Predictive Value of Precision-Cut Lung Slices for the Susceptibility of Three Animal Species for SARS-CoV-2 and Validation in a Refined Hamster Model

In assessing species susceptibility for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and in the search for an appropriate animal model, multiple research groups around the world inoculated a broad range of animal species using various SARS-CoV-2 strains, doses and administration routes. Although in silico analyses based on receptor binding and diverse in vitro cell cultures were valuable, exact prediction of species susceptibility based on these tools proved challenging. Here, we assessed whether precision-cut lung slices (PCLS) could facilitate the selection of animal models, thereby reducing animal experimentation. Pig, hamster and cat PCLS were incubated with SARS-CoV-2 and virus replication was followed over time. Virus replicated efficiently in PCLS from hamsters and cats, while no evidence of replication was obtained for pig PCLS. These data corroborate the findings of many research groups that have investigated the susceptibility of hamsters, pigs and cats towards infection with SARS-CoV-2. Our findings suggest that PCLS can be used as convenient tool for the screening of different animal species for sensitivity to newly emerged viruses. To validate our results obtained in PCLS, we employed the hamster model. Hamsters were inoculated with SARS-CoV-2 via the intranasal route. Susceptibility to infection was evaluated by body weight loss, viral loads in oropharyngeal swabs and respiratory tissues and lung pathology. The broadly used hamster model was further refined by including activity tracking of the hamsters by an activity wheel as a very robust and sensitive parameter for clinical health. In addition, to facilitate the quantification of pathology in the lungs, we devised a semi-quantitative scoring system for evaluating the degree of histological changes in the lungs. The inclusion of these additional parameters refined and enriched the hamster model, allowing for the generation of more data from a single experiment.

ADHD-Relevant Motor and Cognitive Effects of a Fixed-Dose Combination of Caffeine, Gingko Biloba and β-Phenethylamine (PEA)

Background: The aim of the study was to evaluate Cogniben, a fixed-dose combination of caffeine, Ginkgo-biloba and β-Phenylethylamine (PEA) as a potential therapeutic option for attention deficit hyperactivity disorder. Methods: Cogniben-treated mice were tested with the open-field test, object-recognition test, passive avoidance test and activity wheel test. In vitro, the effect of Cogniben and its constituents on release of NO from cultured murine macrophages was assessed. Finally, patients with ADHD were treated with Cogniben and the effect on ADHD Rating Scale-IV and clinical global impression was evaluated. Results: Cogniben exhibited stimulant-like activity, as exhibited by both the open-field test and the activity wheel test. Treatment with Cogniben had positive effects of reducing anxiety and enhancing learning and memory in mice. In-vitro, the Cogniben combination reduced LPS-induced NO release from macrophages, to a similar extent to that of Dexamethazone. In the clinical evaluation, a 43% change from baseline was observed in the ADHD-RS-IV and a 34% reduction in severity from baseline was observed in the CGI-S following treatment with Cogniben. Conclusion: Together, the beneficial effects of the Cogniben combination, suggest that it may be a valuable treatment for ADHD.

Exercise, diet, and the reinforcing value of food in an animal model of anorexia nervosa

Activity-based anorexia (ABA) develops when laboratory rats are subjected to a single meal per day and have access to an activity wheel for the remaining time. Here, we studied the contribution of exercise and diet to the reinforcing value of food during ABA development. Three groups of eight adult male Wistar rats were used: an ABA group with 21.5 hr (then 22 hr) of wheel access and 1 hr (then 30 min) of food access, a control group with the same time exposure to food but without exercise, and a yoked group to the ABA in terms of weight loss. Rats were daily tested on a progressive-ratio schedule to measure their motivation for food. ABA rats gradually reduced their body weight more than the food control group. Animals steadily increased their breaking points in parallel to losses in body weight, but no significant differences were found between groups. Adult rats can develop ABA, but their loss in weight neither resulted in a decrease of food intake nor in the motivation to obtain it.

