Improving bioscience research reporting: the ARRIVE guidelines for reporting animal research

Short small-interfering RNAs produce interferon-α-mediated analgesia

BACKGROUND

There is increasing interest in RNA interference in pain research using the intrathecal route to deliver small-interfering RNA (siRNA). An interferon (IFN) response is a common side-effect of siRNA. However, the IFN response in the spinal cord after intrathecal administration of siRNA remains unknown. We hypothesized that high doses of siRNAs can elicit off-target analgesia via releasing IFN-α. We investigated the IFN response and its role in regulating pain sensitivity in the spinal cords after intrathecal administration of siRNAs.

METHODS

Male Sprague-Dawley rats were given intrathecal injections of non-targeting (NT) siRNAs or IFN-α and tested for complete Freund's adjuvant (CFA)-induced mechanical allodynia and heat hyperalgesia. IFN-α in the spinal cord after injection of NT siRNAs was measured by western blotting and immunohistochemical staining.

RESULTS

IFN-α was up-regulated in the spinal cord after intrathecal treatment of NT siRNAs. Intrathecal injection of NT siRNAs, at high doses of 10 or 20 μg, reduced CFA-induced inflammatory pain (P<0.05). Intrathecal application of IFN-α inhibited pain hypersensitivity in inflamed rats and produced analgesia in naïve rats (P<0.05). Notably, the anti-nociceptive effects elicited by NT siRNAs and IFN-α were reversed by IFN-α neutralizing antibody and naloxone.

CONCLUSIONS

Our data suggest that (i) intrathecal administration of high doses of siRNA (≥ 10 μg) induced up-regulation of IFN-α in the spinal cord and produced analgesic effects through IFN-α, and (ii) IFN-α's analgesic effect is mediated via opioid receptors. Caution must be taken to avoid IFN-α-mediated analgesic effects of siRNAs in pain research.

Quantitative MRI establishes the efficacy of PI3K inhibitor (GDC-0941) multi-treatments in PTEN-deficient mice lymphoma

AIM

To assess the efficacy of multiple treatment of phosphatidylinositol-3-kinase (PI3K) inhibitor on autochthonous tumours in phosphatase and tensin homologue (Pten)-deficient genetically engineered mouse cancer models using a longitudinal magnetic resonance imaging (MRI) protocol.

MATERIALS AND METHODS

Using 3D MRI, B-cell follicular lymphoma growth was quantified in a Pten(+/-)Lkb1(+/hypo) mouse line, before, during and after repeated treatments with a PI3K inhibitor GDC-0941 (75 mg/kg).

RESULTS

Mean pre-treatment linear tumour growth rate was 16.5±12.8 mm(3)/week. Repeated 28-day GDC-0941 administration, with 21 days 'off-treatment', induced average tumour regression of 41±7%. Upon cessation of the second treatment (which was not permanently cytocidal), tumours re-grew with an average linear growth rate of 40.1±15.5 mm(3)/week. There was no evidence of chemoresistance.

CONCLUSION

This protocol can accommodate complex dosing schedules, as well as combine different cancer therapies. It reduces biological variability problems and resulted in a 10-fold reduction in mouse numbers compared with terminal assessment methods. It is ideal for preclinical efficacy studies and for phenotyping molecularly characterized mouse models when investigating gene function.

Aging-related reproductive decline in the male spider monkey (Ateles geoffroyi)

BACKGROUND

It is unknown whether male black-handed spider monkeys (Ateles geoffroyi) undergo a reproductive decline as they age. The purpose of this work was investigating whether serum testosterone and semen quality decrease with age in these primates as occur in other species.

METHODS

In this study, we assessed age variations in the concentration of serum testosterone, sperm counts, and motility in nine males. We took serum blood samples and semen samples by electroejaculation of anesthetized males throughout the fertile season.

RESULTS

We found that testosterone levels and total sperm concentration, motile, progressive, fast linearly moving, medium linearly moving, slow linearly moving and immotile sperm significantly decreased with age.

CONCLUSIONS

Our results show that a reproductive decline occurs in male spider monkeys because of a decrease in sperm counts. These results are similar to those of rhesus monkeys and men, despite the phylogenetic distance between New and Old World primates.

Platelet hyperaggregability in high-fat fed rats: a role for intraplatelet reactive-oxygen species production

Background

Adiposity greatly increases the risk of atherothrombotic events, a pathological condition where a chronic state of oxidative stress is reported to play a major role. This study aimed to investigate the involvement of (NO)-soluble guanylyl cyclase (sGC) signaling pathway in the platelet dysfunction from high fat-fed (HFF) rats.

Methods

Male Wistar rats were fed for 10 weeks with standard chow (SCD) or high-fat diet (HFD). ADP (10 μM)- and thrombin (100 mU/ml)-induced washed platelet aggregation were evaluated. Measurement of intracellular levels of ROS levels was carried out using flow cytometry. Cyclic GMP levels were evaluated using ELISA kits.

Results

High-fat fed rats exhibited significant increases in body weight, epididymal fat, fasting glucose levels and glucose intolerance compared with SCD group. Platelet aggregation induced by ADP (n = 8) and thrombin from HFD rats (n = 8) were significantly greater (P < 0.05) compared with SCD group. Platelet activation with ADP increased by 54% the intraplatelet ROS production in HFD group, as measured by flow cytometry (n = 6). N-acetylcysteine (NAC; 1 mM) and PEG-catalase (1000 U/ml) fully prevented the increased ROS production and platelet hyperaggregability in HFD group. The NO donors sodium nitroprusside (SNP; 10 μM) and SNAP (10 μM), as well as the NO-independent soluble guanylyl cyclase stimulator BAY 41-2272 (10 μM) inhibited the platelet aggregation in HFD group with lower efficacy (P < 0.05) compared with SCD group. The cGMP levels in response to these agents were also markedly lower in HFD group (P < 0.05). The prostacyclin analogue iloprost (1 μM) reduced platelet aggregation in HFD and SCD rats in a similar fashion (n = 4).

