Home Cage Activity Research Articles

Maternal exercise opportunity before, during, and after pregnancy alters maternal care behavior and offspring development and survival, but has few effects on offspring physical activity or body composition

Early-life experiences, especially during critical periods of development and growth, can have long-lasting effects on adult phenotypes. Parents are a crucial part of the offspring early-life environment, particularly in mammals (e.g., via pregnancy), and parental behaviors (e.g., maternal exercise) can modify the early-life environment experienced by offspring. Such changes might be beneficial or detrimental, depending on how they affect offspring development and growth or interact with other key parental behaviors (e.g., nursing).We used mice from a long-term artificial selection experiment for high voluntary wheel-running behavior to determine whether maternal exercise opportunity affected (1) maternal physical activity, (2) maternal care behavior, or (3) offspring physical activity and body composition. Eighty prospective dams (40 from 4 selectively bred High Runner [HR] lines and 40 from 4 non-selected Control [CON] lines) were housed with continuous wheel access starting two weeks prior to breeding and ending 10 days postpartum, after which dams were housed without wheels until offspring weaning (21 days postpartum). An additional 100 dams (50 HR, 50 CON) were housed without wheels.Prospective dams from HR lines ran more revolutions/day (mainly by running faster) than those from CON lines when individually housed and in the days leading up to, but not after, birth. During postpartum days 1-5, HR and CON dams with wheels tended to exhibit less maternal behavior than those without (PWheel = 0.0672). During post-partum days 6-10, HR dams with wheels continued to exhibit less maternal behavior than those without, whereas CON dams with wheels exhibited more than those without (PLinetype*Wheel = 0.0218). The proportion of dams giving birth did not differ among groups. However, CON dams with wheels were less likely to have litter death between birth and weaning than those without wheels, whereas the opposite was true for HR dams (PLinetype*Wheel = 0.0447). Both HR and CON dams with wheels had litters with a higher proportion of females at weaning than those without wheels (PWheel = 0.0129).Maternal wheel access had few statistically significant effects on offspring, but may have resulted in developmental delays (e.g., delayed eye opening and decreased lean mass at weaning and sexual maturity). Additionally, maternal wheel access and sex may have interacted to affect wheel-running distance (PSex*Wheel = 0.0683) and duration (PSex*Wheel = 0.0926); female offspring from dams with wheels ran fewer revolutions per day, by running fewer minutes per day, than from dams without wheels, whereas males ran more. However, maternal exercise had no statistically significant effects on offspring food consumption (mass-adjusted), home-cage activity, open-field behavior, the reproductive characteristics of offspring, their adult body composition, nor relative organ masses; nor did maternal wheel access have statistically significant effects on grand-offspring food consumption, body composition or voluntary exercise behavior.Overall, our results provide some support for maternal exercise opportunity altering maternal care behavior. Altered maternal care could explain the observed trends in offspring survival, development, and voluntary exercise behavior. However, these effects did not have apparent long-lasting impacts on offspring or grand-offspring body composition or reproductive characteristics.

Maternal immune activation exerts long-term effects on activity and sleep in male offspring mice.

Exposure to infectious or non-infectious immune activation during early development is a serious risk factor for long-term behavioural dysfunctions. Mouse models of maternal immune activation (MIA) have increasingly been used to address neuronal and behavioural dysfunctions in response to prenatal infections. One commonly employed MIA model involves administering poly(I:C) (polyriboinosinic-polyribocytdilic acid), a synthetic analogue of double-stranded RNA, during gestation, which robustly induces an acute viral-like inflammatory response. Using electroencephalography (EEG) and infrared (IR) activity recordings, we explored alterations in sleep/wake, circadian and locomotor activity patterns on the adult male offspring of poly(I:C)-treated mothers. Our findings demonstrate that these offspring displayed reduced home cage activity during the (subjective) night under both light/dark or constant darkness conditions. In line with this finding, these mice exhibited an increase in non-rapid eye movement (NREM) sleep duration as well as an increase in sleep spindles density. Following sleep deprivation, poly(I:C)-exposed offspring extended NREM sleep duration and prolonged NREM sleep bouts during the dark phase as compared with non-exposed mice. Additionally, these mice exhibited a significant alteration in NREM sleep EEG spectral powerunder heightened sleep pressure. Together, our study highlights the lasting effects of infection and/or immune activation during pregnancy on circadian activity and sleep/wake patterns in the offspring.

Sex-Dependent Effects of Chronic Circadian Disruption in AβPP/PS1 Mice.

