Nest building is a novel method for indexing severity of alcohol withdrawal in mice

Radiation cataract in Heterogeneous Stock mice after γ-ray or HZE ion exposure

Health effects of space radiation are a serious concern for astronauts on long-duration missions. The lens of the eye is one of the most radiosensitive tissues in the body and, therefore, ocular health risks for astronauts is a significant concern. Studies in humans and animals indicate that ionizing radiation exposure to the eye produces characteristic lens changes, termed "radiation cataract," that can affect visual function. Animal models of radiation cataractogenesis have previously utilized inbred mouse or rat strains. These studies were essential for determining morphological changes and dose-response relationships between radiation exposure and cataract. However, the relevance of these studies to human radiosensitivity is limited by the narrow phenotypic range of genetically homogeneous animal models. To model radiation cataract in genetically diverse populations, longitudinal cataract phenotyping was nested within a lifetime carcinogenesis study in male and female heterogeneous stock (HS/Npt) mice exposed to 0.4 Gy HZE ions (n = 609) or 3.0 Gy γ-rays (n = 602) and in unirradiated controls (n = 603). Cataractous change was quantified in each eye for up to 2 years using Merriam-Focht grading criteria by dilated slit lamp examination. Virtual Optomotry™ measurement of visual acuity and contrast sensitivity was utilized to assess visual function in a subgroup of mice. Prevalence and severity of posterior lens opacifications were 2.6-fold higher in HZE ion and 2.3-fold higher in γ-ray irradiated mice compared to unirradiated controls. Male mice were at greater risk for spontaneous and radiation associated cataracts. Risk for cataractogenesis was associated with family structure, demonstrating that HS/Npt mice are well-suited to evaluate genetic determinants of ocular radiosensitivity. Last, mice were extensively evaluated for cataract and tumor formation, which revealed an overlap between individual susceptibility to both cancer and cataract.

The impact of tethered recording techniques on activity and sleep patterns in rats

Electrophysiological recordings in animals constitute frequently applied techniques to study neuronal function. In this context, several authors described tethered recordings as a semi-restraint situation with negative implications for animal welfare and suggested radiotelemetric setups as a refinement measure. Thus, we here investigated the hypothesis that tethered recordings exert measurable effects on behavioral and sleep patterns in Sprague–Dawley rats. Animals were kept in monitoring glass cages either with or without a head connection to a recording cable. Saccharin preference, nest building, serum corticosterone and fecal corticosterone metabolite levels were in a comparable range in both groups. The proportion of vigilance states was not affected by the cable connection. Minor group differences were detected in bout lengths distributions, with a trend for longer NREM and WAKE stages in animals with a cable connection. However, a relevant effect was not further confirmed by an analysis of the number of sleep/wake and wake/sleep transitions. The analysis of activity levels did not reveal group differences. However, prolonged exposure to the tethered condition resulted in an intra-group increase of activity. In conclusion, the comparison between freely moving vs tethered rats did not reveal major group differences. Our findings indicate that telemetric recordings only offer small advantages vs cabled set ups, though this may differ in other experimental studies where for example anxiety- or drug-induced effects are analyzed.

DL0410 ameliorates cognitive disorder in SAMP8 mice by promoting mitochondrial dynamics and the NMDAR-CREB-BDNF pathway

Alzheimer's disease (AD) is a worldwide problem and there are no effective drugs for AD treatment. Previous studies show that DL0410 is a multi-target, anti-AD agent. In this study, we investigated the therapeutic effect of DL0410 and its action mechanism in SAMP8 mice. DL0410 (1-10 mg·kg^-1·d^-1) was orally administered to 8-month-old SAMP mice (SAMP8) for 8 weeks. We showed that DL0410 administration effectively ameliorated the cognitive deficits in the Morris water maze test, novel object recognition test, and nest building test. We revealed that DL0410 dose-dependently increased the expression levels of the mitochondrial proteins (PGC-1α, Mitofusin 2, OPA1, and Drp1), and subsequently ameliorated the processes of mitochondrial biosynthesis, fusion, and fission in the cortex and hippocampus of SAMP8 mice. Furthermore, DL0410 administration promoted the expression of synaptic proteins (synaptophysin and PSD95) in the brain of SAMP8 mice, and upregulated the protein phosphorylation in NMDAR-CAMKII/CAMKIV-CREB pathway responsible for the synaptic plasticity. DL0410 administration dose-dependently increased the expression of BDNF and TrkB, and the neurotrophic effect was mediated via the ERK1/2 and PI3K-AKT-GSK-3β pathways. DL0410 administration upregulated Bcl-2, increased the Bcl-2/Bax ratio and the level of caspase 3 and PARP-1, alleviating neuronal apoptosis. We proposed that the NMDAR-CREB-BDNF pathway might establish a positive feedback loop between synaptic plasticity and neurotrophy, with CREB at the center. In summary, DL0410 promotes synaptic function and neuronal survival, thus ameliorating cognitive deficits in SAMP8 mice via improved mitochondrial dynamics and increased activity of the NMDAR-CREB-BDNF pathway. DL0410 is a promising candidate to treat aging-related AD, and deserves more research and development in future.

