RESUMO
Quantum dot (QD) nanoparticles are highly promising contrast agents and probes for biomedical applications owing to their excellent photophysical properties. However, toxicity concerns about commonly used cadmium-based QDs hinder their translation to clinical applications. In this study we describe the in vivo biodistribution and toxicology of indium-based water soluble QDs in rats following intravenous administration. The biodistribution measured at up to 90â¯days showed that QDs mainly accumulated in the liver and spleen, with similar elimination kinetics to subcutaneous administration. Evidence for QD degradation in the liver was found by comparing photoluminescence measurements versus elemental analysis. No organ damage or histopathological lesions were observed for the QDs treated rats after 24â¯h, 1 and 4â¯weeks following intravenous administration at 12.5â¯mg/kg or 50â¯mg/kg. Analysis of serum biochemistry and complete blood counts found no toxicity. This work supports the strong potential of indium-based QDs for translation into the clinic.
Assuntos
Cádmio , Índio/farmacocinética , Índio/toxicidade , Fígado/efeitos dos fármacos , Nanopartículas/toxicidade , Pontos Quânticos/toxicidade , Animais , Feminino , Fígado/metabolismo , Modelos Animais , Nanopartículas/metabolismo , Pontos Quânticos/metabolismo , Ratos , Distribuição Tecidual , Testes de ToxicidadeRESUMO
In inhalation toxicity studies, drug-induced lesions are frequently reported in the larynx and sometimes at the tracheal bifurcation (carina) in the rat, but less so in the dog or monkey, bringing into question the relevance of these rodent findings for humans. The rat larynx is widely considered to be more sensitive than that of the dog and monkey in its response to inhaled xenobiotics, although we could find no published data to support this. In this review, data from 52 inhalation studies involving rodent and nonrodent species were collated and reviewed. These data showed that the rodent larynx, and to a lesser extent the carina, was far more commonly affected by treatment than those of the nonrodent. This review indicates the greater susceptibility of the rodent larynx and carina and emphasizes their lack of relevance for man. Observations and data suggest that the human larynx is much closer to the beagle dog and cynomolgus monkey in its response to inhaled xenobiotics and that greater clinical relevance should be placed on any specific findings in these animal models.
Assuntos
Laringe/patologia , Mucosa Respiratória/patologia , Testes de Toxicidade/métodos , Traqueia/patologia , Administração por Inalação , Animais , Cães , Hiperplasia , Laringe/efeitos dos fármacos , Metaplasia , Camundongos , Ratos , Mucosa Respiratória/efeitos dos fármacos , Especificidade da Espécie , Traqueia/efeitos dos fármacos , Pesquisa Translacional BiomédicaRESUMO
Bimagrumab (BYM338) is a novel fully human monoclonal antibody that exerts strong promyogenic effects on skeletal muscle by blocking activin type II receptors (ActRII). We investigated whether such blockade of ActRII by bimagrumab manifests any detrimental effect on outcomes of bone healing in a rat fibula osteotomy model. Animals (n = 150) were divided into 11 groups and received weekly treatment with either bimagrumab (10 or 100 mg/kg) or vehicle. Progression and outcomes of bone healing were assessed by lateral radiographs in vivo as well as by peripheral quantitative computed tomography (pQCT), 4-point bending test, and microscopic examination of the excised fibula at Day 29 or later. The radiographic progression of bone healing showed no significant differences between treatment groups in any comparative setting. In 3-month-old animals, pQCT revealed slightly reduced immature callus size and bone mineral content in bimagrumab-treated animals compared with vehicle-treated animals at Day 29 (p < 0.05). There were, however, no differences in mature callus size, bone mineral density, or biomechanical competency. The aforementioned effects on immature callus size were not present when the treatment was initiated 4 weeks post osteotomy or when treating 6-month-old animals. In summary, these findings suggest that there is no major impact of ActRII blockade on overall fracture healing, and delayed treatment initiation can bypass the small and transient effect of the therapy on immature callus formation observed in younger animals. Verification of these findings in humans is the subject of an ongoing clinical trial on elderly hip fracture patients.
