Gliosis induction on locus coeruleus in a living liver donor experimental model: A brief review.

Living Donor Liver Transplantation (LDLT) is a promising approach to treating end-stage liver diseases, however, some post-operatory complications such as pneumonia, bacteremia, urinary tract infections, and hepatic dysfunction have been reported. In murine models using partial hepatectomy (PHx), a model that emulates LDLT, it has been determined that the synthesis of hepatic cell proliferation factors that are associated with noradrenaline synthesis are produced in locus coeruleus (LC). In addition, studies have shown that PHx decreases GABA and 5-HT2A receptors, promotes loss of dendritic spines, and favors microgliosis in rat hippocampus. The GABA and serotonin-altered circuits suggest that catecholaminergic neurons such as dopamine and noradrenaline neurons, which are highly susceptible to cellular stress, can also be damaged. To understand post-transplant affections and to perform well-controlled studies it is necessary to know the potential causes that explain as a liver surgical procedure can produce brain damage. In this paper, we review several cellular processes that could induce gliosis in LC after rat PHx.

BrdU does not induce hepatocellular damage in experimental Wistar rats.

Bromodeoxyuridine (BrdU) is used in studies related to cell proliferation and neurogenesis. The multiple intraperitoneal injections of this molecule could favor liver function profile changes. In this study, we evaluate the systemic and hepatocellular impact of BrdU in male adult Wistar rats in 30 %-partial hepatectomy (PHx) model. The rats received BrdU 50 mg/Kg by intraperitoneal injection at 0.5, 1, 2, 3, 6, 9 and 16 days after 30 %-PH. The rats were distributed into four groups as follows, control, sham, PHx/BrdU(-) and PHx/BrdU(+). On day 16, we evaluated hepatocellular nuclei and analyzed histopathological features by haematoxylin-eosin stain and apoptotic profile was qualified by caspase-3 presence. The systemic effect was evaluated by liver markers such as alanine transferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (AP), bilirubin, total proteins and serum albumin content. The statistical analysis consisted of a student t-test and one-way ANOVA. BrdU did not induce apoptosis or hepatocellular damage in male rats. Multiple administrations of BrdU in male rats did not induce significant decrease body weight, but increased serum ALT and LDH levels were found. Our results show that the BrdU does not produce hepatocellular damage.

Caspase-3-related apoptosis prevents pathological regeneration in a living liver donor rat model.

PURPOSE: The main goal of this study was to determine the relationship of cleaved-caspase-3 (C3)-related apoptosis and hepatic proliferation, during the liver repopulation in a living liver donor rat model. MATERIAL/METHODS: Thirty-three animals were randomized into eleven groups and evaluated on postoperative from 3 â€‹h until 384 â€‹h after 30%-partial hepatectomy (30%-PHx). Liver sections (5 â€‹µm) were processed by hematoxylin-eosin, and immunostaining for C3, accompanied by hepatic function test. C3 content and the hepatic lobule enlargement were analyzed by optical density, followed by cell counting. RESULTS: Transient variations of alanine transferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were found. Significant increase in the C3 levels, and cell nuclei number, were detected at 12 â€‹h and 48 â€‹h after 30%-PHx, evidencing a correlation of p â€‹= â€‹-0.3679. CONCLUSION: In the 30%-PHx rat model, C3-related apoptosis prevents proliferative pathological conditions during the hepatic lobule re-modeling.

Optimized technique to extract and fix Olive ridley turtle hatchling retina for histological study.

The efficient extraction and fixation of a tissue allows in preserving the cytoarchitecture, chemical composition and tissue organization, which is key in physiological and histopathological studies. The main goal of this study was to establish a microsurgery technique to obtain ocular tissue and provide an optimized immersion fixation protocol based on the 10 % formalin-intraocular injection on Olive ridley sea turtle hatchlings (Lepidochelys olivacea). To evaluate this optimized technique, a histological comparison between traditional immersion and intraocular/immersion protocols was done. The eyeball were processed into five protocols: Frozen eyes (Group 1), frozen eyes immersed in 10 % formalin (Group 2), fresh eyes immersed in 10 % formalin (Group 3), fresh eyes intraocularly injected with 0.1 M phosphate buffer solution (PBS) and then immersed in 10 % formalin (Group 4), and fresh eyes fixed by 10 % formalin-intraocular followed by 10 % formalin-immersion (Group 5). In comparison with all groups evaluated, the intraocular/immersion fixation protocol lead the conservation of eyeball shape, cell integrity and maintenance of the organization of the retina layers of sea turtle hatchlings. If this method will be the key in studying sea turtle, we suppose that this procedure, with minimal adjustments, could be useful in animals with similar eye anatomy.

