Embryonic Stage of Congenital Zika Virus Infection Determines Fetal and Postnatal Outcomes in Mice.

Zika virus (ZIKV) infection during pregnancy causes a wide spectrum of congenital abnormalities and postnatal developmental sequelae such as fetal loss, intrauterine growth restriction (IUGR), microcephaly, or motor and neurodevelopmental disorders. Here, we investigated whether a mouse pregnancy model recapitulated a wide range of symptoms after congenital ZIKV infection, and whether the embryonic age of congenital infection changed the fetal or postnatal outcomes. Infection with ZIKV strain PRVABC59 from embryonic day 6.5 (E6.5) to E8.5, corresponding to the mid-first trimester in humans, caused fetal death, fetal resorption, or severe IUGR, whereas infection from E9.5 to E14.5, corresponding to the late-first to second trimester in humans, caused stillbirth, neonatal death, microcephaly, and postnatal growth deficiency. Furthermore, 4-week-old offspring born to dams infected at E12.5 showed abnormalities in neuropsychiatric state, motor behavior, autonomic function, or reflex and sensory function. Thus, our model recapitulated the multiple symptoms seen in human cases, and the embryonic age of congenital infection was one of the determinant factors of offspring outcomes in mice. Furthermore, maternal neutralizing antibodies protected the offspring from neonatal death after congenital infection at E9.5, suggesting that neonatal death in our model could serve as criteria for screening of vaccine candidates.

Strategies for Behaviorally Phenotyping the Transgenic Mouse.

The techniques and protocols to modify the mouse genome described in this volume allow researchers to produce genetic models of a remarkable number and breadth of human disease. The generation of gene-modified mice offers profoundly powerful approaches for bringing known or purported human gene disruptions into mouse models, but the degree to which the resultant mutant mouse recapitulates the complex physiological and behavioral features of the human disease state is a key variable in the ultimate usefulness of the mouse model organism. Accordingly, the behavioral characterization of mice with novel targeted gene mutations is an important initial step in determining the potential impact of a novel mouse model. This chapter addresses strategies useful in the initial observations of the animal that assist in directing the choice of secondary tests to assess more detailed aspects of potentially disrupted behaviors that may be relevant to the disease being modeled. An initial standardized, comprehensive screen that assesses general health, reflexes, and sensorimotor functions is the first step in characterizing behavioral phenotype, and results often suggest areas where more complex complementary behavioral assays may reveal more detailed disruption of normal behavior. This sequential, standardized approach reduces variability between subjects; this chapter also addresses approaches to reducing experimental artifacts due to handling, test order, testing facility environment, and other sources. This brief overview of behavioral phenotyping approaches is intended to provide practical information to streamline initial characterization of new mouse models and maximize the usefulness of efforts to use these models to study human health and disease.

Behavioral characterization of the anterior injection model of subarachnoid hemorrhage.

BACKGROUND: The applicability of various neurological scores has not been sufficiently characterized in the anterior injection model of subarachnoid hemorrhage (SAH). Therefore this study was performed to evaluate different behavioral tests for quantifying disease severity. METHODS: Different volumes of autologous blood were injected stereotaxically into the prechiasmatic cistern of mice. Sham controls underwent the same procedure without blood injection. The following seven days after surgery, mice were evaluated for behavioral deficits by the SHIRPA score, beam balance and flex field analyses. Brains were further processed for histological analyses. RESULTS: Flex field analysis of SAH animals showed a significant reduction of locomotor activity compared to controls in the first two days after SAH. This reduction was more intense in animals with a higher amount of injected blood. The SHIRPA score revealed a significant reduction in motor behavior in SAH animals two days after surgery. A significant increase of GFAP expression, Fluoro Jade C and TUNEL positive cells as well as microthrombi was observed in SAH animals compared to sham controls in the early phase of SAH. There was a significant negative correlation between flex field righting and the number of degenerative neurons or microthrombi in the first two days after SAH. CONCLUSION: The results of flex field analysis and SHIRPA single test show behavioral and functional deficits in the first two days after SAH in parallel to histological alterations indicating neuronal damage. In summary these tests can be used as functional outcome parameters in the anterior injection model of SAH.

Curcumin enhances the activity of fluconazole against Cryptococcus gattii-induced cryptococcosis infection in mice.

AIM: The aim of this study was to investigate the in vitro and in vivo activities of pure curcumin, as well as its combination with fluconazole, against Cryptococcus gattii. METHODS AND RESULTS: The minimal inhibitory concentrations (MIC) of curcumin and its interactions with fluconazole against C. gattii were assessed in vitro using standard methods. This same combination was used to treat C. gattii-induced cryptococcosis in mice. The behavioural and functional assessment of the mice during treatment was also performed. The average MIC for curcumin was 19·8 µg ml(-1) . Its combination with fluconazole resulted in FICΣ (fractional inhibitory concentration index) values between 0·79 and 2·29. Curcumin (alone or combined with fluconazole) significantly reduced pulmonary damage and fungal burden in the brain. No colonies were found in the brain following combination treatment, which was also confirmed by the improved behaviour of mice. CONCLUSIONS: The combination therapy with curcumin and fluconazole was the most effective among the treatments tested, as in addition to reducing the fungal burden and damage on lung tissues, it was able to eliminate the fungal burden in the brain, enhancing the survival of mice. SIGNIFICANCE AND IMPACT OF THE STUDY: This study points to the possibility of using curcumin in combination with fluconazole as a clinical treatment of cryptococcosis.