Assuntos
Receptores de Ativinas/efeitos dos fármacos , Anticorpos Bloqueadores/farmacologia , Anticorpos Monoclonais/farmacologia , Densidade Óssea/efeitos dos fármacos , Fíbula/efeitos dos fármacos , Fraturas Ósseas/tratamento farmacológico , Receptores de Ativinas/metabolismo , Animais , Anticorpos Monoclonais Humanizados , Fenômenos Biomecânicos/efeitos dos fármacos , Calo Ósseo/efeitos dos fármacos , Consolidação da Fratura/efeitos dos fármacos , Masculino , Osteotomia/métodos , Ratos Sprague-DawleyRESUMO
Escalation of voluntary alcohol consumption is a hallmark of alcoholism, but its neural substrates remain unknown. In rats, escalation occurs following prolonged exposure to cycles of alcohol intoxication, and is associated with persistent, wide-ranging changes in gene expression within the medial prefrontal cortex (mPFC). Here, we examined whether induction of microRNA (miR) 206 in mPFC contributes to escalated alcohol consumption. Following up on a microarray screen, quantitative real-time reverse transcription PCR (qPCR) confirmed that a history of dependence results in persistent (>3weeks) up-regulation of miR-206 expression in the mPFC, but not in the ventral tegmental area, amygdala, or nucleus accumbens. Viral-mediated overexpression of miR-206 in the mPFC of nondependent rats reproduced the escalation of alcohol self-administration seen following a history of dependence and significantly inhibited BDNF expression. Bioinformatic analysis identified three conserved target sites for miR-206 in the 3'-UTR of the rat BDNF transcript. Accordingly, BDNF was downregulated in post-dependent rats on microarray analysis, and this was confirmed by qPCR. In vitro, BDNF expression was repressed by miR-206 but not miR-9 in a 3'-UTR reporter assay, confirming BDNF as a functional target of miR-206. Mutation analysis showed that repression was dependent on the presence of all three miR-206 target sites in the BDNF 3'-UTR. Inhibition of miR-206 expression in differentiated rat cortical primary neurons significantly increased secreted levels of BDNF. In conclusion, recruitment of miR-206 in the mPFC contributes to escalated alcohol consumption following a history of dependence, with BDNF as a possible mediator of its action.
Assuntos
Consumo de Bebidas Alcoólicas/patologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Regulação da Expressão Gênica/fisiologia , MicroRNAs/metabolismo , Córtex Pré-Frontal/metabolismo , Consumo de Bebidas Alcoólicas/sangue , Álcoois/administração & dosagem , Álcoois/sangue , Análise de Variância , Animais , Células Cultivadas , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Masculino , MicroRNAs/genética , Mutação/genética , Neurônios/metabolismo , Córtex Pré-Frontal/citologia , Ratos , Ratos Wistar , Autoadministração , Fatores de Tempo , Transdução GenéticaRESUMO
Purpose. We describe a patient with normal tension glaucoma (NTG) of several years whose management was complicated by the presence of a giant internal carotid-ophthalmic artery aneurysm. Observations. A 72-year-old woman presented to our glaucoma clinic with accelerated deterioration of her vision in her left eye (OS) over a 1-month period. Her ophthalmic history was most notable for bilateral NTG diagnosed 3 years prior which had been treated with several laser trabeculoplasty OS and topical bimatoprost 0.01% eye drops in both eyes (OU). Upon evaluation, her visual acuity OS had worsened, and visual field (VF) testing showed extensive progressive losses temporally and pericentrally OS over a year with stable IOP measurements and no neurological complaints. Given her atypical NTG progression, she was referred for an urgent neurological evaluation which revealed an unruptured giant left internal carotid-ophthalmic aneurysm. Following the successful treatment of the aneurysm with platinum coils, she continued to demonstrate additional bilateral ophthalmic changes including further progression of VF loss and RNFL thinning OS > OD on follow-up. Conclusion and Importance. Overall, this report describes a unique complication in the management of a patient with chronic bilateral NTG in the form of a giant internal carotid-ophthalmic aneurysm. Moreover, it highlights the need for clinicians to maintain a degree of suspicion for compressive lesions of the optic nerve when presented with atypical progression of VFs and/or visual acuity loss in glaucomatous patients.
RESUMO
This paper examines the reductions in care costs that result from inpatient multidisciplinary rehabilitation for younger people with acquired brain injury. Thirty-five consecutive patients admitted following a stroke over one year were recruited to this observational study. Physical ability, dependency and potential community care costs were measured on admission and discharge. Fifty-one community-dwelling patients were transferred to rehabilitation from acute medical wards in a large teaching hospital; 35 met the inclusion criteria. After a median of 59 days of rehabilitation, 29 patients were discharged home and six to nursing homes. Patients made highly significant gains in physical ability (median Barthel index 50 to 64; p < 0.001). Dependency decreased; median calculated costs for care were reduced from pounds 1900 to pounds 1100 per week, a saving of pounds 868 per week. Total annualised care costs reduced from pounds 3,358,056 to pounds 1,807,208, a potential saving of pounds 1,550,848. The median time to repay rehabilitation costs was 21 weeks. Savings occurred in those with moderate and severe disability and they have the potential to continue to accrue for over 12 years. Similar results will probably be found for rehabilitation in other forms of acquired brain injury.