Chronic disruption of the circadian timing system, often reflected as a loss of restful sleep, also includes myriad other pathophysiological effects. The current study examined how chronic circadian disruption (CD) could contribute to pathology and rate of progression in the AβPP/PS1 mouse model of Alzheimer's disease (AD). A chronic CD was imposed until animals reached 6 or 12 months of age in AβPP/PS1 and C57BL/6J control mice. Home cage activity was monitored for a period of 3-4 weeks prior to the endpoint along with a single timepoint measure of glucose sensitivity. To assess long term effects of CD on the AD phenotype, animals were re-entrained to a no disruption (ND) schedule just prior to the endpoint, after which a Morris water maze (MWM) was used to assess spatial learning and memory. Dampening of nighttime activity levels occurred in disrupted animals, and female animals demonstrated a greater adaptability to CD. Diminished arginine vasopressin (AVP) and vasoactive intestinal peptide (VIP) levels in the suprachiasmatic nucleus (SCN) of 12-month male AβPP/PS1 exposed to the CD paradigm were observed, potentially accounting for the diminished re-entrainment response. Similarly, CD worsened performance in the MWM in 12-month male AβPP/PS1 animals, whereas no effect was seen in females. Collectively, these findings show that exposure to chronic CD impairs circadian behavioral patterns and cognitive phenotypes of AβPP/PS1 mouse model in a sex-dependent manner.

Refinement of the motorised laminectomy-assisted rat spinal cord injury model by analgesic treatment.

Usage and reporting of analgesia in animal models of spinal cord injury (SCI) have been sparse and requires proper attention. The majority of experimental SCI research uses rats as an animal model. This study aimed to probe into the effects of some commonly used regimens with NSAIDs and opioids on well-being of the rats as well as on the functional outcome of the model. This eight-week study used forty-two female Wistar rats (Crl: WI), randomly and equally divided into 6 treatment groups, viz. I) tramadol (5mg/kg) and buprenorphine (0.05mg/kg); II) carprofen (5mg/kg) and buprenorphine (0.05mg/kg); III) carprofen (5mg/kg); IV) meloxicam (1mg/kg) and buprenorphine (0.05mg/kg); V) meloxicam (1mg/kg); and VI) no analgesia (0.5 ml sterile saline). Buprenorphine was administered twice daily whereas other treatments were given once daily for five days post-operatively. Injections were given subcutaneously. All animals underwent dental burr-assisted laminectomy at the T10-T11 vertebra level. A custom-built calibrated spring-loaded 200 kilodynes force deliverer was used to induce severe SCI. Weekly body weight scores, Rat Grimace Scale (RGS), and dark-phase home cage activity were used as markers for well-being. Weekly Basso Beattie and Bresnahan (BBB) scores served as markers for functionality together with Novel Object Recognition test (NOR) at week 8 and terminal histopathology using area of vacuolisation and live neuronal count from the ventral horns of spinal cord. It was concluded that the usage of analgesia improved animal wellbeing while having no effects on the functional aspects of the animal model in comparison to the animals that received no analgesics.

Central 5-HTergic hyperactivity induces myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)-like pathophysiology

ObjectivesMyalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a significant medical challenge, with no indisputable pathophysiological mechanism identified to date.MethodsBased on clinical clues, we hypothesized that 5-hydroxytryptamine (5-HT) hyperactivation is implicated in the pathogenic causes of ME/CFS and the associated symptoms. We experimentally evaluated this hypothesis in a series of mouse models.ResultsHigh-dose selective serotonin reuptake inhibitor (SSRI) treatment induced intra- and extracellular serotonin spillover in the dorsal raphe nuclei of mice. This condition resulted in severe fatigue (rota-rod, fatigue rotating wheel and home-cage activity tests) and ME/CFS-associated symptoms (nest building, plantar and open field test), along with dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis response to exercise challenge. These ME/CFS-like features induced by excess serotonin were additionally verified using both a 5-HT synthesis inhibitor and viral vector for Htr1a (5-HT1A receptor) gene knockdown.ConclusionsOur findings support the involvement of 5-HTergic hyperactivity in the pathophysiology of ME/CFS. This ME/CFS-mimicking animal model would be useful for understanding ME/CFS biology and its therapeutic approaches.

Antioxidant associated chemoprophylaxis effect of natural spice and green vegetable on hepatotoxicity.

