1,721,103 research outputs found
Early metabolic changes in peripheral blood cells of renal transplant recipients treated with cyclosporine A
No full textWe histochemically examined (phosphatase acid-AcP, phosphatase alkaline-ALP, succinate dehydrogenase-SDH, lactate dehydrogenase-LDH) the peripheral blood of renal transplant recipients and controls before (day 0) and after Cyclosporine A (CsA) treatment (days 1, 2, 7 and 30). We wanted to detect the metabolic changes induced in the CsA resistant cells (leucocytes) by CsA and to evaluate the early effects determined by the drug. There was no difference in enzyme activities between the control group and renal patients before CsA treatment (day 0). AcP and ALP activity increased 1 day after CsA administration and became similar to the control by the day 30. LDH activity increased one day after CsA treatment and remained high during the treatment period (30 days), while SDH activity did not change. These enzymatic variations may suggest that the LDH enzyme is involved in the drug degradation as are other phosphatase and oxidoreductase enzymes (i.e. cytochrome P450). Moreover, the high activity of LDH, the enzyme responsible for interconversion of pyruvate in lactic acid, would indicate that anaerobic glycolysis is preferentially used in the pyruvate pathway. However, SDH did not seem to be directly involved in CsA metabolism. Our findings showed that the CsA treatment induced clear variations of the activity of the cellular phosphatase and oxidoreductase enzymes from the first days of drug administration. The variation of the enzymes studied and the appearance time and duration of the metabolic changes, may be markers of the cellular stress due to CsA internalization
Effect of combined Cyclosporine A and liposome encapsulated dichloromethylene diphosphonate on the organisation of the rat thymus : evidence for a role of macrophages in guiding the post Cyclosporine A thymic reorganisation
No full textCyclosporine A (CsA) is a powerful immunosuppressant inducing marked involution of the thymic medulla, and disappearance of interdigitating cells (IDCs) and reducing the number of macrophages (Mphi). Usually, while the thymus of rats receiving a short course of CsA promptly recovers after stopping CsA treatment, long term CsA treatment, like mediastinal irradiation, impairs the normal thymic recovery and is thought to be responsible for the development of autoimmune diseases. In the present study we evaluated the role played by the IDCs and Mphi in the normal recovery of the thymic histology at light and ultrastructural level. Besides CsA administration, we also used liposome-encapsulated dichloro-methylene-diphosphonate (lip-CL2MDP), that induces a total depletion of the Mphi resistant to CsA. After a short (21 days) course of CsA and lip-CL2MDP administration, we did not observe the normal recovery of the thymic parenchyma but only cortical zones consisting of lymphoblasts, epithelial cells and Mphi. The CsA/lip-CL2MDP treatment determining the loss of IDCs and Mphi and consequently the loss of the normal thymic histology seems to simulate in the rats, the long term CsA treatment or the mediastinal irradiation. The results obtained suggest that the loss of IDCs and the depletion of Mphi interfere with the normal thymic recovery. The delay in the recovery of I DCs could be a consequence of the absence of macrophages. These findings would indicate that the IDCs, determining the negative selection of T-lymphocytes, are the main cells responsible for the thymic microenvironment
Induction of endothelin in rat kidney after cyclosporine A treatment
No full textIn the present study, we investigated the variation of endothelin (ET) levels in various organs (kidney, liver, spleen and heart) of rats after 7 and 15 days of Cyclosporine A (CsA) treatment. Moreover, we studied whether these modifications are related to major toxic effects, known to be a complication of CsA treatment (i. e. nephrotoxicity). The morphology of liver, spleen and heart in rats treated with CsA for 7 and 15 days was similar to that in control rats. The amounts of ET protein as determined by Western blot analysis were very low in all organs. However, we found lesions in kidneys of rats treated with CsA for 15 days but not in kidneys of rats treated for 7 days. Immunohisto-chemical analysis using an ET polyclonal antibody revealed that proximal tubules of animals treated for 15 days were strongly ET positive whereas distal tubules and glomerula showed only weak positivity as those in control rats. Western blot analysis revealed an increase in ET protein in treated rats. On the basis of these data, we conclude that CsA induced evident nephrotoxicity already after 15 days of treatment and that toxic effects of CsA were related to the amounts of ET found. An explanation for these findings is that ET, produced by epithelial cells, is filtered through the glomerular tuft and resorbed by tubular epithelial cells. Since variation in levels of ET was visible only in proximal tubules, we conclude that CsA treatment during a brief period produced side effects that can be considered as acute toxicity. Our finding may help to understand the mechanism of CsA toxicity and may provide important clues for pharmacological strategies to reduce CsA toxicity