Conclusions

Metabolic abnormalities as consequence of HFD cause platelet hyperaggregability involving enhanced intraplatelet ROS production and decreased NO bioavailability that appear to be accompanied by potential defects in the prosthetic haem group of soluble guanylyl cyclase.

Genetically-engineered pig-to-baboon liver xenotransplantation: histopathology of xenografts and native organs

Orthotopic liver transplantation was carried out in baboons using wild-type (WT, n = 1) or genetically-engineered pigs (α1,3-galactosyltransferase gene-knockout, GTKO), n = 1; GTKO pigs transgenic for human CD46, n = 7) and a clinically-acceptable immunosuppressive regimen. Biopsies were obtained from the WT pig liver pre-Tx and at 30 min, 1, 2, 3, 4 and 5 h post-transplantation. Biopsies of genetically-engineered livers were obtained pre-Tx, 2 h after reperfusion and at necropsy (4–7 days after transplantation). Tissues were examined by light, confocal, and electron microscopy. All major native organs were also examined. The WT pig liver underwent hyperacute rejection. After genetically-engineered pig liver transplantation, hyperacute rejection did not occur. Survival was limited to 4–7 days due to repeated spontaneous bleeding in the liver and native organs (as a result of profound thrombocytopenia) which necessitated euthanasia. At 2 h, graft histology was largely normal. At necropsy, genetically-engineered pig livers showed hemorrhagic necrosis, platelet aggregation, platelet-fibrin thrombi, monocyte/macrophage margination mainly in liver sinusoids, and vascular endothelial cell hypertrophy, confirmed by confocal and electron microscopy. Immunohistochemistry showed minimal deposition of IgM, and almost absence of IgG, C3, C4d, C5b-9, and of a cellular infiltrate, suggesting that neither antibody- nor cell-mediated rejection played a major role.

Differential expression of ADAM15 and ADAM17 metalloproteases in the rat brain after severe hypobaric hypoxia and hypoxic preconditioning

The ADAMs (a disintegrin and metalloprotease) are a family of membrane-anchored glycoproteins capable of shedding a multitude of proteins from the cell surface. Although ADAMs are being considered as crucial modulators of physiological and pathophysiological processes, their roles in neuronal death/survival are largely unexplored. In the present study, changes in brain expression of ADAM15 and ADAM17 (TACE) have been quantitatively examined in rats in response to injurious severe hypoxia (SH) and in animals which acquired hypoxic tolerance through preconditioning to mild hypoxia prior SH. SH persistently up-regulated ADAM15 mRNA and protein levels in hippocampus and neocortex but not in thalamus or hypothalamus. This effect was not observed in the preconditioned rats tolerant to SH. In contrast, hippocampal levels of ADAM17 mRNA and neocortical levels of ADAM17 mRNA and protein were largely reduced following SH in non-preconditioned rats. Hypoxic preconditioning prevented down-regulation of the adam17 gene and considerably enhanced ADAM17 protein expression in hippocampus and neocortex in response to SH. The present findings implicate ADAM15 in the processes of neuronal hypoxic injury. On the other hand, these results also provide evidence for a pro-survival neuroprotective role of ADAM17 and its engagement in the process of preconditioning-induced hypoxic tolerance. The analysis of the protein levels of soluble and membrane-bound forms of APP in the neocortex and hippocampus of rats subjected to SH and SH with preconditioning has demonstrated that an increased ADAM17 expression in preconditioned animals 24h after hypoxia corresponded to a higher level of soluble form of APP and a reduction of the membrane bound fraction which reflects the role of ADAM17 in APP shedding.

Of mice and microflora: considerations for genetically engineered mice

The phenotype of genetically engineered mice is a combination of both genetic and environmental factors that include the microflora of the mouse. The impact a particular microbe has on a mouse reflects the host-microbe interaction within the context of the mouse genotype and environment. Although often considered a confounding variable, many host-microbe interactions have resulted in the generation of novel model systems and characterization of new microbial agents. Microbes associated with overt disease in mice have been the historical focus of the laboratory animal medical and pathology community and literature. The advent of genetic engineering and the complex of mouse models have revealed previously unknown or disregarded agents that now oblige the attention of the biomedical research community. The purpose of this article is to describe and illustrate how phenotypes can be affected by microflora by focusing on the infectious diseases present in genetically engineered mouse (GEM) colonies of our collective institutions and by reviewing important agents that are rarely seen in most research facilities today. The goal is to introduce the concept of the role of microflora on phenotypes and in translational research using GEM models.

Adding more muscle and nerve to clinical trials

In this review we illustrate both the fundamentals and challenges of randomized clinical trials in neuromuscular disorders and suggest directions for prospective efforts to improve the design, conduct, rigor, and objectivity of these trials. Current research in clinical trials for neuromuscular disorders and key issues affecting these trials are reviewed. This perspective addresses the planning of clinical research, level of preclinical data needed to justify trials, patient recruitment and retention, and opportunities to access federal funding and infrastructure in support of clinical trials. The need for innovation in trial design and conduct, rigorous standards for the preclinical efficacy and safety data that support trial rationale, novel collaborative paradigms, objective interpretations of outcomes, and sharing of the lessons learned from trials in any one disorder among all neuromuscular trialists are imperative to improving the heretofore limited success in delivering novel, safe, and effective therapies to patients burdened by neuromuscular disorders.

Publication guidelines for refereeing and reporting on animal use in experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is one of the major pre-clinical models of multiple sclerosis. Use of this model has led to some important observations that has benefited human health, but it must also be said that there are many poor-quality studies using EAE that add little to knowledge or understanding. The lack of quality of clinical trials in humans led to the introduction of publication guidelines that aimed to improve the quality and transparency of studies. Therefore, with a view of doing the same, the ARRIVE (Animals in research: Reporting in vivo experiments) guidelines were developed as a checklist of information required for publication of animal studies. Based on the ARRIVE guidelines, we provide guidance on acceptable data handling and indicate the minimal acceptable standard that should be adhered to when reporting and importantly refereeing all publications relating to EAE. This is designed to constructively improve the quality of published work and reduce the futile use of animals in research.

