Body Temperature Of Mice Research Articles

Static magnetic field attenuates lipopolysaccharide-induced multiple organ failure: A histopathologic study in mice

Purpose: Previous studies demonstrated that static magnetic fields (SMF) were effective in down-regulating the expression of lipopolysaccharide (LPS)-induced inflammatory cytokines. The aim of this study was to provide histological evidence of SMF attenuating LPS-induced multiple organ failure (MOF).Materials and methods: In this study, BALB/cByJNarl (5 weeks, weighing 20–25 g) mice were chosen as test subjects. The tested animals were challenged with 50 mg/kg LPS after they were exposed to a continuous SMF for 2 h. The survival rate and pathological changes in lungs, kidneys, and livers of the LPS- challenged mice were examined with and without SMF treatment. In addition, the effects of SMF exposure on body temperature control of the LPS-challenged mice were monitored.Results: Our results showed that at 30 h the survival rate of LPS-challenged mice increased 3.6-fold (p < 0.05). In addition, 6 h after LPS injection, the average body temperature of SMF-exposed mice was 1.07°C lower than that of unexposed animals. Tissue biopsies demonstrated that SMF exposure reduced damage to the lungs, livers, and kidneys in the LPS-challenged mice.Conclusions: SMF show potential as a viable prophylactic alternative for controlling LPS-induced MOF.

The roles of prostaglandin E2 and D2 in lipopolysaccharide-mediated changes in sleep.

When living organisms become sick as a result of a bacterial infection, a suite of brain-mediated responses occur, including fever, anorexia and sleepiness. Systemic administration of lipopolysaccharide (LPS), a common constituent of bacterial cell walls, increases body temperature and non-rapid eye movement (NREM) sleep in animals and induces the production of pro-inflammatory prostaglandins (PGs). PGE2 is the principal mediator of fever, and both PGE2 and PGD2 regulate sleep-wake behavior. The extent to which PGE2 and PGD2 are involved in the effect of LPS on NREM sleep remains to be clarified. Therefore, we examined LPS-induced changes in body temperature and NREM sleep in mice with nervous system-specific knockouts (KO) for the PGE2 receptors type EP3 or EP4, in mice with total body KO of microsomal PGE synthase-1 or the PGD2 receptor type DP, and in mice treated with the cyclooxygenase (COX) inhibitor meloxicam. We observed that LPS-induced NREM sleep was slightly attenuated in mice lacking EP4 receptors in the nervous system, but was not affected in any of the other KO mice or in mice pretreated with the COX inhibitor. These results suggest that the effect of LPS on NREM sleep is partially dependent on PGs and is likely mediated mainly by other pro-inflammatory substances. In addition, our data show that the main effect of LPS on body temperature is hypothermia in the absence of nervous system EP3 receptors or in the presence of a COX inhibitor.

Dietary glutamine prevents the loss of intestinal barrier function and attenuates the increase in core body temperature induced by acute heat exposure.

Dietary glutamine (Gln) supplementation improves intestinal function in several stressful conditions. Therefore, in the present study, the effects of dietary Gln supplementation on the core body temperature (T core), bacterial translocation (BT) and intestinal permeability of mice subjected to acute heat stress were evaluated. Male Swiss mice (4 weeks old) were implanted with an abdominal temperature sensor and randomly assigned to one of the following groups fed isoenergetic and isoproteic diets for 7d before the experimental trials: group fed the standard AIN-93G diet and exposed to a high ambient temperature (39°C) for 2h (H-NS); group fed the AIN-93G diet supplemented with l-Gln and exposed to a high temperature (H-Gln); group fed the standard AIN-93G diet and not exposed to a high temperature (control, C-NS). Mice were orally administered diethylenetriaminepentaacetic acid radiolabelled with technetium (99mTc) for the assessment of intestinal permeability or 99mTc-Escherichia coli for the assessment of BT. Heat exposure increased T core (approximately 41°C during the experimental trial), intestinal permeability and BT to the blood and liver (3h after the experimental trial) in mice from the H-NS group relative to those from the C-NS group. Dietary Gln supplementation attenuated hyperthermia and prevented the increases in intestinal permeability and BT induced by heat exposure. No correlations were observed between the improvements in gastrointestinal function and the attenuation of hyperthermia by Gln. Our findings indicate that dietary Gln supplementation preserved the integrity of the intestinal barrier and reduced the severity of hyperthermia during heat exposure. The findings also indicate that these Gln-mediated effects occurred through independent mechanisms.

