty acid-free BSA with addition of six molecules of oleic acid (OA-BSA) or saline (SAL). After 12 weeks, proteinuria and SBP were increased in BSA and OA-BSA rats compared to saline-injected controls (P < 0.05), but OA loading had no additional effect compared to albumin alone. This was also true for glomerular and interstitial inflammation, fibrotic changes and focal glomerulosclerosis (OA-BSA versus BSA, all P = ns). Axolotls injected with OA-loaded albumin showed comparable protein storage in tubular epithelial cells, tubular dilatation and peritubular fibrosis around tubules draining the peritoneal cavity compared with Axolotls injected with albumin alone. This was also true for TGF-beta (inflammation marker) and collagen I (fibrosis marker) (OA-BSA versus BSA, all P = ns). In the Axolotl and chronic rat model, OA loading of albumin did not aggravate renal damage compared to albumin alone. Although in vitro studies clearly show induction of changes in cultured tubular epithelial cells exposed to albumin-bound fatty acids that are consistent with a role in induction of tubulointerstitial disease, our experiments suggest that currently available models for demonstrating such an effect in vivo are insufficient.

The effect of clomipramine on wake/sleep and orexinergic expression in rats

We have previously found that neonatal treatment with clomipramine (CLI) induced a decrease in brain orexins during the juvenile period and that these changes were reversed at adulthood. This study investigated the effect of CLI on the orexinergic component and sleep/wake states. Two groups of adult male rats were conducted for 48-h polysomnographic recording. One group of rats was treated with CLI (20 mg/kg every 12 h), and a second group was treated with equivolume of saline (SAL) simultaneously after the first 24 h of polysomnographic recording. Rats were killed 2 h after the third dose of treatment. Brain tissues were collected for radioimmunoassay quantification of orexins and real-time PCR analysis of prepro-orexin and orexin receptor mRNA. The CLI group had significantly shorter rapid eye movement (REM) sleep and longer REM latency compared with both the baseline day and the SAL group and had significantly less active wake and more quiet wake. Compared with the control rats, the CLI rats had significantly higher mRNA expression of prepro-orexin in the hypothalamus and the frontal cortex, but not in the hippocampus. The CLI rats also had significantly less orexin B in the hypothalamus than the control rats. These results suggest that suppression of active wake and orexin B by CLI may be a factor responsible for CLI-induced depression and that the increase of prepro-orexin mRNA may be a sign of increased brain orexins found in this model.

Influence of acute pancreatitis on the in vitro responsiveness of rat mesenteric and pulmonary arteries

BackgroundAcute pancreatitis is an inflammatory disease characterized by local tissue injury and systemic inflammatory response leading to massive nitric oxide (NO) production and haemodynamic disturbances. Therefore, the aim of this work was to evaluate the vascular reactivity of pulmonary and mesenteric artery rings from rats submitted to experimental pancreatitis.Male Wistar rats were divided into three groups: saline (SAL); tauracholate (TAU) and phospholipase A2 (PLA2). Pancreatitis was induced by administration of TAU or PLA2 from Naja mocambique mocambique into the common bile duct of rats, and after 4 h of duct injection the animals were sacrificed. Concentration-response curves to acetylcholine (ACh), sodium nitroprusside (SNP) and phenylephrine (PHE) in isolated mesenteric and pulmonary arteries were obtained. Potency (pEC50) and maximal responses (EMAX) were determined. Blood samples were collected for biochemical analysis.ResultsIn mesenteric rings, the potency for ACh was significantly decreased from animals treated with TAU (about 4.2-fold) or PLA2 (about 6.9-fold) compared to saline group without changes in the maximal responses. Neither pEC50 nor EMAX values for Ach were altered in pulmonary rings in any group. Similarly, the pEC50 and the EMAX values for SNP were not changed in both preparations in any group. The potency for PHE was significantly decreased in rat mesenteric and pulmonary rings from TAU group compared to SAL group (about 2.2- and 2.69-fold, for mesenteric and pulmonary rings, respectively). No changes were seen in the EMAX for PHE. The nitrite/nitrate (NOx-) levels were markedly increased in animals submitted to acute pancreatitis as compared to SAL group, approximately 76 and 68% in TAU and PLA2 protocol, respectively.ConclusionAcute pancreatitis provoked deleterious effects in endothelium-dependent relaxing response for ACh in mesenteric rings that were strongly associated with high plasma NOx- levels as consequence of intense inflammatory responses. Furthermore, the subsensitivity of contractile response to PHE in both mesenteric and pulmonary rings might be due to the complications of this pathological condition in the early stage of pancreatitis.