Binge-like Acquisition of α-pyrrolidinopentiophenone (α-PVP) Self-Administration in Female Rats

The synthetic cathinone α-pyrrolidinopentiophenone (α-PVP) has been associated with violent and/or bizarre public behavior in users. Association of such behavior with extended binges of drug use motivates additional investigation, particularly since a prior study found that half of male rats experience a binge of exceptionally high intake, followed by sustained lower levels of self-administration during the acquisition of intravenous self-administration (IVSA) of a closely related drug, 3,4-methylenedioxypyrovalerone. The binge-like acquisition pattern appeared to be novel for rat IVSA, thus the present study was designed to determine if this effect generalizes to IVSA of α-PVP in female rats. Female Wistar rats were trained in IVSA of α-PVP (0.05 mg/kg/inf) in experimental chambers that contained an activity wheel. Groups of animals were trained with the wheels fixed (No-Wheel group), fixed for the initial 5 days of acquisition or free to move throughout acquisition (Wheel group). The groups were next subjected to a wheel-access switch and then all animals to dose-substitution (0.0125-0.3 mg/kg/inf) with the wheels alternately fixed and free to move. Approximately half of the rats initiated their IVSA pattern with a binge day of exceptionally high levels of drug intake, independent of wheel access condition. Wheel activity was much lower in the No-Wheel group in the wheel switch post-acquisition. Dose-effect curves were similar for wheel-access training groups, for binge/no binge phenotypic subgroups and were not altered with wheel access during the dose-substitution. This confirms the high reinforcer efficacy of α-PVP in female rats and the accompanying devaluation of wheel activity as a naturalistic reward.

Wheel running increases hyperthermia and mortality rate following 3,4-methylenedioxymethamphetamine (MDMA) in rats

Hyperthermic responses are commonly reported in cases of human medical emergency following recreational use of 3,4-methylenedioxymethamphetamine (MDMA, “Ecstasy”), but a precise determination of contributing environmental factors has been elusive given the relative scarcity of threatening and fatal reactions in humans. This study was conducted to determine if elevated physical activity contributes to hyperthermic responses to MDMA in a well controlled animal model. Unrestrained male Wistar rats were monitored with minimally-invasive radiotelemetry techniques following challenge with MDMA (1.0, 5.6 and 10.0 mg/kg, s.c.). Studies were conducted in low (23-25°C) and high (27°C) ambient temperature (TA), with and without access to an activity wheel. The study confirmed dose dependent effects on body temperature, chamber activity and wheel activity which were modified by different TA conditions. Increases in wheel and home chamber activity produced by 10 mg/kg MDMA increased the magnitude of hyperthermia under 27°C TA. Furthermore, greater subject mortality was observed in the wheel-access condition compared with the no-wheel condition. These data provide direct evidence that sustained physical activity increases the hyperthermic response to MDMA and that this is associated with increased lethality. This is the first direct experimental confirmation that increased physical activity may be a risk factor for adverse reactions to MDMA in human user populations.

A Murine Effort Model for Studying the Influence of Trichinella on Muscular Activity of Mice

Trichinella are nematodes parasitic in the skeletal muscles of terrestrial vertebrates, generally transmitted via predatorism. It is expected that the infection would have certain influences on the muscular activity in infected animals. The aim of the study was to develop an experimental model for studying the muscular effort in laboratory mice prior to the experimental infection with Trichinella and to evaluate the method in trained (with free access to a voluntary activity wheel) and untrained (without access to activity wheel) animals. Ten laboratory mice (all adult males), equally divided in two groups were used: a control group (untrained mice) and a second group (trained). The weight was evaluated individually. The muscular activity was evaluated using an effort-wheel. Values were expressed in instantaneous power (IP) and data were recorded using a constant speed of 5 rpm for 5 and 20 minutes. The instantaneous power (IP) developed by the effort wheel at 5 minutes was significantly lower in the control group than in trained mice. Similar results were obtained for the maximum power (MP). Interestingly, for the trained mice, there was no difference between the average IP at 5 and 20 minutes of activity. The results show the utility of trained mice, establish the necessary experiment time and validate the method for evaluating the influence of Trichinella spp. on the muscular activity of experimentally infected mice.

Dietary supplementation in alzheimer's disease prevention

Concerning aging society problem of dementia is getting more and more significant. The causes of Alzheimer Disease (AD) are still not well known. The potential role of diet in the prevention of dementia including AD arouses increasing interest. Poly-unsaturated fatty acids (PUFA) are essential for brain growth and development playing an important role as critical modulators of neuronal function and regulation of oxidative stress mechanisms, in brain health and disease. Behavioral research studies with animals proved that ω-3 acids have antioxidant protection on neurons during pathogenesis of AD. DHA diet supplementation in animal models proved that ω-3 acids have positive influence on memory, attention, concentration and locomotor abilities in battery of tests such as 5/9 choice, X- or T-maze and activity wheel. DHA is obtained mainly through dietary intake being not produced by mammals, whereas DHA makes up 60% of fatty acids building neuronal cell membranes. These acids have beneficial effect on cardio-vascular system and may also reduce pathology processes of dementia diseases other than AD. Updated scientific data of ω-3 acids dietary intake in elderly will be presented and discussed.