Dietary supplementation of sulforaphane improves glucose tolerance and insulin sensitivity in middle‐aged obese mice (809.4)

Obesity and diabetes are growing health problems world‐wide. In this study, we tested whether sulforaphane, a compound derived from cruciferous vegetables, has anti‐diabetic action using animal model. One year old male mice were fed either a high‐fat diet (FHD) or HFD supplemented with sulforaphane (0.3 g/kg diet) for 7 weeks. We found that dietary provision of sulforaphane greatly improved fasting blood glucose, glucose tolerance, and peripheral insulin sensitivity in mice fed HFD. Sulforaphane treatment had no effect on body weight gain or body composition of obese mice. In addition, body temperature, energy expenditure, or cage activity of mice were not altered by sulforaphane treatment. These data for the first time suggest that sulforaphane may be a potent natural compound for preventing the development of insulin resistance and diabetes in old adult mice.Grant Funding Source: Supported by grants from the NCCAM of NIH (R01AT007077) and ADA Basic Research Award

Tempol intake improves inflammatory status in aged mice.

Oxidative stress is associated with both healthy aging and age-related disease states. In connection with oxidative stress, immunity is also a major component as a result of the chronic, low-grade inflammation associated with the development of tissue aging. Here we show that long-term treatment with the antioxidant tempol extends life-span in mice. Tempol-treated mice exhibited a reduction in mortality at 20 months. Tempol drinking did not have any effect on body weight, amount of visceral adipose tissue, or plasma biochemical parameters in aged mice. Body temperature of aged control mice (which drank only water) was significantly lower than young mice, but this reduction of body temperature was partially restored in aged mice which drank tempol. Plasma thiobarbituric acid-reactive substances and C-reactive protein were significantly increased in the control aged mice compared with young mice, but levels of both were normalized by tempol drinking. One of the endogenous antioxidants, ascorbic acid, was significantly increased in the plasma of mice which consumed tempol. The proportion of CD4 lymphocytes in the blood of aged tempol-treated mice was partially increased in comparison to aged control mice. These results suggest that the reduction of mortality by tempol is due to amelioration of chronic inflammation and improved function of the immune system through antioxidant effects.

Efficacy Comparison of Korean Ginseng and American Ginseng on Body Temperature and Metabolic Parameters

Ginseng has beneficial effects in cancer, diabetes and aging. There are two main varieties of ginseng: Panax ginseng (Korean ginseng) and Panax quinquefolius (American ginseng). There are anecdotal reports that American ginseng helps reduce body temperature, whereas Korean ginseng improves blood circulation and increases body temperature; however, their respective effects on body temperature and metabolic parameters have not been studied. We investigated body temperature and metabolic parameters in mice using a metabolic cage. After administering ginseng extracts acutely (single dose of 1000 mg/kg) or chronically (200 mg/kg/day for four weeks), core body temperature, food intake, oxygen consumption and activity were measured, as well as serum levels of pyrogen-related factors and mRNA expression of metabolic genes. Acute treatment with American ginseng reduced body temperature compared with PBS-treated mice during the night; however, there was no significant effect of ginseng treatment on body temperature after four weeks of treatment. VO 2, VCO 2, food intake, activity and energy expenditure were unchanged after both acute and chronic ginseng treatment compared with PBS treatment. In acutely treated mice, serum thyroxin levels were reduced by red and American ginseng, and the serum prostaglandin E2 level was reduced by American ginseng. In chronically treated mice, red and white ginseng reduced thyroxin levels. We conclude that Korean ginseng does not stimulate metabolism in mice, whereas a high dose of American ginseng may reduce night-time body temperature and pyrogen-related factors.

The antinociceptive effect of 4-substituted derivatives of 5-(4-chlorophenyl)-2-(morpholin-4-ylmethyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione in mice

The aim of the present experiments was to examine the antinociceptive activity of 4-substituted derivatives of 5-(4-chlorophenyl)-2-(morpholin-4-ylmethyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione in mice. The compounds were synthesized using the so-called Mannich reaction and their structures were confirmed using IR and 1H-NMR spectra. The antinociceptive activity was investigated in two behavioral tests: the hot plate test and the writhing test. For preliminary estimation of other behavioral effects, the locomotor activity of mice, the motor coordination in the rota-rod test, and the myorelaxation in the chimney test were also studied. The changes in body temperature of animals were also recorded. We demonstrated that all examined compounds produced antinociceptive effect, both in the hot plate test and in the writhing test, without impact on the motor coordination and myorelaxation of animals. The pharmacological effect of all drugs has been developed within 60 min after administration of drugs; and in two cases (T-103 and T-104), it has been a short-lasting effect (up to 90 min). Two compounds (T-100 and T-102) also inhibited the locomotor activity of animals. T-104 induced the changes in body temperature of mice. Generally, we demonstrated that combination of two different heterocyclic systems (morpholine and 1,2,4-triazole) might be beneficial for reduction of nociception.

