Search Results (35)

Background/Objectives: The mouse model of postoperative ileus separates the gastrointestinal tract into 15 sections, 10 of which are in the small intestine, to measure intestinal transit time. Usually, mice are standardised according to age or body weight. This inherently assumes that intestinal lengths are similar among the included mice irrespective of the method of standardisation. We aimed to test this assumption by comparing intestinal lengths, measuring their variability in commonly used out- and inbred strains. Methods: Mice were humanely killed, and their intestines were removed and measured in a standardised fashion. We compared the coefficients of variability via the modified signed-rank likelihood test. Results: We included 125 mice of the Crl:CD1(ICR) background and 10 mice of the C57Bl/6J and C57Bl/6NCrl substrains. The mean small intestinal length of Crl:CD1(ICR) mice was 437 mm (standard deviation 54), while it was 473 mm (standard deviation 29) in C57Bl/6J mice and 419 mm (standard deviation 57) in C57Bl/6NCrl mice. The respective coefficients of variation were 12.4%, 6.1%, and 13.6% and did not differ between the out- and inbred strains (modified signed likelihood ratio 5.878, p = 0.053). This was not the case for caecal and large intestinal lengths. Conclusions: Due to substantial variation in small intestinal length, the separation of the small intestine into ten equally sized segments to measure intestinal transit time might not be warranted. This could be addressed by measuring small intestinal transit time in absolute values and relative to the intestinal length. Full article

Bacille Calmette-Guérin (BCG) remains the only licensed vaccine against tuberculosis (TB), administered to >100 million neonates annually. It confers approximately 70–80% protection against tuberculous meningitis and miliary TB in early childhood, under-pinning its continued use in high-burden settings. As a live-attenuated vaccine, however, BCG can rarely cause adverse reactions ranging from self-limited local lesions to life-threatening disseminated BCG disease (BCGosis), which almost exclusively occurs in infants with severe primary or acquired immunodeficiencies such as SCID, MSMD, CGD, or symptomatic HIV infection. Implementation of universal newborn screening for severe combined immunodeficiency (SCID) using the T-cell receptor excision circle (TREC) assay now enables prospective identification and deferral of these high-risk neonates, virtually eliminating fatal BCGosis. Here we synthesize global data published since 2010 on the clinical spectrum, immunopathogenesis, and epidemiology of BCG-related complications, highlighting the impact of vaccine substrain, administration technique, and host immune status on adverse-event rates. On the basis of this evidence, we propose a practical, evidence-based risk-assessment checklist (BCG-RAKE) to support safer vaccine deployment while preserving the substantial TB-control benefits of universal BCG immunization. Full article

Influenza is a communicable disease caused by RNA viruses. Strains A (affecting animals, humans), B (affecting humans), C (affecting rarely humans and pigs), and D (affecting cattle) comprise a variety of substrains each. Influenza A strain, affecting both humans and animals, is considered the most infectious, causing pandemics. There is an emerging need for the accurate classification of the different influenza A virus (IAV) subtypes, elucidating their mode of infection, as well as their fast and accurate diagnosis. Notably, in recent years, oligomeric sequences (words) that are present in the pathogen genomes and entirely absent from the host human genome were suggested to provide robust biomarkers for virus classification and rapid detection. To this end, we performed updated phylogenetic analyses of the IAV hemagglutinin genes, focusing on the sub H1N1 and H5N1. More importantly, we applied in silico methods to identify minimum length “words” that exist consistently in the IAV genomes and are entirely absent from the human genome; these sequences identified in our current analysis may represent minimal signatures that can be utilized to distinguish IAV from other influenza viruses, as well as to perform rapid diagnostic tests. Full article