Assessment of nest building and social interaction behavior in mice exposed to acute social defeat stress using a three-dimensional depth camera

Nest building is an instinctive behavior toward protection from predators, body temperature regulation, and courtship. Previously, we discovered that acute and chronic social defeat stress suppresses the onset of nest-building behavior in male mice (C57BL/6J). Here, we analyzed nest building and other behavioral deficits induced by acute social defeat stress (ASDS). We utilized a customized cage and specifically developed observational programs for nest building, social avoidance, and other behaviors using an infrared depth camera to acquire three-dimensional (3D) data of animal behavior (Negura system). We determined the volume of nesting materials from these 3D depth images. Mice exposed to ASDS showed increased spontaneous activities, decreased rearing, and delayed nest building; however, nest-building activity was gradually recovered during the dark period of the 24 hr observation interval. At the endpoint following 24 hr, the ASDS and control groups showed no differences in nest volumes. Furthermore, we observed the time courses of both nest building and social avoidance behaviors and their relationship using the Negura system. Our data demonstrated a weak positive correlation between nest-building delay and social avoidance in ASDS mice. The Negura system can observe various behaviors that reflect the effects of social defeat stress.

DL0410 ameliorates cognitive deficits in APP/PS1 transgenic mice by promoting synaptic transmission and reducing neuronal loss

At present, few available drugs can be used to either improve pathological features or prevent the progression of Alzheimer's disease (AD). DL0410 ((1,1'-([1,1'-biphenyl]-4,4'-diyl) bis (3-(piperidin-1-yl) propan-1-one) dihydrochloride) is a multiple-target small molecule that has been found to reverse cognitive impairment in different animal models of AD. In this study we evaluated the cognition-improving effects of DL0410 in APP/PS1 transgenic mice and explored the underlying mechanisms. APP/PS1 transgenic mice were administered DL0410 (3, 10, 30 mg· kg-1· d-1, ig) for 2 months. We found that DL0410 administration significantly ameliorated cognitive deficits in both the nest-building and Morris water maze tests. In electrophysiological analysis of hippocampal slices, we showed that DL0410 administration significantly enhanced the field EPSP slope and HFS-induced LTP in CA1 area. Furthermore, we revealed that DL0410 administration significantly increased the phosphorylation of AKT and the activity of GSK-3β in the hippocampus and cortex. Moreover, DL0410 administration dose-dependently increased the expression level of phosphorylated ERK1/2 in the hippocampus and cortex. In addition, DL0410 dose-dependently decreased the neuronal loss by decreasing the production of Aβ deposition, inhibited glial overactivation, and the production of inflammatory cytokines such as TNF-α, IL-1β, and IL-6. We conclude that DL0410 ameliorates cognitive deficits in APP/PS1 transgenic mice by promoting synaptic transmission via activating the AKT/GSK-3β and MAPK/ERK signaling pathway and reducing neuronal loss. DL0410 may be an effective agent for AD treatment in the future.