Cyclosporine A affects the organization of cytoskeletal fibrillar proteins in rat thymus
No full textWe have evaluated whether cyclosporine A affects cell structure and cytoskeletal proteins of the thymus of Wistar rats. Immunohistochemical analysis showed that expression of the cytoskeletal proteins vimentin and desmin was much higher in epithelial cells, dendritic cells and lymphocytes in the thymus of treated rats than in untreated controls. Protein expression was observed as a positive condensation in a distinct area near the nucleus with a capping-like configuration. An ultrastructural study showed that the amount of cytoskeletal fibrillar structures was increased in the treated rats. The structures were assembled in a limited area of the cell with a nuclear capping-like configuration which was in agreement with the light microscopical observations. Immunoblotting analysis demonstrated that vimentin and desmin had a lower molecular weight in treated rats than in controls (57 and 53 kDa versus 55 and 51 kDa, respectively). The results clearly indicate that cyclosporine A affects the structure of the cytoskeleton suggesting that this could be the first step in its immunosuppressive effects by altering nucleus/cytoplasm signaling
Immunohistochemical study of neurons in the rat abducens nucleus that project to the flocculus
No full textThe neurons of the rat abducens nucleus that project to the flocculus of the cerebellum were studied by double labelling using the retrograde transport of horseradish peroxidase (HRP) and choline acetyltransferase (ChAT) immunohistochemistry. Double-labelled cells were present bilaterally in the dorsal and dorsomedial zones of the cranial pole of the nucleus. They represented about half of the total number of HRP-positive neurons. These findings show the existence of a bilateral projection from the abducens nucleus to the flocculus which uses acetylcholine as a neurotransmitter. This projection could be part of the system of nerve circuits through which the cerebellum modulates visual activities
Expression of Fos immunoreactivity in the rat supraspinal regions following noxious visceral stimulation
No full textWe used immunohistochemical detection of the Fos protein to study the neuronal activation in the brain of methoxyfluorane-anesthetized rats after noxious deep somatic or visceral stimulation. The anesthesia was effective in triggering gene induction in many brain regions. Nevertheless, Fos appeared de novo in several brain nuclei following noxious stimulation in anesthetized animals. This could be of clinical relevance, as it suggests that the gas anesthetic does not suppress noxious stimulus-evoked reactivity in brain neurons. Two types of visceronociceptive stimuli were used to compare the effects of a diffuse visceral inflammation (peritoneal inflammation) with those of a more restricted inflammation (urinary bladder inflammation). In the same supraspinal areas, there were very few immunostained neurons in unstimulated controls, whereas Fos-positive cells were slightly more numerous in anesthetized controls and significantly more numerous after noxious stimulation. The peritoneal inflammation induced more Fos-labeled neurons than the restricted visceral stimulation. Labeled cells were found in these cases mainly in the ventrolateral medulla, parabrachial complex, dorsal raphe nucleus, periaqueductal gray, several hypothalamic and thalamic nuclei, amygdaloid complex, and cortex. Altogether these findings indicated that somatic and visceral inputs generally activate the same neuronal groups. However, a separation between the activation of somatic and visceral pathways was found in some brain nuclei, such as the parabrachial complex, hypothalamic, and thalamic nuclei
Cyclosporine-A treatment prevents apoptosis in rat lumbar ganglion cells