Assuntos
Custos de Cuidados de Saúde , Hospitais de Ensino/economia , Pacientes Internados , Tempo de Internação/economia , Avaliação de Resultados em Cuidados de Saúde , Alta do Paciente/economia , Reabilitação do Acidente Vascular Cerebral , Atividades Cotidianas , Adulto , Idoso , Análise Custo-Benefício , Dependência Psicológica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Acidente Vascular Cerebral/economiaRESUMO
There is considerable interest in biomedical applications of quantum dot (QD) nanoparticles, in particular their use as imaging agents for diagnostic applications. In order to investigate the in vivo biodistribution and the potential toxicity of quantum dots (QDs), it is crucial to develop pharmacokinetic (PK) models as basis for prediction of QDs exposure profiles over time. Here, we investigated the in vivo biodistribution of novel indium-based QDs in mice for up to three months after intravenous administration and subsequently developed a translational population PK model to scale findings to humans. This evaluation was complemented by a comprehensive overview of the in vivo toxicology of QDs in rats. The QDs were primarily taken up by the liver and spleen and were excreted via hepatobiliary and urinary pathways. A non-linear mixed effects modelling approach was used to describe blood and organ disposition characteristics of QDs using a multi-compartment PK model. The observed blood and tissue exposure to QDs was characterised with an acceptable level of accuracy at short and long-term. Of note is the fast distribution of QDs from blood into liver and spleen in the first 24 h post-injection (half-life of 28 min) followed by a long elimination profile (half-life range: 47-90 days). This is the first study to assess the PK properties of QDs using a population pharmacokinetic approach to analyse in vivo preclinical data. No organ damage was observed following systemic administration of QDs at doses as high as 48 mg/kg at 24 h, 1 week and 5 weeks post-injection. In conjunction with the data arising from the toxicology experiments, PK parameter estimates provide insight into the potential PK properties of QDs in humans, which ultimately allow prediction of their disposition and enable optimisation of the design of first-in-human QDs studies.
Assuntos
Nanopartículas , Pontos Quânticos , Animais , Índio/toxicidade , Fígado , Camundongos , Pontos Quânticos/toxicidade , Ratos , Distribuição TecidualRESUMO
Capillaria hepatica is a nematode parasite of wild rodents and other mammals. Adult worms inhabit the liver. Recently, during the necropsy examination of a group of 160 rabbits from a commercial supplier, firm pale or cystic areas (1-5 mm) were noted on the liver in thirteen animals. On further investigation, these animals were found to be infected with C. hepatica. The histopathological features of the infection in the rabbit are described for the first time and diagnostic features recorded. Lesions were identified predominantly in portal tracts consisting of dilated bile ducts with luminal debris, peribiliary inflammatory cell infiltrates, and fibrosis. Large granulomas (macrogranulomas) were evident in portal areas and involved the bile ducts. Macrogranulomas contained collections of characteristic C. hepatica eggs, macrophages, eosinophils, and lymphocytes. Small granulomas (microgranulomas), characterized by epithelioid macrophages surrounded by lymphocytes and eosinophils, were also identified. C. hepatica eggs were also observed in the lumina of the bile ducts and gall bladder. No adult C. hepatica worms were identified. Oocysts of Eimeria stiedae were also evident in the biliary epithelium in some animals. The unique characteristics of the C. hepatica life cycle are described, and the differential diagnosis of hepatic capillariasis is discussed.
Assuntos
Capillaria/crescimento & desenvolvimento , Infecções por Enoplida/veterinária , Hepatopatias Parasitárias/veterinária , Coelhos , Animais , Infecções por Enoplida/parasitologia , Infecções por Enoplida/patologia , Feminino , Histocitoquímica , Hepatopatias Parasitárias/parasitologia , Hepatopatias Parasitárias/patologia , MasculinoRESUMO
Large eosinophilic cytoplasmic inclusions (ECIs) are occasionally seen in untreated rat Clara cells. Following inhalation exposure to a corticosteroid, the number of ECIs was increased. This is the first histopathological description of rat ECIs and attempted characterization by immunohistochemistry, in situ hybridization, and electron microscopy. ECIs were strongly positive for surfactant protein D (SP-D) and weakly positive for Clara cell specific protein (CCSP). Clara cell cytoplasm was positive for CCSP mRNA regardless of ECIs, but not within ECIs. Corticosteroid treatment and ECI presence did not affect the immunohistochemistry and in situ hybridization staining intensities. Electron microscopy revealed large intracytoplasmic granules with an irregular limiting membrane. The ECI number was microscopically quantified in rats from three-, six-, and twenty-four-month studies. The mean ECI counts in treated rats increased from three- to fifty-four-fold with a positive dose-related trend, when compared with vehicle controls. Although the mechanism is unclear, SP-D and to a lesser extent CCSP accumulate in the ECIs. As human bronchial epithelium does not appear to contain structures analogous to the ECI, it is suggested that the observation of an increased number of ECIs in the treated rats is not likely to be relevant for human clinical risk assessment.
