Reliability of the Mouse Grimace Scale in C57BL/6JRj Mice

HPV+ head and neck cancer-derived small extracellular vesicles communicate with TRPV1+ neurons to mediate cancer pain

ABSTRACT

Severe pain is often experienced by patients with head and neck cancer and is associated with a poor prognosis. Despite its frequency and severity, current treatments fail to adequately control cancer-associated pain because of our lack of mechanistic understanding. Although recent works have shed some light of the biology underlying pain in HPV-negative oral cancers, the mechanisms mediating pain in HPV+ cancers remain unknown. Cancer-derived small extracellular vesicles (cancer-sEVs) are well positioned to function as mediators of communication between cancer cells and neurons. Inhibition of cancer-sEV release attenuated pain in tumor-bearing mice. Injection of purified cancer-sEVs is sufficient to induce pain hypersensitivity in naive mice that is prevented by QX-314 treatment and in Trpv1-/- mice. Cancer-sEVs triggered calcium influx in nociceptors, and inhibition or ablation of nociceptors protects against cancer pain. Interrogation of published sequencing data of human sensory neurons exposed to human cancer-sEVs suggested a stimulation of protein translation in neurons. Induction of translation by cancer-sEVs was validated in our mouse model, and its inhibition alleviated cancer pain in mice. In summary, our work reveals that HPV+ head and neck squamous cell carcinoma-derived sEVs alter TRPV1+ neurons by promoting nascent translation to mediate cancer pain and identified several promising therapeutic targets to interfere with this pathway.

Neuronal-immune axis alters pain and sensory afferent damage during dental pulp injury

ABSTRACT

Dental pulp tissue is densely innervated by afferent fibers of the trigeminal ganglion. When bacteria cause dental decay near the pulpal tissue, a strong neuronal and immune response occurs, creating pulpitis, which is associated with severe pain and pulp tissue damage. Neuroimmune interactions have the potential to modulate both the pain and pathological outcome of pulpitis. We first investigated the role of the neuropeptide calcitonin gene-related peptide (CGRP), released from peptidergic sensory afferents, in dental pain and immune responses by using Calca knockout (Calca -/- ) and wild-type (Calca +/+ ) mice, in a model of pulpitis by creating a mechanical exposure of the dental pulp horn. We found that the neuropeptide CGRP, facilitated the recruitment of myeloid cells into the pulp while also increasing spontaneous pain-like behavior 20% to 25% at an early time point. Moreover, when we depleted neutrophils and monocytes, we found that there was 20% to 30% more sensory afferent loss and increased presence of bacteria in deeper parts of the tissue, whereas there was a significant reduction in mechanical pain response scores compared with the control group at a later time point. Overall, we showed that there is a crosstalk between peptidergic neurons and neutrophils in the pulp, modulating the pain and inflammatory outcomes of the disease.

Review of Rat (Rattus norvegicus), Mouse (Mus musculus), Guinea pig (Cavia porcellus), and Rabbit (Oryctolagus cuniculus) Indicators for Welfare Assessment

The monitoring and assessment of animals is important for their health and welfare. The appropriate selection of multiple, validated, and feasible welfare assessment indicators is required to effectively identify compromises or improvements to animal welfare. Animal welfare indicators can be animal or resource based. Indicators can be collated to form assessment tools (e.g., grimace scales) or animal welfare assessment models (e.g., 5 Domains) and frameworks (e.g., 5 Freedoms). The literature contains a wide variety of indicators, with both types needed for effective animal welfare assessment; however, there is yet to be an ideal constellation of indicators for animal-based welfare assessment in small mammals such as guinea pigs (Cavia Porcellus), mice (Mus musculus), rabbits (Oryctolagus cuniculus), and rats (Rattus norvegicus). A systematic review of grey and peer-reviewed literature was performed to determine the types of animal-based welfare indicators available to identify and assess animal health and welfare in these small mammals maintained across a wide variety of conditions. The available indicators were categorised and scored against a selection of criteria, including potential ease of use and costs. This review and analysis aim to provide the basis for further research into animal welfare indicators for these species. Future applications of this work may include improvements to animal welfare assessments or schemes, guiding better management, and implementing future strategies to enable better animal welfare.