This is a case control and cohort study, conducted at Department of Biochemistry in FUAST, compressing 24 number of albino Wistar rats. Illicium verum (star anise) natural spice and green vegetable broccoli are used for chemo-preventive herbal treatment in relation with vitamin C antioxidant activity. Hepatotoxicity was induced in liver of model rats by giving interperitoneally single injection of 200 mg/kg bod weight (B.W) of N-nitrosodiethylamine and orally giving 1 mg/kg BW phenobarbital for 14 days during disease prorogation period. The vitamin C analysis from Illicium verum (star anise), green broccoli, orange juice, orange peel and orange pulp was done by iodometric quantitative and qualitative titration method. Rats were given compound according to their bodyweight as 1 mg/kg B.W. After 14 days (Disease Promotion and Propagation Period) and 28 days (Disease cure period) of treatment behavioral activity was monitored by locomotors activity in open field experiment, stimulatory activity in home cage and anxiolytic effects observed in light and dark apparatus and also in T maze. Behavioral activity were significantly increased in Illicium verum and green broccoli treated rats. Hematological study including hemoglobin (Hb), white blood cells (WBC), red blood cells (RBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red cell distribution width (RDW) and Platelets was done by abbot laboratory analyzer cell. The value of Hb and RBC was also significantly increased in star anise and broccoli treated rats, showed proper function of RBC in microcirculation. WBC was also in normal range revealed that no disease regards to bone marrow and leukemia's. The biochemical activity of rats including urea, creatinine, total protein, albumin, globulin, A/G ratio, amylase and calcium in blood serum were analyzed while, liver health or performance was also determined by LFT (liver function test). Behavioral and laboratorial variables were analyzed by using SPSS v. 20 and p-value < 0.05 was considered statistically significant. The study report noticeable significant effect of Illicium verum and broccoli on hepatotoxicity of experimental model. Recent experimental study statistical outcomes show reciprocal relationship between the consumption of vegetable diet and natural spice with the risk of Hepatotoxicity. Thus, the aim of the study is to enhance the function of star anise or illicium verum natural spice and green vegetable broccoli as an anticancer or chemoprophylaxis agent.

Abnormal patterns of sleep and waking behaviors are accompanied by neocortical oscillation disturbances in an Ank3 mouse model of epilepsy-bipolar disorder comorbidity

ANK3 is a leading bipolar disorder (BD) candidate gene in humans and provides a unique opportunity for studying epilepsy-BD comorbidity. Previous studies showed that deletion of Ank3-1b, a BD-associated variant of Ank3 in mice leads to increased firing threshold and diminished action potential dynamic range of parvalbumin (PV) interneurons and absence epilepsy, thus providing a biological mechanism linking epilepsy and BD. To explore the behavioral overlap of these disorders, we characterized behavioral patterns of Ank3-1b KO mice during overnight home-cage activity and examined network activity during these behaviors using paired video and EEG recordings. Since PV interneurons contribute to the generation of high-frequency gamma oscillations, we anticipated changes in the power of neocortical EEG signals in the gamma frequency range (> 25 Hz) during behavioral states related to human BD symptoms, including abnormal sleep, hyperactivity, and repetitive behaviors. Ank3-1b KO mice exhibited an overall increase in slow gamma (~25-45 Hz) power compared to controls, and slow gamma power correlated with seizure phenotype severity across behaviors. During sleep, increased slow gamma power correlated with decreased time spent in the rapid eye movement (REM) stage of sleep. Seizures were more common during REM sleep compared to non-REM (NREM) sleep. We also found that Ank3-1b KO mice were hyperactive and exhibited a repetitive behavior phenotype that co-occurred with increased slow gamma power. Our results identify a novel EEG biomarker associating Ank3 genetic variation with BD and epilepsy and suggest modulation of gamma oscillations as a potential therapeutic target.

Assessment of apathy‐like behaviour in transgenic mouse models of neurodegenerative diseases

AbstractBackgroundApathy is the most common behavioural and psychological symptom in neurodegenerative diseases like Alzheimer’s disease (AD), frontotemporal dementia (FTD) or Parkinson’s disease (PD). Apathy typically includes a loss of motivation, initiative and interest, listlessness and indifference, flattening of emotions, absence of drive and passion. Scientists have defined this as a reduction/lack in goal direct behaviour. There are currently no specific treatment options for apathy. In experimental models, selective symptoms of apathy‐like behaviour are measured in goal directed or nesting behavioural tasks, which report on their motivation to perform daily activities. A richer understanding of apathy, however, may be achieved through the development of a battery of tests including goal directed, nesting, anhedonia, activity monitoring, and social interaction. These have been applied here to several animal models of neurodegeneration.MethodMale and female transgenic mice (aged 6 – 8 months) including tau over‐expressors L1 for AD and L66 for FTD (Melis et al. 2015); PLB4 BACE1 mouse model for AD (Plucinska et al. 2014); L62 alpha‐synuclein mouse model of PD (Frahm et al. 2018) and relevant wild type (WT) controls were utilised in this study. Animals were tested in a series of behavioural tests including the nest building task, sucrose preference test, buried cookie test, social interaction, and home cage activity. Performance was recorded and analysed by behavioural tracking software as indicators of apathy‐like behaviour.ResultTwo models showed reproducible results compared with previous studies. Intriguingly, L66 FTD mice presented with deficits in sucrose preference and nest‐building, but not a lowering of general activity. Although this was not found for the sister strain, L1 mice which has AD‐like pathology. Very much unexpected is the observation that neither the amyloid nor the synuclein‐based models showed any significant behavioural anomalies. Further detailed investigations are ongoing.ConclusionInitial observations have confirmed that the transgenic models for neurodegenerative diseases show different levels of apathy‐like behaviour. It appears that the phenotype in L66 is a tau‐related anomaly specific to the tau species expressed, i.e. the mutation at P301S. The lack of deficits in all other models warrants in‐depth confirmation and analysis.