Assuntos
Corticosteroides/farmacologia , Corpos de Inclusão/metabolismo , Exposição por Inalação/efeitos adversos , Uteroglobina/metabolismo , Administração por Inalação , Animais , Relação Dose-Resposta a Droga , Eosinófilos/metabolismo , Eosinófilos/ultraestrutura , Células Epiteliais/metabolismo , Células Epiteliais/ultraestrutura , Feminino , Imuno-Histoquímica , Hibridização In Situ , Corpos de Inclusão/ultraestrutura , Masculino , Proteína D Associada a Surfactante Pulmonar/genética , Proteína D Associada a Surfactante Pulmonar/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Uteroglobina/genética , Uteroglobina/ultraestruturaRESUMO
Azathioprine (AZA) is a cytotoxic immunosuppressive drug used in the prevention of rejection in organ transplants and the treatment of auto-immune diseases. However, AZA is haemotoxic causing significant bone marrow depression. The present studies were to characterize the haemotoxicity of AZA in the female CD-1 mouse. In Experiment 1, a dose-ranging study, with AZA gavaged daily for 10 days, clinical evidence of toxicity was evident at 125 mg/kg and above. Experiment 2 was a dose-response study with AZA gavaged daily for 10 days at 40-120 mg/kg. At day 1 after the final dose, AZA induced a dose-related pancytopaenia, reduced femoral marrow cellularity, increases in serum levels of the cytokine fms-like tyrosine kinase 3 ligand, reduction in granulocyte-monocyte colony-forming units and erythroid colonies, and increased bone marrow apoptosis. Histology demonstrated hepatocyte hypertrophy, thymic atrophy, reduced splenic extramedullary haemopoiesis, and reduced cellularity of sternal bone marrow. In Experiment 3, AZA was dosed for 10 days at 100 mg/kg with autopsies at 1, 3, 9, 22, 29, 43 and 57 days postdosing. At 1, 3 and 9 days, haematological parameters reflected changes in Experiment 2. At 22/29 days, many blood parameters were returning towards normal; at 43/57 days, most parameters compared with controls. However, there was some evidence of a persistent (i.e. residual/late-stage) mild reduction in RBC and erythroid progenitor cell counts at day 43/57. We conclude that the CD-1 mouse provides an acceptable model for the haemotoxicity of AZA in man.
Assuntos
Azatioprina/toxicidade , Células da Medula Óssea/efeitos dos fármacos , Imunossupressores/toxicidade , Pancitopenia/induzido quimicamente , Animais , Apoptose/efeitos dos fármacos , Azatioprina/administração & dosagem , Peso Corporal/efeitos dos fármacos , Células da Medula Óssea/patologia , Ensaio de Unidades Formadoras de Colônias , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Esquema de Medicação , Células Precursoras Eritroides/efeitos dos fármacos , Feminino , Células-Tronco Hematopoéticas/efeitos dos fármacos , Imunossupressores/administração & dosagem , Camundongos , Camundongos Endogâmicos ICRRESUMO
GABAergic signaling is involved in modulating the reinforcing properties of alcohol, and GABAB receptors have been proposed as a potential target for clinical treatment of alcoholism. The orthosteric GABAB receptor agonist baclofen has been shown to suppress operant self-administration of alcohol in animals and alcohol use in alcohol-dependent patients, but its utility is limited by a narrow therapeutic index. We tested the effects of ADX71441, a novel GABAB receptor positive allosteric modulator, on alcohol-related behaviors in rats. We first assessed the effects of ADX71441 (1, 3, 10 and 30 mg/kg, I.P.) on both non-dependent and dependent male Wistar rats trained to self-administer 20% alcohol. We then determined the effects of ADX71441 on stress-induced as well as cue-induced relapse-like behavior. Finally, we sought to identify the brain regions through which ADX71441 may act to prevent relapse-like behavior by mapping the neuronal activation induced by stress-induced reinstatement of alcohol-seeking using c-Fos immunohistochemistry. ADX71441 dose-dependently decreased alcohol self-administration of both dependent and non-dependent animals, but its potency was higher in alcohol-dependent rats. Furthermore, both cue- and stress-induced alcohol seeking were blocked by the GABAB receptor positive allosteric modulator. Finally, pretreatment with 3 mg/kg of ADX71441 before stress-induced reinstatement significantly decreased c-Fos expression in a network of brain regions implicated in stress-induced relapse, comprising the nucleus accumbens shell, the dorsal raphe nucleus and the medial prefrontal cortex. Our findings support a causal role of GABAB receptors in alcohol reinforcement and relapse to alcohol seeking. These effects are observed in the absence of significant sedative side effects. Jointly, these observations indicate that GABAB receptor positive allosteric modulators merit being tested clinically for the treatment of alcoholism. Our data also point to a potential biomarker of target engagement for early clinical studies.