Tanshinone IIA ameliorates cognitive deficits by inhibiting endoplasmic reticulum stress-induced apoptosis in APP/PS1 transgenic mice

Our previous data indicated that tanshinone IIA (tan IIA) improves learning and memory in a mouse model of Alzheimer's disease (AD) induced by streptozotocin via restoring cholinergic function, attenuating oxidative stress and blocking p38 MAPK signal pathway activation. This study aims to estimate whether tan IIA inhibits endoplasmic reticulum (ER) stress-induced apoptosis to prevent cognitive decline in APP/PS1 transgenic mice. Tan IIA (10 mg/kg and 30 mg/kg) was intraperitoneally administered to the six-month-old APP/PS1 mice for 30 consecutive days. β-amyloid (Aβ) plaques were measured by immunohistochemisty and Thioflavin S staining, apoptotic cells were observed by TUNEL, ER stress markers and apoptosis signaling proteins were investigated by western blotting and RT-PCR. Our results showed that tan IIA significantly ameliorates cognitive deficits and improves spatial learning ability of APP/PS1 mice in the nest-building test, novel object recognition test and Morris water maze test. Furthermore, tan IIA significantly reduced the deposition of Aβ plaques and neuronal apoptosis, and markedly prevented abnormal expression of glucose regulated protein 78 (GRP78), initiation factor 2α (eIF2α), inositol-requiring enzyme 1α (IRE1α), activating transcription factor 6 (ATF6), as well as suppressed the activation of C/EBP homologous protein (CHOP) and c-Jun N-terminal kinase (JNK) pathways in the parietal cortex and hippocampus. Moreover, tan IIA induced an up-regulation of the Bcl-2/Bax ratio and down-regulation of caspase-3 protein activity. Taken together, the above findings indicated that tan IIA improves learning and memory through attenuating Aβ plaques deposition and inhibiting ER stress-induced apoptosis. These results suggested that tan IIA might become a promising therapeutic candidate drug against AD.

Nest-building performance in rats: impact of vendor, experience, and sex

Nest building behavior has been intensely applied as a parameter for severity assessment in mice. In contrast, only a limited number of studies have reported nest building data from rats. Here, we assessed nest building in rats in two different facilities addressing the hypotheses that the vendor, previous experience with the nesting material as well as sex of the rats has an impact on the performance. Data from two study sites and three raters were compared to obtain information about the robustness of nest complexity scoring. The findings demonstrate a generally poor nest building performance in rats with a pronounced day-to-day fluctuation, and site-specific differences. Application of a newly developed scoring system resulted in an intermediate inter-rater reliability. Previous experience with the nesting material did not exert a consistent impact on nest complexity scores. Sex differences proved to depend on vendor and animal facility without consistent findings supporting a superior performance in female or male rats. In conclusion, our findings argue against a robust and consistent influence of sex and familiarity with the nesting material. The comparison between facilities suggests that local conditions need to be considered as influencing factors, which should be explored in more detail by future multicenter approaches. Considering the day-to-day fluctuation and the intermediate inter-rater reliability, we highly recommend to base nest complexity evaluation on means from several subsequent days analyzed by a group of experienced raters.

Fish oil treatment reduces chronic alcohol exposure induced synaptic changes

Alcohol addiction is a chronic neuropsychiatric disorder that represents one of the most serious global public health problems. Yet, currently there still lacks an effective pharmacotherapy. Omega-3 polyunsaturated fatty acids (N-3 PUFAs) have exhibited beneficial effects in a variety of neurological disorders, particularly in reversing behavioral deficits and neurotoxicity induced by prenatal alcohol exposure and binge drinking. In the present study, we investigated if fish oil, which is rich in N-3 PUFAs, had beneficial effects on preventing relapse and alleviating withdrawal symptoms after chronic alcohol exposure. Our results demonstrated that fish oil significantly reduced the chronic alcohol exposure-induced aberrant dendritic morphologic changes of the medium-sized spiny neurons in the core and the shell of nucleus accumbens. This inhibited the expression of AMPAR2-lacking AMPARs and their accumulation on the post synaptic membranes of medium-sized spiny neurons and eventually alleviated withdrawal symptoms and alcohol dependence. Our study therefore suggests that N-3 PUFAs are promising for treating withdrawal symptoms and alcohol dependence.