Effect of photobiological modulation therapy on cognitive impairment and cardiovascular structure in an APP/PS1 mouse model of Alzheimer’s Disease

AbstractBackgroundPhotobiological modulation (PBM) therapy, a form of low‐dose light therapy, is beneficial in treating various disease conditions including Alzheimer’s disease (AD). Double‐transgenic mice (APPswe/PS1dE9) develop progressive accumulation of amyloid‐β (Aβ) plaques, cognitive impairment, and alterations in cardiovascular structure and function, and represent a model of AD. Prior studies have shown that PBM therapy reduces the size and number of Aβ plaques in the neocortex and hippocampus in the mouse models of AD. The aim of this study was to investigate the effects of PBM on cardiovascular structure and function and cognitive function in the aged AD mice.MethodsSix‐month old female AD (APPswe/PS1dE9; AD‐PBM, n = 8) and wild type mice (WT‐PBM, n = 8) were exposed to near‐infrared light (wavelength 850 nm, 4.5 J/cm2, 3min/day, 5 days/week) for 6 months. Control mice (AD‐CNT, n = 6; WT‐CNT, n = 6) were placed under the PBM apparatus without turning the light on for 3min/day, 5 days/week. Cardiac parameters were measured by echocardiography. Gait analysis (DigiGait), home cage activity (HCA), and spatial working memory (indicated by alternation rate in cross maze test, CM) were assessed after 6 months of treatment. Group differences were identified by two‐way ANOVA.ResultsIn HCA test, the AD‐CNT mice exhibited circadian locomotor hyperactivity at night‐time relative to WT‐CNT mice (Figure 1A, B), which was reduced by PBM. AD‐CNT mice had lower alternation rates in CM, indicating spatial working memory impairment. PBM had minimal effect on this parameter (Table 1). The AD‐CNT vs. WT‐CNT mice manifested differences in several gait parameters, specifically, they demonstrated a lower fore propel time than WT‐CNT. PBM normalized this parameter in AD‐PBM mice to the level of WT‐CNT (Figure 1C). Both WT‐PBM and AD‐PBM mice had improved cardiovascular structure, which was demonstrated by lower relative wall thickness of left ventricle (LV) and LV mass, and higher LV volume at the end of diastole in PBM‐treated vs. correspondent CNT groups (Table 1, Figure 2).ConclusionPBM improved cardiovascular structure and AD‐associated cognitive impairment in the APP/PS1 mouse model. It is possible that more effective cardiovascular structure and function contributes to Aβ removal from the brain after PBM treatment. Supported by NIA/NIH/IRP

Calorie restriction partially attenuates sickness behavior induced by viral mimetic poly I:C

Calorie restriction (CR) has been shown to extend the mean and maximum lifespan in both preclinical and clinical settings. We have previously demonstrated that CR attenuates lipopolysaccharide (LPS)-induced fever and sickness behavior. CR also leads to reductions in pro-inflammatory and increases in anti-inflammatory profiles. LPS is a bacterial mimetic; however, few studies have explored this phenomenon utilizing a viral mimetic, such as polyinosinic:polycytidylic acid (poly I:C). Dose-dependently, poly I:C induced an increase in core body temperature (Tb), with the largest dose (5000 µg/kg) resulting in a 1.62 °C ( ± 0.23 °C) Tb increase at 7 h post-injection in ad libitum mice and was associated with reduced home-cage locomotor activity. We then investigated the effect of 50% CR for 28 days to attenuate fever and sickness behavior induced by a poly I:C (5000 µg/kg) viral immune challenge. CR resulted in the partial attenuation of fever and sickness behavior measures post-poly I:C. The freely fed, control mice demonstrated a 2.02 °C ( ± 0.22 °C) increase in Tb at 7 h post-injection compared to the CR poly I:C group which demonstrated an increase in Tb of 0.94 °C ( ± 0.27 °C). Locomotor patterns post-injection were different, CR mice displayed a reduction in activity during the light phase, and the control group displayed a reduction during the dark phase. CR moderately attenuated the neuroinflammatory response with a reduction in microglial density in the ventromedial nucleus of the hypothalamus. The fever and sickness behavior attenuation seen after CR may be driven by similar anti-inflammatory processes as after LPS; however, further investigation is required.

