20 Sep 2021, 5:17 am
Laboratory Animals
Laboratory Animals, Ahead of Print.
Mice and rats are among the most used laboratory animals. They share numerous similarities along with differences, some yet unexplored. One of them is the morphometry of their adrenal glands, whose characteristics may be related to differences in energy management, immune response, drug metabolism, behaviour and temperament. The present study tries to fill this knowledge gap with the evaluation and comparison of adrenal gland anatomical/morphometric parameters of mice and rats. In groups of 10 (n = 10) adult, male and female BALB/c mice and Wistar rats, one in every 20 sections transverse to the longitudinal axis of the gland was used for measuring entire gland area, capsule, entire cortex, cortex zones and medulla with the aid of an image analysis system and subjected to statistical analysis. Quotients of the individual areas were calculated and comparison between the resulting ratios was performed. Gland length and volume were also calculated. Statistically significant differences were revealed between the rat female and male cortex area, rat and mouse medulla/cortex, medulla/gland, zona glomerulosa/cortex and cortex/gland ratios, male and female rats’ medulla/cortex, medulla/gland, capsule/gland, zona glomerulosa/cortex, zona reticularis/cortex and zona glomerulosa/zona fasciculata ratios, length and volume. The correlation evaluation revealed that in male rats and in female mice the larger medulla area was accompanied by a larger cortex area and vice versa. In general, a larger cortex area was accompanied by larger areas of cortex zones. The collected data and the revealed differences can possibly contribute to the understanding of the physiology of the two species.
12 Sep 2021, 6:11 pm
Laboratory Animals
Laboratory Animals, Ahead of Print.
An integrated rearing system for Cantareus aspersus under environmental conditions in an experimental orchard is proposed. In this study, the natural behaviour, circadian rhythms and suitable rearing conditions of the edible snail were optimised to produce homogeneous growth and low variability. The growth was standardised, and growth pattern fit was assessed with various models. One thousand fry were cultured in the orchard, and a random sample of 100 snails were measured weekly for 23 weeks. The rearing system had the following characteristics: snails and earthworms were included in the experimental rearing orchard; a homogeneous group of juvenile snails of the same age and size and high rearing density (500 snails/m2) was used; snails were fed with layers mash ad libitum; and mixed and fringes vegetation was planted in the orchard. A commercial size of 60% of snails was achieved in 21 weeks and 95% in 23 weeks. The different models showed a good fit, and the quadratic model obtained the best fit. This experimental snail orchard proposal can be extended to other areas, although it must be corrected according to different environmental conditions and fit to other species of interest. This experimental model could constitute a viable alternative to traditional models of animal experimentation with mammals, and given its high adaptability, it could be applied in different fields of science.
9 Sep 2021, 12:34 am
Laboratory Animals
Laboratory Animals, Ahead of Print.
This report describes transurethral catheterization with a Foley catheter in 19 anaesthetized, laterally recumbent female pigs with a chest circumference of 72.1 ± 4.2 cm and weighing approximately 40 kg. Catheterization within five minutes was successful in 78.9% of the pigs. Catheterization depth, measured as the distance between the bladder neck and the mucocutaneous junction of the vulva, was 14.5 ± 1.3 cm and correlated with chest circumference but not body length. Measurement of catheterization depth aids in optimal positioning and may prevent inflation of the Foley catheter in the urethra.
9 Sep 2021, 12:34 am
Laboratory Animals
Laboratory Animals, Ahead of Print.
Melanomas are the most common cancer of the eye in canines, felines and humans. The treatment approaches vary, since no gold standard exists. Therefore, this systematic review aimed to compare the treatment modalities in ocular melanoma in rabbits. Medline/PubMed, Cochrane Library, Web of Science and Embase were searched for articles published until 21 April 2021 in English, Portuguese or Spanish, reporting animal studies evaluating photodynamic therapy (PDT), laser, radiotherapy or surgical excision. Twenty-seven articles were included for the qualitative synthesis, with publication dates from 1970 to 2018. Of the selected studies, 19 used PDT, six used radiotherapy and two used laser as treatment. No studies regarding surgical therapy that met the inclusion criteria were obtained. The tumour therapy results were evaluated in a heterogeneous manner for different periods and various methods, including microscopy, angiographic, histological examination, fundoscopy, ultrasound exam and electroretinogram. The treatment modalities analysed successfully treated the ocular melanoma, with tumour necrosis being commonly observed. Despite the therapeutic efficacy shown, side effects have been reported for all the therapies. The studies showed high heterogeneity, and therefore, in the future, new studies should be carried out to increase knowledge about ocular melanoma treatment. The analysed therapies can be used successfully in the treatment of ocular melanoma, with more conservative options such as PDT presenting great potential.
9 Sep 2021, 12:34 am
Laboratory Animals
Laboratory Animals, Ahead of Print.
Students and course providers have found online options for laboratory animal science (LAS) courses helpful because the content is accessible with flexible timing options. This study aimed to explore whether a blended LAS course with video lectures would be preferred and perceived effective, accounting for students’ educational levels as well as prior experiences and future expectations in the use of animals. Data were collected by a feedback survey including three 5-Likert type scales and open-ended questions created by the authors. Of the 134 course students from various programmes, 101 consented to the use of their responses in this study. The analyses indicated that the respondents were generally satisfied with the blended course, especially the hands-on components, even though some found video lectures challenging due to their own ineffective time and study management skills. Plans to use animals in the future increased satisfaction with the course significantly, while the education level or previous experience with animals did not affect the outcome. Background variables did not affect views about video lectures significantly. Conclusively, the blended structure seemed to provide sustainable LAS course experiences for normal and unpredictable times.