Enhanced Expression of Secreted α-Klotho in the Hippocampus Alters Nesting Behavior and Memory Formation in Mice

The klotho gene family consists of α-, β-, and γ-Klotho, which encode type I single-pass transmembrane proteins with large extracellular domains. α-Klotho exists as a full-length membrane-bound and as a soluble form after cleavage of the extracellular domain. Due to gene splicing, a short extracellular Klotho form can be expressed and secreted. Inactivation of α-Klotho leads to a phenotype that resembles accelerated aging, as the expression level of the α-Klotho protein in the hippocampal formation of mice decreases with age. Here, we show that intrahippocampal viral expression of secreted human α-Klotho alters social behavior and memory formation. Interestingly, overexpression of secreted human α-Klotho in the CA1 changed the nest-building behavior and improved object recognition, object location and passive avoidance memory. Moreover, α-Klotho overexpression increased hippocampal synaptic transmission in response to standardized stimulation strengths, altered paired-pulse facilitation of synaptic transmission, and enhanced activity-dependent synaptic plasticity. These results indicate that memory formation benefits from an augmented level of secreted α-Klotho.

Distinct Roles for Two Chromosome 1 Loci in Ethanol Withdrawal, Consumption, and Conditioned Place Preference

We previously identified a region on chromosome 1 that harbor quantitative trait loci (QTLs) with large effects on alcohol withdrawal risk using both chronic and acute models in mice. Here, using newly created and existing QTL interval-specific congenic (ISC) models, we report the first evidence that this region harbors two distinct alcohol withdrawal QTLs (Alcw1₁and Alcw1₂), which underlie 13% and 3–6%, respectively, of the genetic variance in alcohol withdrawal severity measured using the handling-induced convulsion. Our results also precisely localize Alcw1₁ and Alcw1₂ to discreet chromosome regions (syntenic with human 1q23.1–23.3) that encompass a limited number of genes with validated genotype-dependent transcript expression and/or non-synonymous sequence variation that may underlie QTL phenotypic effects. ISC analyses also implicate Alcw1₁and Alcw1₂ in withdrawal-induced anxiety-like behavior, representing the first evidence for their broader roles in alcohol withdrawal beyond convulsions; but detect no evidence for Alcw1₂ involvement in ethanol conditioned place preference (CPP) or consumption. Our data point to high-quality candidates for Alcw1₂, including genes involved in mitochondrial respiration, spatial buffering, and neural plasticity, and to Kcnj9 as a high-quality candidate for Alcw1₁. Our studies are the first to show, using two null mutant models on different genetic backgrounds, that Kcnj9^−/− mice demonstrate significantly less severe alcohol withdrawal than wildtype littermates using acute and repeated exposure paradigms. We also demonstrate that Kcnj9^−/− voluntarily consume significantly more alcohol (20%, two-bottle choice) than wildtype littermates. Taken together with evidence implicating Kcnj9 in ethanol CPP, our results support a broad role for this locus in ethanol reward and withdrawal phenotypes. In summary, our results demonstrate two distinct chromosome 1 QTLs that significantly affect risk for ethanol withdrawal, and point to their distinct unique roles in alcohol reward phenotypes.

Affective Disturbances During Withdrawal from Chronic Intermittent Ethanol Inhalation in C57BL/6J and DBA/2J Male Mice

BACKGROUND

Alcohol use disorders are characterized by a complex behavioral symptomatology, which includes the loss of control over alcohol consumption and the emergence of a negative affective state when alcohol is not consumed. Some of these symptoms can be recapitulated in rodent models, for instance following chronic intermittent ethanol (EtOH; CIE) vapor inhalation. However, the detection of negative affect in mice withdrawn from CIE has proven challenging and variable between strains. This study aimed to detect reliable indices of negative emotionality in CIE-exposed C57BL/6J (C57) and DBA/2J (DBA) mice. Males were used because they are known to escalate their voluntary EtOH consumption upon CIE exposure, which is hypothesized to be driven by negative reinforcement (relief from negative affect).

METHODS

Adult male mice were exposed to 4 to 6 weeks of CIE and were evaluated 3 to 10 days into withdrawal in the social approach, novelty-suppressed feeding, digging, marble burying, and bottle brush tests.

RESULTS

Withdrawal from CIE decreased sociability in DBA mice but not in C57 mice. Conversely, hyponeophagia was exacerbated by CIE in C57 mice but not in DBA mice. Withdrawal from CIE robustly increased digging activity in both strains, even in the absence of marbles. Aggressive responses to bottle brush attacks were elevated in both C57 and DBA mice following CIE exposure, but CIE had an opposite effect on defensive responses in the 2 strains (increase in C57 vs. decrease in DBA).