Assuntos
Alcoolismo/tratamento farmacológico , Proteínas de Bactérias/farmacologia , Agonistas dos Receptores de GABA-B/farmacologia , Fatores de Transcrição/farmacologia , Acetamidas , Dissuasores de Álcool , Alcoolismo/metabolismo , Alcoolismo/patologia , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Depressores do Sistema Nervoso Central/administração & dosagem , Sinais (Psicologia) , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Comportamento de Procura de Droga/efeitos dos fármacos , Comportamento de Procura de Droga/fisiologia , Etanol/administração & dosagem , Imuno-Histoquímica , Masculino , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos Wistar , Receptores de GABA-B/metabolismo , Recidiva , Autoadministração , Estresse Psicológico/tratamento farmacológico , Estresse Psicológico/metabolismo , Estresse Psicológico/patologia , TriazinasRESUMO
To safeguard patients, regulatory authorities require that new drugs that are to be given by the intravitreal (IVT) route are assessed for their safety in a laboratory species using the same route of administration. Due to the high similarity of ocular morphology and physiology between humans and nonhuman primates (NHPs) and due to the species specificity of many biotherapeutics, the monkey is often the only appropriate model. To this end, intravitreal administration and assessment of ocular toxicity are well established in cynomolgus monkeys (Macaca fascicularis). In contrast, the common marmoset monkey (Callithrix jacchus) is not a standard model for ocular toxicity studies due to its general sensitivity to laboratory investigations and small eye size. It was the purpose of the present work to study whether the marmoset is a useful alternative to the cynomolgus monkey for use in intravitreal toxicological studies. Six marmoset monkeys received repeated (every 2 weeks for a total of four doses) intravitreal injections of 10 or 20⯠µ L of a placebo. The animals were assessed for measurements of intraocular pressure (IOP), standard ophthalmological investigations and electroretinography (ERG). At the end of the dosing period, the animals were sacrificed and the eyes were evaluated histologically. ERG revealed similar results when comparing predose to end-of-study data, and there was no difference between the two dose volumes. A transient increase in the IOP was seen immediately after dosing, which was more pronounced after dosing of 20⯠µ L compared to 10⯠µ L. Ophthalmologic and microscopic observations did not show any significant changes. Therefore, it can be concluded that 10⯠µ L as well as 20⯠µ L intravitreal injections of a placebo are well tolerated in the marmoset. These results demonstrate that the common marmoset is an alternative to the cynomolgus monkey for intravitreal toxicity testing.
RESUMO
The aim of this study was to develop an immunohistochemical (IHC) method for calbindin D-28 (CB-28) and microtubule-associated protein-2 (MAP-2) and evaluate their expression as markers in the detection, characterisation and grading of unexpected cerebellar toxicity in the rat. High power examination of H&E-stained brain sections of treated rats 2 days following a single oral dose of a novel compound revealed irregular vacuolation of the molecular layer and Purkinje cell degeneration. Animals killed after 14 days recovery showed Purkinje cell degeneration but vacuolation of the molecular layer was absent. In control animals, CB-28 and MAP-2 expression was high in Purkinje cell dendrites and cell bodies in the molecular layer. In treated animals, low power examination revealed loss of CB-28 and MAP-2 expression in degenerating neurons arranged in parasagittal stripes within the vermis. This is the first description of successful use of these two markers in a regulatory toxicity study using FFPE brain. In particular, CB-28 provides a sensitive method for characterising CNS toxicity which can be detected at low power enabling easier detection, screening and grading of neurotoxicity.