Translational research in transcranial direct current stimulation (tDCS): a systematic review of studies in animals

Recent therapeutic human studies testing transcranial direct current stimulation (tDCS) has shown promising results, although many questions remain unanswered. Translational research with experimental animals is an appropriate framework for investigating its mechanisms of action that are still undetermined. Nevertheless, animal and human studies are often discordant. Our aim was to review tDCS animal studies, examining and comparing their main findings with human studies. We performed a systematic review in Medline and other databases, screening for animal studies in vivo that delivered tDCS. Studies in vitro and using other neuromodulatory techniques were excluded. We extracted data according to Animal Research: Reporting In Vivo Experiments (ARRIVE) guidelines for reporting in vivo animal research. Thus, we collected data on sample characteristics (size, gender, weight and specimen) and methodology (experimental procedures, experimental animals, housing and husbandry, as well as analysis). We also collected data on methods for delivering tDCS (location, size, current and current density of electrodes and electrode montage), experimental effects (polarity-, intensity- and after-effects) and safety. Only 12 of 48 potentially eligible studies met our inclusion criteria and were reviewed. Quality assessment reporting was only moderate and studies were heterogeneous regarding tDCS montage methodology, position of active and reference electrodes, and current density used. Nonetheless, almost all studies demonstrated that tDCS had positive immediate and long-lasting effects. Vis-à-vis human trials, animal studies applied higher current densities (34.2 vs. 0.4 A/m(2), respectively), preferred extra-cephalic positions for reference electrodes (60% vs. 10%, respectively) and used electrodes with different sizes more often. Potential implications for translational tDCS research are discussed.

Inclusion of policies on ethical standards in animal experiments in biomedical science journals

Most published biomedical research involving animal models is evaluated carefully to ensure that appropriate ethical standards are met. In the current study, 500 journals randomly selected from MedLine were assessed for whether they presented animal research. Of the 138 journals that did, the instructions to authors of 85 (61.6%) included a requirement for author assurance of adherence to ethical standards during experiments involving animals. In comparison to a wider range of biologic journals, biomedical science journals were more likely to have some sort of ethical policy concerning the reporting and presentation of animal experiments.

Experimental intracerebral hemorrhage: avoiding pitfalls in translational research

Intracerebral hemorrhage (ICH) has the highest mortality of all stroke subtypes, yet treatments are mainly limited to supportive management, and surgery remains controversial. Despite significant advances in our understanding of ICH pathophysiology, we still lack preclinical models that accurately replicate the underlying mechanisms of injury. Current experimental ICH models (including autologous blood and collagenase injection) simulate different aspects of ICH-mediated injury but lack some features of the clinical condition. Newly developed models, notably hypertension- and oral anticoagulant therapy-associated ICH models, offer added benefits but further study is needed to fully validate them. Here, we describe and discuss current approaches to experimental ICH, with suggestions for changes in how this condition is studied in the laboratory. Although advances in imaging over the past few decades have allowed greater insight into clinical ICH, there remains an important role for experimental models in furthering our understanding of the basic pathophysiologic processes underlying ICH, provided limitations of animal models are borne in mind. Owing to differences in existing models and the failed translation of benefits in experimental ICH to clinical practice, putative neuroprotectants should be trialed in multiple models using both histological and functional outcomes until a more accurate model of ICH is developed.

Effects of granulocyte-colony stimulating factor (G-CSF) on diabetic cardiomyopathy in Otsuka Long-Evans Tokushima fatty rats

BACKGROUND

Diabetic cardiomyopathy (CMP) is a common and disabling disease in diabetic patients, however no effective treatments have been developed. Although granulocyte-colony stimulating factor (G-CSF) improves heart function in myocardial infarction, its effect on non-ischemic CMP such as diabetic CMP is unknown. In the present study, we investigated the effects of G-CSF on diabetic CMP in a rat model of type II diabetes.

METHODS

Twenty 7-week-old male Otsuka Long-Evans Tokushima Fatty (OLETF: a rat model of diabetes) rats and 10 male Long-Evans Tokushima Otsuka (LETO: normal controls) rats were used. All of the LETO and 8 OLETF rats were fed on tap water while the rest were fed on sucrose-containing water. After 10 weeks, saline or recombinant human G-CSF (100 μg/kg/day) was injected intraperitoneally for 5 days. Blood levels of glucose, total cholesterol and triglyceride, and Doppler echocardiograms for diastolic dysfunction were obtained just before and 4 weeks after the saline or G-CSF treatment. Light microscopy, electron microscopy (EM) and immunohistochemistry for transforming growth factor-β were employed to examine myocardial histology 4 weeks after the saline or G-CSF treatment.

RESULTS

Diastolic dysfunction developed at 17 weeks (before the saline or G-CSF treatment) in the OLETF rats whether or not they were fed sucrose water, but were more severe in those fed sucrose water. Four weeks after saline or G-CSF treatment, diastolic function had recovered in the G-CSF-treated group regardless of sucrose water feeding, and perivascular and/or interstitial fibrosis in the G-CSF-treated group had decreased significantly. TGF-β immunoreactivity in the interstitial and perivascular tissue was also reduced in the G-CSF-treated group, and EM studies revealed less severe disruption of myofilaments and mitochondrial cristae, and decreased collagen deposition.

CONCLUSIONS

G-CSF can ameliorate cardiac diastolic dysfunction and morphological damage, especially fibrosis of the myocardium, in OLETF rats with diabetic CMP.