Bacteria hijack a meningeal neuroimmune axis to facilitate brain invasion

The meninges are densely innervated by nociceptive sensory neurons that mediate pain and headache1,2. Bacterial meningitis causes life-threatening infections of the meninges and central nervous system, affecting more than 2.5 million people a year3-5. How pain and neuroimmune interactions impact meningeal antibacterial host defences are unclear. Here we show that Nav1.8+ nociceptors signal to immune cells in the meninges through the neuropeptide calcitonin gene-related peptide (CGRP) during infection. This neuroimmune axis inhibits host defences and exacerbates bacterial meningitis. Nociceptor neuron ablation reduced meningeal and brain invasion by two bacterial pathogens: Streptococcus pneumoniae and Streptococcus agalactiae. S. pneumoniae activated nociceptors through its pore-forming toxin pneumolysin to release CGRP from nerve terminals. CGRP acted through receptor activity modifying protein 1 (RAMP1) on meningeal macrophages to polarize their transcriptional responses, suppressing macrophage chemokine expression, neutrophil recruitment and dural antimicrobial defences. Macrophage-specific RAMP1 deficiency or pharmacological blockade of RAMP1 enhanced immune responses and bacterial clearance in the meninges and brain. Therefore, bacteria hijack CGRP-RAMP1 signalling in meningeal macrophages to facilitate brain invasion. Targeting this neuroimmune axis in the meninges can enhance host defences and potentially produce treatments for bacterial meningitis.

Grimace scale, burrowing, and nest building for the assessment of post-surgical pain in mice and rats-A systematic review

Several studies suggested an informative value of behavioral and grimace scale parameters for the detection of pain. However, the robustness and reliability of the parameters as well as the current extent of implementation are still largely unknown. In this study, we aimed to systematically analyze the current evidence-base of grimace scale, burrowing, and nest building for the assessment of post-surgical pain in mice and rats. The following platforms were searched for relevant articles: PubMed, Embase via Ovid, and Web of Science. Only full peer-reviewed studies that describe the grimace scale, burrowing, and/or nest building as pain parameters in the post-surgical phase in mice and/or rats were included. Information about the study design, animal characteristics, intervention characteristics, and outcome measures was extracted from identified publications. In total, 74 papers were included in this review. The majority of studies have been conducted in young adult C57BL/6J mice and Sprague Dawley and Wistar rats. While there is an apparent lack of information about young animals, some studies that analyzed the grimace scale in aged rats were identified. The majority of studies focused on laparotomy-associated pain. Only limited information is available about other types of surgical interventions. While an impact of surgery and an influence of analgesia were rather consistently reported in studies focusing on grimace scales, the number of studies that assessed respective effects was rather low for nest building and burrowing. Moreover, controversial findings were evident for the impact of analgesics on post-surgical nest building activity. Regarding analgesia, a monotherapeutic approach was identified in the vast majority of studies with non-steroidal anti-inflammatory (NSAID) drugs and opioids being most commonly used. In conclusion, most evidence exists for grimace scales, which were more frequently used to assess post-surgical pain in rodents than the other behavioral parameters. However, our findings also point to relevant knowledge gaps concerning the post-surgical application in different strains, age levels, and following different surgical procedures. Future efforts are also necessary to directly compare the sensitivity and robustness of different readout parameters applied for the assessment of nest building and burrowing activities.

The neurobiology of pain and facial movements in rodents: Clinical applications and current research

One of the most controversial aspects of the use of animals in science is the production of pain. Pain is a central ethical concern. The activation of neural pathways involved in the pain response has physiological, endocrine, and behavioral consequences, that can affect both the health and welfare of the animals, as well as the validity of research. The strategy to prevent these consequences requires understanding of the nociception process, pain itself, and how assessment can be performed using validated, non-invasive methods. The study of facial expressions related to pain has undergone considerable study with the finding that certain movements of the facial muscles (called facial action units) are associated with the presence and intensity of pain. This review, focused on rodents, discusses the neurobiology of facial expressions, clinical applications, and current research designed to better understand pain and the nociceptive pathway as a strategy for implementing refinement in biomedical research.

