Functional and histopathological changes induced by intraparenchymal injection of kainic acid in the rat cervical spinal cord

Kainic acid (KA) is an analog of the neurotransmitter glutamate and is widely used as an excitotoxic agent to lesion spinal cord networks, thus, providing an interesting model to learn basic mechanisms of spinal cord injury. The present work was aimed to evaluate motor and sensory performance of rats and analyze morphometric parameters of spinal cord neurons after KA injection. Animals were injected either with 0.75, 1 or 1.25. mM of KA at the C5 segment of the cervical spinal cord. Motor and sensory performance of the rats were evaluate at day 0 (before injection) and at days 1, 2, 3 and 7 post-injection (pi) and compared with those of saline-treated and non-operated animals. Animals were sacrificed at each time point for morphometric and histopathological analysis and compared among groups. All KA-treated animals showed a significant impairment at the motor and sensory tests for the ipsilateral forelimb in a concentration-dependent manner in comparison to saline-treated and non-operated animals. Neuronal cell count showed a significant loss of neurons at C4, C5 and C6 cervical segments when compared with those of saline-treated and non-operated animals. The contralateral side of the cervical segments in KA-treated rats remained unchanged. Some improvement at the motor and sensory tests was observed in animals injected with 0.75 and 1. mM KA. Moreover, a mild increase in the neuronal count of the damaged segments was also recorded. The improvement recorded in the motor and sensory tests by day 7 pi may be a consequence of a neuron repairing mechanism triggered soon after the KA excitotoxic effect.Facultad de Ciencias VeterinariasLaboratorio de Análisis de Imágene

The colonic groove of the plains viscacha (<i>Lagostomus maximus</i>) : Histochemical evidence of an abrupt change in the glycosylation pattern of goblet cells

The ascending colon of most rodent species shows a longitudinal colonic groove that works as a retrograde transport pathway for a mixture of bacteria and mucus toward the cecum. We describe the morphology and glycosylation pattern of the colonic groove of Lagostomus maximus to analyze the role of mucins in this anatomical feature. We also studied the distribution pattern of the interstitial cells of Cajal (ICC) to evaluate their regulatory influence on gut motility. The groove originated near the cecocolic junction and extended along the mesenteric side of the ascending colon, limited at both ends by nonpapillated ridges. These ridges divided the lumen of the ascending colon into two compartments: a narrow channel and a large channel, called the groove lumen and the main lumen, respectively. The histochemical analysis showed differences in the glycosylation pattern of the goblet cells inside and outside the groove. Unlike the mucosa lining the main lumen of the colon, the groove was rich in goblet cells that secrete sulfomucins. The PA/Bh/KOH/ PAS technique evidenced an abrupt change in the histochemical profile of goblet cells, which presented a negative reaction in the groove and a strongly positive one in the rest of the colonic mucosa. The anti-c-kit immunohistochemical analysis showed different ICC subpopulations in the ascending colon of L. maximus. Of all types identified, the ICC-SM were the only cells located solely within the colonic groove.Facultad de Ciencias Veterinaria

Sistema urinario

El sistema urinario de los mamíferos está formado por algunos órganos pares, como los riñones y los uréteres, y otros únicos, como la vejiga y la uretra. Este capítulo describe los componentes de cada uno de ellos.Facultad de Ciencias Veterinaria

Tejido conectivo y tejido adiposo

Este capítulo se centra en la descripción del tejido conectivo ordinario, también llamado tejido conectivo propiamente dicho, y en el tejido adiposo.Facultad de Ciencias Veterinaria

Lidocaine protects neurons of the spinal cord in an excitotoxicity model

Motor Neuron Disease disorders, described in domestic animals, are characterized by neuronal degeneration at the spinal cord. Excitotoxicity is a crucial factor for the selective loss of these neurons, being the fundamental processes involved in lesion progression after spinal cord injury, where glutamate is one of the main neurotransmitters involved. Kainic acid (KA) resembles the effects induced by the pathological release of glutamate. Lidocaine administered by different routes exerts some neuroprotective effects in the CNS. The aim of the present work was to determine whether lidocaine simultaneously injected with KA into the spinal cord could prevent the excitotoxic effects of the latter. Sprague-Dawley rats were injected by intraparenchymal route with KA or with KA plus 0.5% lidocaine into the C5 segment. Sham rats were injected with saline. Animals were motor and sensory tested at 0, 1, 2, 3, 7 and 14 post-injection days and then euthanized. Sections of the C5 segment were used for histological and immunohistochemical analysis. No KA-induced motor and sensitive impairments were observed when lidocaine was simultaneously injected with KA. Moreover, neuronal counting was statistically higher when compared with KA-injected animals. Thus, lidocaine could be considered as a neuroprotective drug in diseases and models involving excitotoxicity.Fil: Sisti, María Susana. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Nishida, Fabian. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Zanuzzi, Carolina Natalia. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Laurella, Sergio Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Cantet, Rodolfo Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; ArgentinaFil: Portiansky, Enrique Leo. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Effects of Different Anesthetics in the Murine Model of EHV-1 Infection