Activity in Group-Housed Home Cages of Mice as a Novel Preclinical Biomarker in Oncology Studies.

Improving experimental conditions in preclinical animal research is a major challenge, both scientifically and ethically. Automated digital ventilated cages (DVC®) offer the advantage of continuous monitoring of animal activity in their home-cage. The potential utility of this technology remains understudied and deserves investigation in the field of oncology. Using the DVC® platform, we sought to determine if the continuous assessment of locomotor activity of mice in their home cages can serve as useful digital readout in the monitoring of animals treated with the reference oncology compounds cisplatin and cyclophosphamide. SCID mice of 14 weeks of age were housed in DVC® cages in groups of four and followed with standard and digital examination before and after treatment over a 17-day total period. DVC® detected statistically significant effects of cisplatin on the activity of mice in the short and long term, as well as trends for cyclophosphamide. The activity differences between the vehicle- and chemotherapy-treated groups were especially marked during the nighttime, a period when animals are most active and staff are generally not available for regular checks. Standard clinical parameters, such as body weight change and clinical assessment during the day, provided additional and complementary information. The DVC® technology enabled the home cage monitoring of mice and non-invasive detection of animal activity disturbances. It can easily be integrated into a multimodal monitoring approach to better capture the different effects of oncology drugs on anti-tumor efficacy, toxicity, and safety and improve translation to clinical studies.

Somatostatin-expressing neurons in the ventral tegmental area innervate specific forebrain regions and are involved in stress response.

Expanding knowledge about the cellular composition of subcortical brain regions demonstrates large heterogeneity and differences from the cortical architecture. Recently, we described three subtypes of somatostatin-expressing (Sst) neurons in the mouse ventral tegmental area (VTA) and showed their local inhibitory action on the neighbouring dopaminergic neurons (Nagaeva et al., 2020). Here, we report that mouse Sst+ neurons especially from the anterolateral part of the VTA also project far outside the VTA and innervate forebrain regions that are mainly involved in the regulation of emotional behaviour, including the ventral pallidum (VP), lateral hypothalamus (LH), the medial part of the central amygdala (CeM), anterolateral division of the bed nucleus of stria terminalis (alBNST), and paraventricular thalamic nucleus (PVT). Deletion of these VTASst neurons in mice affected several behaviours, such as home cage activity, sensitization of locomotor activity to morphine, fear conditioning responses and reactions to the inescapable stress of forced swimming, often in a sex-dependent manner. Together, these data demonstrate that VTASst neurons have selective projection targets distinct from the main targets of VTA dopamine neurons. VTASst neurons are involved in the regulation of behaviours primarily associated with the stress response, making them a relevant addition to the efferent VTA pathways and stress-related neuronal network.Significance StatementThe ventral tegmental area (VTA) is involved in many reward- and aversion-related processes contributing to brain disorders, but the cellular composition and brain-wide connections of this subcortical brain region are still poorly known. We recently described a heterogeneous somatostatin-expressing (Sst) neuron population in the mouse VTA, and, here, we revealed that, in addition to being local interneurons, VTA Sst neurons send long-distance projections to specific forebrain regions. Deletion of these neurons altered behavioural reactions to acute stressors and to repeated morphine administration. The results add the VTA Sst neurons to the stress-related network of the brain and establish a possibility to find out the exact roles of these neurons acting as behaviourally relevant interneurons and/or projection neurons.

Effect of Hippocampal Overexpression of Dopamine Neurotrophic Factor (CDNF) on Behavior of Mice with Genetic Predisposition to Depressive-Like Behavior.

