Automated and Continuous Monitoring of Animal Welfare through Digital Alerting.

A primary goal in preclinical animal research is respectful and responsible care aimed toward minimizing stress and discomfort while enhancing collection of accurate and reproducible scientific data. Researchers use hands-on clinical observations and measurements as part of routine husbandry procedures or study protocols to monitor animal welfare. Although frequent assessments ensure the timely identification of animals with declining health, increased handling can result in additional stress on the animal and increased study variability. We investigated whether automated alerting regarding changes in behavior and physiology can complement existing welfare assessments to improve the identification of animals in pain or distress. Using historical data collected from a diverse range of therapeutic models, we developed algorithms that detect changes in motion and breathing rate frequently associated with sick animals but rare in healthy controls. To avoid introducing selec- tion bias, we evaluated the performance of these algorithms by using retrospective analysis of all studies occurring over a 31-d period in our vivarium. Analyses revealed that the majority of the automated alerts occurred prior to or simultaneously with technicians' observations of declining health in animals. Additional analyses performed across the entire duration of 2 studies (animal models of rapid aging and lung metastasis) demonstrated the sensitivity, accuracy, and utility of automated alerting for detecting unhealthy subjects and those eligible for humane endpoints. The percentage of alerts per total subject days ranged between 0% and 24%, depending on the animal model. Automated alerting effectively complements standard clinical observations to enhance animal welfare and promote responsible scientific advancement.

Retrospective Analysis of the Effects of Identification Procedures and Cage Changing by Using Data from Automated, Continuous Monitoring.

Many variables can influence animal behavior and physiology, potentially affecting scientific study outcomes. Laboratory and husbandry procedures-including handling, cage cleaning, injections, blood collection, and animal identification-may produce a multitude of effects. Previous studies have examined the effects of such procedures by making behavioral and physiologic measurements at specific time points; this approach can be disruptive and limits the frequency or duration of observations. Because these procedures can have both acute and long-term effects, the behavior and physiology of animals should be monitored continuously. We performed a retrospective data analysis on the effects of 2 routine procedures, animal identification and cage changing, on motion and breathing rates of mice continuously monitored in the home cage. Animal identification, specifically tail tattooing and ear tagging, as well as cage changing, produced distinct and reproducible postprocedural changes in spontaneous motion and breathing rate patterns. Behavioral and physiologic changes lasted approximately 2 d after tattooing or ear tagging and 2 to 4 d for cage changing. Furthermore, cage changes showed strain-, sex-, and time-of-day-dependent responses but not age-dependent differences. Finally, by reviewing data from a rodent model of multiple sclerosis as a retrospective case study, we documented that cage changing inadvertently affected experimental outcomes. In summary, we demonstrate how retrospective analysis of data collected continuously can provide high-throughput, meaningful, and longitudinal insights in to how animals respond to routine procedures.

Involvement of the neurotensin receptor 1 in the behavioral effects of two neurotensin agonists, NT-2 and NT69L: lack of hypothermic, antinociceptive and antipsychotic actions in receptor knockout mice.

Neurotensin (NT) is a neuropeptide implicated in the pathophysiology of schizophrenia and in mediating the efficacy of antipsychotic drugs. NT is also involved in the regulation of body temperature and pain sensitivity. Using neurotensin receptor 1 (NTR1) knockout (KO) and wild-type (WT) mice, these studies evaluated the involvement of NTR1 in the behavioral responses produced by peripheral administration of NT agonists (NT-2 and NT69L). Animals were characterized in paradigms designed to assess hypothermia, antinociception, and antipsychotic-like effects. Under basal conditions, there were no phenotypic differences between NTR1 KO and WT mice. In WT mice, both NTR1 agonists decreased core body temperature (active doses in mg/kg, i.p., for NT-2 and NT69L, respectively: 1 and 3), increased tail withdrawal latencies (1 and 3), produced decreased spontaneous climbing (0.1, 0.3, 1 and 1, 3, 10) and reversed apomorphine-induced climbing (0.3, 1 and 1, 3). In contrast, none of the effects of either agonist were present in KO mice. These results suggest that NTR1: (1) does not play a major role in the control of basal thermoregulation, nociception or psychomotor stimulation in mice (barring possible developmental plasticity), (2) does mediate these behavioral responses to NT agonists, and (3) may play a role in the potential antipsychotic effects of these agonists.

Treatment with the atypical antipsychotic, olanzapine, prevents the expression of amphetamine-induced place conditioning in the rat.

Place conditioning (PC) experiments were conducted as a means to further elaborate the treatment potential of the atypical antipsychotic, olanzapine (OLZ), for stimulant abuse. The resulting preference/aversion provides an indirect measure of the incentive salience (i.e., euphoria/dysphoria) produced by a drug. Male Sprague-Dawley rats (n=48) were conditioned in two unique environments (i.e., vertical vs. horizontal stripped walls, large vs. small grid flooring) using injections (1.0 mg/kg ip) of either amphetamine (AMPH) or saline (SAL). On average, animals displayed a significant preference for the AMPH-paired location after 2.5 weeks of conditioning (five pairings each of AMPH and SAL). Once the preference was established, animals were pretreated (60 min) with a single dose of OLZ (0.0, 0.56, 1.0 or 1.5 mg/kg sc) given on the test (AMPH-free) day. For the following week's test, animals were injected with SAL (1.0 mg/kg ip) in an attempt to recapture the side preference exhibited before OLZ treatment. OLZ treatment prevented the expression of the AMPH-conditioned preference and reduced locomotor activity. Inhibition of preference resulted from the highest dose of OLZ (1.5 mg/kg), while the inhibition of locomotor activity occurred across all three doses. Additionally, while the effects on preference were no longer apparent by the SAL test the following week (reversible), the activity was still depressed during the SAL tests in animals that had experienced the highest dose of OLZ (1.5 mg/kg). Control experiments, in which OLZ was used as the conditioning drug, suggest that OLZ itself possesses no aversive effects in the PC paradigm, and may even produce a preference for the drug-paired chamber. Because the AMPH preference is dependent on dopamine (DA) release in the nucleus accumbens (NAcc), these experiments suggest that OLZ pretreatment interferes with the rewarding, as well as the subjective effects of AMPH.

Attenuation of the amphetamine discriminative cue in rats with the atypical antipsychotic olanzapine.

Sixteen male Sprague-Dawley rats were trained to discriminate between saline and amphetamine injections (1.0 mg/kg ip) using a standard two-lever (FR10) drug discrimination paradigm. A baseline dose-effect curve was generated for amphetamine administration alone, using doses both above and below the training dose (0.0-2.2 mg/kg ip). Once completed, a single dose of olanzapine (OLZ; 1.5 mg/kg sc) was tested for its ability to attenuate the amphetamine cue. OLZ pretreatment (60 min) successfully interfered with an animal's ability to discriminate amphetamine injections across various doses. The percentage of correct responding on the amphetamine lever and rate of responding were both significantly decreased across some but not all of the amphetamine doses. Therefore, we believe that this preliminary investigation has successfully shown that an OLZ dose of 1.5 mg/kg sc at 60 min can interfere with an animal's ability to detect some subjective cue(s) associated with amphetamine administration.