Seasonal variation of vocal behaviour in a temperate songbird: assessing the effects of laboratory housing on wild-caught, seasonally breeding birds

Many laboratories are conducting research using songbirds as their animal model. In particular, songbirds are widely used for studying the behavioural and neural mechanisms underlying vocal learning. Many researchers use wild-caught birds to conduct this research, although few studies of behaviour have been conducted to determine the effects of captive housing on these species. We investigated the vocal production pattern of wild-caught black-capped chickadees (Poecile atricapillus) over an entire season in laboratory housing. We documented the frequency of production of four vocalizations (fee-bee song, chick-a-dee calls, dee calls, and gargle calls) across seasons and diurnal pattern and compared the observed pattern of laboratory vocalizations to those previously observed and reported in the wild. Laboratory-housed chickadees had seasonal and diurnal vocal production shifts that were related to both photoperiodic changes (season) and diurnal pattern. For instance, there was significantly more fee-bee song in the spring than summer, autumn, and winter with the most fee-bee song occurring at spring dawn as seen in the wild. Our results also confirmed that the general pattern of vocalizations was consistent between wild and laboratory populations, with no significant differences for either the seasonal or diurnal pattern of fee-bee song production between populations. Differences between settings were observed in the pattern of chick-a-dee calls at dawn and sunset between field and laboratory populations. However, differences in the quantity of vocalization types between laboratory and wild populations suggest that housing conditions are influencing the normal vocal behavioural patterns.

Designing phenotyping studies for genetically engineered mice

A phenotyping study records physiologic or morphologic changes in an experimental animal resulting from an intervention. In mice, this intervention is most frequently genetic, but it may be any type of experimental manipulation. Accurate representation of the human condition under study is essential if the model is to yield useful conclusions. In this review, general approaches to the design of phenotyping studies are considered. These approaches take into account major sources of reduced model validity, such as unexpected phenotypic variation in mice, evolutionary divergence between mice and humans, unanticipated sources of variation, and common design errors. As poor design is the most common reason why studies fail to yield enduring results, emphasis is placed on reduction of bias, sampling, controlled study design, and appropriate statistical analysis.

Experimental in vivo and in vitro models of multiple sclerosis: EAE and beyond

Although the primary cause of multiple sclerosis (MS) is unknown, the widely accepted view is that aberrant (auto)immune responses possibly arising following infection(s) are responsible for the destructive inflammatory demyelination and neurodegeneration in the central nervous system (CNS). This notion, and the limited access of human brain tissue early in the course of MS, has led to the development of autoimmune, viral and toxin-induced demyelination animal models as well as the development of human CNS cell and organotypic brain slice cultures in an attempt to understand events in MS. The autoimmune models, collectively known as experimental autoimmune encephalomyelitis (EAE), and viral models have shaped ideas of how environmental factors may trigger inflammation, demyelination and neurodegeneration in the CNS. Understandably, these models have also heavily influenced the development of therapies targeting the inflammatory aspect of MS. Demyelination and remyelination in the absence of overt inflammation are better studied in toxin-induced demyelination models using cuprizone and lysolecithin. The paradigm shift of MS as an autoimmune disease of myelin to a neurodegenerative disease has required more appropriate models reflecting the axonal and neuronal damage. Thus, secondary progressive EAE and spastic models have been crucial to develop neuroprotective approaches. In this review the current in vivo and in vitro experimental models to examine pathological mechanisms involved in inflammation, demyelination and neuronal degeneration, as well as remyelination and repair in MS are discussed. Since this knowledge is the basis for the development of new therapeutic approaches for MS, we particularly address whether the currently available models truly reflect the human disease, and discuss perspectives to further optimise and develop more suitable experimental models to study MS.

The methodological quality of systematic reviews of animal studies in dentistry

Systematic reviews and meta-analyses of animal studies are important for improving estimates of the effects of treatment and for guiding future clinical studies on humans. The purpose of this systematic review was to assess the methodological quality of systematic reviews and meta-analyses of animal studies in dentistry through using a validated checklist. A literature search was conducted independently and in duplicate in the PubMed and LILACS databases. References in selected systematic reviews were assessed to identify other studies not captured by the electronic searches. The methodological quality of studies was assessed independently and in duplicate by using the AMSTAR checklist; the quality was scored as low, moderate, or high. The reviewers were calibrated before the assessment and agreement between them was assessed using Cohen's Kappa statistic. Of 444 studies retrieved, 54 systematic reviews were selected after full-text assessment. Agreement between the reviewers was regarded as excellent. Only two studies were scored as high quality; 17 and 35 studies were scored as medium and low quality, respectively. There is room for improvement of the methodological quality of systematic reviews of animal studies in dentistry. Checklists, such as AMSTAR, can guide researchers in planning and executing systematic reviews and meta-analyses. For determining the need for additional investigations in animals and in order to provide good data for potential application in human, such reviews should be based on animal experiments performed according to sound methodological principles.

Evaluation of social and physical enrichment in modulation of behavioural phenotype in C57BL/6J female mice

Housing conditions represent an important environmental variable playing a critical role in the assessment of mouse behaviour. In the present study the effects of isolation and nesting material on the behaviour of female C57BL/6J mice were evaluated. The mice were subjected to different rearing conditions from weaning (at the age of 3 weeks). The study groups were group- and single-housed mice, divided further into groups with or without nesting material (species-specific enrichment). After 8 weeks spent in respective conditions the behavioural testing began. Both factors (social conditions and nesting material) appeared to have a significant impact on the behavioural phenotype. However, it is important to stress that the interaction between the factors was virtually absent. We established that isolation increased locomotor activity and reduced anxiety-like behaviour in several tests of exploration. In contrast, absence of nesting material increased anxiety-like behaviour. Neither factor affected rota-rod performance, nociception and prepulse inhibition. Contextual fear memory was significantly reduced in single-housed mice, and interestingly, in mice with nesting material. Cued fear memory was reduced by single-housing, but not affected by enrichment. Mice from enriched cages displayed faster and better learning and spatial search strategy in the water maze. In contrast, isolation caused significant impairment in the water maze. In conclusion, both isolation and species-specific enrichment have profound effects on mouse behaviour and should be considered in design of the experiments and in assessment of animal welfare issues.