Chronic consumption of cassava juice induces cellular stress in rat substantia nigra.

OBJECTIVES: Cassava (Manihot esculenta Crantz) contains cyanogenic glycosides (linamarin and lotaustralin) that have been associated with neurological disorders in humans and rats. In basal ganglia, the dopaminergic neurons of substantia nigra pars compacta (SNpc) show high cytotoxic susceptibility; therefore, the chronic consumption of cassava (CCC) could induce neurodegeneration in SNpc. In this study we examine the impact of CCC on the integrity of the nigrostriatal system, including apoptosis and microgliosis. MATERIALS AND METHODS: Male Wistar rats were administered cassava juice daily (3.57 g/kg and 28.56 g/kg, per os) or linamarin (0.15 mg/ml, IP), and its effects were evaluated in rota-rod and swim tests at days 7, 14, 21, 28, and 35 of administration. In SNpc, oxidative/nitrosative stress was determined by malondialdehyde/4-hydroxyalkenals (MDA-4-HAD) and nitrite contents. Tyrosine hydroxylase immunoreactivity (TH-IR) was evaluated in SNpc, neostriatum (NE), and nucleus accumbens (NA). Apoptosis and microgliosis were determined by active-caspase-3 (C3) and CD11b/c (OX42) expression in the medial region of SNpc. RESULTS: Chronic administration of cassava juice, or linamarin, increased motor impairment. The rats that received 28.56 g/kg cassava showed increased MDA-4-HAD content in SNpc and nitrite levels in NE with respect to controls. Significant loss of TH-IR in SNpc, NE, and NA was not found. The 28.56 g/kg cassava administration produced dopaminergic atrophy and microgliosis, whereas linamarin induced hypertrophy and C3-related apoptosis in SNpc. CONCLUSION: CCC induces cellular stress on dopaminergic neurons, which could contribute to motor impairment in the rat.

Lipopolysaccharide-based endotoxemia produce toxicity in peripheral organs and microglia migration in a dose-dependent manner in rat substantia nigra.

The peripheral inflammatory stimulus could induce cell damage in peripheral organs and activate microglial cells in the brain. One such stimulus was given to adult male Wistar rats by injecting different concentrations of lipopolysaccharide (LPS; 50, 300, 500 g/kg and 5 mg/kg i.p.). To verify the systemic effect of the LPS administration, the serum content of C-reactive protein (CRP), the variation of body weight and cellular changes in the spleen, liver and kidney were determined. Motor impairment was evaluated by rotarod and open field tests. Microglia activation and dopaminergic degeneration was confirmed by immunolabelling for CD11b/c (microglia) and tyrosine hydroxylase (TH), respectively. The cell counting was performed in substantia nigra pars compacta (SNpc), microglial activation was explored in SNpc, substantia nigra pars reticulata (SNpr), substantia nigra pars compacta dorsal (SNcd) and the ventral tegmental area (VTA). For the statistical analysis, one-way ANOVA followed by Tukey post hoc test (p ≤ 0.05) was used. On day 7 post intraperitoneal administration of LPS, cellular atrophy was detected in the liver, kidney and spleen at 5 mg/kg, without significant changes in CRP levels. Body weight loss and motor impairment was present only on day 1 post LPS administration. The dosage of 500 g/kg and 5 mg/kg of LPS caused the loss of dopaminergic neurons (40%) in SNpc and microglia migration in a dose-dependent manner in SNcd, SNpc and SNpr. LPS-induced endotoxemia favours damage to the peripheral organs and microglial migration in a dose-dependent manner in rat substantia nigra.

Cytotoxicity induced by carbon nanotubes in experimental malignant glioma.

Despite multiple advances in the diagnosis of brain tumors, there is no effective treatment for glioblastoma. Multiwalled carbon nanotubes (MWCNTs), which were previously used as a diagnostic and drug delivery tool, have now been explored as a possible therapy against neoplasms. However, although the toxicity profile of nanotubes is dependent on the physicochemical characteristics of specific particles, there are no studies exploring how the effectivity of the carbon nanotubes (CNTs) is affected by different methods of production. In this study, we characterize the structure and biocompatibility of four different types of MWCNTs in rat astrocytes and in RG2 glioma cells as well as the induction of cell lysis and possible additive effect of the combination of MWCNTs with temozolomide. We used undoped MWCNTs (labeled simply as MWCNTs) and nitrogen-doped MWCNTs (labeled as N-MWCNTs). The average diameter of both pristine MWCNTs and pristine N-MWCNTs was ~22 and ~35 nm, respectively. In vitro and in vivo results suggested that these CNTs can be used as adjuvant therapy along with the standard treatment to increase the survival of rats implanted with malignant glioma.