A model-specific simplification of the Mouse Grimace Scale based on the pain response of intraperitoneal CCl4 injections

Despite its long establishment and applicability in mice pain detection, the Mouse Grimace Scale still seems to be underused in acute pain detection during chronic experiments. However, broadening its applicability can identify possible refinement approaches such as cumulative severity and habituation to painful stimuli. Therefore, this study focuses on two main aspects: First, five composite MGS criteria were evaluated with two independent methods (the MoBPs algorithm and a penalized least squares regression) and ranked for their relative importance. The most important variable was used in a second analysis to specifically evaluate the context of pain after an i.p. injection (intervention) in two treatment groups (CCl₄ and oil (control)) at fixed times throughout four weeks in 24 male C57BL/6 N mice. One hour before and after each intervention, video recordings were taken, and the MGS assessment was performed. In this study, the results indicate orbital tightening as the most important criterion. In this experimental setup, a highly significant difference after treatment between week 0 and 1 was found in the CCl₄ group, resulting in a medium-sized effect (W = 62.5, p value < 0.0001, r_CCl4 = 0.64). The oil group showed no significant difference (week 0 vs 1, W = 291.5, p value = 0.7875, r_control = 0.04). Therefore, the study showed that the pain caused by i.p. injections was only dependent on the applied substance, and no significant cumulation or habituation occurred due to the intervention. Further, the results indicated that the MGS system can be simplified.

Medicine, Value, and Knowledge in the Veterinary Clinic: Questions for and From Medical Anthropology and the Medical Humanities

The welcome development of the veterinary humanities, and veterinary anthropology specifically, raises the question of its potential relationship with the now well-established field(s) of the medical humanities, and of medical anthropology. Although there are national variations, the term “medical humanities” generally refers to either the tapping of the humanities to improve medical education by developing, through engagement with the humanities like literature and visual art, skills in empathy, visualization and expressivity, or alternatively, it refers to the application of humanities approaches of cultural critique to the presumptions, practices and institutions of the human medical world to denaturalize the ideologies of knowledge that contemporary human medicine professions depend upon. This article reflects on the potential impact that the development of a veterinary medical humanities could have on the field of (human) medical humanities and vice versa. Could such a development force a re-conception of notions of agency, of consent, and of the position of “patient” when the (human based) medical humanities is expanded to include both human and veterinary medicine? What would the potential usefulness, or limitations, both in conceptual and in applied terms, be of constructing a multi-species notion of “medical humanities?” What can such a comparative approach offer to veterinary medicine, in practice and in terms of the curricula of veterinary training? To reflect on these questions, this article draws on my multiple years of fieldwork in veterinary clinics and classrooms to first lay out the constituent components of the formal practice of contemporary veterinary medicine (at least in the U.S.) in terms of the roles that species specificity and relations to humans play in the delivery of care, and then seeks to center the animal in these practices to ask questions about consent, resistance, veterinary obligation, and the role of finance in comparison with human medicine. These similarities and differences will form the basis for a consideration of the effects of enlarging the medical humanities to encompass more than one species.

Proper animal experimental designs for preclinical research of biomaterials for intervertebral disc regeneration

Low back pain is a vital musculoskeletal disease that impairs life quality, leads to disability and imposes heavy economic burden on the society, while it is greatly attributed to intervertebral disc degeneration (IDD). However, the existing treatments, such as medicines, chiropractic adjustments and surgery, cannot achieve ideal disc regeneration. Therefore, advanced bioactive therapies are implemented, including stem cells delivery, bioreagents administration, and implantation of biomaterials etc. Among these researches, few reported unsatisfying regenerative outcomes. However, these advanced therapies have barely achieved successful clinical translation. The main reason for the inconsistency between satisfying preclinical results and poor clinical translation may largely rely on the animal models that cannot actually simulate the human disc degeneration. The inappropriate animal model also leads to difficulties in comparing the efficacies among biomaterials in different reaches. Therefore, animal models that better simulate the clinical charateristics of human IDD should be acknowledged. In addition, in vivo regenerative outcomes should be carefully evaluated to obtain robust results. Nevertheless, many researches neglect certain critical characteristics, such as adhesive properties for biomaterials blocking annulus fibrosus defects and hyperalgesia that is closely related to the clinical manifestations, e.g., low back pain. Herein, in this review, we summarized the animal models established for IDD, and highlighted the proper models and parameters that may result in acknowledged IDD models. Then, we discussed the existing biomaterials for disc regeneration and the characteristics that should be considered for regenerating different parts of discs. Finally, well-established assays and parameters for in vivo disc regeneration are explored.