Neurobehavioral Anomalies in the Pitx3/ak Murine Model of Parkinson's Disease and MPTP.

Pitx3/ak null mutants are characterized by basal ganglia pathology in a manner resembling Parkinson's disease (PD), with decline in substantia nigra cell numbers as well as striatal tyrosine hydroxylase expression. Although young adult Pitx3/ak mutants were deficient in motor coordination tests, they were more active than non-transgenic controls in the open-field, unlike PD-related bradykinesia. On the SHIRPA primary screen, the mutants displayed body tremor, hyperactivity in the viewing jar, anomalies in eye morphology as well as a higher degree of hindlimb clasping and myoclonic jumping. Increased hindlimb clasping time and rotorod deficits seen in mutants were also exhibited by mice injected with MPTP, indicating an influence of dopamine on these behaviors.

Behavioral characterization of CD36 knockout mice with SHIRPA primary screen.

CD36 is a member of the class B scavenger receptor family of cell surface proteins, which plays a major role in fatty acid, glucose and lipid metabolism. Besides, CD36 functions as a microglial surface receptor for amyloid beta peptide. Regarding this, we suggest CD36 might also contribute to neuropsychiatric disease. The aim of this study was to achieve a behavioral phenotype of CD36 knockout (CD36(-/-)) mice. We characterized the behavior of CD36(-/-) mice and C57BL/6J mice by subjecting them to a series of tests, which include SHIRPA primary behavioral screen test, 1% sucrose preference test, elevated plus-maze test, open-field test and forced swimming test. The results showed that CD36(-/-) mice traversed more squares, emitted more defecation, exhibited higher tail elevation and had more aggressive behaviors than C57BL/6J mice. The CD36(-/-) mice spent more time and traveled longer distance in periphery zone in the open-field test. Meanwhile, the numbers that CD36(-/-) mice entered in the open arms of elevated plus-maze were reduced. These findings suggest that CD36(-/-) mice present an anxious phenotype and might be involved in neuropsychiatric disorders.

The Severity of Cecal Ligature and Puncture-Induced Sepsis Correlates with the Degree of Encephalopathy, but the Sepsis Does Not Lead to Acute Activation of Spleen Lymphocytes in Mice.

Septic encephalopathy represents the most frequently observed form of encephalopathy in intensive care units. Interactions between the immune and nervous systems have been observed in experimental sepsis. Therefore, the aim of the current study was to characterize the effect of different severities of sepsis on encephalopathy and the inflammatory profile of the spleen. We hypothesized that different grades of sepsis severity would lead to variations in encephalopathy and activation of spleen cells. We induced sepsis of different severities in Balb/c mice by cecal ligature and puncture (CLP). Six and 12 h after CLP induction, behavioral impairment was assessed by the SmithKline/Harwell/Imperial College/Royal Hospital/Phenotype Assessment (SHIRPA) test. The animals were then killed, and the plasma, spleen, and hippocampus were removed. Levels of the encephalopathy marker S100ß were measured in plasma. Spleens were weighed and then a characterization of splenic lymphocytes was performed by flow cytometry (cytotoxic T lymphocyte, T helper lymphocytes, B lymphocytes, T regulatory cells, and Th17 cells). Cytokine levels in the spleen and hippocampus were determined by enzyme-linked immunosorbent assay (ELISA), and cytokine levels in plasma were performed with MilliPlex® technology. Our results showed that behavioral impairment as measured by the SHIRPA test and elevation in plasma S100ß levels were significant in moderate and severe CLP groups compared to those in the sham control group. Regarding immunological alterations, we were unable to observe changes in the weights of the spleen and the profile of lymphocytes 6 h after CLP. However, several cytokines, including IL-6, IL-10, and IL-1ß, were increased in spleen and plasma. In conclusion, we observed variations in encephalopathy as measured by plasma S100ß, which were mediated by the severity of sepsis; however, we did not observe a different activation of spleen cells 6 h post-CLP, despite evidence of inflammation. Taken together, our data indicate that the severity of sepsis impacts the brain in absence of a change in the spleen lymphocyte profile.

Behavioral effects of neonatal lesions on the cerebellar system.