Early expression of the receptor for advanced glycation end products in a toxic model produced by 6-hydroxydopamine in the rat striatum.

The receptor for advanced glycation end products (RAGE) is commonly involved in different neurodegenerative and inflammatory disorders. The cellular signaling associated to RAGE activation may occur upon binding to different ligands. In this study we investigated whether the toxic model produced by 6-hydroxydopamine (6-OHDA) in rats comprises early noxious responses related to RAGE-mediated signaling cascades. In order to explore a possible interaction between 6-OHDA and RAGE, affinity parameters of RAGE with 6-OHDA were estimated by different means. The possible binding sites of 6-OHDA with the VC1 homodimer for both rat and human RAGE were also modeled. Our results show that the striatal infusion of 6-OHDA recruits RAGE upregulation, as evidenced by an early expression of the receptor. 6-OHDA was also found to bind the VC1 homodimer, although its affinity was moderate when compared to other ligands. This work contributes to the understanding of the role of RAGE activation for 6-OHDA-induced neurotoxicity.

Immunohistochemical Study of Nrf2-Antioxidant Response Element as Indicator of Oxidative Stress Induced by Cadmium in Developing Rats.

In developing animals, Cadmium (Cd) induces toxicity to many organs including brain. Reactive oxygen species (ROS) are often implicated in Cd-inducedtoxicity and it has been clearly demonstrated that oxidative stress interferes with the expression of genes as well as transcriptional factors such as Nrf2-dependent Antioxidant Response Element (Nrf2-ARE). Cd-generated oxidative stress and elevated Nrf2 activity have been reported in vitro and in situ cells. In this study we evaluated the morphological changes and the expression pattern of Nrf2 and correlated them with the Cd concentrations in different ages of developing rats in heart, lung, kidney, liver, and brain. The Cd content in different organs of rats treated with the metal was increased in all ages assayed. Comparatively, lower Cd brain levels were found in rats intoxicated at the age of 12 days, then pups treated at 5, 10, or 15 days old, at the same metal dose. No evident changes, as a consequence of cadmium exposure, were evident in the morphological analysis in any of the ages assayed. However, Nrf2-ARE immunoreactivity was observed in 15-day-old rats exposed to Cd. Our results support that fully developed blood-brain barrier is an important protector against Cd entrance to brain and that Nrf2 increased expression is a part of protective mechanism against cadmium-induced toxicity.

Modeling the interaction between quinolinate and the receptor for advanced glycation end products (RAGE): relevance for early neuropathological processes.

The receptor for advanced glycation end products (RAGE) is a pattern-recognition receptor involved in neurodegenerative and inflammatory disorders. RAGE induces cellular signaling upon binding to a variety of ligands. Evidence suggests that RAGE up-regulation is involved in quinolinate (QUIN)-induced toxicity. We investigated the QUIN-induced toxic events associated with early noxious responses, which might be linked to signaling cascades leading to cell death. The extent of early cellular damage caused by this receptor in the rat striatum was characterized by image processing methods. To document the direct interaction between QUIN and RAGE, we determined the binding constant (Kb) of RAGE (VC1 domain) with QUIN through a fluorescence assay. We modeled possible binding sites of QUIN to the VC1 domain for both rat and human RAGE. QUIN was found to bind at multiple sites to the VC1 dimer, each leading to particular mechanistic scenarios for the signaling evoked by QUIN binding, some of which directly alter RAGE oligomerization. This work contributes to the understanding of the phenomenon of RAGE-QUIN recognition, leading to the modulation of RAGE function.

Safety of the intravenous administration of neurotensin-polyplex nanoparticles in BALB/c mice.