Risk of bias of animal studies on regenerative procedures for periodontal and peri-implant bone defects - a systematic review

OBJECTIVES

(1) To assess the risk of bias of studies in which animal models were used for investigating regenerative therapies for periodontal and peri-implant defects. (2) To investigate changes in risk of bias by comparing samples drawn from two different publication periods.

MATERIAL & METHODS

We searched the PubMed and LILACS electronic databases, independently and in duplicate, for randomized and controlled trials published from 1998 to 2000 and from 2008 to 2010. Hand searching included search of 10 dental journals, in the issues published between August 2008 and August 2010. Studies on non-human primates and canines were included. We assessed independently and in triplicate the risk of bias with reference to a six-item checklist based on the Cochrane Collaboration's tool for assessing the risk of bias and information about formal sample size calculation.

RESULTS

One hundred and seven studies were included in the review. Checklist items were poorly reported in the studies selected, and therefore for most of the studies, the risk of bias was unclear.

CONCLUSION

As a result of the unclear risk of bias of animal studies in periodontal and peri-implant treatments, it is difficult to determine the accuracy of treatment effect estimates. There is a need for standardization of reporting procedures on animal experiments.

A search filter for increasing the retrieval of animal studies in Embase

Collecting and analysing all available literature before starting a new animal experiment is important and it is indispensable when writing systematic reviews of animal research. In practice, finding all animal studies relevant to a specific research question turns out to be anything but simple. In order to facilitate this search process, we previously developed a search filter for retrieving animal studies in the most often used biomedical database, PubMed. It is a general requirement for systematic reviews, however, that at least two databases are searched. In this report, we therefore present a similar search filter for a second important database, namely Embase. We show that our filter retrieves more animal studies than (a combination of) the options currently available in Embase. Our search filters for PubMed and Embase therefore represent valuable tools for improving the quality of (systematic) reviews and thereby of new animal experiments.

Optimised and rapid pre-clinical screening in the SOD1(G93A) transgenic mouse model of amyotrophic lateral sclerosis (ALS)

The human SOD1^G93A transgenic mouse has been used extensively since its development in 1994 as a model for amyotrophic lateral sclerosis (ALS). In that time, a great many insights into the toxicity of mutant SOD1 have been gained using this and other mutant SOD transgenic mouse models. They all demonstrate a selective toxicity towards motor neurons and in some cases features of the pathology seen in the human disease. These models have two major drawbacks. Firstly the generation of robust preclinical data in these models has been highlighted as an area for concern. Secondly, the amount of time required for a single preclinical experiment in these models (3–4 months) is a hurdle to the development of new therapies. We have developed an inbred C57BL/6 mouse line from the original mixed background (SJLxC57BL/6) SOD1^G93A transgenic line and show here that the disease course is remarkably consistent and much less prone to background noise, enabling reduced numbers of mice for testing of therapeutics. Secondly we have identified very early readouts showing a large decline in motor function compared to normal mice. This loss of motor function has allowed us to develop an early, sensitive and rapid screening protocol for the initial phases of denervation of muscle fibers, observed in this model. We describe multiple, quantitative readouts of motor function that can be used to interrogate this early mechanism. Such an approach will increase throughput for reduced costs, whilst reducing the severity of the experimental procedures involved.

Therapeutic effects of neuregulin-1 in diabetic cardiomyopathy rats

Background

Diabetic cardiomyopathy (DCM) is a disorder of the heart muscle in people with diabetes, which is characterized by both systolic and diastolic dysfunction. The effective treatment strategy for DCM has not been developed.

Methods

Rats were divided into 3 groups with different treatment. The control group was only injected with citrate buffer (n = 8). The diabetes group and diabetes treated group were injected with streptozotocin to induce diabetes. After success of diabetes induction, the rats with diabetes were treated with (diabetes treated group, n = 8) or without (diabetes group, n = 8) recombinant human Neuregulin-1 (rhNRG-1). All studies were carried out 16 weeks after induction of diabetes. Cardiac catheterization was performed to evaluate the cardiac function. Apoptotic cells were determined by TUNEL staining. Left ventricular (LV) sections were stained with Masson to investigate myocardial collagen contents. Related gene expressions were analyzed by quantitative real-time PCR (qRT-PCR).

Results

Diabetes impaired cardiac function manifested by reduced LV systolic pressure (LVSP), maximum rate of LV pressure rise and fall (+dp/dt max and -dp/dt max) and increased LV end-diastolic pressure (LVEDP). The rhNRG-1 treatment could significantly alleviate these symptoms and improve heart function. More TUNEL staining positive cells were observed in the diabetic group than that in the control group, and the rhNRG-1 treatment decreased apoptotic cells number. Furthermore, qRT-PCR assay demonstrated that rhNRG-1 treatment could decrease the expression of bax and caspase-3 and increase that of bcl-2. Collagen volume fraction was higher in the diabetic group than in the control group. Fibrotic and fibrotic related mRNA (type I and type III collagen) levels in the myocardium were significantly reduced by administration of rhNRG-1.

Conclusion

rhNRG-1 could significantly improve the heart function and reverse the cardiac remodeling of DCM rats with chronic heart failure. These results support the clinical possibility of applying rhNRG-1 as an optional therapeutic strategy for DCM treatment in the future.

Effect of silibinin on endothelial dysfunction and ADMA levels in obese diabetic mice

BACKGROUND

Cardiovascular diseases (CVD) in diabetic patients have endothelial dysfunction as a key pathogenetic event. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), plays a pivotal role in endothelial dysfunction. Different natural polyphenols have been shown to preserve endothelial function and prevent CVD. In this study, we assessed the effect of silibinin, a widely used flavonolignan from milk thistle, on ADMA levels and endothelial dysfunction in db/db mice.

METHODS

Eight-week-old db/db mice were administrated a 20 mg/Kg i.p. daily dose of silibinin (n = 6) or vehicle (n = 6) for four weeks. Heterozygous lean db/m mice served as control. Plasma, aorta and liver ADMA levels were determined by ELISA. Vascular reactivity to phenilephrine (PE), acetylcholine (ACh), sodium nitroprusside (SNP) and ADMA was assessed in isolated aortic segments, in wire myograph.