Sickness behaviour after lipopolysaccharide treatment in ghrelin deficient mice

Ghrelin is an orexigenic hormone produced mainly by the gastrointestinal system and the brain. Much evidence also indicates a role for ghrelin in sleep and thermoregulation. Further, ghrelin was recently implicated in immune system modulation. Administration of bacterial lipopolysaccharide (LPS) induces fever, anorexia, and increased non-rapid-eye movement sleep (NREMS) and these actions are mediated primarily by proinflammatory cytokines. Ghrelin reduces LPS-induced fever, suppresses circulating levels of proinflammatory cytokines and reduces the severity and mortality of various models of experimental endotoxemia. In the present study, we determined the role of intact ghrelin signaling in LPS-induced sleep, feeding, and thermoregulatory responses in mice. Sleep-wake activity was determined after intraperitoneal, dark onset administration of 0.4, 2 and 10 μg LPS in preproghrelin knockout (KO) and wild-type (WT) mice. In addition, body temperature, motor activity and changes in 24-h food intake and body weight were measured. LPS induced dose-dependent increases in NREMS, and suppressed rapid-eye movement sleep, electroencephalographic slow-wave activity, motor activity, food intake and body weight in both Ppg KO and WT mice. Body temperature changes showed a biphasic pattern with a decrease during the dark period followed by an increase in the light phase. The effects of the low and middle doses of LPS were indistinguishable between the two genotypes. Administration of 10 μg LPS, however, induced significantly larger changes in NREMS and wakefulness amounts, body temperature, food intake and body weight in the Ppg KO mice. These findings support a role for ghrelin as an endogenous modulator of inflammatory responses and a central component of arousal and feeding circuits.

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Introduction: Heatstroke is a life-threatening illness caused by an elevation of the body temperature due to exposure to high temperature and/or humidity environments, and its incidence has been increasing in the summer in Japan. It is considered to be important to drink water to prevent the development of heatstroke. OS-1 is an oral rehydration solution which was designed to alleviate dehydration due to various conditions, such as cholera, and contains electrolyte ions such as sodium (50 mEq/l), potassium (20 mEq/l), chloride (50 mEq/l), magnesium (2 mEq/l), sulfate (2 mEq/l) and phosphate (2 mmol/l), as well as lactate (31 mEq/l) and glucose (18 g/l). Although drinking OS-1 is in the summer time, the effects of OS-1 supplementation on heatstroke have not been examined in detail. We produced a non-lethal experimental heatstroke model in mice, and then determined their core body temperature after supplying either pure water or OS-1. Methods: Experimental heatstroke was produced in a moisture chamber. The mean conditions of the chamber were an ambient temperature of 41 ± 0.5 ºC and relative humidity at 70 - 99% during the heat-exposure (HE). During the experiment, the ambient temperature, relative humidity and Wet-Bulb Globe Temperature (WGBT) were monitored every 1 minute. Male C57BL/6J mice had a thermometer implanted into the abdominal cavity three weeks before the experiments, and were maintained at a normal temperature (ambient temperature 24 ± 1ºC and relative humidity 20–40%) with free access to food and water. The animals were randomly divided into three groups: a no supplement group (control, n=6), 30 mg/kg water supplement group (Water, n=6) and 30 mg/kg OS-1 supplement group (OS-1, n=6) and were subsequently not allowed access to any drink for three hours. Then, the animals were subjected to HE for 60 min in the moisture chamber. The supplement was administered twice orally three hours after dehydration (before HE) and immediately after HE. The animals were then returned to a normal temperature environment and maintained for a further seven days with free access to food and water. It was previously reported that the core body temperature of mice rapidly elevated and reached the maximal temperature after the onset of HE, then it decreased immediately and severe hypothermia was induced after the HE. It took several hours to recover to the normal circadian rhythms. The level of hypothermia was correlated with the severity of HE in mice. In our experiments, the core body temperature was recorded every five minutes from one day prior to HE to five days post-HE in all the mice. The circadian rhythms of the core body temperatures before HE were recorded. The maximum core body temperature during the HE, minimum core body temperatures after the HE and the time to recover to normal circadian rhythm post-HE were compared among the groups. Results: Actual mean condition of the moisture chamber during HE was ambient temperature (39.0 ± 0.16 ºC), relative humidity (93.7 ± 0.11 %) and WGBT (41.6 ± 0.18 ºC). The control group was account for maximal temperature at 32 ± 2.5 min after onset of HE and measured at 41.1 ± 0.1 ºC. The maximal temperature in water and OS-1 groups was 40.9 ± 0.4 ºC and 39.7 ± 0.17 ºC, respectively. Maximal temperature in OS-1 group was significantly lower than that in control (p<0.05). Minimal body temperature which was account for 236 ± 33 min after onset of HE, was no difference between three groups (Control: 31.7 ± 1.45 ºC, water: 31.3kelou ºC, and OS-1: 33.3 ± 0.44 ºC). However, while the circadian rhythm of body temperature was lost during the HE, recovery of the rhythm in OS-1 group (495 ± 48 minutes) was significantly shorter than that in water group (961 ± 138 minutes, p<0.05) and was tend to shorter than control (881 ± 120 minutes, p = 0.056). Conclusions: These results suggest that OS-1 supplementation before and after HE decreased the dysregulation of body temperature, likely due to the efficient rehydration.