CONCLUSIONS

Our results indicate that withdrawal from CIE elicits negative emotionality in both C57 and DBA mice, but different tests need to be used to measure the anxiogenic-like effects of withdrawal in each strain. Increased digging activity and irritability-like behavior represent novel indices of affective dysfunction associated with withdrawal from CIE in both mouse strains. Our findings enrich the characterization of the affective symptomatology of protracted withdrawal from CIE in mice.

Nest-building activity as a reproducible and long-term stroke deficit test in a mouse model of stroke

INTRODUCTION

Neuroprotective therapeutics achieved from animal studies have not been able to translate into clinical stroke therapies. A major reason may be that the functional tests and outcomes between animal stroke studies and clinical trials are significantly different. Ultimately, functional recovery is most important for stroke patients, but it remains challenging to identify animal functional tests that reflect human stroke deficits. This study aimed to explore whether the nest-building activity can be used as a functional test of mouse stroke deficit.

METHODS

Forty-one C57B6 male mice were randomly assigned into a sham-operated control group and 20-, 40- and 60-min middle cerebral artery occlusion (MCAO) groups. Mice were perfusion-fixed at 21 days following sham surgery or MCAO. Infarct volumes were assessed under the light microscopy. The nest-building activity was characterized and quantitatively evaluated.

RESULTS

The results show that only a small portion of striatum was damaged after 20-min MCAO. The brain damage areas were expanded from striatum to the neocortex and hippocampus proportionally after 40-min and 60-min MCAO, respectively. Consistently, relative to that of the sham-operated mice, the nest-building activity was insignificantly altered after 20-min MCAO, but dramatically and significantly reduced proportionally following 40-min and 60-min MCAO, respectively. The nest-building deficit was a long-lasting event and could be seen for as long as 14-21 days of recovery, the longest endpoint of this study.

CONCLUSIONS

The results suggest that the nest-building activity may be a novel, objective, easy to use, highly sensitive, and long-lasting test that may reflect the multifaceted sensorimotor and cognitive deficits after stroke in humans. Our findings may provide a novel multifaceted test for bridging the gap between animal stroke studies and clinical trials.

An alcohol withdrawal test battery measuring multiple behavioral symptoms in mice

Despite acceptance that risk for alcohol-use disorder (AUD) has a large genetic component, the identification of genes underlying various components of risk for AUD has been hampered in humans, in part by the heterogeneity of expression of the phenotype. One aspect of AUD is physical dependence. Alcohol withdrawal is a serious consequence of alcohol dependence with multiple symptoms, many of which are seen in multiple species, and can be experienced over a wide-ranging time course. In the present three studies, we developed a battery of withdrawal tests in mice, examining behavioral symptoms from multiple domains that could be measured over time. To permit eventual use of the battery in different strains of mice, we used male and female mice of a genetically heterogeneous stock developed from intercrossing eight inbred strains. Withdrawal symptoms were assessed using commonly used tests after administration of ethanol in vapor for 72 continuous hours. We found significant effects of ethanol withdrawal versus air-breathing controls on nearly all symptoms, spanning 4 days following ethanol vapor inhalation. Withdrawal produced hypothermia, greater neurohyperexcitability (seizures and tremor), anxiety-like behaviors using an apparatus (such as reduced transitions between light and dark compartments), anhedonia (reduced sucrose preference), Straub tail, backward walking, and reductions in activity; however, there were no changes in thermal pain sensitivity, hyper-reactivity to handling, or anxiety-like emergence behaviors in other apparatus. Using these data, we constructed a refined battery of withdrawal tests. Individual differences in severity of withdrawal among different tests were weakly correlated at best. This battery should be useful for identifying genetic influences on particular withdrawal behaviors, which should reflect the influences of different constellations of genes.