Cerebral dopamine neurotrophic factor (CDNF) is a promising agent for Parkinson's disease treatment. However, its role in regulation of non-motor behavior including various psychopathologies remains unclear. In this regard, the aim of the present work was to study effect of CDNF overexpression in hippocampus on behavior of the ASC mice (Antidepressant Sensitive Cataleptics) with genetic predisposition to depressive-like behavior. CDNF overexpression in the mouse hippocampal neurons was induced using an adeno-associated viral vector. Four weeks after stereotaxic injection of the AAV-CDNF construct into the dorsal hippocampus home cage activity, exploratory, anxious and depressive-like types of behavior, as well as spatial and associative learning were assessed. We found significant improvements in the dynamics of spatial learning in the Morris water maze in the CDNF-overexpressing animals. At the same time, no effect of CDNF was found on other types of behavior under study. Behavior of the experimental animals under home cage conditions did not differ from that in the control group, except for the decrease in the total amount of food eaten and slight increase in the number of sleep episodes during the light phase of the day. In the present study we also attempted to determine molecular basis for the above-mentioned changes through assessment of the gene expression pattern. We did not find significant changes in the mRNA level of key kinases genes involved in neuroplasticity and neuronal survival, as well as genes encoding receptors for the main neurotransmitter systems. However, the CDNF-overexpressing animals showed increased level of the spliced Xbp indicating activation of the Ire1α/Xbp-1 pathway traditionally associated with ER stress. Immunohistochemical analysis showed that CDNF was co-localized with the ER marker calreticulin. Thus, the effects of endogenous CDNF on behavior that we have found could be mediated by a specific molecular cascade, which emphasizes its difference from the classical neurotrophic factors.

Effects of Na/K‐ATPase Inhibitor Marinobufagenin on Gene Expression and Cognition in a Mouse Model of Alzheimer’s Disease

AbstractBackgroundAlzheimer’s disease (AD) is characterized by brain amyloid‐β plaque formation, neuroinflammation and neurodegeneration, which lead to cognitive impairment (CI) and disruption of circadian rhythm. Bioactive steroidal Na/K‐ATPase inhibitor marinobufagenin (MBG) modulates neuroinflammation. In 16‐mo old double transgenic APPswe/PS1dE9 AD mice with advanced AD, treatment with MBG reduced mRNA expression of inflammatory markers. Here, we investigated whether treatment with MBG at early‐stage AD may impact AD manifestation in this AD mouse model.MethodsFive months old male AD mice (n = 15) and WT mice (n = 28) were administered MBG (100 µg/day/kg body weight) (AD‐MBG, n = 8; WT‐MBG, n = 14) or vehicle for control (AD‐C, n = 7; WT‐C, n = 14) via subcutaneous ALZET osmotic minipumps for 3 months. At 8‐mo of age, the mice underwent turn‐based discrimination learning in a water T‐maze (WTM) to assess procedural learning and 72‐hour home cage activity (HCA) analysis to assess circadian rhythm. The hippocampal inflammatory and AD mRNAs (by qPCR) and MBG levels (by immunoassay) were measured.ResultsMBG administration increased plasma MBG levels in WT and AD mice (Table 1). AD‐C mice exhibited greater home cage activity disruption vs. WT‐C (Fig.1a); in WTM, AD‐C required more trials to learn the turn‐based task than WT‐C (Fig. 1b). Though statistically insignificant, trends showed that MBG numerically worsened activity disruption by HCA and decreased ability to learn turn‐based task by WTM in WT mice, while numerically improving both measures in AD mice. During the reversal phase of WTM where response requirements were reversed, WT‐C mice performed significantly better than AD‐C mice, measured by the cumulative amount of time spent in the incorrect arm until reaching criterion performance (p = 0.038). Similar patterns of numerical improvement in AD‐MBG compared to AD‐C are shown (Fig. 1c). Hippocampal inflammatory and AD markers mRNAs were upregulated in AD‐C vs. WT‐C, and MBG treatment downregulated the expression of TNF and GFAP in AD mice (Table 1).ConclusionsBehavioral testing results illustrate CI and circadian impairment in 8‐mo old AD mice compared to WT. Numerical trends show a potential protective effect of MBG on AD CI likely via downregulation of hippocampal TNF and GFAP genes.0Supported by the NIH/NIA Intramural Research Program