Assuntos
Biomarcadores/metabolismo , Fármacos do Sistema Nervoso Central/toxicidade , Cerebelo/efeitos dos fármacos , Proteínas Associadas aos Microtúbulos/metabolismo , Proteína G de Ligação ao Cálcio S100/metabolismo , Testes de Toxicidade/métodos , Xenobióticos/toxicidade , Administração Oral , Animais , Calbindinas , Cerebelo/metabolismo , Cerebelo/patologia , Feminino , Técnicas Imunoenzimáticas , Masculino , Degeneração Neural/induzido quimicamente , Degeneração Neural/metabolismo , Degeneração Neural/patologia , Células de Purkinje/efeitos dos fármacos , Células de Purkinje/metabolismo , Células de Purkinje/patologia , Ratos , Ratos WistarRESUMO
Liraglutide and exenatide are glucagon-like peptide receptor (GLP-1R) agonists used in the treatment of type 2 diabetes. Both molecules have been associated with the development of thyroid C-cell tumors after lifetime exposure in rodents. Previously, it has been reported that these tumors are preceded by increased plasma calcitonin and C-cell hyperplasia. We can now document that the murine C-cell effects are mediated via GLP-1R. Thus, 13 wk of continuous exposure to GLP-1R agonists was associated with marked increases in plasma calcitonin and in the incidence of C-cell hyperplasia in wild-type mice. In contrast, similar effects were not seen in GLP-1R knockout mice. Human C-cell cancer is often caused by activating mutations in the rearranged-during-transfection (RET) protooncogene. We developed an immunohistochemical method to assess RET activation in tissues. Liraglutide dosing to mice was not found to activate RET. Further evaluation of the signaling pathways demonstrated that liraglutide increased ribosomal S6, but not MAPK kinase, phosphorylation. These observations are consistent with effects of GLP-1R agonists on rodent C cells being mediated via mammalian target of rapamycin activation in a RET- and MAPK-independent manner.
Assuntos
Receptores de Glucagon/agonistas , Glândula Tireoide/metabolismo , Animais , Calcitonina/sangue , Calcitonina/metabolismo , Feminino , Peptídeo 1 Semelhante ao Glucagon/análogos & derivados , Peptídeo 1 Semelhante ao Glucagon/farmacologia , Receptor do Peptídeo Semelhante ao Glucagon 1 , Imuno-Histoquímica/métodos , Ligantes , Liraglutida , Masculino , Camundongos , Camundongos Knockout , Modelos Genéticos , Fosfoproteínas/química , Proteínas Proto-Oncogênicas c-ret/genética , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Fatores de TempoRESUMO
Spontaneous follicular and C-cell tumors of the thyroid gland in the Han Wistar rat were examined using two morphologic procedures. Firstly, in situ hybridization (ISH) was used to localize thyroglobulin (TG) and calcitonin (CT) mRNAs. Secondly, the proteins for these markers were detected using immunohistochemistry (IHC). The aim was to study the morphology of the tumors and to examine the usefulness of TG and CT markers in the differential diagnosis of these lesions. Follicular tumors with cystic, papillary and follicular patterns showed relatively consistent expression of TG mRNA by ISH, thereby confirming the diagnostic value of this technique. However, no staining for TG markers was observed in solid lesions. In general, C-cell tumors comprised well-differentiated cells that continued to express CT mRNA and peptides even after embolic spread and metastasis. Therefore, the performance of either ISH or IHC for CT markers can be used for diagnostic confirmation. Additional features noted in C-cell tumors included the appearance of tumor emboli or metastases in association with small primary lesions (less than 5 average follicular diameters in size) and the presence of eosinophilic (amyloid-like) material showing immunopositivity for CT peptides. Finally, evidence is provided for the sequestration of TG protein by proliferating C-cells.
Assuntos
Biomarcadores Tumorais/metabolismo , Calcitonina/metabolismo , Tireoglobulina/metabolismo , Neoplasias da Glândula Tireoide/metabolismo , Animais , Diagnóstico Diferencial , Imuno-Histoquímica , Hibridização In Situ , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Neoplasias da Glândula Tireoide/classificação , Neoplasias da Glândula Tireoide/diagnóstico , Neoplasias da Glândula Tireoide/patologiaRESUMO
Pulmonary Neuroendocrine Cells (PNEC) are found as clusters called neuroepithelial bodies (NEB) or as single cells scattered in the respiratory epithelium. Pulmonary neuroendocrine cell hyperplasia is recorded in humans and experimentally manipulated rodents. The objectives of this work were to identify the optimal immunohistochemical markers for PNEC in the rat for use on paraffin-embedded, formalin-fixed material and to provide the first comparative incidence of PNEC hyperplasia in untreated 2-year-old rats of different strains. Calcitonin-gene related peptide (CGRP) and protein G product 9.5 (PGP9.5) antibodies identified PNEC consistently and selectively. In contrast, PNEC did not express chromogranin-A or S-100. PNEC hyperplasia was defined as foci of PNEC with greater than 40 nuclei, excluding overlying respiratory epithelium and submucosal PNEC. PNEC hyperplasia was observed at low incidence (0-7%) in untreated 2-year-old Sprague-Dawley, Han Wistar and Wistar rats but not Fischer 344 rats. This is the first report of spontaneous PNEC hyperplasia in rats. The cause of this hyperplasia is unknown, but experimental models that induce PNEC hyperplasia by causing bronchiolar cell injury are discussed. PNEC neoplasia in the rat is unreported in the literature and was not observed in animals examined in this study.