Several rodent models with spontaneous mutations causing cerebellar pathology are impaired in motor functions during the neonatal period, including Grid2(Lc), Rora(sg), Dab1(scm), Girk2(Wv), Lmx1a(dr-sst), Myo5a(dn), Inpp4a(wbl), and Cacna1a(rol) mice as well as shaker and dystonic rats. Deficits are also evident in murine null mutants such as Zic1, Fgfr1/FgFr2, and Xpa/Ercc8. Behavioral deficits are time-dependent following X-irradiated- or aspiration-induced lesions of the cerebellum in rats. In addition, motor functions are deficient after lesions in cerebellar-related pathways. As in animal subjects, sensorimotor disturbances have been described in children with cerebellar lesions. These results underline the importance of the cerebellum and its connections in the development of motor functions.

Increased levels of glutamate in the central nervous system are associated with behavioral symptoms in experimental malaria

Cerebral malaria (CM) is a severe complication resulting from Plasmodium falciparum infection. This condition has been associated with cognitive, behavioral and motor dysfunctions, seizures and coma. The underlying mechanisms of CM are incompletely understood. Glutamate and other metabolites such as lactate have been implicated in its pathogenesis. In the present study, we investigated the involvement of glutamate in the behavioral symptoms of CM. Seventeen female C57BL/6 mice (20-25 g) aged 6-8 weeks were infected with P. berghei ANKA by the intraperitoneal route using a standardized inoculation of 10(6) parasitized red blood cells suspended in 0.2 mL PBS. Control animals (N = 17) received the same volume of PBS. Behavioral and neurological symptoms were analyzed by the SmithKline/Harwell/Imperial College/Royal Hospital/Phenotype Assessment (SHIRPA) battery. Glutamate release was measured in the cerebral cortex and cerebrospinal fluid of infected and control mice by fluorimetric assay. All functional categories of the SHIRPA battery were significantly altered in the infected mice at 6 days post-infection (dpi) (P ≤ 0.05). In parallel to CM symptoms, we found a significant increase in glutamate levels in the cerebral cortex (mean ± SEM; control: 11.62 ± 0.90 nmol/mg protein; infected at 3 dpi: 10.36 ± 1.17 nmol/mg protein; infected at 6 dpi: 26.65 ± 0.73 nmol/mg protein; with EGTA, control: 5.60 ± 1.92 nmol/mg protein; infected at 3 dpi: 6.24 ± 1.87 nmol/mg protein; infected at 6 dpi: 14.14 ± 0.84 nmol/mg protein) and in the cerebrospinal fluid (control: 128 ± 51.23 pmol/mg protein; infected: 301.4 ± 22.52 pmol/mg protein) of infected mice (P ≤ 0.05). These findings suggest a role of glutamate in the central nervous system dysfunction found in CM.

A thioacetamide-induced hepatic encephalopathy model in C57BL/6 mice: a behavioral and neurochemical study / Modelo de encefalopatia hepática induzida por tioacetamida em camundongos C57BL/6: estudo comportamental e neuroquímico

OBJECTIVE: Hepatic encephalopathy (HE) is a neuropsychiatric syndrome resulting from liver failure. In the present study, we aimed to standardize an animal model of HE induced by thioacetamide (TAA) in C57BL/6 mice evaluating behavioral symptoms in association with liver damage and alterations in neurotransmitter release. METHOD: HE was induced by an intraperitoneal single dose of TAA (200 mg/kg, 600 mg/kg or 1,200 mg/kg). Behavioral symptoms were evaluated using the SHIRPA battery. Liver damage was confirmed by histopathological analysis. The glutamate release was measured using fluorimetric assay. RESULTS: The neuropsychiatric state, motor behavior and reflex and sensory functions were significantly altered in the group receiving 600 mg/kg of TAA. Biochemical analysis revealed an increase in the glutamate release in the cerebral cortex of HE mice. CONCLUSION: HE induced by 600mg/kg TAA injection in C57BL/6 mice seems to be a suitable model to investigate the pathogenesis and clinical disorders of HE.

OBJETIVO: A encefalopatia hepática (EH) é uma síndrome neuropsiquiátrica resultante da falência hepática. O objetivo do presente estudo foi estabelecer um modelo de EH induzida por tioacetamida (TAA) em camundongos C57BL/6 avaliando transtornos comportamentais, falência hepática e alterações na liberação de neurotransmissores. MÉTODO: A EH foi induzida por meio de uma única dose intraperitoneal de TAA (200 mg/kg, 600 mg/kg, 1.200 mg/kg). As alterações comportamentais foram avaliadas utilizando a bateria SHIRPA. A falência hepática foi confirmada através de análises histopatológicas e a liberação de glutamato medida, por ensaio fluorimétrico. RESULTADOS: Foram encontradas alterações significativas no estado neuropsiquiátrico, comportamento motor e função reflexa e sensorial no grupo que recebeu 600 mg/kg de TAA. Análises bioquímicas revelaram aumento na liberação de glutamato no córtex cerebral dos camundongos com EH. CONCLUSÃO: A EH induzida por 600 mg/kg de TAA em camundongos C57BL/6 parece ser um modelo apropriado para a investigação da patogênese e dos transtornos clínicos da EH.