Circadian Phase Determines Effects of Repeated Ethanol Vapor Exposure and Withdrawal on Body Temperature and Activity Rhythms of Male Mice

Physiological responses to acute ethanol (EtOH) injection depend critically on the timing of their administration. Whether daily timing modulates effects of longer intoxication intervals characteristic of alcohol-dependent humans remains unknown. The present work examines time-of-day effects during EtOH exposure and withdrawal measured by locomotor activity (ActLoc ) and body temperature (Tb ) across multiple rounds of EtOH exposure/withdrawal. Two groups of C57BL/6J mice (n=8 per group), implanted with radio-telemeters, were entrained to opposite light-dark periods (14:10 LD cycle) so that their rest/activity cycles were 12hours apart. Under a 2-hour skeleton photoperiod animals were simultaneously exposed to 3 daily cycles of EtOH vapor inhalation (14hours EtOH on) and withdrawal (10hours EtOH off). During this time, air-only control groups (n=4 per group) matched for entrainment were handled in a comparable manner. After the third cycle of EtOH vapor, the animals were left undisturbed for 11days to recover. The 14-day protocol was repeated 3 additional times. During intoxication, mice exposed to EtOH in the subjective night exhibited greater hypothermia and more overall disruptions in the Tb and ActLoc rhythms. Acute withdrawal induced hypothermia during the subjective night and hyperthermia during the subjective day. Animals in both phases demonstrated significant disruptions in ActLoc during withdrawal. ActLoc had little effect on Tb during EtOH exposure, but it significantly influenced Tb during acute withdrawal. The physiological responses of both EtOH exposure and withdrawal differ as a function of time of day. These findings suggest that controlling for the circadian phase of exposure and/or withdrawal may mitigate the severity of symptomatic withdrawal.

Heme-Induced Neutrophil Extracellular Traps (NETs) Formation Contributes To Sickle Cell Disease Pathogenesis

Sickle cell disease (SCD) is characterized by chronic inflammation, continuous oxidative stress and severe hemolysis. Activation of endothelial cells, adhesion of sickle erythrocytes and polymorphonuclear neutrophils (PMNs) have been reported to mediate SCD vaso-occlusion. PMNs from SCD patients produce significantly higher basal levels of reactive oxygen species (ROS) and contain less intracellular ROS scavengers than normal individuals. The formation of neutrophil extracellular traps (NETs), which requires the upregulation of intracellular ROS, has been described as a critical innate mechanism to contain infectious insults and to participate in thromboinflammatory injury. In addition, histones and granular proteins released during NET formation can directly damage lung microvascular endothelial cells. Based on these results, we explored the possibility that neutrophils contribute to SCD pathophysiology through NETs. To investigate the presence of NETs in vivo, we used a humanized mouse model of SCD that expresses human sickle hemoglobin exclusively and shares many features of human SCD. Immunofluorescence images of lung samples revealed a significantly higher number of NET DNA fibers in SCD mice (22.6 ± 2.8 NETs/field of view) compared to control mice (5.96 ± 0.86 NETs/field of view, p<0.0001) following proinflammatory cytokine (TNF-α) challenge. We confirmed that these DNA fibers were not resulting from section artifacts or remnants of apoptotic or necrotic cells by co-staining these fibers with antibodies against citrullinated histone H3 and neutrophil elastase (NE), both of which have been identified as markers of NETs. Citrullinated histone H3+ NE+ NETs were identified in the lungs of SCD mice and were found within blood vessels. Concurrently, the soluble NET component plasma DNA was significantly higher in the peripheral blood of SCD mice compared to control mice (∼524 versus ∼48 ng/ml, p<0.001). Further, plasma nucleosomes were detectable only in SCD mice (∼0.11 U/ml). We also found that SCD mice experienced body temperature decline (a reduction of 5.3 ± 1.0°C) following TNF-α challenge whereas the body temperature of control mice was unaffected. A significant positive correlation was found between numbers of NETs and reduction of body temperature in these mice (r=0.72, p<0.0001). DNase I treatment reduced NETs by 38% in SCD mice (12.2 ± 0.9 versus 7.5 ± 0.7 NETs/field of view, for vehicle- and DNase I-treated, respectively, p<0.001), protected these mice from NET-associated hypothermia and significantly prolonged their survival (p<0.05) compared to vehicle-treated SCD mice. As a result of chronic hemolysis, SCD is associated with increased plasma heme. Like SCD patients, SCD mice have significantly higher plasma heme concentration compared to control mice (50.8 ± 5.2 versus 23.8 ± 2.8 μM, p<0.001). We hypothesized that heme is the plasma factor that stimulates PMNs to produce NETs in SCD mice. In vitro study showed that heme activated PMNs to produce citrullinated histone H3+ NE+ NETs in a ROS- and heme-iron dependent manner. Heme injection significantly increased NET formation in control mice (4.5 ± 0.7 versus 9.6 ± 1.7 NETs/field of view for vehicle- and heme-treated, respectively, p<0.01) and accounted for the acute body temperature decline in these mice (3.1 ± 0.8°C, p<0.01). On the other hand, hemopexin administration, which decreased total plasma heme concentration in SCD mice, reduced NET formation by 41% (11.6 ± 0.8 versus 6.9 ± 0.7 NETs/field of view, for vehicle- and hemopexin-treated, respectively, p<0.0001) and protected treated mice from NET-associated hypothermia. Our study thus demonstrates that NETs may contribute to the pathogenesis of SCD and that heme released during hemolysis promotes NET generation in vivo. Targeting heme-mediated NET formation may represent a useful strategy in managing SCD and other pathological states involving severe hemolysis. Disclosures:No relevant conflicts of interest to declare.