8 Sep 2021, 3:01 am
Laboratory Animals
Laboratory Animals, Ahead of Print.
The term ‘culture of care’ in the context of using animals for scientific purpose describes the culture in organisations that provides support to staff to strive for continuous improvement in:• animal care and welfare;• support and recognition of staff involved in the animal care and use programme;• scientific quality;• openness and transparency.We developed a systematic process for reporting observations and events that have the potential to help with continuous learning, improving animal welfare and supporting staff. The process took learning from the safety, health and environment arena on accident prevention. The two key aspects were (a) the systematic logging of observations and events; and (b) the learning approach to following up on observations. Underpinning our systematic process is the ‘Learning from Observations and Events Log’. Reported observations and events can relate to positive practices, general observations as well as near misses.We created an environment to promote continuous improvement for both animals and staff by recognising, rewarding and sharing good practice, as well as where near misses are openly reported and learnt from. Supporting animal welfare, staff welfare, improving scientific quality and transparency are the four key pillars of a positive culture of care.We recognised early on that using a system and learning approach to follow up on observations and events rather than a people and blame approach was key to developing open reporting and a positive culture. In the systems approach, errors are consequences rather than causes, having their origins in systemic factors.
6 Sep 2021, 1:19 am
Laboratory Animals
Laboratory Animals, Ahead of Print.
6 Sep 2021, 1:19 am
Laboratory Animals
Laboratory Animals, Ahead of Print.
Effective multimodal analgesia techniques are required when pigs are used as models in orthopedic human research. Regional anesthesia is a widely used technique to provide perioperative analgesia in animals undergoing orthopedic surgery. The brachial plexus (BP) block is indicated to desensitize the forelimb in many species but has not been yet described in pigs. The main aims of this study were to develop an ultrasound-guided axillary approach for the BP and to evaluate injectate spread and nerve staining in pig cadavers. Eight fresh F1 cross breed German Large White and German Landrace male pig cadavers were enrolled. Two cadavers were used for anatomical dissection of the axillary space and to determine the disposition of the BP. Six cadavers were used to perform a bilateral axillary ultrasound-guided approach for the BP, and after injecting 0.3 ml/kg of a solution of 2% lidocaine and new methylene blue (L-NMB), these were dissected to determine injectate spread and nerve staining. Upon dissection, the BP was observed in all the cases surrounded by the axillary sheath and in close proximity to the axillary artery. Ultrasonographic scanning and guidance for the approach to the BP was feasible in all cadavers and upon dissection, all the nerves forming the BP were stained in all their quadrants and in all the cases. In conclusion, the injection of 0.3 ml/kg of L-NMB through an ultrasound-guided axillary approach to the BP was feasible and adequate to entirely stain the BP in all pig cadavers. Further clinical studies are required to evaluate the effectiveness of this technique in live animals.
19 Aug 2021, 12:26 am
Laboratory Animals
Laboratory Animals, Ahead of Print.
Open chest surgery in rodents requires assisted breathing and the most common approach for ventilation is via an endotracheal tube. Even with well-trained operators the endotracheal intubation is technically challenging and may lead to prolonged procedures and endotracheal intubation complications. Nose cone ventilation is a simpler procedure compared to endotracheal intubation and has the potential to improve animal welfare by reducing procedure time and endotracheal intubation associated complications. Rats are obligate nose breathers, and therefore replacing intubation with air supply from a nose cone would be an advantage and a more natural way of breathing. Here, we compared the values for several blood gases, blood pressure and heart rate from rats that were nose cone ventilated with rats that underwent endotracheal intubation at 12 timepoints equally distributed across three surgical stages: baseline, open chest and closed chest. Throughout the monitoring period the hemodynamic and blood gas values for both methods of ventilation were within published, normal ranges for the rat and were biologically equivalent (equivalence test p value ≤ 0.05). Our data showed that nose cone ventilation-maintained blood gases and hemodynamic homeostasis equivalent to endotracheal intubation. Nose cone ventilation can be recommended as an alternative to endotracheal intubation in rat experiments where investigators require airway control.
14 Aug 2021, 12:50 am
Laboratory Animals
Laboratory Animals, Ahead of Print.
Preclinical drug studies routinely administer experimental compounds to animal models with the goal of minimizing potential adverse events from the procedure. In this study, we assessed the ability to train adult male Long Evans rats to accept daily voluntarily syringe feedings of l-3,4-dihydroxyphenylalanine (L-DOPA) compared to intraperitoneal (IP) injections. Rats were trained to become familiar with the syringe and then fed a training solution that did not contain the experimental compound. If the rat was compliant during the training phase, the dilution of training solution was continuously decreased and replaced with the experimental solution. Voluntary oral dosing compliance was recorded and quantified throughout the study. To assess drug activity within the drug-targeted tissues, the striatum and retina were collected and analyzed for L-DOPA, dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) levels by high performance liquid chromatography (HPLC). Drug delivery efficiency by oral dosing was directly compared to IP injection by collecting plasma and analyzing L-DOPA levels with HPLC. Adult male rats had high compliance for voluntary oral dosing. HPLC showed that oral administration of the compound at the same dose as IP injection yielded significantly lower plasma levels, and that higher oral L-DOPA doses yield higher plasma L-DOPA content. This study describes detailed methodology to train adult rats to syringe feed experimental compounds and provides important preclinical research on drug dosing and drug delivery to the striatum and retina.