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1.
Schizophr Res ; 268: 252-260, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38151432

RESUMO

There is no established treatment for patients with clozapine-resistant schizophrenia (CRS). Clozapine augmentation strategies with antipsychotics or others substances are effective in comparison with placebo while and Electroconvulsive therapy (ECT) showed to be effective in comparison with treatment as usual (TAU) but not with placebo (sham-ECT). In the present double- blind randomized controlled trial, we compared 40 outpatients who received 20 sessions of ECT (n = 21) or sham-ECT (n = 19) (age = 37.40 ± 9.62, males = 77.5 %, illness duration = 14.95 ± 8.32 years, mean total Positive and Negative Syndrome Scale (PANSS) = 101.10 ± 24.91) who fulfilled well-defined CRS criteria including baseline clozapine plasma levels ≥350 ng/mL. The primary outcome was the ≥50 % PANSS Total Score reduction; secondary outcomes were the scores of the PANSS subscales, PANSS five-factor dimensions, PANSS-6 and the Calgary Depression Rating Scale (CDRS). Treatment response was analyzed by percentage reduction, Linear Mixed Models and effect sizes. At baseline both groups showed no differences except for years of school education (included as a covariate). At endpoint, only 1/19 of the completers (5.26 %) in the ECT group and 0/17 in the sham-ECT group showed a ≥50 % total PANSS score reduction. Both groups showed no significant differences of the total PANSS score (F = 0.12; p = 0.73), Positive (F = 0.27, p = 0.61), Negative (F = 0.25, p = 0.62), and General Psychopathology scores (F = 0.01, p = 0.94) as well for all PANSS five factors, the PANSS-6 and CDRS. Thus, the present study found no evidence that ECT is better than Sham-ECT in patients with CRS. Future sham-ECT controlled studies with larger sample sizes are warranted to test the efficacy of ECT for patients with CRS.


Assuntos
Antipsicóticos , Clozapina , Eletroconvulsoterapia , Esquizofrenia Resistente ao Tratamento , Humanos , Masculino , Feminino , Eletroconvulsoterapia/efeitos adversos , Adulto , Clozapina/uso terapêutico , Clozapina/efeitos adversos , Método Duplo-Cego , Antipsicóticos/uso terapêutico , Pessoa de Meia-Idade , Esquizofrenia Resistente ao Tratamento/terapia , Esquizofrenia Resistente ao Tratamento/tratamento farmacológico , Escalas de Graduação Psiquiátrica , Resultado do Tratamento , Esquizofrenia/terapia , Esquizofrenia/tratamento farmacológico , Avaliação de Resultados em Cuidados de Saúde
2.
Braz J Biol ; 82: e267996, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36541982

RESUMO

Estuaries are constantly subject to continuous environmental impacts of human activities, such as fisheries, port or industry, and domestic sewage, with fish being one of the most affected aquatic animals, reflecting the impacts directly on their bodies. Thus, the aim of this study was to carry out the biomonitoring of an estuary located on the Amazonian Equatorial Coast through analysis of PAHs (Polycyclic Aromatic Hydrocarbons) in the water, in addition to trace metals, histopathological alterations and analysis of erythrocyte micronuclei in Sciades herzbergii. S. herzbergii was used as a model species, due to its estuarine-resident behavior. Gonad and gill samples were subjected to histopathological evaluations. The quantification of trace metals was performed in samples of skeletal muscles of the animals collected, where concentrations of Lead (Pb), Copper (Cu), Zinc (Zn), Cadmium (Cd), Magnesium (Mg), Iron (Fe) and Aluminum (Al) were found. Except for Cadmium (Cd), all the concentrations were above the recommended limits. The PAHs analysis revealed the presence of Naphthalene and Acenaphthene in the water samples Histopathological and genotoxic analyses revealed of lesions in 100% of the study specimens. Thus, the histological and genotoxic alterations found in 100% of S. herzbergii specimens captured in São José Bay-MA are potentially associated with PAH concentrations present in the water. These results are potentially associated with the presence of PAH and trace metals, both in water and in animal tissues, inferring a general scenario of environmental contamination which directly implies a risk to the health and survival of the local biota. This study shows the relevance of continuous biomonitoring of estuarine ecosystems, in order to guide authorities regarding sewage management and ensure the evolutionary development of estuarine species, especially fishes of importance in the local cuisine, therefore related to human food security.


