Browsing by Author "Laboratory Animal Resource Center, School of Medicine"

Now showing 1 - 6 of 6
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    Acute Effects of Hypothermia and Inhalant Anesthesia on Ultrasonic Vocalizations and Neuroendocrine Markers in Neonatal Rats
    (American Association for Laboratory Animal Science, 2024) Lamont, Katherine A.; Boynton, Marcella H.; Hickman, Debra L.; Fletcher, Craig A.; Williams, Morika D.; Laboratory Animal Resource Center, School of Medicine
    Neonatal rodents undergo anesthesia for numerous procedures and for euthanasia by anesthetic overdose. However, data regarding whether neonatal anesthesia is humane are limited. Hypothermia (cryoanesthesia) is the most commonly used anesthetic protocol for neonatal rats 10 d of age or younger. However, hypothermia has recently been restricted in several countries due to perceived painful effects, including pain on rewarming. Minimizing the potential pain and distress of neonates in research is imperative, although very challenging. Traditional validated and nonvalidated behavioral and physiologic outcome measures used for adult rats undergoing anesthesia are unsuitable for evaluating neonates. Therefore, we investigated the effects of several anesthetic methods on neonatal rats by using the innovative objective approaches of noninvasive ultrasonic vocalizations and more invasive neuroendocrine responses (i. e., serum corticosterone, norepinephrine, glucose). Our results show that hypothermia leads to heightened acute distress in neonatal rats as indicated by prolonged recovery times, increased duration of vocalizations, and elevated corticosterone levels, as compared with neonates undergoing inhalational anesthesia. We demonstrate that inhalational anesthesia is preferable to cryoanesthesia for neonatal rats, and researchers using hypothermia anesthesia should consider using inhalational anesthesia as an alternative method.
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    Effectiveness of the Glass Bead Sterilizer for Sterilizing Surgical Instruments
    (American Association for Laboratory Animal Science, 2022) Skiles, Beth; Johnston, Nancy A.; Hendrix, G. Kenitra; Hickman, Debra L.; Laboratory Animal Resource Center, School of Medicine
    Survival rodent surgery requires the use of sterile instruments for each animal, which can be challenging when performing multiple surgeries on batches of animals. Glass bead sterilizers (GBS) are widely considered to facilitate this practice by sterilizing the tips of the instruments between animals. However, other disciplines have raised questions about the efficacy of the GBS, especially when used with surgical tools that have grooves or ridges that may contain organic debris. In this study, we evaluated the efficacy of the GBS to sterilize instruments commonly used in rodent surgery by intentionally contaminating a selection of instruments with a standardized bacterial broth inoculated with Staphylococcus aureus and Escherichia coli. As expected, a simple ethanol wipe was ineffective in sterilizing instruments in all treatment groups. An ethanol wipe followed by GBS was effective in sterilizing 82.5% (99 of 120) of the instruments. Our study suggests that the GBS may not be effective for consistent sterilization of surgical instruments.
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    Evaluation of Treatment Options for Ulcerative Dermatitis in the P Rat
    (American Association for Laboratory Animal Science, 2021) Skiles, Beth A.; Boehm, Chris A.; Peveler, Jessica L.; Hickman, Debra L.; Laboratory Animal Resource Center, School of Medicine
    Rotational outbred adult rats, phenotypically selected to prefer drinking alcohol ("P" rats) frequently present with self-inflicted wounds and ulcerative dermatitis, similar to that seen in C57BL/6 mice. Historically, veterinary interventions used to address this clinical condition have included triple antibiotic ointment (TABO), Columbia wound powder (CPW), nail trims, or plastic tubes that allow affected animals to hide. More recent studies have suggested that nail trims are the most successful intervention in mice, but this has not been evaluated previously in rats. In this study, we evaluated nail trims in rats and also tested whether placing a pumice stone in the cage would reduce the need for nail trims to reduce self-inflicted wounds. Our hypothesis was that interacting with the pumice stone would dull/trim the rats' nails without causing stress or illness and allow the wounds time to heal. We used 66 P rats that were assigned to 1 of 6 treatment groups (pumice stone, TABO, CWP, huts, nail trims, and an untreated control group) of 11 rats each. Rats were transferred to this study from a colony of experimentally naïve animals that had evidence of dermatitis. The wounds were photographed and measured for 12 wk at 2 wk intervals. At the end of the study, representative skin samples from the site of the wound were collected for histopathologic evaluation of inflammation. Our data showed no significant differences in the inflammation scores. The rats treated with nail trims healed significantly more often than did all of the other treatment groups. This suggests that nail trims are the most effective intervention for treating self-inflicted wounds in P rats.