RESULTS

Plasma and aorta ADMA levels were higher in db/db than in control lean mice. Silibinin administration markedly decreased plasma ADMA; consistently, aorta ADMA was reduced in silibinin-treated animals. Plasma and aorta ADMA levels exhibited a positive correlation, whereas liver ADMA was inversely correlated with both plasma and aorta ADMA concentrations. Endothelium-(NO)-dependent vasodilatation to ACh was impaired in db/db mice and was restored in the silibinin group, in accordance with the observed reduction of plasma and vascular levels of ADMA. Endothelium-independent vasodilatation to SNP was not modified by silibinin administration; contractile tone induced in isolated aorta from db/db mice by challenging with exogenous ADMA was not affected by the treatment.

CONCLUSIONS

Silibinin markedly improves endothelial dysfunction in db/db mice by reducing circulating and vascular ADMA levels. Clinical studies are warranted to assess the efficacy of silibinin for cardiovascular protection.

Dietary saturated fat/cholesterol, but not unsaturated fat or starch, induces C-reactive protein associated early atherosclerosis and ectopic fat deposition in diabetic pigs

BACKGROUND

Diabetes is thought to accelerate cardiovascular disease depending on the type of diet. This study in diabetic subjects was performed to investigate the metabolic, inflammatory and cardiovascular effects of nutritional components typically present in a Western, Mediterranean or high glycaemic diet.

METHODS

Streptozotocin-diabetic pigs (~45 kg) were fed for 10 weeks supplemental (40% of dietary energy) saturated fat/cholesterol (SFC), unsaturated fat (UF) or starch (S) in an eucaloric dietary intervention study.

RESULTS

Fasting plasma total, LDL and HDL cholesterol concentrations were 3-5 fold higher (p < 0.01) in SFC compared to UF and S pigs. Fasting plasma NEFA concentrations (mmol/L) were highest (p < 0.05) in SFC (1.09 ± 0.17), intermediate in UF (0.80 ± 0.14) and lowest in S pigs (0.58 ± 0.14) whereas plasma glucose (~13 mmol/L), triglyceride (~0.5 mmol/L) and insulin (~24 pmol/L) concentrations were comparable among SFC, UF and S pigs. The postprandial response area under the curves (AUC, 0-4 h) for glucose but not for insulin and triglyceride responses were intermediate in SFC (617 ± 144) and lowest (p < 0.05) in UF (378 ± 157) compared to S pigs (925 ± 139). Fasting hepatic glucose production, hepatic and peripheral insulin sensitivity and blood pressure were not different among pigs. C-reactive protein (CRP) concentrations (mg/L) were highest (p < 0.05) in SFC (25 ± 4), intermediate in S (21 ± 3) and lowest in UF pigs (14 ± 2). Liver weights, liver and muscle triglyceride concentrations, and the surface area of aorta fatty streaks were highest (p < 0.01) in SFC pigs. A positive correlation between postprandial plasma CRP and aorta fatty streaks was observed in SFC pigs (R(2) = 0.95). Retroperitoneal fat depot weight (g) was intermediate in SFC (260 ± 72), lowest in S (135 ± 51) and highest (p < 0.05) in UF (571 ± 95) pigs.

CONCLUSION

Dietary saturated fat/cholesterol induces inflammation, atherosclerosis and ectopic fat deposition whereas an equally high dietary unsaturated fat load does not induce these abnormalities and shows beneficial effects on postprandial glycaemia in diabetic pigs.

An early treatment with 17-β-estradiol is neuroprotective against the long-term effects of neonatal ionizing radiation exposure

Ionizing radiations can induce oxidative stress on target tissues, acting mainly through reactive oxygen species (ROS). The aim of this work was to investigate if 17-β-estradiol (βE) was able to prevent hippocampal-related behavioral and biochemical changes induced by neonatal ionizing radiation exposure and to elucidate a potential neuroprotective mechanism. Male Wistar rats were irradiated with 5 Gy of X-rays between 24 and 48 h after birth. A subset of rats was subcutaneously administered with successive injections of βE or 17-α-estradiol (αE), prior and after irradiation. Rats were subjected to different behavioral tasks to evaluate habituation and associative memory as well as anxiety levels. Hippocampal ROS levels and protein kinase C (PKC) activity were also assessed. Results show that although βE was unable to prevent radiation-induced hippocampal PKC activity changes, most behavioral abnormalities were reversed. Moreover, hippocampal ROS levels in βE-treated irradiated rats approached control values. In addition, αE administered to irradiated animals was effective in preventing radiation-induced alterations. In conclusion, βE was able to counteract behavioral and biochemical changes induced in irradiated animals, probably acting through an antioxidant mechanism.

Animal models of asthma: value, limitations and opportunities for alternative approaches

Asthma remains an area of considerable unmet medical need. Few new drugs have made it to the clinic during the past 50 years, with many that perform well in preclinical animal models of asthma, failing in humans owing to lack of safety and efficacy. The failure to translate promising drug candidates from animal models to humans has led to questions about the utility of in vivo studies and to demand for more predictive models and tools based on the latest technologies. Following a workshop with experts from academia and the pharmaceutical industry, we suggest here a disease modelling framework designed to better understand human asthma, and accelerate the development of safe and efficacious new asthma drugs that go beyond symptomatic relief.

Changes in cardiac heparan sulfate proteoglycan expression and streptozotocin-induced diastolic dysfunction in rats

Background

Changes in the proteoglycans glypican and syndecan-4 have been reported in several pathological conditions, but little is known about their expression in the heart during diabetes. The aim of this study was to investigate in vivo heart function changes and alterations in mRNA expression and protein levels of glypican-1 and syndecan-4 in cardiac and skeletal muscles during streptozotocin (STZ)-induced diabetes.