Systemic blockade of LPA1/3 lysophosphatidic acid receptors by ki16425 modulates the effects of ethanol on the brain and behavior

The systemic administration of lysophosphatidic acid (LPA) LPA_1/3 receptor antagonists is a promising clinical tool for cancer, sclerosis and fibrosis-related diseases. Since LPA₁ receptor-null mice engage in increased ethanol consumption, we evaluated the effects of systemic administration of an LPA_1/3 receptor antagonist (intraperitoneal ki16425, 20 mg/kg) on ethanol-related behaviors as well as on brain and plasma correlates. Acute administration of ki16425 reduced motivation for ethanol but not for saccharine in ethanol self-administering Wistar rats. Mouse experiments were conducted in two different strains. In Swiss mice, ki16425 treatment reduced both ethanol-induced sedation (loss of righting reflex, LORR) and ethanol reward (escalation in ethanol consumption and ethanol-induced conditioned place preference, CPP). Furthermore, in the CPP-trained Swiss mice, ki16425 prevented the effects of ethanol on basal c-Fos expression in the medial prefrontal cortex and on adult neurogenesis in the hippocampus. In the c57BL6/J mouse strain, however, no effects of ki16425 on LORR or voluntary drinking were observed. The c57BL6/J mouse strain was then evaluated for ethanol withdrawal symptoms, which were attenuated when ethanol was preceded by ki16425 administration. In these animals, ki16425 modulated the expression of glutamate-related genes in brain limbic regions after ethanol exposure; and peripheral LPA signaling was dysregulated by either ki16425 or ethanol. Overall, these results suggest that LPA_1/3 receptor antagonists might be a potential new class of drugs that are suitable for treating or preventing alcohol use disorders. A pharmacokinetic study revealed that systemic ki16425 showed poor brain penetration, suggesting the involvement of peripheral events to explain its effects.

The thermoregulation system and how it works

Heat exchange processes between the body and the environment are introduced. The definition of the thermoneutral zone as the ambient temperature range within which body temperature (T_b) regulation is achieved only by nonevaporative processes is explained. Thermoreceptors, thermoregulatory effectors (both physiologic and behavioral), and neural pathways and T_b signals that connect receptors and effectors into a thermoregulation system are reviewed. A classification of thermoeffectors is proposed. A consensus concept is presented, according to which the thermoregulation system is organized as a dynamic federation of independent thermoeffector loops. While the activity of each effector is driven by a unique combination of deep (core) and superficial (shell) T_bs, the regulated variable of the system can be viewed as a spatially distributed T_b with a heavily represented core and a lightly represented shell. Core T_b is the main feedback; it is always negative. Shell T_bs (mostly of the hairy skin) represent the auxiliary feedback, which can be negative or positive, and which decreases the system's response time and load error. Signals from the glabrous (nonhairy) skin about the temperature of objects in the environment serve as feedforward signals for various behaviors. Physiologic effectors do not use feedforward signals. The system interacts with other homeostatic systems by "meshing" with their loops. Coordination between different thermoeffectors is achieved through the common controlled variable, T_b. The term balance point (not set point) is used for a regulated level of T_b. The term interthreshold zone is used for a T_b range in which no effectors are activated. Thermoregulatory states are classified, based on whether: T_b is increased (hyperthermia) or decreased (hypothermia); the interthreshold zone is narrow (homeothermic type of regulation) or wide (poikilothermic type); and the balance point is increased (fever) or decreased (anapyrexia). During fever, thermoregulation can be either homeothermic or poikilothermic; anapyrexia is always a poikilothermic state. The biologic significance of poikilothermic states is discussed. As an example of practical applications of the concept presented, thermopharmacology is reviewed. Thermopharmacology uses drugs to modulate specific temperature signals at the level of a thermoreceptor (transient receptor potential channel).

Multi-Protection of DL0410 in Ameliorating Cognitive Defects in D-Galactose Induced Aging Mice