0025 Effects of NLS-4 (Lauflumide) and modafinil in a rat model of circadian rhythm and chronic severe fatigue

Abstract Introduction The chronic fatigue syndrome (CFS) is a heterogeneous disorder characterized by easy fatigability, feverishness, diffuse pains, and depression. Many COVID-19 patients expressed a long-term effect of coronavirus (long-COVID), with some characteristics typically found in CFS. To examine the efficacy of NLS-4 (Lauflumide), in comparison with a positive control, modafinil, which has been shown to improve recovery from CFS in human, to improve recovery from severe fatigue in rats. Methods Male 7-8 weeks old Sprague-Dawley rats were subjected to a fatigue procedure for seven consecutive days. Their locomotor activity in home cage was then recorded for 3 days following the end of the fatigue procedure. A Sham group was subjected to the same measurement of circadian activity but without the fatigue procedure. Rats were divided into different groups which received, before the start of the dark period, three daily administrations of NLS-4, modafinil or vehicle (Control and Sham groups). Results The fatigue procedure induced an impairment in the circadian activity, that is a decrease in motor activity during the dark period and an increase in motor activity during the period of light. Accordingly, the difference of distance travelled between the dark period and the light period was lower in the Control group than in the Sham group. This impairment was still present 3 days after the end of the fatigue procedure. modafinil and NLS-4 dose-dependently increased locomotor activity during the dark phase and, to a lesser extent, during the light phase. The increase in activity during the dark phase was significant at doses of 16, 32 and 64 mg/kg with NLS-4 and at doses 64 and 128 mg/kg with modafinil but the effect of NLS-4 was more sustainable than that of modafinil. Conclusion This study suggests that the impairment of circadian rhythm induced by a fatigue procedure was reduced to a similar magnitude by modafinil (64 mg/kg) and NLS-4 (16 mg/kg). Since modafinil has been shown to improve recovery from chronic fatigue in human, these results show that NLS-4 could improve recovery from CFS in human at doses four times lower than that used for modafinil. Support (if any) NLS Pharmaceutics

Non-invasive detection of narcolepsy type I phenotypical features and disease progression by continuous home-cage monitoring of activity in two mouse models: the HCRT-KO and DTA model.

Narcolepsy type 1 (NT1) is a neurological disorder caused by disruption of hypocretin (HCRT; or orexin) neurotransmission leading to fragmented sleep/wake states, excessive daytime sleepiness, and cataplexy (abrupt muscle atonia during wakefulness). Electroencephalography and electromyography (EEG/EMG) monitoring is the gold standard to assess NT1 phenotypical features in both humans and mice. Here, we evaluated the digital ventilated home-cage (DVC®) activity system as an alternative to detect NT1 features in two NT1 mouse models: the genetic HCRT-knockout (-KO) model, and the inducible HCRT neuron-ablation hcrt-tTA;TetO-DTA (DTA) model, including both sexes. NT1 mice exhibited an altered dark phase activity profile and increased state transitions, compared to the wild-type (WT) phenotype. An inability to sustain activity periods >40 min represented a robust activity-based NT1 biomarker. These features were observable within the first weeks of HCRT neuron degeneration in DTA mice. We also created a nest-identification algorithm to differentiate between inactivity and activity, inside and outside the nest as a sleep and wake proxy, respectively, showing significant correlations with EEG/EMG-assessed sleep/wake behavior. Lastly, we tested the sensitivity of the activity system to detect behavioral changes in response to interventions such as repeated saline injection and chocolate. Surprisingly, daily consecutive saline injections significantly reduced activity and increased nest time of HCRT-WT mice. Chocolate increased total activity in all mice, and increased the frequency of short out-of-nest inactivity episodes in HCRT-KO mice. We conclude that the DVC® system provides a useful tool for non-invasive monitoring of NT1 phenotypical features, and has the potential to monitor drug effects in NT1 mice.

Sarm1 Regulates Circadian Rhythm Disorder in Alzheimer's Disease in Mice.

Sarm1 (Sterile alpha and TIR motif-containing 1) is a key protein that regulates neurodegenerative pathologies. Alzheimer's disease (AD) is highly associated with neurodegenerative lesions and biorhythmic disturbances. This study aims to decipher the role of Sarm1 in AD-induced circadian rhythm disturbances and AD progression. Open field and water maze tests were used to assess the cognitive function of mice. Thioflavin-S staining was used to assess amyloid-β (Aβ) plaque deposition in the hippocampus and cortex. Rhythmic waveform of home cage activity and temperature was recorded to evaluate circadian rhythm. Expression of clock molecules including Bmal1 and Per2 in the hippocampus were analyzed using western blot and real-time PCR. Further, HT22 cells with Sam1 knockout were treated with Aβ31-35 treatment to initiate circadian rhythm disorder in the cellular level to assess the changes in Bmal1 and Per2. Our data suggested that Sarm1 deficiency rescued cognitive disorder, decreased Aβ plaque deposition in the hippocampus and cortex, inhibited astrocyte activation, improved circadian rhythm, altered clock molecule expression in the cortex and hippocampus in APP/PS1 mice. Sarm1 attenuates circadian rhythm disturbances and reduces AD progression. These data support the potential use of Sarm1 as a therapeutic target to improve circadian rhythm to impede AD progression.