Methods

Diabetes was induced in male Wistar rats by STZ administration. The rats were assigned to one of the following groups: control (sham injection), after 24 hours, 10 days, or 30 days of STZ administration. Echocardiography was performed in the control and STZ 10-day groups. Western and Northern blots were used to quantify protein and mRNA levels in all groups. Immunohistochemistry was performed in the control and 30-day groups to correlate the observed mRNA changes to the protein expression.

Results

In vivo cardiac functional analysis performed using echocardiography in the 10-day group showed diastolic dysfunction with alterations in the peak velocity of early (E) diastolic filling and isovolumic relaxation time (IVRT) indices. These functional alterations observed in the STZ 10-day group correlated with the concomitant increase in syndecan-4 and glypican-1 protein expression. Cardiac glypican-1 mRNA and skeletal syndecan-4 mRNA and protein levels increased in the STZ 30-day group. On the other hand, the amount of glypican in skeletal muscle was lower than that in the control group. The same results were obtained from immunohistochemistry analysis.

Conclusion

Our data suggest that membrane proteoglycans participate in the sequence of events triggered by diabetes and inflicted on cardiac and skeletal muscles.

Refining cage change routines: comparison of cardiovascular responses to three different ways of cage change in rats

Cage change is one of the unavoidable routines in laboratory rodent care. However, cage change disrupts the rodents' olfactory environment and can evoke stress reactions. In this study, the short-term cardiovascular responses to three different cage change procedures were compared with telemetric monitoring. These procedures were: placing the rats into a new, clean cage (NEW), transferring the old cage lid into the clean cage (LID) and transferring an enrichment object into the clean cage (ENR) with the animals. Seven outbred rats (four Hsd:Sprague-Dawley and three HsdBrlHan:WIST) were instrumented with telemetric transmitters. The reactions were recorded during the 24 h following the cage change procedures. All cage change procedures (and also simple handling) caused elevated heart rate and mean arterial pressure levels for up to 5 h after the procedure, with the largest effect seen during the first hour. The reactions observed after cage change were significantly (P < 0.05) greater than those observed after simple handling. The reactions after NEW were significantly higher than the reactions after ENR or LID, though the results were dependent on the stock. In Wistar rats the LID procedure resulted in smaller reactions than ENR. In Sprague-Dawley rats, the differences between ENR and LID were not so clear, but the transfer of scent-marked material into the new cage decreased the reactions compared with the NEW procedure also in this stock. Based on these results, using the old cage lid on the new cage could reduce the disturbance of cage change in rats.

Protection of Eurasian badgers (Meles meles) from tuberculosis after intra-muscular vaccination with different doses of BCG

Mycobacterium bovis infection is widespread in Eurasian badger (Meles meles) populations in Great Britain and the Republic of Ireland where they act as a wildlife reservoir of infection for cattle. Removal of infected badgers can significantly reduce the incidence of bovine tuberculosis (TB) in local cattle herds. However, control measures based on culling of native wildlife are contentious and may even be detrimental to disease control. Vaccinating badgers with bacillus Calmette-Guerin (BCG) has been shown to be efficacious against experimentally induced TB of badgers when administered subcutaneously and orally. Vaccination may be an alternative or complementary strategy to other disease control measures. As the subcutaneous route is impractical for vaccinating wild badgers and an oral vaccine bait formulation is currently unavailable, we evaluated the intramuscular (IM) route of BCG administration. It has been demonstrated that the IM route is safe in badgers. IM administration has the practical advantage of being relatively easy to perform on trapped wild badgers without recourse to chemical immobilisation. We report the evaluation of the efficacy of IM administration of BCG Danish strain 1331 at two different doses: the dose prescribed for adult humans (2-8×10(5)colony forming units) and a 10-fold higher dose. Vaccination generated a dose-dependent cell-mediated immune response characterised by the production of interferon-γ (IFNγ) and protection against endobronchial challenge with virulent M. bovis. Protection, expressed in terms of a significant reduction in the severity of disease, the number of tissues containing acid-fast bacilli, and reduced bacterial excretion was statistically significant with the higher dose only.

Hyperglycemia can delay left ventricular dysfunction but not autonomic damage after myocardial infarction in rodents

Background

Although clinical diabetes mellitus is obviously a high risk factor for myocardial infarction (MI), in experimental studies disagreement exists about the sensitivity to ischemic injury of an infarcted myocardium. Recently, our group demonstrated that diabetic animals presented better cardiac function recovery and cellular resistance to ischemic injury than nondiabetics. In the present study, we evaluated the chronic effects of MI on left ventricular (LV) and autonomic functions in streptozotocin (STZ) diabetic rats.

Methods

Male Wistar rats were divided into 4 groups: control (C, n = 15), diabetes (D, n = 16), MI (I, n = 21), and diabetes + MI (DI, n = 30). MI was induced 15 days after diabetes (STZ) induction. Ninety days after MI, LV and autonomic functions were evaluated (8 animals each group). Left ventricular homogenates were analyzed by Western blotting to evaluate the expression of calcium handling proteins.

Results

MI area was similar in infarcted groups (~43%). Ejection fraction and +dP/dt were reduced in I compared with DI. End-diastolic pressure was additionally increased in I compared with DI. Compared with DI, I had increased Na⁺-Ca²⁺ exchange and phospholamban expression (164%) and decreased phosphorylated phospholamban at serine¹⁶ (65%) and threonine¹⁷ (70%) expression. Nevertheless, diabetic groups had greater autonomic dysfunction, observed by baroreflex sensitivity and pulse interval variability reductions. Consequently, the mortality rate was increased in DI compared with I, D, and C groups.

Conclusions

LV dysfunction in diabetic animals was attenuated after 90 days of myocardial infarction and was associated with a better profile of calcium handling proteins. However, this positive adaptation was not able to reduce the mortality rate of DI animals, suggesting that autonomic dysfunction is associated with increased mortality in this group. Therefore, it is possible that the better cardiac function has been transitory, and the autonomic dysfunction, more prominent in diabetic group, may lead, in the future, to the cardiovascular damage.