Mice are commonly used as an experimental model to investigate the Equid herpesvirus 1 (EHV-1) infection. This model easily reproduces the disease, and the clinical signs are more or less similar to those observed in the horse, the natural host. During natural infection, the acute course of respiratory infection is mandatory for the development of adaptive immune response. Since interactions between EHV-1 and anesthetics are possible, the study investigated whether the early events of murine pulmonary immune response could be affected by different anesthetics. Therefore, mice were experimentally infected with a unique EHV-1 strain under the effects of ether, ketamine/xylazine, or isoflurane. Clinical signs and histopathological lesions in the lungs were described, and the cell death and proliferation rates of sham-inoculated or infected animals were quantified using immunohistochemistry. Clinical signs were more severe in animals anesthetized with ether. Qualitative differences in the recruited inflammatory cells were observed following application of anesthesia. The level of infection between the infected groups was not statistically significant. However, lungs from ketamine/xylazine-anesthetized animals showed the highest cell death rates, whereas those from isoflurane-anesthetized animals showed the highest proliferation rates. It has been emphasized that anesthetics alone or their interactions with EHV-1 modify the response against the infection. An appropriate selection of the anesthetic during experimental studies is relevant to minimize wrong conclusions.Facultad de Ciencias Veterinaria

Effects of an intraparenchymal injection of lidocaine in the rat cervical spinal cord

Lidocaine effects in the spinal cord have been extensively investigated over the years. Although the intrathecal route is usually used to treat insults occurring in the spinal cord, the local delivery drug via intraparenchymal infusions has gained increasing favor for the treatment of some neurodegenerative disorders. The aim of the present study was to evaluate the behavioral and tissue effects of the intraparenchymal injection of different concentrations of lidocaine into the rat cervical spinal cord. Young male Sprague-Dawley rats were intraparenchymally injected with 0.5%, 1% or 2% lidocaine at the C5 segment of the spinal cord. Other rats were injected with saline solution (sham group). Hot plate test was determined at 0, 1, 2, 3, 7 and 14 post-injection (pi) days. Rats of each experimental group were euthanized either at 1, 2, 3, 7 or 14 pi days. Intact animals were used as controls. Sections of the C5 segment were used for histological, immunohistochemical or immunofluorescence analysis. Injection of 0.5% lidocaine did not affect neuronal counting, did not evoke an inflammatory reaction, nor induce astrocyte activation. Therefore, a concentration of 0.5% lidocaine is suggested to promote anti-inflammatory effects after injury.Laboratorio de Análisis de Imágene

Atrofia do timo em bovinos intoxicados por Solanum glaucophyllum

Solanum glaucophyllum (Sg) [= S. malacoxylon] is a calcinogenic plant inducing "Enzootic Calcinosis" in cattle. The 1,25-dihydroxyvitamin D3, its main toxic principle, regulates bone and calcium metabolism and also exerts immunomodulatory effects. Thymocyte precursors from bone marrow-derived progenitor cells differentiate into mature T-cells. Differentiation of most T lymphocytes is characterized not only by the variable expression of CD4/CD8 receptor molecules and increased surface density of the T cell antigen receptor, but also by changes in the glycosylation pattern of cell surface glycolipids or glycoproteins. Thymocytes exert a feedback influence on thymic non-lymphoid cells. Sg-induced modifications on cattle thymus T-lymphocytes and on non-lymphoid cells were analysed. Heifers were divided into 5 groups (control, intoxicated with Sg during 15, 30 or 60 days, and probably recovered group). Histochemical, immunohistochemical, lectinhistochemical and morphometric techniques were used to characterize different cell populations of the experimental heifers. Sg-poisoned heifers showed a progressive cortical atrophy that was characterized using the peanut agglutinin (PNA) lectin that recognizes immature thymocytes. These animals also increased the amount of non-lymphoid cells per unit area detected with the Picrosirius technique, WGA and DBA lectins, and pancytokeratin and S-100 antibodies. The thymus atrophy found in intoxicated animals resembled that of the physiological aging process. A reversal effect on these changes was observed after suppression of the intoxication. These findings suggest that Sg-intoxication induces either directly, through the 1,25-dihydroxyvitamin D3 itself, or indirectly through the hypercalcemia, the observed alteration of the thymus.Facultad de Ciencias Veterinaria

Corazón prediabético: señalización intracelular en la apoptosis cardíaca inducida por una dieta rica en fructosa

Los objetivos del presente trabajo son verificar la presencia de apoptosis en el corazón con TGA y definir las vías de señalización intracelular que conducen a ella, apuntando a esclarecer el rol de la CaMKII en esta cascada de señales.Facultad de Ciencias Médica

Paneth cells: histochemical and morphometric study in control and Solanum glaucophyllum intoxicated rabbits

The intestinal epithelium has a critical roll in host defence. One specialised cell type involved in this function is the Paneth cell, which secretes many substances with antimicrobial properties in response to different stimuli. Under pathological conditions, changes in the Paneth cell number, morphology and location as well as in granule number, morphology and composition have been reported. In the normal animal, 1,25-dihydroxyvitamin D3 participates in the maintenance of mineral homeostasis, immunomodulation and cell proliferation and differentiation. Solanum glaucophyllum, a calcinogenic plant containing high levels of 1,25-dihydroxyvitamin D3, is responsible for a condition known as enzootic calcinosis in ruminants, characterised by loss of body condition and mineralization of soft tissues. Using and established rabbit model, this study analyses the changes that rabbit Paneth cells undergo during intoxication with S. glaucophyllum. Male New Zealand white rabbits were experimentally intoxicated with S. glaucophyllum for 15 or 30 days. Lectin, immunohistochemical and morphometric studies were carried out on Paneth cells from samples of jejunum. SBA, DBA and WGA lectins bound to Paneth cells-granules in both normal and intoxicated rabbits, with more heterogenity in the labelling of granules from intoxicated rabbits. Paneth cells in both groups were immunonegative for lysosyme. A time and dose-dependent increase in the size and number of Paneth cells was found in both intoxicated groups. We suggest that the changes described in these cells may be directly or indirectly induced by S. glaucophyllum intoxication.Facultad de Ciencias Veterinaria