Implementation of an Alternative Training Method for Cardiac Blood Collection in Mice.

Training personnel to work with animals presents a variety of challenges, both logistically and with regard to animal welfare. These issues make training an ideal opportunity to evaluate practices and to implement the 3R principles (refinement, replacement, and reduction). Cardiac blood collection from mice is a procedure that can compromise the 3Rs by requiring repeated practice and animal euthanasia. The development of a non-animal training model would promote the 3R principles. Our goals for the development of a new training model for cardiac blood collection from mice were to reduce the number of mice needed to achieve competency, improve our culture of care, and refine the training approach by improving competency. The training model was developed using commonly available materials. The total cost of the model was less than $15 USD per model. Two training curricula were conducted concurrently over a 5-mo period: 1) a curriculum in which trainees used the model before progressing to live mice and 2) the traditional curriculum, which used euthanized mice throughout. The measured variables included the total number of mice used, proportions of trainees who reached competency, the time needed to reach competency, method comprehension, quality of skill performance, trainer and trainee feedback, and training costs. The alternative group used at least 10 fewer mice per technician as compared with the traditionally trained group. The alternative group had a higher competency rate, with 82% (9 of 11 trainees) reaching competency compared with 60% (3 of 5 trainees) in the traditional group. Skill comprehension and quality were superior in the alternative group, as evidenced by fewer gross lesions at necropsy. Overall, personnel in the alternative group provided positive feedback with regard to the use of fewer mice, acquisition of both skill and confidence, and benefits for compassion fatigue. The use of this model is now our standard approach for training personnel in cardiac blood collection in mice. Our results demonstrate that the use of models in training curricula can enhance skill development and reduce the use of mice.

Evaluation of Submental Blood Collection in Mice ( Mus musculus).

The submental route is an option for nonterminal and serial blood collection in mice. This study compared the submental route to the maxillary route (also referred to as the submandibular route). The study used male CD1 and C57BL/6 strains of mice in 2 age groups: 8 and 19 wk. To simulate repeated toxicokinetic blood collection, blood was collected from each mouse at 1 and 24-h on Study Day 1, and at 1, 4 and 24 h on Study Day 16. Food consumption, body weights, and clinical observations were assessed daily. No apparent differences were found between the 2 blood collection sites in terms of either food consumption or body weight. Mice bled via the submental route showed fewer adverse clinical effects than did mice bled via the maxillary route. Clinical pathology showed no differences between the 2 methods. In addition, 7 trained technicians, who were inexperienced with the 2 bleeding methods prior to these evaluations, were surveyed to gain insights into expectations and overall experience of using the 2 routes. All 7 technicians preferred the submental route to the maxillary route. Furthermore, the average time needed to become proficient in submental blood collection (1.6 d) was less than that required to become proficient in maxillary blood collection (2.6 d). The qualitative aspects of this study, combined with fewer adverse clinical events, suggest ways to improve both animal and staff welfare. Our findings suggest that the submental route is safe, effective, and easier than the maxillary route for nonterminal serial blood collection in mice.

Extraintestinal Pathogenic Escherichia Coli Causes Necrohemorrhagic Pneumonia in Multiple Research Dogs.

Extraintestinal pathogenic Escherichia coli expressing cytotoxic necrotizing factor (CNF) 1 and 2 virulence factors is a rarely reported cause of acute, fatal necrohemorrhagic pneumonia in canines. A review of cases of necrohemorrhagic pneumonia in beagles at our facility between 2013 and 2021 revealed 21 dogs that died or were euthanized after acute onset lethargy, dyspnea, and hemorrhage. Some affected animals had recently been transported to the facility. In all dogs, lung lobes were discolored dark red and consolidated. Histologic lesions in 17 of these included alveolar necrosis, hemorrhage, edema, fibrin, acute inflammation, and intralesional colonies of bacilli. Lung was cultured for 10 dogs with E. coli isolated and CNF1 identified by virulence factor PCR in 7 of those. Based on these findings, extraintestinal E. coli should be considered an important cause of acute fatal necrohemorrhagic pneumonia in purpose-bred beagle research dogs and may be associated with a recent history of transport.

Extracellular vesicle-induced cyclic AMP signaling.

Second messenger signaling is required for cellular processes. We previously reported that extracellular vesicles (EVs) from stimulated cultured endothelial cells contain the biochemical second messenger, cAMP. In the current study, we sought to determine whether cAMP-enriched EVs induce second messenger signaling pathways in naïve recipient cells. Our results indicate that cAMP-enriched EVs increase cAMP content sufficient to stimulate PKA activity. The implications of our work are that EVs represent a novel intercellular mechanism for second messenger, specifically cAMP, signaling.