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BACKGROUND: Several studies have attempted to characterise the origin of canine transmissible venereal tumour (CTVT). However, the participation of cancer stem cells (CSC) has not been reported OBJECTIVES: Herein we describe the expression patterns of CSC markers CD44, CD34, CD90 and CD133 in CTVT METHODS: Thirty-eight samples were selected and assessed through flow cytometry and immunohistochemistry RESULTS AND CONCLUSIONS: Twenty-two tumours were classified as plasmacytoid and 16 as mixed. Almost all tumours showed high CD44 and low CD34 levels. CD133 and CD90 expression varied among tumours. Cytological groups did not differ in the proportion of CSC markers. Our results suggest that CSC subpopulations might participate in CTVT.

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RESUMEN El propósito de este estudio fue para presentar y documentar un leiomiosarcoma peritoneal en un canino y sus hallazgos histopatológicos e Inmunohistoquímica. El paciente, una hembra de 5 años de edad, de raza Chow-Chow, fue llevada a la Clínica Veterinaria de la Universidad de los Llanos, debido a pérdida de peso, postración y baja condición corporal. Al examen físico presentó mucosas pálidas, aumento de la silueta abdominal con contenido de fluido serosanguinolento. A la palpación se evidenció en el epigastrio craneal una masa no dolorosa, de consistencia dura, de superficie irregular y desplazable caudalmente. Anormalidades bioquímicas séricas incluyeron proteínas totales plasmáticas aumentadas, globulina y creatinina. Así, una laparotomía exploratoria fue realizada, identificando una masa en el mesenterio unida a la porción de intestino grueso. En el reporte se señalaron los siguientes hallazgos macroscópicos: una masa firme de 18 cm de longitud y 13 cm de ancho, con una superficie irregular, gran vascularización. Las muestras de tejido fueron fijadas en formalina buferada al 10% para análisis histopatológico e Inmunohistoquímica. Las muestras fueron procesadas por los métodos de rutina para microscopía y coloración con hematoxilina-eosina (HE), tricrómico de Masson, anticuerpos anti-citoqueratina CK5, anti-actina de músculo liso, vimentina y KIT(CD117). En conclusión, el tumor fue clasificado por histopatología como de origen mesenquimal e inmunopositividad citoplasmática difusa interna de células neoplásicas para actina de músculo liso, vimentina y negatividad para KIT, condujo al diagnóstico de leiomiosarcoma.

ABSTRACT The purpose of this study is to present a peritoneal leiomyosarcoma in a canine and its histopathological and immunohistochemical findings. The patient, a 5-year old female Chow-Chow, was brought to Los Llanos University veterinary clinic due to loss of appetite, prostration and poor corporal condition. Physical examination showed pale mucous membranes, increased abdominal silhouette with a serosanguineous fluid content. Palpation at the cranial epigastrium evidenced a painless mass of hard consistency, irregular surface and caudally displaceable. Serum biochemical abnormalities included increased plasma total protein, globulin and creatinine. Thus, an exploratory laparotomy was performed, identifying a mass in the mesentery attached to a portion of the small intestine. In its report it was stated the following macroscopic findings: a firm mass of 18 cm long and 13 cm wide, with irregular surface, great vascularization. Tissue samples were fixed in 10% buffered formalin for histopathological and immunohistochemical analysis. Samples were processed by routine methods for microscopy and stained with hematoxylin-eosin (HE), Masson trichrome, anti-cytokeratin CK5, anti-smooth muscle actin, vimentin and KIT(CD117) antibodies. In conclusion, the tumor was classified by histopathology as of mesenchymal origin and internal diffuse cytoplasmic immunopositivity of neoplastic cells for smooth muscle actin, vimentin and was negative for KIT led to diagnose of leiomyosarcoma.

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Euphorbia tirucalli (E. tirucalli) is a tropical and subtropical plant that produces a latex which is used for several purposes. The components of E. tirucalli latex include triterpenes, diterpenes and steroids. The aim of the present study was to evaluate the effects of diluted E. tirucalli latex on murine B16/F10 melanoma cells and lung metastasis. For this purpose, an in vitro study was first performed, in which B16/F10 cells were treated with diluted (1/2 to 1/11,192) E. tirucalli latex. In a second study, B16/F10 melanoma cells were inoculated into the tail vein of mice to generate lung metastases; the mice then received 0.467 µg of latex diluted in 200 ml saline by gavage for 14 days. A significant decrease in B16/F10 cell viability was observed using the MTT assay at 24 and 48 h after treatment with E. tirucalli latex. In addition, a significant decrease in the volume fraction occupied by B16/F10 metastatic colonies in the lungs was observed in mice treated with E. tirucalli latex. These results confirm the antineoplastic effects of diluted E. tirucalli latex.