Assuntos
Pulmão/patologia , Sistemas Neurossecretores/patologia , Envelhecimento , Animais , Peptídeo Relacionado com Gene de Calcitonina/análise , Hiperplasia , Imuno-Histoquímica , Incidência , Ratos , Ratos Endogâmicos F344 , Ratos Sprague-Dawley , Ratos Wistar , Ubiquitina Tiolesterase/análiseRESUMO
Aplastic anaemia (AA) in man is an often fatal disease characterized by pancytopenia of the peripheral blood and aplasia of the bone marrow. AA is a toxic effect of many drugs and chemicals (e.g. chloramphenicol, azathioprine, phenylbutazone, gold salts, penicillamine and benzene). However, there are no widely used or convenient animal models of drug-induced AA. Recently, we reported a new model of chronic bone marrow aplasia (CBMA = AA) in the busulphan (BU)-treated mouse: eight doses of BU (10.50 mg/kg) were administered to female BALB/c mice over a period of 23 days; CBMA was evident at day 91/112 post-dosing with significantly reduced erythrocytes, platelets, leucocytes and nucleated bone marrow cell counts. However, mortality was high (49.3%). We have now carried out a study to modify the BU-dosing regime to induce CBMA without high mortality, and investigated the patterns of cellular responses in the blood and marrow in the post-dosing period. Mice (n = 64/65) were dosed 10 times with BU at 0 (vehicle control), 8.25, 9.0 and 9.75 mg/kg over 21 days and autopsied at day 1, 23, 42, 71, 84, 106 and 127 post-dosing (n = 7-15); blood and marrow samples were examined. BU induced a predictable bone marrow depression at day 1 post-dosing; at day 23/42 post-dosing, parameters were returning towards normal during a period of recovery. At day 71, 84, 106 and 127 post-dosing, a stabilized, late-stage, nondose-related CBMA was evident in BU-treated mice, with decreased erythrocytes, platelets and marrow cell counts, and increased MCV. At day 127 post-dosing, five BU-treated mice showed evidence of lymphoma. In this study, mortality was low, ranging from 3.1% (8.25 mg/kg BU) to 12.3% (9.75 mg/kg BU). It is concluded that BU at 9.0 mg/kg (or 9.25 mg/kg) is an appropriate dose level to administer (10 times over 21 days) to induce CBMA at approximately day 50-120 post-dosing.
Assuntos
Anemia Aplástica/patologia , Células da Medula Óssea/patologia , Bussulfano , Modelos Animais , Agonistas Mieloablativos , Anemia Aplástica/mortalidade , Animais , Apoptose , Contagem de Células Sanguíneas , Células da Medula Óssea/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Linfoma/induzido quimicamente , Linfoma/patologia , Camundongos , Camundongos Endogâmicos BALB C , Baço/efeitos dos fármacos , Baço/patologia , Neoplasias Esplênicas/induzido quimicamente , Neoplasias Esplênicas/patologia , Coloração e Rotulagem , Timo/efeitos dos fármacos , Timo/patologia , Neoplasias do Timo/induzido quimicamente , Neoplasias do Timo/patologiaRESUMO
The aim of this study was to use immunohistochemistry with morphometry to investigate COX-1 and COX-2 expression in the normal rat gastrointestinal (GI) tract and examine if sites of ulceration previously observed with long-term COX-2 inhibitor administration in mice correlate with differential COX-1/COX-2 expression. COX-2 positive cells were observed predominantly in the apical lamina propria of intestinal villi with fewer cells in the mucosal epithelium. The highest level of COX-2 expression was observed at the ileocaecal junction (ICJ). COX-2 expression was also present in parasympathetic ganglia of the submucosa and muscularis. In the stomach, the highest grade of COX-2 expression was observed in the apical lamina propria of the fundus adjacent to the junctional ridge. In contrast, COX-1 positive cells within the lamina propria were evenly distributed along the GI tract but were present in higher numbers than COX-2 positive cells. The mean level of COX-1 expression at the ICJ was not significantly different from the ileum and caecum. Evidence that the highest level of COX-2 expression in normal rats is located on the ileal side of the ICJ provides the first mechanism to explain spontaneous ulceration and perforation of the distal ileum in COX-2 -/- animals.