Background: The genetic quality of laboratory mice may have a direct impact on the results of research. Therefore, it is essential to improve genetic monitoring methods to guarantee research quality. However, few current methods boast high efficiency, high throughput, low cost, and general applicability at the same time. Methods: First, we got 34 SNP loci from previous studies for inbred strains and screened out 15 loci with good polymorphism for outbred groups from these 34 loci. Then, by using the Luminex xTAG assay, we tested inbred strains and outbred groups. Results: We tested commonly used inbred strains and five DNA samples from the International Council for Laboratory Animal Science, obtaining correct genotyping results. Additionally, some loci were potentially confirmed to be useful for distinguishing C57BL/6 and BALB/c mouse substrains. Furthermore, we tested three outbred groups and analyzed the genetic structure, and we compared the results of the SNP markers by xTAG assay to the STR markers by PCR, the trends of the three groups are the same. Conclusions: In our studies, the panels could meet the requirements for method promotion and provide a good choice for the genetic monitoring of inbred and outbred mice. Full article

Background: It is believed that alterations in the functioning of the cytochrome P450 (CYP), which participates in metabolic transformations of endogenous polyunsaturated fatty acids (PUFAs) (with the formation of cardioprotective or cardiotoxic products), affects the development of age-related cardiovascular diseases and reduces the effectiveness of some cardioselective drugs. For example, CYP2J2 activation or CYP1B1 inhibition protects against the cardiovascular toxicity of anticancer drugs. It is currently unclear whether CYPs capable of metabolizing arachidonic acid and ω-3 PUFAs to vasodilatory and vasoconstrictive derivatives are expressed in all heart regions. Methods: The work was performed on senescence-accelerated OXYS rats featuring elevated blood pressure, OXYSb rats (an OXYS substrain with normal blood pressure), and Wistar rats as a “healthy” control. The mRNA level was determined in the right and left ventricles, the right and left atria, and the aorta of 1-, 3-, and 12-month-old rats. Results: We showed that all heart regions express CYPs capable of metabolizing arachidonic acid and ω-3 PUFAs and revealed significant differences between heart regions both in the mRNA level of genes CYP1B1, CYP2J3, and CYP1A1 and in the time course of expression changes with age. Conclusions: We noticed that expression levels of these CYPs in the heart regions and aorta differ between hypertensive OXYS rats, normotensive OXYSb rats, and healthy Wistar rats but could not detect any clear-cut patterns associated with the hypertensive status of OXYS rats. Full article

Consuming an unbalanced diet and being overweight represent a global health problem in young people and adults of both sexes, and may lead to metabolic syndrome. The diet-induced obesity (DIO) model in the C57BL/6J mouse substrain that mimics the gradual weight gain in humans consuming a “Western-type” (WD) diet is of great interest. This study aims to characterize this animal model, using high-frequency ultrasound imaging (HFUS) as a complementary tool to longitudinally monitor changes in the liver, heart and kidney. Long-term WD feeding increased mice body weight (BW), liver/BW ratio and body condition score (BCS), transaminases, glucose and insulin, and caused dyslipidemia and insulin resistance. Echocardiography revealed subtle cardiac remodeling in WD-fed mice, highlighting a significant age–diet interaction for some left ventricular morphofunctional parameters. Qualitative and parametric HFUS analyses of the liver in WD-fed mice showed a progressive increase in echogenicity and echotexture heterogeneity, and equal or higher brightness of the renal cortex. Furthermore, renal circulation was impaired in WD-fed female mice. The ultrasound and histopathological findings were concordant. Overall, HFUS can improve the translational value of preclinical DIO models through an integrated approach with conventional methods, enabling a comprehensive identification of early stages of diseases in vivo and non-invasively, according to the 3Rs. Full article

After the detection of bovine spongiform encephalopathy (BSE), and a zoonotic transmissible spongiform encephalopathy (TSE) caused by the pathological prion protein (PrP^Sc) in two goats, the investigation of goat prions became of greater interest. Therefore, a broad collection of European goat TSE isolates, including atypical scrapie, CH1641 and goat BSE as reference prion strains were biochemically characterised and subsequently inoculated into seven rodent models for further analysis (already published results of this comprehensive study are reviewed here for comparative reasons). We report here the histopathological and immunohistochemical data of this goat TSE panel, obtained after the first passage in Tgshp IX (tg-shARQ) mice, which overexpress the ovine prion protein. In addition to the clear-cut discrimination of all reference prion strains from the classical scrapie (CS) isolates, we were further able to determine three categories of CS strains. The investigation further indicates the occurrence of sub-strains that slightly resemble distant TSE strains, such as BSE or CH1641, reinforcing the theory that CS is not a single strain but a mixture of sub-strains, existing at varying extents in one isolate. This study further proved that Tgshp IX is a potent and reliable tool for the in-depth characterisation of prion strains. Full article