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Ivermectin is a human and veterinary antiparasitic drug which is one of the most widely used in the world. Studies from our group have revealed several behavioral and neurochemical impairments induced by therapeutic doses of ivermectin in adult rats. However, the effects on juveniles remain unknown. Ivermectin has been prescribed for juvenile humans, pets and farm animals, which still show remarkable development and postnatal maturation and may be more susceptible to drug interventions. Hence, we studied the behavioral and neurochemical effects of two therapeutical doses (0.2 and 1.0 mg/kg) of ivermectin in juvenile rats. As it is underestimated in prescriptions, the stress factor was also studied. Ivermectin 1.0 mg/kg induced hyperlocomotion in juvenile rats. Association of 1.0 mg/kg ivermectin with stress induced hypolocomotion in rats. Ivermectin 1.0 mg/kg whether or not associated with stress exacerbated socialization of rats. Ivermectin did not induce anxiety-like behavior neither affected corticosterone levels of juvenile rats. The motor/exploratory behavioral findings induced by association of ivermectin and stress seem to be triggered after the increase in the striatal serotonergic system activity. Association of ivermectin with stress increased striatal dopamine levels, which increased (excessive) social play behavior. Our results suggest a review of the prescribed dose of ivermectin for juvenile humans and pets. Moreover, the stress factor should be considered for ivermectin medical prescriptions, since it may exacerbate behavioral and neurochemical disturbances.

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Grooming behaviour has different functions on many species during development and can be observed and affected during periods of stress. By selecting male mice with high (HI) and low (LI) immobility traits in the tail suspension test, a screening for antidepressant drugs, we investigate how these phenotypes associated with grooming behaviour may be influenced by the effects of repeated restraint stress. For this we used the sucrose preference test and the splash test in a novel and a familiar cage performed before and after exposure to 2 days of restraint stress. Animals were submitted to an additional day of restraint stress before the hypothalamus, prefrontal cortex and midbrain extraction for dopamine activity analysis. Corticosterone analysis was made in three distinct moments: without stress (prior first restraint session), immediately after the last restrain, and 1 hr after the last restrain episode. Compared to LI group, HI animals exhibited an increased frequency and decreased time of grooming in the familiar cage. In the novel cage, stress increased frequency and time of grooming of HI animals compared to LI. Corticosterone levels were increased in HI animals after 3 days of stress. Lower hypothalamic dopaminergic activity without stress and decreased hypothalamic dopaminergic activity immediately after stress in HI group were observed. The HI group displayed decreased prefrontal cortex dopaminergic activity and increased activity in the mesolimbic area. We proposed that through the influence of stress the two phenotypes manifested as a resilient (LI) and a not resilient (HI) trait in response to restraint stress.

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PURPOSE: We have previously shown that domperidone-induced short-term hyperprolactinemia reduces the lung's allergic inflammatory response in an ovalbumin antigenic challenge model. Since purinergic receptor P2X7R activity leads to proinflammatory cytokine release and is possibly related to the pathogenesis of allergic respiratory conditions, the present study was designed to investigate a possible involvement of purinergic and prolactin receptors in this phenomenon. METHODS: To induce hyperprolactinemia, domperidone was injected intraperitoneally in rats at a dose of 5.1 mg × kg-1 per day for 5 days. P2X7 expression was evaluated by lung immunohistochemistry while prolactin receptor expression in bronchoalveolar lavage leukocytes was analyzed through flow cytometry. RESULTS: Previous reports demonstrated that rats subjected to short-term hyperprolactinemia exhibited a decrease in leukocyte counts in bronchoalveolar lavage, especially granulocytes. Here, it is revealed that hyperprolactinemia promotes an increased expression of prolactin receptors in granulocytes. Also, increased expression of purinergic P2X7R observed in allergic animals was significantly reduced by hyperprolactinemia. CONCLUSIONS: Both purinergic and prolactin receptor expression changes occur during the anti-asthmatic effect of hyperprolactinemia.

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The dopaminergic antagonist drug Domperidone has immunomodulatory effects. We investigated the effects of repeated Domperidone treatment in a model of Lypopolyssacharide (LPS)-induced acute lung inflammation. Adult C57BL/6J mice were treated with either Vehicle or Domperidone for 5days, and challenged intranasally with LPS in the following day. The behavior of mice was analyzed in the open field and elevated plus-maze test before and 24h after LPS challenge. The bronchoalveolar lavage fluid, blood and lung tissue were collected 24h and 48h after LPS challenge. Domperidone treatment increased LPS-induced tumor necrosis factor (TNF) and interleukin (IL)-6 production in the bronchoalveolar lavage fluid, without altering tissue damage and the number of immune cells in the lungs and circulation. Locomotor and anxiety-like behavior were unchanged after Domperidone and/or LPS treatment. Cytokine data indicate that Domperidone promotes a change in activity of other cell types, likely alveolar epithelial cells, without affecting immune cell migration in the present model. Due to the role of these cytokines in progression of inflammation, Domperidone treatment may exacerbate a subsequent inflammatory injury.