Assuntos
Peixes-Gato , Poluentes Ambientais , Metais Pesados , Poluentes Químicos da Água , Animais , Humanos , Cádmio , Poluentes Ambientais/análise , Ecossistema , Esgotos , Monitoramento Ambiental/métodos , Estuários , Água , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/análise , Metais Pesados/toxicidade , Metais Pesados/análise
3.
Braz J Biol ; 82: e262017, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36197367

RESUMO

The aim of the current study is to evaluate gene expression patterns of LH (lhr) and estrogen (er) receptors and plasma steroid levels during testicular development in Genyatremus luteus. Males were histologically classified as immature (n=7), maturing (n=7) and mature (n=7), based on the cellular structure of their testes. Plasma 11-KT concentration recorded peak at the final maturation stage. The highest plasma 17α-OHP concentrations were observed at the immature stage; they decreased at the maturation and mature stages. On the other hand, 17ß-estradiol (E2) recorded higher concentrations at the maturation stage. Er expression has significantly increased along the maturational development of animals' testes. The mRNA observed for the LH receptor has decreased from immature to maturing stage; it presented expression peak at the mature stage. There was high association between receptor gene expression and plasma steroid levels, mainly E2. The current study was the first to feature different reproductive maturation stages in male G. luteus specimens, based on cellular, endocrine and molecular aspects. In addition, it has shown that the gene expression profile for er and lhr receptors, as well as plasma 11-KT and E2 concentrations, are directly linked to testicular maturation, although they are not necessarily associated with the gonadosomatic index.


Assuntos
Perciformes , Receptores do LH , Animais , Estradiol , Estrogênios , Peixes , Expressão Gênica , Hormônios Esteroides Gonadais , Masculino , Perciformes/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores do LH/genética
4.
Hum Exp Toxicol ; 39(3): 338-354, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31726875

RESUMO

Fridericia platyphylla (Cham.) L.G. Lohmann (FP) has cytotoxic, anti-inflammatory, and analgesic properties. We aimed to characterize the cytotoxic and antiproliferative effects of FP extract on normal (GAS) and tumor-derived (ACP02 and HepG2) cell lines. The effective concentrations (EC50s) by tetrazolium bromide assay (MTT) were 56.16, 43.68, and 42.57 µg mL-1 and 69.38, 41.73, and 52.39 µg mL-1 by neutral red assay for GAS, ACP02, and HepG2 cells, respectively. The extract decreased nuclear division indices, which was not reflected in cell proliferation curves. Flow cytometric analyses showed that even 30 µg mL-1 extract (shown to be noncytotoxic by MTT assay) increased the sub-G1 population, indicating cell death due to apoptosis and necrosis. A cytokinesis-block micronucleus cytome assay showed that 30 µg mL-1 of the extract increased the frequency of nuclear buds in tumor cells. Real-time quantitative polymerase chain reaction showed CCND1 upregulation in doxorubicin-treated GAS cells and BCL-XL, BIRC5, and MET downregulation in 5 or 30 µg mL-1 in FP extract-treated ACP02 cells. In conclusion, FP extract modulated apoptosis- and cell cycle-related genes and presented selective cytotoxicity toward tumor cells that deserves further investigation by testing other cell types. Our results demonstrated that even medicinal plants exert adverse effects depending on the extract concentrations used and tissues investigated.


Assuntos
Bignoniaceae/química , Extratos Vegetais/farmacologia , Raízes de Plantas/química , Neoplasias Gástricas/tratamento farmacológico , Survivina/metabolismo , Proteína bcl-X/metabolismo , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Necrose , Extratos Vegetais/química , Proteínas Proto-Oncogênicas c-met/genética , Proteínas Proto-Oncogênicas c-met/metabolismo , Espécies Reativas de Oxigênio , Survivina/genética , Proteína bcl-X/genética
5.
Int J Biol Macromol ; 127: 425-432, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30654040

RESUMO

Hepatocellular carcinoma incidence rates have increased worldwide, which encouraged the development of new chemotherapeutic drugs. l-Amino acid oxidases from snake venoms are cytotoxic towards human tumor cells in in vitro monoculture systems, which do not simulate the tumor microenvironment. We examined the antitumor potential of BjussuLAAO-II, an l-amino acid oxidase from Bothrops jararacussu venom, in hepatocarcinoma cells (HepG2) in monoculture and co-culture with human umbilical vein endothelial cells (HUVEC) in vitro. All the concentrations tested (0.25-5.00 µg/mL) were cytotoxic (MTT and clonogenic survival assays) towards HepG2 and HUVEC cells in monoculture, and increased oxidative stress by 2',7'-dichlorofluorescin diacetate fluorescence assay. Only 1.00 and 5.00 µg/mL exerted these effects in HepG2 cells co-cultured with HUVEC cells, and were genotoxic (comet assay) to HUVEC cells in monoculture. BjussuLAAO-II at 5.00 µg/mL induced DNA, but not chromosomal damage (micronucleus assay) in HepG2 cells in mono- and co-culture. The cytotoxicity and genotoxicity was more pronounced in monoculture, indicating that the tumor microenvironment influences the cellular response. BjussuLAAO-II caused cell death and DNA damage in HepG2 cells in vitro by inducing oxidative stress. Therefore, BjussuLAAO-II is a promising molecule for the development of new antitumor drugs.