Neonatal dexamethasone administration causes progressive renal damage due to induction of an early inflammatory response

Glucocorticoids (GCs) are widely used to prevent chronic lung disease in immature newborns. Emerging evidence indicates that GC exposure in early life may interfere with kidney function and is associated with hypertension in later life. In this study, we have investigated the effect of neonatal dexamethasone (DEX) administration on renal function in rats. Male rats were treated with DEX in the first 3 days after birth, controls received saline (SAL). Severe renal damage associated with premature death was found at 50 wks upon DEX treatment, while renal function and morphology were normal in controls. A subsequent time-course study was performed from 2 days to 32 wks. Compared with controls, neonatal DEX administration led to significant and persistent growth retardation. Progressive proteinuria and increased systolic blood pressure were found from 8 wks onwards in DEX-treated animals. Renal alpha-SMA gene expression was elevated from wk 24 onwards and morphological fibrosis was noted at 32 wks of age following DEX treatment. Markedly increased renal gene expression of TNF-alpha and MCP-1 in DEX -treated rats was observed at day 7, probably contributing to the permanent increase in interstitial macrophage numbers that started at 14 days. Permanently elevated renal TGF-beta gene expression was induced by DEX administration from 4 wks onwards. Our data indicate that neonatal DEX administration in rats leads to renal failure in later life, presumably due to an early inflammatory trigger that elicits a persistent pro-fibrotic process that eventually results in progressive renal deterioration.

Activation of glucagon receptor signaling stimulates regulators of hepatic fat oxidation in vivo

Evidence suggests that glucagon (GN) has persistent effects on the liver that we hypothesize are related to AMPK, PPARα, and FGF‐21. These proteins are known to promote hepatic oxidative processes. We aimed to define signaling pathways downstream of the hepatic GN receptor in vivo. The role of GN stimulation was tested using wild type (WT) and glucagon receptor null (KO) mice catheterized in a carotid artery and jugular vein 5d prior to study. In 5h fasted mice, GN (10ng/kg/min) or saline (SAL) was infused for 2h and the interaction of GN with circulating fat levels was tested in separate studies in which intralipid (IL) was also infused. Pfloridzin was infused in all studies to prevent high glucose and insulin levels. Euglycemia (150mg/dL) was maintained using a variable glucose infusion. Elevated GN (∼5‐fold) in WT increased glucose production and caused increases in AMP:ATP (7.7±0.5 fold), p‐AMPK (2.1±0.3 fold), and PPARα and FGF‐21 mRNA (2.0±0.3 and 2.0±0.4 fold) in liver compared to SAL. IL alone had no effects. However, IL led to marked potentiation of GN‐induced stimulation of FGF‐21 mRNA (12.3±4.2‐fold) in WT mice. Effects of GN with and without IL were eliminated in KO mice. We show in vivo that glucagon drops the liver to a low energy state which corresponds to increased activation of AMPK and induction of PPARα and FGF‐21 mRNA. Effects of GN on FGF‐21 are potentiated by IL. In conclusion, GN not only acutely regulates glucose homeostasis, but also causes adaptations in processes that improve the ability of the liver to oxidize fat. Supported by DK 50277.

Effects of Ototopical Antihistamine on Otitis Media in an Allergic Rat

A reliable model of allergy has been created in the Brown Norway rat. In this model, allergen presentation to the middle ear causes functional disruption of the eustachian tube, predisposing to the development of otitis media with effusion. The purpose of this study was to study the effects of ototopical antihistamine on lipopolysaccharide (LPS)-induced otitis media in the allergic rat model. Prospective animal-based research study. Fifteen (n = 15) rats were made allergic via sensitization to ovalbumin (OVA) by subcutaneous injection and randomized into three groups: saline (SAL) + LPS, olopatadine (OLO) + LPS, and azelastine (AZE) + LPS. Allergic rats were transtympanically injected with OVA 24 hours prior to challenge, creating a subclinical inflammatory response in which there is no visible middle ear effusion. Thirty-five microliters of test substance (SAL + LPS, OLO + LPS, or AZE + LPS) were injected into the middle ear at 0, 2, and 4 hours. Effusion was collected at 2, 4, and 6 hours. Statistical analysis was performed on effusion volume and albumin concentration. Significant increase in effusion volume with respect to time was noted for the SAL + LPS group, whereas the AZE + LPS group demonstrated a decrease. Intergroup comparison revealed a significant decrease in effusion volume at hour 6, with both AZE and OLO less than LPS alone. A significant decrease in albumin concentration over time was noted in the AZE group. Intergroup comparison revealed a significant difference inalbumin concentration at hour 6, with OLO significantly lower than LPS. Ototopical antihistamines are effective in reducing effusion volume and albumin concentration in LPS-induced otitis media in an allergic rat model. This finding supports the hypothesis that ototopic antihistamines may prove effective in treating patients with allergy-induced eustachian tube dysfunction.