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    Gender of Authors in Laboratory Animal Medicine and Science in 2 Peer-Reviewed U.S. Journals
    (American Association for Laboratory Animal Science, 2022) Niemi, Steven M.; Hickman, Debra L.; Crisler, Robin; Laboratory Animal Resource Center, School of Medicine
    Multiple recent surveys have examined the prevalence of female first or senior authors on publications for various scientific and medical disciplines. First and senior authorships are significant achievements for purposes of professional advancement, especially in academia. Such surveys can also provide information regarding diversity and inclusion. In this report, we present the findings of a survey performed to assess how frequently female contributors were first or senior authors in 2 of the most widely-circulated peer-reviewed journals of laboratory animal medicine and science in the United States; data were collected at 3 time points over a recent 20-y span. These data were then compared against estimated populations of potential female authors, as determined from membership rolls in the American Society of Laboratory Animal Practitioners and the American College of Laboratory Animal Medicine. Survey results suggest that female authors increased their representation as influential authors over time, in contrast to representation trends reported for other disciplines. However, whether this increase has mirrored the increase in women overall in the veterinary profession during this time span is unknown. In an era of greater attention and sensitivity to equity and inclusion, this survey is offered as a starting point for further conversation within the field of laboratory animal medicine and science.
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    Minimal Exposure Times for Irreversible Euthanasia with Carbon Dioxide in Mice and Rats
    (American Association for Laboratory Animal Science, 2022) Hickman, Debra L.; Laboratory Animal Resource Center, School of Medicine
    When using an anesthetic overdose to euthanize laboratory rodents, a secondary method of euthanasia is recommended to ensure that the apparent death is irreversible. This secondary method usually is accomplished through the collection of tissues that are required to complete the research project. However, frequently laboratory rodents must be euthanized because they cannot be used for studies; in these cases, caretakers must perform a secondary method of euthanasia. Performing physical methods of euthanasia, even on unconscious rodents, can contribute to compassion fatigue in these persons. The current study was designed based on existing literature regarding minimal exposure times for preweanling rats and mice euthanized with carbon dioxide. The study evaluated the minimal time that adult rats and mice must remain in 100% carbon dioxide for death to be irreversible on removal. Adult rats (14 stocks and strains) and mice (more than 40 stocks and strains) were euthanized using a 50% volume per minute displacement rate of carbon dioxide for 2 min. The cages were then left undisturbed for predetermined times, ranging from 0 to almost 12 min. Upon removal from the cage, the animals were stimulated to determine whether they could be resuscitated. If an animal recovered, it was euthanized by using a physical method of euthanasia, and a duration that was 30 s longer than the previous predetermined time was assessed using other animals. The study demonstrated that exposure times of at least 3 min in carbon dioxide reliably result in irreversible euthanasia of mice but that exposure times of at least 10.5 min in carbon dioxide were required to ensure irreversible euthanasia of rats. Although an irreversible death can be attained with carbon dioxide, the use of appropriate species-specific exposure times is critical.
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    The Future Is Not Bright: Evaluation of Rat Preferences for Color and Intensity of Light
    (MDPI, 2024-07-12) Swan, Melissa; Horvath, Aidan; Pritchett, Rebecca K.; Barabas, Amanda J.; Hickman, Debra; Gaskill, Brianna N.; Laboratory Animal Resource Center, School of Medicine
    Light is a key factor influencing the welfare of laboratory rodents, but little is known about their optimal lighting condition. It i common knowledge that rats prefer dim light, so bright light is mitigated with red-tinted shelters or cages, which alter both the color and intensity of light. Because both aspects are altered, the contribution of each feature to rodent preference is unknown. Further, it is unknown if this preference is influenced by previous experience. We hypothesized that rats would prefer lower light intensity and that their preferences would be influenced by their housing environment. Breeder pairs of rats were randomly separated into four treatments groups: red 200 lux, red 25 lux, clear 200 lux, and clear 25 lux. The breeders' offspring were tested three times in an apparatus that offered access to each environment, and their preferences were analyzed. Generally, the rats preferred the lower-lux environments and showed no color preference. However, the rats from the clear, 200 lux cages, preferred clear caging and only showed a preference for 25 lux conditions during the second and third preference tests. These results suggest that the light intensity, more than color, should be considered when designing rodent housing and testing facilities.