Supplementation with >Your< Iron Syrup Corrects Iron Status in a Mouse Model of Diet-Induced Iron Deficiency

The objective of this study was to compare the effects of >Your< Iron Syrup, a novel oral liquid iron-containing food supplement, with the commonly prescribed iron sulphate (Fe-sulphate) in a mouse model of diet-induced iron deficiency. Standard inbred BALB/cOlaHsd mice were fed low-iron diet for 11 weeks to induce significant decrease in blood haemoglobin and haematocrit and were then supplemented by gavage with either >Your< Iron Syrup or Fe-sulphate for two weeks. In >Your< Iron Syrup group, several markers of iron deficiency, such as serum iron concentration, transferrin saturation and ferritin level were significantly improved in both female and male mice. Fe-sulphate induced similar responses, except that it did not significantly increase iron serum in females and serum ferritin in both sexes. Fe-sulphate significantly increased liver-iron content which >Your< Iron Syrup did not. Transcription of Hamp and selected inflammatory genes in the liver was comparable between the two supplementation groups and with the Control diet group. Some sex-specific effects were noted, which were more pronounced and less variable in males. In conclusion, >Your< Iron Syrup was efficient, comparable and in some parameters superior to Fe-sulphate in improving iron-related parameters without inducing a response of selected liver inflammation markers in a mouse model of diet-induced iron deficiency.

Methods Used and Application of the Mouse Grimace Scale in Biomedical Research 10 Years on: A Scoping Review

The Mouse Grimace Scale (MGS) was developed 10 years ago as a method for assessing pain through the characterisation of changes in five facial features or action units. The strength of the technique is that it is proposed to be a measure of spontaneous or non-evoked pain. The time is opportune to map all of the research into the MGS, with a particular focus on the methods used and the technique's utility across a range of mouse models. A comprehensive scoping review of the academic literature was performed. A total of 48 articles met our inclusion criteria and were included in this review. The MGS has been employed mainly in the evaluation of acute pain, particularly in the pain and neuroscience research fields. There has, however, been use of the technique in a wide range of fields, and based on limited study it does appear to have utility for pain assessment across a spectrum of animal models. Use of the method allows the detection of pain of a longer duration, up to a month post initial insult. There has been less use of the technique using real-time methods and this is an area in need of further research.

Validation of the Equine Behaviour Assessment and Research Questionnaire (E-BARQ): A New Survey Instrument for Exploring and Monitoring the Domestic Equine Triad

Simple Summary

The Equine Behaviour Assessment and Research Questionnaire (E-BARQ) is an online questionnaire collecting information from horse-owners and riders on their horses’ training, management and behaviour. In order to compare different populations of domestic equids—for example, according to their breed, discipline, training or management type—it is important that the questionnaire administered to participants has been validated and found to be reliable. The questionnaire must reflect a true assessment of the horse’s behaviour, and, when taken by different users or the same user over time, the results should remain consistent. This article describes the process of validating the E-BARQ questionnaire, using three separate procedures. The results confirmed that the E-BARQ represents a standardised and validated behavioural assessment tool for horses.

Abstract

The Equine Behaviour Assessment and Research Questionnaire (E-BARQ) was developed to obtain quantitative data on the domestic equine triad: training, management and behaviour. It can be taken repeatedly, thus collecting longitudinal data to enable evaluation of how changes in a horse’s training and management are reflected in that horse’s behaviour over time and how these changes can impact horse welfare in the longer term. Questionnaire validation and reliability were tested by determining (a) whether an owner’s subjective ratings of their horse’s problematic behaviours or undesirable temperament traits were reflected in the questionnaire scores obtained for that horse (construct validity), (b) whether two respondents, equally familiar with a particular horse, reported comparable scores for that horse through the questionnaire (inter-rater reliability), and (c) whether the same respondent, scoring the same horse after a known interval of time, recorded similar responses (intra-rater reliability). Construct validity testing of 1923 responses showed significant alignment between owners’ reported experience of focal horses’ behaviour and those horses’ E-BARQ scores, with scores varying from 1.13 to 1.34 for ridden horse behaviour (all p < 0.001) and from 1.06 to 1.43 for non-ridden horse behaviour (all p < 0.001). Inter-rater reliability testing of ten horse–rider pairs revealed that 203 of the 215 question items were significantly aligned (p < 0.001) when tested by two independent raters. Of the remaining 19 items, four had fair alignment (ĸ = 0.174–0.316; p = 0.281) and ten items, largely related to whether the horse shows behavioural signs related to anxiety when taken away from home, did not align (ĸ = 0; p = 1). Intra-rater reliability tests showed that the responses significantly aligned on all 215 question items tested (p < 0.001). The results of these tests confirmed the construct validity and reliability of E-BARQ as a standardised behavioural assessment tool for horses.