Retinal degenerative diseases, including age-related macular degeneration and retinitis pigmentosa, significantly contribute to adult blindness. The Royal College of Surgeons (RCS) rat is a well-established disease model for studying these dystrophies; however, molecular investigations remain limited. We conducted a comprehensive analysis of retinal degeneration in RCS rats, including an immunodeficient RCS (iRCS) sub-strain, using ocular coherence tomography, electroretinography, histology, and molecular dissection using transcriptomics and immunofluorescence. No significant differences in retinal degeneration progression were observed between the iRCS and immunocompetent RCS rats, suggesting a minimal role of adaptive immune responses in disease. Transcriptomic alterations were primarily in inflammatory signaling pathways, characterized by the strong upregulation of Tnfa, an inflammatory signaling molecule, and Nox1, a contributor to reactive oxygen species (ROS) generation. Additionally, a notable decrease in Alox15 expression was observed, pointing to a possible reduction in anti-inflammatory and pro-resolving lipid mediators. These findings were corroborated by immunostaining, which demonstrated increased photoreceptor lipid peroxidation (4HNE) and photoreceptor citrullination (CitH3) during retinal degeneration. Our work enhances the understanding of molecular changes associated with retinal degeneration in RCS rats and offers potential therapeutic targets within inflammatory and oxidative stress pathways for confirmatory research and development. Full article

Throughout the SARS-CoV-2 pandemic, several variants of concern (VOCs) have been identified, many of which share recurrent mutations in the spike glycoprotein’s receptor-binding domain (RBD). This region coincides with known epitopes and can therefore have an impact on immune escape. Protracted infections in immunosuppressed patients have been hypothesized to lead to an enrichment of such mutations and therefore drive evolution towards VOCs. Here, we present the case of an immunosuppressed patient that developed distinct populations with immune escape mutations throughout the course of their infection. Notably, by investigating the co-occurrence of substitutions on individual sequencing reads in the RBD, we found quasispecies harboring mutations that confer resistance to known monoclonal antibodies (mAbs) such as S:E484K and S:E484A. These mutations were acquired without the patient being treated with mAbs nor convalescent sera and without them developing a detectable immune response to the virus. We also provide additional evidence for a viral reservoir based on intra-host phylogenetics, which led to a viral substrain that evolved elsewhere in the patient’s body, colonizing their upper respiratory tract (URT). The presence of SARS-CoV-2 viral reservoirs can shed light on protracted infections interspersed with periods where the virus is undetectable, and potential explanations for long-COVID cases. Full article

COVID-19 had stormed through the world in early March of 2019, and on 5 May 2023, SARS-CoV-2 was officially declared to no longer be a global health emergency. The rise of new COVID-19 variants XBB.1.5 and XBB.1.16, a product of recombinant variants and sub-strains, has fueled a need for continued surveillance of the pandemic as they have been deemed increasingly infectious. Regardless of the severity of the variant, this has caused an increase in hospitalizations, a strain in resources, and a rise of concern for public health. In addition, there is a growing population of patients experiencing cardiovascular complications as a result of post-acute sequelae of COVID-19. This review aims to focus on what was known about SARS-CoV-2 and its past variants (Alpha, Delta, Omicron) and how the knowledge has grown today with new emerging variants, with an emphasis on cardiovascular complexities. We focus on the possible mechanisms that cause the observations of chronic cardiac conditions seen even after patients have recovered from the infection. Further understanding of these mechanisms will help to close the gap in knowledge on post-acute sequelae of COVID-19 and the differences between the effects of variants. Full article