Restricted cafeteria feeding and treadmill exercise improved body composition, metabolic profile and exploratory behavior in obese male rats

The aim of this study was to evaluate, in male Long-Evans rats, whether a restricted-cafeteria diet (CAFR), based on a 30% calorie restriction vs continuous ad libitum cafeteria (CAF) fed animals, administered alone or in combination with moderate treadmill exercise (12 m/min, 35 min, 5 days/week for 8 weeks), was able to ameliorate obesity and the associated risk factors induced by CAF feeding for 18 weeks and to examine the changes in circadian locomotor activity, hypothalamic–pituitary–adrenal (HPA) axis functionality, and stress response elicited by this dietary pattern. In addition to the expected increase in body weight and adiposity, and the development of metabolic dysregulations compatible with Metabolic Syndrome, CAF intake resulted in a sedentary profile assessed by the home-cage activity test, reduced baseline HPA axis activity through decreased corticosterone levels, and boosted exploratory behavior. Both CAFR alone and in combination with exercise reduced abdominal adiposity and hypercholesterolemia compared to CAF. Exercise increased baseline locomotor activity in the home-cage in all dietary groups, boosted exploratory behavior in STD and CAF, partially decreased anxiety-like behavior in CAF and CAFR, but did not affect HPA axis-related parameters.

Latrophilin-3 heterozygous versus homozygous mutations in Sprague Dawley rats: Effects on egocentric and allocentric memory and locomotor activity.

Latrophilin-3 (LPHN3) is a brain specific G-protein coupled receptor associated with increased risk of attention deficit hyperactivity disorder (ADHD) and cognitive deficits. CRISPR/Cas9 was used to generate a constitutive knockout (KO) rat of Lphn3 by deleting exon 3, based on human data that LPHN3 variants are associated with some cases of ADHD. Lphn3 KO rats are hyperactive with an attenuated response to ADHD medication and have cognitive deficits. Here, we tested KO, heterozygous (HET), and wildtype (WT) rats to determine if there was a gene-dosage effect. We tested the rats in home-cage activity starting at postnatal day (P)35 and P50, followed by tests of egocentric learning (Cincinnati water maze [CWM]), spatial learning (Morris water maze [MWM]), working memory (radial water maze [RWM]), incidental learning (novel object recognition [NOR]), acoustic startle response (ASR) habituation, tactile startle response (TSR) habituation, prepulse modification of acoustic startle, shuttle-box passive avoidance, conditioned freezing, and a mirror image version of the CWM. KO and HET rats were hyperactive. KO and HET rats had egocentric (CWM) and spatial deficits (MWM), increased startle response, and KO rats showed less conditioned freezing on contextual and cued memory; there were no effects on working memory (RWM) or passive avoidance. The selective gene-dosage effect in Lphn3 HET rats indicates that Lphn3 exhibits dominate expression on functions where it is most abundantly expressed (striatum, hippocampus) but not on behaviors mediated by regions of low expression. The data add further evidence to the impact of this synaptic protein on brain function and behavior.

Female fertility does not require Bmal1 in suprachiasmatic nucleus neurons expressing arginine vasopressin, vasoactive intestinal peptide, or neuromedin-S.

Disruptions to the circadian system alter reproductive capacity, particularly in females. Mice lacking the core circadian clock gene, Bmal1, are infertile and have evidence of neuroendocrine disruption including the absence of the preovulatory luteinizing hormone (LH) surge and enhanced responsiveness to exogenous kisspeptin. Here, we explore the role of Bmal1 in suprachiasmatic nucleus (SCN) neuron populations known to project to the neuroendocrine axis. We generated four mouse lines using Cre/Lox technology to create conditional deletion of Bmal1 in arginine vasopressin (Bmal1fl/fl:Avpcre ), vasoactive intestinal peptide (Bmal1fl/fl:Vipcre ), both (Bmal1fl/fl:Avpcre+Vipcre ), and neuromedin-s (Bmal1fl/fl:Nmscre ) neurons. We demonstrate that the loss of Bmal1 in these populations has substantial effects on home-cage circadian activity and temperature rhythms. Despite this, we found that female mice from these lines demonstrated normal estrus cycles, fecundity, kisspeptin responsiveness, and inducible LH surge. We found no evidence of reproductive disruption in constant darkness. Overall, our results indicate that while conditional Bmal1 knockout in AVP, VIP, or NMS neurons is sufficient to disrupted locomotor activity, this disruption is insufficient to recapitulate the neuroendocrine reproductive effects of the whole-body Bmal1 knockout.