Neurotensin (NTS)-polyplex is a gene nanocarrier that has potential nanomedicine-based applications for the treatment of Parkinson's disease and cancers of cells expressing NTS receptor type 1. We assessed the acute inflammatory response to NTS-polyplex carrying a reporter gene in BALB/c mice. The intravenous injection of NTS-polyplex caused the specific expression of the reporter gene in gastrointestinal cells. Six hours after an intravenous injection of propidium iodide labeled-NTS-polyplex, fluorescent spots were located in the cells of the organs with a mononuclear phagocyte system, suggesting NTS-polyplex clearance. In contrast to lipopolysaccharide and carbon tetrachloride, NTS-polyplex did not increase the serum levels of tumor necrosis factor alpha, interleukin (IL)-1ß, IL-6, bilirubin, aspartate transaminase, and alanine transaminase. NTS-polyplex increased the levels of serum amyloid A and alkaline phosphatase, but these levels normalized after 24 h. Compared to carrageenan, the local injection of NTS-polyplex did not produce inflammation. Our results support the safety of NTS-polyplex. FROM THE CLINICAL EDITOR: This study focuses on the safety of neurotensin (NTS)-polyplex, a gene nanocarrier that has potential in the treatment of Parkinson's disease and cancers of cells expressing NTS receptor type 1. NTS polyplex demonstrates a better safety profile compared with carrageenan, lipopolysaccharide, and carbon tetrachloride in a murine model.

Adjuvant immunotherapy of C6 glioma in rats with pertussis toxin.

PURPOSE: In spite of the recent advances in surgery and antitumor drugs, the brain tumors, like glioblastoma, have shown a poor prognosis. The aim of this study was to determine the effect of pertussis toxin (PTx) as immunomodulatory molecule on glial tumors induced by C6 glioma cells. METHODS: Given the pleiotropic effect of PTx on the immune system, we analyzed the effect of PTx on CD4+/CD25+/FoxP3+ (Treg) cells like as immunotherapeutic adjuvant. Thirty rats with a glial tumor of 1.5 cm in diameter were separated in two groups: the first group was treated with PTx and the second group was non-treated (controls). Tumoral volume was measured weekly; tumor, blood and spleen were taken for analysis of subpopulations of T cells, apoptotic index and cytokine contents, in both groups. RESULTS: We observed a significant decrease in tumor volume in the PTx group; this was associated with a decreased in the number of Treg cells, in both spleen and tumor. The percentage of apoptotic cells was increased as compared with that of controls. The production of proinflammatory cytokines was increased in mRNA for IL-6 as well as a small increase in the mRNA expression of perforin and granzime in tumors from rats treated with PTx. No changes were found in the mRNA expression of MCP-1 and MIP-1α. CONCLUSION: These results suggest that PTx could be an immunotherapeutic adjuvant in the integral therapy against glial tumors.

Molsidomine modulates the cNOS activity in an experimental model of cholinergic damage induced by 192-IgG saporin.

The aim of this work was to study the effect of molsidomine (MOLS), a nitric oxide (NO) donor, on the nitrergic system changes in an experimental model of cholinergic damage induced by 192 IgG saporin (SAP). Male rats were injured by intraseptal administration of SAP (0.22 µg), after seven days, rats were administered with MOLS (4 mg/kg, i.p.) 60 min before sacrifice. Prefrontal cortex (PC), striatum (S) and hippocampus (HC) were dissected out. Results showed significant recovery of the constitutive NOS activity (cNOS) in PC and S regions by MOLS but not in HC compared against controls. SAP reduced the cellular population in the lesion site and MOLS was able to avoid the progression of damage in this area. NO donor is able to modulate the nitrergic status in an experimental model induced by SAP.

Epithelial cell adhesion molecule expression in pituitary adenomas: an immunohistochemical study.

An important amount of data correlating the expression of epithelial cell adhesion molecule (Ep-CAM) with cellular proliferation and de-differentiation could directly contribute to carcinogenesis. The aim of this study is to evaluate prognosis relevance of Ep-CAM expression in a group of pituitary adenomas. Epithelial cell adhesion molecule, proliferating cell nuclear antigen, and microvascular density labeling indices in pituitary adenomas were determined by immunohistochemistry on tissue samples obtained from each adenoma after surgery. We evaluated 45 adenomas. Sixty-two percent were nonsecretor adenomas and 37.8% were secretor tumors. Immunohistochemistry was scored for immunoexpression of Ep-CAM (cytoplasmic, membrane, and mixed pattern). Proliferating cell nuclear antigen and vascular density (CD34) labeling indices were assessed. Statistical significance was observed between Ep-CAM cytoplasmic immunoreactions (P = .000) and higher proliferating cell nuclear antigen (P = .001) in secretor adenomas compared with nonsecretor tumors. Vascular density labeling indices did not show statistical significance. Therefore, Ep-CAM could be evaluated to distinguish secretor and nonsecretor pituitary adenomas. These suggest that the markers could predict the growth potential of individual pituitary adenomas.

Study of the telomerase hTERT fraction, PCNA and CD34 expression on pituitary adenomas. Association with clinical and demographic characteristics.