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There are many factors which make canine cancer like cancer in humans. The occurrence of spontaneous mammary tumors in pet dogs, tumor genetics, molecular targets and exposure to the same environmental risk factors are among these factors. Therefore, the study of canine cancer can provide useful information to the oncology field. This study aimed to establish and characterize a panel of primary mixed cell cultures obtained from spontaneous canine mammary tumors. Eight established cell cultures obtained from one normal mammary gland, one complex adenoma, one mixed adenoma, two complex carcinomas and two mixed carcinomas were analyzed. The gene expression levels of classic molecular cancer players such as fibroblast growth factor receptor (FGFR) 2, breast cancer (BRCA) 1, BRCA2 and estrogen receptor (ESR) 1 were evaluated. For the first time, three orphan nuclear receptors, estrogen-related receptors (ERRs) α, ß and γ were studied in canine mammary cancer. The highest expression level of ERRα was observed in complex carcinoma-derived cell culture, while the highest levels of ERRß and γ were observed in cells derived from a mixed carcinoma. Meanwhile, complex carcinomas presented the highest levels of expression of ESR1, BRCA1 and FGFR2 among all samples. BRCA2 was found exclusively in complex adenoma. The transcription factor GATA3 had its highest levels in mixed carcinoma samples and its lowest levels in complex adenoma. Proliferation assays were also performed to evaluate the mixed cell cultures response to ER ligands, genistein and DES, both in normoxia and hypoxic conditions. Our results demonstrate that morphological and functional studies of primary mixed cell cultures derived from spontaneous canine mammary tumors are possible and provide valuable tool for the study of various stages of mammary cancer development.

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OBJECTIVES: A common problem during the postpartum period and during lactation is being affected by infection due to Gram-negative bacteria. In this situation, a sick mother needs to choose between caring for her pups or the need for survival. This study analyzed the effects of lipopolysaccharide (LPS)-induced sickness behavior on selection between maternal behavior (MB) and predatory behavior (PB) in lactating rats. To assess the LPS-induced sickness behavior, the plasma tumor necrosis factor-α (TNF-α) levels were measured. METHODS: Lactating rats received 100 µg/kg LPS or saline solution on day 5 or 6 of lactation, 2 h before testing. Five pups and 5 cockroaches were introduced to the experimental cage at the same time and maternal and PB were observed for 30 min. The MB was measured by the pup contact, grouping, grooming, and kyphosis and the PB by contacting, eating, and foraging insects. General maternal activity was also observed, including exploration, self-grooming, and immobility. Immediately after the observations, blood was collected to measure the plasma TNF-α levels. RESULTS: LPS administration reduced the time and frequency of pup contact, grouping, grooming, and kyphosis, with an increase in the latency to first pup contact and grouping. With regard to PB, the time of foraging and eating insects increased, and the latencies to first insect contact, eating insects, and foraging decreased. With regard to general maternal activity, immobility time and TNF-α levels increased in the LPS-treated group. CONCLUSIONS: LPS exposure switched MB to PB, prioritizing maternal survival. Thus, in more favorable situations, these rats may have new offspring and therefore her species would survive for long.

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OBJECTIVE: The present study evaluated the nociceptive response induced by dentin hypersensitivity after dental erosion in rats that were exhibited to unpredictable chronic mild stress (UCMS)-induced depressive-like behavior. DESIGN: Adult male rats were subjected to UCMS (depression [D] group) or not (no depression [ND] group) for 30days and received either acidic solution to induce dental erosion (E) or water (W), thus forming the WND, END, WD, and ED groups. After the end of treatment, depressive-like parameters (i.e., sucrose preference and immobility in the forced swim test) and dentin hypersensitivity were evaluated. Plasma tumor necrosis factor α (TNF-α) and corticosterone levels were measured, and astrocytic glial fibrillary acidic protein (GFAP) expression was evaluated in the prefrontal cortex, hippocampus, amygdala, and hypothalamus. RESULTS: Administration of the acidic solution potentiated dentin hypersensitivity and increased corticosterone levels in the ED group compared with the WD group. TNF-α levels only increased in the WD group. The ED group exhibited an increase in astrocytic GFAP expression in the hypothalamus and prefrontal cortex but decreases in the hippocampus. CONCLUSIONS: These results suggest that UCMS exacerbated the nociceptive response associated with dentin hypersensitivity, concomitant with an increase in plasma corticosterone levels. Hypothalamic and prefrontal cortex astrogliosis in the ED group may be attributable to the increase in corticosterone associated to UCMS procedure. The reduction of astrocytic GFAP expression in the hippocampus in the ED group supports the association between dentin hypersensitivity and depression.

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