Optimization of a Pain Model: Effects of Body Temperature and Anesthesia on Bladder Nociception in Mice

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating urological condition that is resistant to treatment and poorly understood. To determine novel molecular treatment targets and to elucidate the contribution of the nervous system to IC/BPS, many rodent bladder pain models have been developed. In this study we evaluated the effects of anesthesia induction and temperature variation in a mouse model of bladder pain known as urinary bladder distension (UBD). In this model compressed air is used to distend the bladder to distinct pressures while electrodes record the reflexive visceromotor response (VMR) from the overlying abdominal muscle. Two isoflurane induction models are commonly used before UBD: a short method lasting approximately 30 minutes and a long method lasting approximately 90 minutes. Animals were anesthetized with one of the methods then put through three sets of graded bladder distensions. Distensions performed following the short anesthesia protocol were significantly different from one another despite identical testing parameters; this same effect was not observed when the long anesthesia protocol was used. In order to determine the effect of temperature on VMRs, animals were put through three graded distension sets at 37.5 (normal mouse body temperature), 35.5, and 33.5°C. Distensions performed at 33.5 and 35.5°C were significantly lower than those performed at 37.5°C. Additionally, Western blot analysis revealed significantly smaller increases in spinal levels of phosphorylated extracellular-signal regulated kinase 2 (pERK2) following bladder distension in animals whose body temperature was maintained at 33.5°C as opposed to 37.5°C. These results highlight the significance of the dynamic effects of anesthesia on pain-like changes and the importance of close monitoring of temperature while performing UBD. For successful interpretation of VMRs and translation to human disease, body temperature should be maintained at 37.5°C and isoflurane induction should gradually decrease over the course of 90 minutes.

Toll-like receptors 2 and 4 modulate autonomic control of heart rate and energy metabolism

Toll-like receptors (TLR) are innate immune receptors typically activated by microbial-associated molecular patterns (MAMPs) during infection or damage-associated molecular patterns (DAMPs) as a result of tissue injury. Recent findings suggest that TLR2 and TLR4 signaling play important roles in developmental and adult neuroplasticity, and in learning and memory. In addition, activation of TLR2 and TLR4 worsens ischemic injury to the heart and brain in animal models of myocardial infarction and stroke. TLR activation is also implicated in thermoregulation and fever in response to infection. However, it is not known whether TLRs participate in the regulation of the sympathetic and/or parasympathetic components of the autonomic nervous system (ANS). Here we provide evidence that TLR2 and TLR4 influence autonomic regulation of heart rate (HR) body temperature and energy metabolism in mice. We show that mice lacking TLR2 or TLR4 exhibit reduced basal HR, which results from an increase of parasympathetic tone. In addition, thermoregulatory responses to stress are altered in TLR2-/- and TLR4-/- mice, and brown fat-dependent thermoregulation is altered in TLR4-/- mice. Moreover, TLR2-/- and TLR4-/- mice consume less food and exhibit a greater mass compared to wild type mice. Collectively, our findings suggest important roles for TLR2 and TLR4 in the ANS regulation of cardiovascular function, thermoregulation, and energy metabolism.