We examined sex differences in behavioral responses to fear-related learning through ultrasonic vocalization. Adult male and female rats of two inbred rat strains (WAG/Rij rats with genetic predisposition absence epilepsy, n = 25; and the minor substrain NEW with non-epileptic phenotype, n = 32) were examined in the two-way active avoidance task (50 trials). Three behavioral responses were defined: successful learning, unsuccessful learning, and freezing (motionless behavior). We found that males were more likely to experience freezing (40%) than females (3.7%). Females performed significantly better than males: 93% of females showed “successful learning”, while only 43.2% of males did. Long-lasting 22 kHz ultrasonic calls, so-called aversive ultrasonic vocalizations aUSVs, were recorded in 26% of females (only successful learners) and in 50% of males. The density of aUSVs in females was lower than in males. WAG/Rij males performed much poorer than the NEW males. In general, males, in contrast to females, showed significantly poorer avoidance learning, more frequently experienced freezing, and produced more aversive USVs. Males thus experienced a negative emotional state, rather than exhibiting poor cognitive abilities. Perhaps, WAG/Rij rats and a minor NEW substrain showed an increased emotionally in fear-related tasks, because they are prone to emotional disorders or emotional exhaustion. Sex differences in freezing and in aUSVs might result from the poorly understood neuromodulatory effects of the cholinergic system. Full article

Considering the imminence of new SARS-CoV-2 variants and COVID-19 vaccine availability, it is essential to understand the impact of the disease on the most vulnerable groups and those at risk of death from the disease. To this end, the odds ratio (OR) for mortality and hospitalization was calculated for different groups of patients by applying an adjusted logistic regression model based on the following variables of interest: gender, booster vaccination, age group, and comorbidity occurrence. A massive number of data were extracted and compiled from official Brazilian government resources, which include all reported cases of hospitalizations and deaths associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Brazil during the “wave” of the Omicron variant (BA.1 substrain). Males (1.242; 95% CI 1.196–1.290) aged 60–79 (3.348; 95% CI 3.050–3.674) and 80 years or older (5.453; 95% CI 4.966–5.989), and hospitalized patients with comorbidities (1.418; 95% CI 1.355–1.483), were more likely to die. There was a reduction in the risk of death (0.907; 95% CI 0.866–0.951) among patients who had received the third dose of the anti-SARS-CoV-2 vaccine (booster). Additionally, this big data investigation has found statistical evidence that vaccination can support mitigation plans concerning the current scenario of COVID-19 in Brazil since the Omicron variant and its substrains are now prevalent across the entire country. Full article

How many RBPMS⁺ retinal ganglion cells (RGCs) does a standard C57BL/6 laboratory mouse have on average and is this number substrain- or sex-dependent? Do RGCs of (European) C57BL/6J and -N mice show a different intrinsic vulnerability upon glaucomatous injury? Global RGC numbers and densities of common laboratory mice were previously determined via axon counts, retrograde tracing or BRN3A immunohistochemistry. Here, we report the global RGC number and density by exploiting the freely available tool RGCode to automatically count RGC numbers and densities on entire retinal wholemounts immunostained for the pan-RGC marker RBPMS. The intrinsic vulnerability of RGCs from different substrains to glaucomatous injury was evaluated upon introduction of the microbead occlusion model, followed by RBPMS counts, retrograde tracing and electroretinography five weeks post-injury. We demonstrate that the global RGC number and density varies between substrains, yet is not sex-dependent. C57BL/6J mice have on average 46K ± 2K RBPMS⁺ RGCs per retina, representing a global RGC density of 3268 ± 177 RGCs/mm². C57BL/6N mice, on the other hand, have on average less RBPMS⁺ RGCs (41K ± 3K RGCs) and a lower density (3018 ± 189 RGCs/mm²). The vulnerability of the RGC population of the two C57BL/6 substrains to glaucomatous injury did, however, not differ in any of the interrogated parameters. Full article