Assuntos
Trato Gastrointestinal/metabolismo , Prostaglandina-Endoperóxido Sintases/metabolismo , Animais , Ceco/citologia , Ceco/metabolismo , Ciclo-Oxigenase 1 , Ciclo-Oxigenase 2 , Ectodisplasinas , Feminino , Trato Gastrointestinal/citologia , Íleo/citologia , Íleo/metabolismo , Técnicas Imunoenzimáticas , Masculino , Proteínas de Membrana/metabolismo , Ratos , Ratos Wistar , Inclusão do Tecido/métodosRESUMO
Mitomycin (MMC), like many antineoplastic drugs, induces a predictable, dose-related, bone marrow depression in man and laboratory animals; this change is generally reversible. However, there is evidence that MMC may also cause a late-stage or residual bone marrow injury. The present study in female CD-1 mice investigated the haematological and bone marrow changes induced by MMC in a repeat dose study lasting 50 days. Control and MMC-treated mice were dosed intraperitoneally on eight occasions over 18 days with vehicle, or MMC at 2.5 mg/kg, autopsied (n = 6-12) at 1, 7, 14, 28, 42 and 50 days after the final dose and haematological changes investigated. Femoral nucleated bone marrow cell counts and levels of apoptosis were also evaluated and clonogenic assays carried out; serum levels of FLT3 ligand (FL) were assessed. At day 1 post-dosing, MMC induced significant reductions in RBC, Hb and haematocrit (HCT) values, and there were decreases in reticulocyte, platelet, and femoral nucleated cell counts (FNCC); neutrophil, lymphocyte and monocyte values were also significantly reduced. On days 7 and 14 post-dosing, all haematological parameters showed evidence of a return towards normal values, but at these times, and at day 28, values for RBC and FNCC remained significantly reduced in comparison with controls. At days 42 and 50 post-dosing, many haematological parameters in MMC-treated mice had returned to control levels; however, there remained evidence of late-stage effects on RBC, Hb and HCT values, and FNCC also continued to be significantly decreased. Results for granulocyte-macrophage colony-forming units and erythroid colonies showed a profound decrease immediately post-dosing, but a return to normal values was evident at day 50. Serum FL concentrations demonstrated very significant increases in the immediate post-dosing period, but a return to normal was seen at day 50 post-dosing; a relatively similar pattern was seen in the number of apoptotic femoral marrow nucleated cells. The histopathological examination of kidney tissues from MMC animals at day 42 and 50 post-dosing showed evidence of hydronephrosis with cortical glomerular/tubular atrophy and degeneration. It is therefore concluded that MMC administered on eight occasions over 18 days to female CD-1 mice at 2.5 mg/kg induced profound changes in haematological and bone marrow parameters in the immediate post-dosing period with a return to normal levels at day 50 post-dosing; however, there was evidence of mild but significant late-stage/residual effects on RBC and FNCC, and on cells of the erythroid lineage in the bone marrow.
Assuntos
Antibióticos Antineoplásicos/administração & dosagem , Células da Medula Óssea/patologia , Células-Tronco Hematopoéticas/patologia , Mitomicina/administração & dosagem , Animais , Antibióticos Antineoplásicos/efeitos adversos , Apoptose , Células da Medula Óssea/efeitos dos fármacos , Contagem de Células , Esquema de Medicação , Contagem de Eritrócitos , Feminino , Fêmur , Hematócrito , Células-Tronco Hematopoéticas/efeitos dos fármacos , Hemoglobinas/análise , Rim/efeitos dos fármacos , Rim/patologia , Proteínas de Membrana/sangue , Camundongos , Camundongos Endogâmicos , Mitomicina/efeitos adversosRESUMO
C-cell tumours of the thyroid gland are among the most common spontaneous neoplasms of the laboratory rat. With the exception of calcitonin, little attention has been paid to the secretory peptides of C cells during the development of neoplasia. Of these peptides, somatostatin (SS) is of particular interest because it has been shown to have a direct anti-secretory effect on both thyroid follicular and C cells in vitro. In the present study, in situ hybridization and immunohistochemistry were used to investigate the expression of SS mRNA and SS peptides, in normal C cells and a range of spontaneous proliferative C-cell lesions in the Han Wistar rat. It was confirmed that a small minority of C cells in the normal rat thyroid gland produce and store SS peptides; however, approximately half of all C-cell adenomas and C-cell carcinomas stained positively for SS mRNA and peptides. SS expression was also observed in all metastatic deposits of carcinomas in drainage lymph nodes. From these observations, it appears that C-cell tumours are more likely to develop from SS-expressing stem cells, rather than from non-SS-expressing stem cells. In addition, a lack of differentiation of neoplastic C cells, or reversion to more primitive cell types, could account for increased number of cells expressing SS in C-cell tumours relative to the normal C-cell population. Finally, the mean percentage of cells that stained positively for SS mRNA and peptides appeared to be significantly higher in small C-cell tumours, suggesting that SS may have exerted a growth-controlling influence on these lesions.