To determine the frequency of human telomerase reverse transcriptase (hTERT) catalytic fraction expression and its association with clinical and demographic characteristics of the patient, as well as with the expression of CD34 and proliferating cell nuclear antigen (PCNA) indexes on adenohypophyseal hormone tissues. A transverse study was realized with 49 cases of hypophyseal adenoma with analysis type cases and controls. The different adenohypophyseal hormones [prolactin (PRL), growth hormone (GH), follicle stimulating hormone, luteinizing hormone, thyroid gland stimulant hormone, adrenocorticotropic hormone (ACTH)], the catalytic fraction of the telomerase hTERT, the PCNA index and the CD34 density were determined by means of immunohistochemical techniques. The clinical, demographic and histopathological characteristics of the patients with and without hTERT expression were compared by means of Pearson's Chi-squared, Fisher's exact test and Mann-Whitney's U. Twenty-eight point six percent of the adenomas had positive expression for hTERT. The variables significantly correlated with hTERT's expression were younger age of presentation, diagnostic of adenoma producer, higher PCNA index, higher CD34 density, increased GH on serum and the expression on PRL tissue, GH and ACTH. Tobacco history had a negative association with hTERT's expression. The telomerase could be a marker of cellular proliferation associated with angiogenesis and hormonal activity. Evaluation of these variables could provide information about their biological behavior.

Late development of intraventricular papillary pituitary carcinoma after irradiation of prolactinoma.

BACKGROUND: Intracranial dissemination of pituitary adenomas is a rare event that does not equate malignancy. Most of the cases have been reported as metastases from pituitary carcinoma. A case of papillary pituitary carcinoma developed 12 years after radiotherapy for prolactin-secreting hormone pituitary adenoma is presented. CASE DESCRIPTION: A 37-year-old woman was admitted for the second time with neurologic disturbance and hypertension. A gadolinium-enhanced magnetic resonance scan of the brain demonstrated a 50-mm enhanced mass (absent on previous studies) on the lateral ventricle, involving the left temporal lobe. The patient underwent a craniotomy and biopsy of the lesion that was consistent with pituitary carcinoma; it was immunoreactive to follicle-stimulating hormone, adrenocorticotropic hormone, pituitary tumor-transforming gene, and epithelial cell adhesion molecule. Transmission electron microscopy analysis confirmed the secretory pituitary tumor diagnosis. CONCLUSIONS: The tumor was considered a primary pituitary papillary carcinoma. The clinical course indicated that this tumor was the seedling of a pituitary tumor, although it could be interpreted as metastases from a pituitary carcinoma.

S-Allylcysteine, a garlic-derived antioxidant, ameliorates quinolinic acid-induced neurotoxicity and oxidative damage in rats.

Excitotoxicity elicited by overactivation of N-methyl-D-aspartate receptors is a well-known characteristic of quinolinic acid-induced neurotoxicity. However, since many experimental evidences suggest that the actions of quinolinic acid also involve reactive oxygen species formation and oxidative stress as major features of its pattern of toxicity, the use of antioxidants as experimental tools against the deleterious effects evoked by this neurotoxin becomes more relevant. In this work, we investigated the effect of a garlic-derived compound and well-characterized free radical scavenger, S-allylcysteine, on quinolinic acid-induced striatal neurotoxicity and oxidative damage. For this purpose, rats were administered S-allylcysteine (150, 300 or 450 mg/kg, i.p.) 30 min before a single striatal infusion of 1 microl of quinolinic acid (240 nmol). The lower dose (150 mg/kg) of S-allylcysteine resulted effective to prevent only the quinolinate-induced lipid peroxidation (P < 0.05), whereas the systemic administration of 300 mg/kg of this compound to rats decreased effectively the quinolinic acid-induced oxidative injury measured as striatal reactive oxygen species formation (P < 0.01) and lipid peroxidation (P < 0.05). S-Allylcysteine (300 mg/kg) also prevented the striatal decrease of copper/zinc-superoxide dismutase activity (P < 0.05) produced by quinolinate. In addition, S-allylcysteine, at the same dose tested, was able to reduce the quinolinic acid-induced neurotoxicity evaluated as circling behavior (P < 0.01) and striatal morphologic alterations. In summary, S-allylcysteine ameliorates the in vivo quinolinate striatal toxicity by a mechanism related to its ability to: (a) scavenge free radicals; (b) decrease oxidative stress; and (c) preserve the striatal activity of Cu,Zn-superoxide dismutase (Cu,Zn-SOD). This antioxidant effect seems to be responsible for the preservation of the morphological and functional integrity of the striatum.