A simple and inexpensive system for controlling body temperature in small animal experiments using MRI and the effect of body temperature on the hepatic kinetics of Gd-EOB-DTPA

The purpose of this study was to develop a simple and inexpensive system for controlling body temperature in small animal experiments using magnetic resonance imaging (MRI) and to investigate the effect of body temperature on the kinetic behavior of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) in the liver.In our temperature-control system, body temperature was controlled using a feedback-regulated heated or cooled air flow generated by two Futon dryers. The switches of the two Futon dryers were controlled using a digital temperature controller, in which the rectal temperature of a mouse measured by an optical fiber thermometer was used as the input.In experimental studies, male ICR mice aged 8weeks old were used and allocated into 5 groups (39-, 36-, 33-, 30-, and 27-degree groups, n=10), in which the body temperature was maintained at 39 °C, 36 °C, 33 °C, 30 °C, and 27 °C, respectively, using our system. The dynamic contrast-enhanced MRI (DCE-MRI) data were acquired with an MRI system for animal experiments equipped with a 1.5-Tesla permanent magnet, for approximately 43min, after the injection of Gd-EOB-DTPA into the tail vein. After correction of the image shift due to the temperature-dependent drift of the Larmor frequency using the gradient-based image registration method with robust estimation of displacement parameters, the kinetic behavior of Gd-EOB-DTPA was analyzed using an empirical mathematical model. With the use of this approach, the upper limit of the relative enhancement (A), the rates of contrast uptake (α) and washout (β), the parameter related to the slope of early uptake (q), the area under the curve (AUC), the maximum relative enhancement (REmax), the time to REmax (Tmax), and the elimination half-life of the contrast agent (T1/2) were calculated.The body temperature of mice could be controlled well by use of our system. Although there were no significant differences in α, AUC, and q among groups, there were significant differences in A, REmax, β, Tmax, and T1/2, indicating that body temperature significantly affects the kinetic behavior of Gd-EOB-DTPA in the liver.In conclusion, our system will be useful for controlling body temperature in small animal experiments using MRI. Because body temperature significantly affects the kinetic behavior of Gd-EOB-DTPA in the liver, the control of body temperature is essential and should be carefully considered when performing DCE-MRI studies in small animal experiments.

OP08 The hydrogen sulfide donor GYY4137 attenuates transient receptor potential vanilloid 1 (TRPV1) antagonist-mediated hyperthermia

The transient receptor potential vanilloid 1 (TRPV1) ion channel is a member of the TRP superfamily of receptors and a well-known integrator of noxious stimuli. The expression of TRPV1 on primary sensory neurons has been very well characterised, however, recent studies have shown that they are also expressed in non-neuronal tissue [1] . Whilst TRPV1 antagonism is a promising analgesic strategy, early generation antagonists, such as JNJ17203212 [2] resulted in poorly-understood hyperthermia. Hydrogen sulfide (H 2 S) is a well-known vasodilator [3] , [4] , and inhalation of H 2 S can suspend animation, which includes a decreased body temperature [5] . We investigated whether the H 2 S donor GYY4137 [6] would attenuate the hyperthermia caused by JNJ17203212. Male CD1 mice (Charles River, 35–40 g) were used for all experiments in accordance with the Scientific Procedures Act (1986). Radiotelemetry devices allowed the measurement of temperature and activity of freely moving, conscious singly-housed mice in their home cages. Probes (TA-T10A, DSI, USA) were surgically implanted into the peritoneal cavity under 2–5% isoflurane anaesthesia. Preoperative analgesia was administered to aid recovery. Mice were left to recover for one week before temperature monitoring began. A 2-h baseline measurement was taken before i.p. treatment of the mice with either: 30 mg/kg JNJ17203212 ( n = 5), 50 mg/kg GYY4137 ( n = 5) or 11 mg/kg d , l - propargylglycine (PAG, n = 5) or vehicle (10 ml/kg). A pre-treatment of 50 mg/kg GYY4137 30 min before 30 mg/kg JNJ17203212 was performed to determine the effect of GYY4137 on JNJ17203212-mediated hyperthermia. Results were analysed using repeated measures 2-way ANOVA and expressed as mean ±SEM. JNJ17203212 (30 mg/kg) caused a significant increase in body temperature compared to vehicle (10%DMSO) treated mice at 2–3 h post administration ( n = 5, P P n = 4) and 50 mg/kg GYY4137 ( n = 4) treatment did not significantly change body temperature compared to vehicle (saline) treated mice). Treatment of mice with 50 mg/kg GYY4137 30 min before 30 mg/kg JNJ17203212 resulted in a reduction in amplitude of the JNJ17203212-mediated hyperthermia compared to saline-pre-treated mice ( n = 6, P This study provides an intriguing insight into a possible way of overcoming TRPV1 antagonist-induced hyperthermia. Under physiological conditions, GYY4137 and PAG did not affect core body temperature. The TRPV1 antagonist JNJ17203212 significantly increased body temperature of male CD1 mice compared to vehicle treated mice. The H 2 S donor GYY4137 reduced the JNJ17203212-mediated increase in body temperature. Further studies will determine whether GYY4137 will affect body temperature under pathological conditions and the mechanism involved in these changes.