Systematic survey of the design, statistical analysis, and reporting of studies published in the 2008 volume of the Journal of Cerebral Blood Flow and Metabolism

Translating experimental findings into clinically effective therapies is one of the major bottlenecks of modern medicine. As this has been particularly true for cerebrovascular research, attention has turned to the quality and validity of experimental cerebrovascular studies. We set out to assess the study design, statistical analyses, and reporting of cerebrovascular research. We assessed all original articles published in the Journal of Cerebral Blood Flow and Metabolism during the year 2008 against a checklist designed to capture the key attributes relating to study design, statistical analyses, and reporting. A total of 156 original publications were included (animal, in vitro, human). Few studies reported a primary research hypothesis, statement of purpose, or measures to safeguard internal validity (such as randomization, blinding, exclusion or inclusion criteria). Many studies lacked sufficient information regarding methods and results to form a reasonable judgment about their validity. In nearly 20% of studies, statistical tests were either not appropriate or information to allow assessment of appropriateness was lacking. This study identifies a number of factors that should be addressed if the quality of research in basic and translational biomedicine is to be improved. We support the widespread implementation of the ARRIVE (Animal Research Reporting In Vivo Experiments) statement for the reporting of experimental studies in biomedicine, for improving training in proper study design and analysis, and that reviewers and editors adopt a more constructively critical approach in the assessment of manuscripts for publication.

Quality of reporting statistics in two Indian pharmacology journals

OBJECTIVE

To evaluate the reporting of the statistical methods in articles published in two Indian pharmacology journals.

MATERIALS AND METHODS

All original articles published since 2002 were downloaded from the journals' (Indian Journal of Pharmacology (IJP) and Indian Journal of Physiology and Pharmacology (IJPP)) website. These articles were evaluated on the basis of appropriateness of descriptive statistics and inferential statistics. Descriptive statistics was evaluated on the basis of reporting of method of description and central tendencies. Inferential statistics was evaluated on the basis of fulfilling of assumption of statistical methods and appropriateness of statistical tests. Values are described as frequencies, percentage, and 95% confidence interval (CI) around the percentages.

RESULTS

Inappropriate descriptive statistics was observed in 150 (78.1%, 95% CI 71.7-83.3%) articles. Most common reason for this inappropriate descriptive statistics was use of mean ± SEM at the place of "mean (SD)" or "mean ± SD." Most common statistical method used was one-way ANOVA (58.4%). Information regarding checking of assumption of statistical test was mentioned in only two articles. Inappropriate statistical test was observed in 61 (31.7%, 95% CI 25.6-38.6%) articles. Most common reason for inappropriate statistical test was the use of two group test for three or more groups.

CONCLUSION

Articles published in two Indian pharmacology journals are not devoid of statistical errors.

Dopamine agonists in animal models of Parkinson's disease: a systematic review and meta-analysis

BACKGROUND

Parkinson's disease (PD) can be a severely disabling condition in spite of therapies currently available. Systematic review and meta-analysis can provide an overview of a field of research and identify potential sources of bias and limits to efficacy. In this study we use these tools to describe the reported efficacy of dopamine agonists in animal models of PD.

METHODS

Publications were identified by electronic searching of three online databases. Data were extracted for neurobehavioural outcome, for study design and for the reporting of measures to avoid bias. Standardised mean difference meta-analysis was used to provide summary estimates of efficacy, with the effects of study quality and study design explored using stratified meta-analysis.

RESULTS

253 publications reported the use of a dopamine agonist in an animal model of PD; of these 121 reported data suitable for inclusion in meta-analysis. 47 interventions were tested in 601 experiments using 4181 animals. Overall, neurobehavioural outcome was improved by 1.08 standard deviations (SD; 95% Confidence Interval (CI) 0.97-1.19). Reporting of measures to reduce bias was low and publications which reported the blinded assessment of outcome had significantly smaller effect sizes (0.85, 95% CI 0.64 to 1.07) than those which did not (1.18, 95% CI 1.05 to 1.31, p < 0.005).

CONCLUSIONS

While dopamine agonists do appear to have efficacy in animal models of PD the low prevalence of reporting of measures to avoid bias is of concern. Systematic review of individual interventions may be helpful in the design of future preclinical and clinical trials.

Critical appraisal of animal models of multiple sclerosis

Experimental autoimmune encephalomyelitis (EAE) is a spectrum of neurological disorders in laboratory animals that is used to model multiple sclerosis (MS). However, few agents have translated from efficacy in EAE to the treatment of human disease. Although this may reflect species differences in pathological disease mechanisms, importantly it may also relate to the practice of how drugs and models are currently used. This often bears very little resemblance to the clinical scenarios where treatments are investigated, such that lack of appreciation of the biology of disease may doom drugs to failure. The use of EAE is critically appraised with the aim of provoking thought, improving laboratory practise and aiding researchers and reviewers to address quality issues when undertaking, reporting and interpreting animal studies related to MS research. This is important as many researchers using EAE could and should do more to improve the quality of the studies.

Ethical Considerations in Mouse Experiments

Mice count morally because they can be harmed. This raises a moral issue in animal experimentation. Three main ethical attitudes towards animals are reviewed here. The Kantian view denies moral value to animals because they lack reason. The second view, by Singer, considers animals as sentient creatures (i.e., able to suffer). Finally, Regan considers that animals are subjects of their own life; they are autonomous and therefore have moral rights. Singer is a reformist and allows animal experimentation under certain conditions. Regan is abolitionist, saying that animals have moral rights that cannot be negotiated. Current animal protection legislation strives to put in balance the human and animal interests to decide whether an animal experiment is morally justified or not. An ethical evaluation process is conducted based on the harm-benefit assessment of the experiment. The researcher has to implement the 3Rs (Replacement, Reduction, Refinement) to minimize the harms to the animals and make sure that the outcomes are scientifically significant and that the quality of the science is high, in order to maximize benefits to humans and animals. Curr. Protoc. Mouse Biol. 1:155-167. © 2011 by John Wiley & Sons, Inc.