D-galactose has been reported to accelerate senescence in rodents, accompanied by a decline in learning and memory. We used a model of D-galactose-induced amnesia for the efficacy evaluation and pharmacologic studies of active compounds against Alzheimer's disease (AD). DL0410 is a potent inhibitor against acetylcholinesterase (AChE) and, in the present study, the effect of DL0410 was evaluated in this model. We found that DL0410 could significantly improve the learning and memory of D-galactose induced aging mice in a series of behavioral tests: novel-object recognition test, nest-building test, Morris water maze test and step-through test. Pharmacologic studies were conducted from several aspects: the cholinergic system, mitochondrial respiration, oxidative stress, neuroinflammation, apoptosis and synaptic loss. The acetylcholine level and AChE activity were not altered by D-galactose but were slightly affected by DL0410 in the brain. DL0410 could significantly improve decreased mitochondrial respiration in the NADH chain and FADH2 chain, and protect mitochondrial ultrastructure. DL0410 reduced the accumulation of advanced glycation end products (AGEs) and malondialdehyde (MDA) and increase the total antioxidant capability of the brain via an increase in activity of catalase, glutathione peroxidase (GPx) and superoxide dismutase (SOD). RAGE expression was inhibited by DL0410, followed by the decreased activation of astrocytes and microglia. Subsequent phosphorylation of NF-κB was also reversed by DL0410, with lower expression of cyclooxygenase-2 (COX2) and iNOS. With respect to apoptosis, the activation of caspase 3 and cleavage of PARP were downregulated significantly by DL0410, after the inhibition of phosphorylation of JNK induced by inflammation and oxidative stress. Synaptic protection by DL0410 was also demonstrated. These data suggest that mitochondrial protection has a primary role in the ameliorating effect of DL0410 on the impaired learning and memory, oxidative stress, inflammation, apoptosis and synaptic loss induced by D-galactose. DL0410 is a promising candidate for the treatment of aging-related AD, and this study lays an important foundation for its further research and development.

The acute social defeat stress and nest-building test paradigm: A potential new method to screen drugs for depressive-like symptoms

Psychosocial stress can cause mental conditions such as depression in humans. To develop drug therapies for the treatment of depression, it is necessary to use animal models of depression to screen drug candidates that exhibit anti-depressive effects. Unfortunately, the present methods of drug screening for antidepressants, the forced-swim test and tail-suspension test, are limiting factors in drug discovery because they are not based on the constructive validity of objective phenotypes in depression. Previously, we discovered that the onset of nest building is severely delayed in mice exposed to subchronic mild social defeat stress (sCSDS). Therefore, a novel paradigm combining acute social defeat stress (ASDS) and the nest-building test (SNB) were established for the efficient screening of drugs for depressive-like symptoms. Since ASDS severely delayed the nest-building process as shown in chronically social defeated mice, we sought to rescue the delayed nest-building behavior in ASDS mice. Injecting a specific serotonin 2a receptor antagonist (SR-46349B), the nest-building deficit exhibited by ASDS mice was partially rescued. On the other hand, a selective serotonin reuptake inhibitor (fluoxetine) did not rescue the nest-building deficit in ASDS mice. Therefore, we conclude that the SNB paradigm is an another potential behavioral method for screening drugs for depressive-like symptoms including attention deficit, anxiety, low locomotion, and decreased motivation.

Effects of acute alcohol withdrawal on nest building in mice selectively bred for alcohol withdrawal severity

Nest building has been used to assess thermoregulatory behavior and positive motivational states in mice. There are known genetic influences on ethanol withdrawal severity as well as individual/thermoregulatory nest building. Withdrawal Seizure-Prone (WSP-1, WSP-2) and Withdrawal Seizure-Resistant (WSR-1, WSR-2) mice were selectively bred for high vs low handling-induced convulsion (HIC) severity, respectively, during withdrawal from chronic ethanol vapor inhalation. They also differ in HIC severity during withdrawal from an acute, 4g/kg ethanol injection. In our initial study, withdrawal from an acute dose of ethanol dose-dependently impaired nest building over the initial 24h of withdrawal in genetically segregating Withdrawal Seizure Control (WSC) mice. In two further studies, acute ethanol withdrawal suppressed nest building for up to two days in WSP-1 females. Deficits in nest building from ethanol were limited to the initial 10h of withdrawal in WSR-1 females and to the initial 24h of withdrawal in WSP-1 and WSR-1 males. Effects of ethanol on nest building for up to two days were found in WSP-2 and WSR-2 mice of both sexes. Nest building deficits in female mice from the first replicate could not be explained by a general decrease in locomotor behavior. These results suggest that nest building is a novel behavioral phenotype for indexing the severity of acute ethanol withdrawal, and that genes contributing to this trait differ from those affecting acute withdrawal HIC severity.