Vaccination with recombinant modified vaccinia virus Ankara prevents the onset of intestinal allergy in mice

Modified vaccinia virus Ankara (MVA)-encoding antigens are considered as safe vaccine candidates for various infectious diseases in humans. Here, we investigated the immune-modulating properties of MVA-encoding ovalbumin (MVA-OVA) on the allergen-specific immune response. The immune-modulating properties of MVA-OVA were investigated using GM-CSF-differentiated BMDCs from C57BL/6 mice. OVA expression upon MVA-OVA infection of BMDCs was monitored. Activation and maturation markers on viable MVA-OVA-infected mDCs were analyzed by flow cytometry. Secretion of INF-γ, IL-2, and IL-10 was determined in a co-culture of BMDCs infected with wtMVA or MVA-OVA and OVA-specific OT-I CD8(+) and OT-II CD4(+ ) T cells. BALB/c mice were vaccinated with wtMVA, MVA-OVA, or PBS, sensitized to OVA/alum and challenged with a diet containing chicken egg white. OVA-specific IgE, IgG1, and IgG2a and cytokine secretion from mesenteric lymph node (MLN) cells were analyzed. Body weight, body temperature, food uptake, intestinal inflammation, and health condition of mice were monitored. Infection with wtMVA and MVA-OVA induced comparable activation of mDCs. MVA-OVA-infected BMDCs expressed OVA and induced enhanced IFN-γ and IL-2 secretion from OVA-specific CD8(+ ) T cells in comparison with OVA, wtMVA, or OVA plus wtMVA. Prophylactic vaccination with MVA-OVA significantly repressed OVA-specific IgE, whereas OVA-specific IgG2a was induced. MVA-OVA vaccination suppressed TH 2 cytokine production in MLN cells and prevented the onset of allergic symptoms and inflammation in a mouse model of OVA-induced intestinal allergy. Modified vaccinia virus Ankara-ovalbumin (MVA-OVA) vaccination induces a strong OVA-specific TH 1- immune response, likely mediated by the induction of IFN-γ and IgG2a. Finally, MVA-based vaccines need to be evaluated for their therapeutic potential in established allergy models.

Physical exercise-induced changes in the core body temperature of mice depend more on ambient temperature than on exercise protocol or intensity

The mechanisms underlying physical exercise-induced hyperthermia may be species specific. Therefore, the present study aimed to investigate the effects of exercise intensity and ambient temperature on the core body temperature (T core) of running mice, which provide an important experimental model for advancing the understanding of thermal physiology. We evaluated the influence of different protocols (constant- or incremental-speed exercises), treadmill speeds and ambient temperatures (T a) on the magnitude of exercise-induced hyperthermia. To measure T core, a telemetric sensor was implanted in the abdominal cavity of male adult Swiss mice under anesthesia. After recovering from the surgery, the animals were familiarized to running on a treadmill and then subjected to the different running protocols and speeds at two T a: 24 °C or 34 °C. All of the experimental trials resulted in marked increases in T core. As expected, the higher-temperature environment increased the magnitude of running-induced hyperthermia. For example, during incremental exercise at 34 °C, the maximal T core achieved was increased by 1.2 °C relative to the value reached at 24 °C. However, at the same T a, neither treadmill speed nor exercise protocol altered the magnitude of exercise-induced hyperthermia. We conclude that T core of running mice is influenced greatly by T a, but not by the exercise protocols or intensities examined in the present report. These findings suggest that the magnitude of hyperthermia in running mice may be regulated centrally, independently of exercise intensity.

Elevated blood pressure, heart rate and body temperature in mice lacking the XLαs protein of the Gnas locus is due to increased sympathetic tone