No full textWe evaluated the expression of pro-apoptotic Bax and anti-apoptotic Bcl-2 in lumbar ganglion cells of rats by immunohistochemistry under normal conditions and after 7, 14 and 21 days of cyclosporine-A treatment (7 and 15 mg/kg/daily). In normal rats, Bax was weakly expressed in all types of neurons, whereas satellite cells showed moderate immunostaining. Bcl-2 expression was weak in type A neurons and weak or moderate in type B and C neurons and also into satellite cells. In cyclosporine-A-treated rats, we found changes in Bax staining of neurons: type A neurons and type B neurons were weakly stained, whereas type C neurons were moderately stained. Bax expression in satellite cells was moderate after 7 days of treatment and increased strongly after 14 and 21 days of treatment. Bcl-2 expression increased significantly in neurons after 14 and even more after 21 days of treatment with 7 mg/kg cyclosporine-A, mainly in type B and C neurons. With 15 mg/kg cyclosporine-A, Bcl-2 increased moderately in type A and B neurons and strongly in type C neurons only after 7 days. After 14 and 21 days, Bcl-2 expression was moderate in type A neurons whereas it was strong or even very strong in type B and C neurons. Satellite cells showed a moderate increase in Bcl-2 after 7 and 14 days of treatment whereas after 21 days, expression was strong. We conclude that (1) in normal conditions, Bax and Bcl-2 were differently expressed in neurons and satellite cells; (2) cyclosporine-A treatment rapidly enhanced Bax expression in satellite cells only, whereas Bcl-2 expression increased moderately in type A neurons and was strongly expressed in type B and C neurons; (3) cyclosporine-A has a protective role in neurons but not in satellite cells; and (4) the neuroprotective role of cyclosporine-A is dose dependent. Furthermore, the strong expression of Bax in satellite cells can explain the temporary nature of the neurotoxic effect commonly observed after cyclosporine-A administration
Distribution of heat shock proteins in kidneys of rats after immunosuppressive treatment with cyclosporine A
No full textCyclosporine A (CsA), a fungal undecapeptide, is the most common immunosuppressive drug used in organ transplantation and auto-immune diseases. However, it has severe side effects mainly on renal structures and functions. Therefore, nephrotoxicity is the major limiting side effect. Heat shock proteins (HSPs) are molecular chaperones, that are induced or expressed at high levels in mammalian cells due to a variety of adverse effects. HSPs have beneficial roles in protein processing and protection against cell injury. In the present study, we examined immunohistochemically levels of expression and localization patterns of various HSPs in rat kidneys after administration of a therapeutic CsA dose during 30 days. After CsA treatment, both constitutive HSP 25 and alpha B-crystallin immunoreactivity became stronger in glomeruli, proximal tubules and collecting ducts. Nuclear translocation of these proteins was detected in renal tubules. HSP 47 was detected in the interstitial space between tubules, vascular smooth muscle and medullary rays. Finally, HSP 72 was induced in the cytoplasm of epithelial cells of proximal and distal tubules, and in the cytoplasm of epithelial cells of Henle limbs and collecting ducts. These data demonstrate that CsA clearly induces increased immunoreactivity of HSPs in defined structures of rat kidneys. These findings suggest that these proteins are functionally involved in the defence against renal cellular damage caused by prolonged drug treatment in rat
Small heat shock proteins expression in rat kidneys treated with cyclosporine A alone and combined with melatonin
No full textSmall heat shock proteins (sHSPs) are cytoskeletal chaperones constitutively expressed in the normal kidney but enhanced with beneficial roles during adverse stimuli. Cyclosporine A is an immunosuppressive drug with major adverse side effect such as severe nephrotoxicity. Among possible mechanisms of cyclosporine A-induced renal damage, oxidative stress and cytoskeletal damage have been suggested. Melatonin has been successfully used as antioxidant against many renal diseases. This in vivo study was performed to shed light on the protective effect of melatonin against cyclosporine A-induced renal alterations. We treated rats with cyclosporine A alone, or combined with melatonin, and with melatonin alone (as controls) for 40 days and analysed the renal abundance and distribution of two sHSPs, HSP25 and alpha B-crystallin. These data were correlated with the histopathological effects of the treatments. Cyclosporine A induced insoluble isoforms that moved to soluble fractions after melatonin coadministration as in controls. After cyclosporine A treatment, an intense signal for sHSPs was found within the glomeruli, nucleus and cytoplasm of cortical tubules, collecting ducts and vascular wall. After melatonin supply, the staining was faint, limited to the cytoplasm of cortical tubules, similar to controls. Both fibrosis and tubular alterations significantly decreased after melatonin coadministration. In conclusion, HSP25 and alpha B-crystallin are overexpressed in the rat kidney treated with cyclosporine A but are similar to controls after combined melatonin. This could be a consequence of the cytoprotective effect of melatonin in this nephrotoxic model so that a beneficial sHSPs response is unnecessary
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