Methamphetamine (MA) is a highly addictive psychostimulant drug, and the number of MA-related overdose deaths has reached epidemic proportions. Repeated MA exposure induces a robust and persistent neuroinflammatory response, and the evidence supports the potential utility of targeting neuroimmune function using non-selective phosphodiesterase 4 (PDE4) inhibitors as a therapeutic strategy for attenuating addiction-related behavior. Off-target, emetic effects associated with non-selective PDE4 blockade led to the development of isozyme-selective inhibitors, of which the PDE4B-selective inhibitor A33 was demonstrated recently to reduce binge drinking in two genetically related C57BL/6 (B6) substrains (C57BL/6NJ (B6NJ) and C57BL/6J (B6J)) that differ in their innate neuroimmune response. Herein, we determined the efficacy of A33 for reducing MA self-administration and MA-seeking behavior in these two B6 substrains. Female and male mice of both substrains were first trained to nose poke for a 100 mg/L MA solution followed by a characterization of the dose–response function for oral MA reinforcement (20 mg/L–3.2 g/L), the demand-response function for 400 mg/L MA, and cue-elicited MA seeking following a period of forced abstinence. During this substrain comparison of MA self-administration, we also determined the dose–response function for A33 pretreatment (0–1 mg/kg) on the maintenance of MA self-administration and cue-elicited MA seeking. Relative to B6NJ mice, B6J mice earned fewer reinforcers, consumed less MA, and took longer to reach acquisition criterion with males of both substrains exhibiting some signs of lower MA reinforcement than their female counterparts during the acquisition phase of the study. A33 pretreatment reduced MA reinforcement at all doses tested. These findings provide the first evidence that pretreatment with a selective PDE4B inhibitor effectively reduces MA self-administration in both male and female mice of two genetically distinct substrains but does not impact cue-elicited MA seeking following abstinence. If relevant to humans, these results posit the potential clinical utility of A33 or other selective PDE4B inhibitors for curbing active drug-taking in MA use disorder. Full article

Rats, including those of the Sprague Dawley strain, may kill mice. Because of this muricidal behavior, it is standard practice in many research animal housing facilities to separate mice from rats (i.e., the predators) to minimize stress for the mice. We tested the effect of cohousing on the stress levels of mice from either the C57BL/6J (BL6) or the CD1 strain and Sprague Dawley rats (SD rat) by quantifying their fecal corticosterone and metabolites (FCM) concentration. We also investigated cohousing impacts a behavioral assay, i.e., conditioned place preference for intragenus (i.e., mouse–mouse or rat–rat) dyadic social interaction (DSI CPP) that was shown be sensitive to social factors, especially to handling by humans. We found that the two delivery batches of BL6 mice or SD rats, respectively, had different stress levels at delivery that were statistically significant for the BL6 mice. Even so, the BL6 mice cohoused with rats had significantly increased FCM concentrations, indicative of higher stress levels, as compared to (1) BL6 mice housed alone or (2) BL6 mice at delivery. In contrast to their elevated stress levels, the attractiveness of contextual cues associated with mouse–mouse social interaction (DSI CPP) even increased in rat-cohoused BL6 mice, albeit non-significantly. Thus, cohousing BL6 mice and rats did not impair a behavioral assay in BL6 mice that was proven to be sensitive to handling stress by humans in our laboratory. SD rats cohoused with BL6- or CD1 mice, and CD1 mice cohoused with SD rats, showed DSI CPP that was not different from our previously published data on SD rats and BL6 mice of the Jackson- or NIH substrain obtained in the absence of cohousing. CD1 mice cohoused with rats did not show an increased FCM concentration compared to delivery. Our findings suggest that the effect of cohousing rats and mice under the conditions described above on their stress levels as opposed to their behavior might be less clearcut than generally assumed and might be overriden by conditions that cannot be controlled, i.e., different deliveries. Our findings can help to use research animal housing resources, which are usually limited, more efficiently. Full article