New FindingsWhat is the central question of this study?Previously, we showed that Gnasxl knock-out mice are lean and hypermetabolic, with increased sympathetic stimulation of adipose tissue. Do these mice also display elevated sympathetic cardiovascular tone? Is the brain glucagon-like peptide-1 system involved?What is the main finding and its importance?Gnasxl knock-outs have increased blood pressure, heart rate and body temperature. Heart rate variability analysis suggests an elevated sympathetic tone. The sympatholytic reserpine had stronger effects on blood pressure, heart rate and heart rate variability in knock-out compared with wild-type mice. Stimulation of the glucagon-like peptide-1 system inhibited parasympathetic tone to a similar extent in both genotypes, with a stronger associated increase in heart rate in knock-outs. Deficiency of Gnasxl increases sympathetic cardiovascular tone.Imbalances of energy homeostasis are often associated with cardiovascular complications. Previous work has shown that Gnasxl-deficient mice have a lean and hypermetabolic phenotype, with increased sympathetic stimulation of adipose tissue. The Gnasxl transcript from the imprinted Gnas locus encodes the trimeric G-protein subunit XLαs, which is expressed in brain regions that regulate energy homeostasis and sympathetic nervous system (SNS) activity. To determine whether Gnasxl knock-out (KO) mice display additional SNS-related phenotypes, we have now investigated the cardiovascular system. The Gnasxl KO mice were ∼20 mmHg hypertensive in comparison to wild-type (WT) littermates (P≤ 0.05) and hypersensitive to the sympatholytic drug reserpine. Using telemetry, we detected an increased waking heart rate in conscious KOs (630 ± 10 versus 584 ± 12 beats min−1, KO versus WT, P≤ 0.05). Body temperature was also elevated (38.1 ± 0.3 versus 36.9 ± 0.4°C, KO versus WT, P≤ 0.05). To investigate autonomic nervous system influences, we used heart rate variability analyses. We empirically defined frequency power bands using atropine and reserpine and verified high-frequency (HF) power and low-frequency (LF) LF/HF power ratio to be indicators of parasympathetic and sympathetic activity, respectively. The LF/HF power ratio was greater in KOs and more sensitive to reserpine than in WTs, consistent with elevated SNS activity. In contrast, atropine and exendin-4, a centrally acting agonist of the glucagon-like peptide-1 receptor, which influences cardiovascular physiology and metabolism, reduced HF power equally in both genotypes. This was associated with a greater increase in heart rate in KOs. Mild stress had a blunted effect on the LF/HF ratio in KOs consistent with elevated basal sympathetic activity. We conclude that XLαs is required for the inhibition of sympathetic outflow towards cardiovascular and metabolically relevant tissues.

MGlu2/3 Agonist-Induced Hyperthermia: An In Vivo Assay for Detection of mGlu2/3 Receptor Antagonism and its Relation to Antidepressant-Like Efficacy in Mice

An assay to detect the on-target effects of mGlu2/3 receptor antagonists in vivo would be valuable in guiding dosing regimens for the exploration of biological effects of potential therapeutic import. Multiple approaches involving blockade of mGlu2/3 receptor agoinist-driven behavioral effects in mice and rats were investigated. Most of these methods failed to provide a useful method of detection of antagonists in vivo (e.g., locomotor activity). In contrast, the mGlu2/3 receptor agonist LY379268 produced dose-dependent increases in body temperature of mice. The hyperthermic effects of LY379268 was abolished in mGlu2 and in mGlu2/3 receptor null mice but not in mGlu3 null mice. Hyperthermia was not produced by an mGlu8 receptor agonist. Agonist-induced hyperthermia was prevented in a dose-dependent manner by structurally-distinct mGlu2/3 receptor antagonists. The blockade was stereo-specific. Moreover, this biological readout was responsive to both orthosteric and to negative allosteric modulators of mGlu2/3 receptors. Antagonism of agonist-induced hyperthermia predicted antidepressant-like efficacy in the mouse forced swim test. As with the hyperthermic response, the antidepressant-like effects of mGlu2/3 receptor antagonists were shown to be due to mGlu2 and not to mGlu3 or mGlu8 receptors through the use of receptor knock-out mice. The ability to rapidly assess on-target activity of mGlu2/3 receptor antagonists enables determination of parameters for setting efficacy doses in vivo. In turn, efficacy-related data in the preclinical laboratory can help to set expectations of therapeutic potential and dosing in humans.

Involvement of PAF metabolism in anaphylaxis and prevention by Rush-SOTI

Background Allergy is a critical problem of public health in developed countries. Anaphylaxis is a rapid allergic response with symptoms such as urticarial, itching, diarrhea, and even death. Since allergy is caused by the failure of tolerance induction to exogenous antigens, its establishment of tolerance is a fundamental therapy for allergic diseases. Oral tolerance is a physiological way to actively induce unresponsiveness to food antigens. However, oral immunotherapy using antigens occasionally fails to induce complete tolerance in patients that hinder the development of the therapy. Methods To clarify the mechanism of the induction of allergy and oral tolerance, we have established a protocol with rush administration of oral antigen and evaluated how anaphylaxis is suppressed. Results Using this rush specific oral tolerance induction (RushSOTI) protocol, we found that the drop of body temperature was partially blocked and recovery was accelerated. Antigen-specific IgE was not reduced by RushSOTI. Antagonists of both histamine and platelet-activating factor (PAF) completely prevented the drop of body temperature in anaphylactic mice. From the kinetics, it is suggested that histamine acts in the early phase while PAF functions in the late phase.We further analyze the cell population involved in the temperature drop. Depletion of Gr-1 + neutrophils but not mast cells