Assuntos
Bothrops , Venenos de Crotalídeos , Citotoxinas , Dano ao DNA , Células Endoteliais da Veia Umbilical Humana/metabolismo , L-Aminoácido Oxidase , Estresse Oxidativo/efeitos dos fármacos , Animais , Técnicas de Cocultura , Venenos de Crotalídeos/química , Venenos de Crotalídeos/farmacologia , Citotoxinas/química , Citotoxinas/farmacologia , Células Hep G2 , Humanos , L-Aminoácido Oxidase/química , L-Aminoácido Oxidase/farmacologia
6.
Int J Biol Macromol ; 109: 212-219, 2018 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-29222016

RESUMO

Colorectal carcinoma is one of the most common cancers in adults. As chemotherapy, the first-choice treatment for colorectal carcinoma, is often infeasible due to acquired tumor resistance and several adverse effects, it is important to discover and explore new molecules with better therapeutic action. Snake venom toxins have shown promising results with high cytotoxicity against tumor cells, but their mechanisms of action remain unclear. Here we examined how BjussuLAAO-II, an L-amino acid oxidase isolated from Bothrops jararacussu snake venom, exerts cytotoxicity towards colorectal adenocarcinoma human cells (Caco-2) and human umbilical vein endothelial cell line (HUVEC). A 24-h treatment with BjussuLAAO-II at 0.25 - 5.00 µg/mL diminished cell viability by decreasing (i) mitochondrial activity, assessed by reduction of 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide and resazurin; (ii) the activity of acid phosphatases; and (iii) lysosomal function, assessed by neutral red uptake. BjussuLAAO-II also increased intracellular levels of reactive oxygen species and DNA damage, as assessed by fluorescence and the comet assay, respectively. BjussuLAAO-II altered the expression of cell proliferation-related genes, as determined by RT-qPCR: it elevated the expression of the inflammatory cytokine genes TNF and IL6, and lowered the expression of the apoptotic-related genes BAX, BCL2, and RELA. Therefore, BjussuLAAO-II induces Caco-2 cells death by acting on multiple intracellular targets, providing important data for further studies to assess whether these effects are seen in both tumor and normal cells, with the aim of selecting this drug for possible therapeutic purposes in the future.


Assuntos
Proteínas Reguladoras de Apoptose/genética , Citocinas/genética , Dano ao DNA/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Mediadores da Inflamação , Estresse Oxidativo/efeitos dos fármacos , Venenos de Serpentes/química , Venenos de Serpentes/farmacologia , Apoptose/genética , Linhagem Celular Tumoral , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Humanos , Interleucina-6/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Espécies Reativas de Oxigênio/metabolismo , Fator de Transcrição RelA/genética , Fatores de Necrose Tumoral/genética , Proteína X Associada a bcl-2/genética
7.
Toxicology ; 376: 66-74, 2017 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-27181935

RESUMO

The lasiodiplodan (LS) is a ß-(1→6)-d-glucan produced by the fungus Lasiodiplodia theobromae and some of the biological activities of LS were reported as hypoglycemic, anticoagulant, anti-proliferative and anticancer action; however, its effects on DNA instability and modulation of gene expression are still unclear. Aims of study were investigate the genotoxic effects of lasiodiplodan, and its protective activity against DNA damage induced by doxorubicin (DXR) and its impact on the expression of genes associated with DNA damage and inflammatory response pathways. Therefore, Wistar rats were treated (15 days) orally with LS (5.0; 10 and 20mg/kg bw) alone and in combination with DXR (15mg/kg bw; administrated intraperitoneally on 14th day) as well as their respective controls: distilled water and DXR. Monitoring of DNA damage was assessed by comet and micronucleus (MN) assays and gene expression was evaluated by PCR-Arrays. Treatments with LS alone did not induce disturbances on DNA; when LS was given in combination with DXR, comet and MN formations were reduced to those found in the respective controls. Moreover, LS was able to reduce the disturbances on gene expressions induced by DXR treatment, since the animals that receive LS associated with DXR showed no alteration in the expression of genes related to DNA damage response. Also, DXR induced several up- and down-regulation of several genes associated to inflammatory process, while the animals that received LS+DXR had their gene expression patterns similar to those found in the control group. In conclusion, our results showed that LS did not induce disturbances on DNA stability and significantly reduce the DNA damage and inflammation caused by DXR exposure. In addition, we give further information concerning the molecular mechanisms associated to LS protective effects which seems to be a promising nutraceutical with chemopreventive potential.


Assuntos
Análise Citogenética , Dano ao DNA/efeitos dos fármacos , Doxorrubicina/toxicidade , Polissacarídeos Fúngicos/farmacologia , Mediadores da Inflamação/antagonistas & inibidores , Zearalenona/análogos & derivados , Animais , Antibióticos Antineoplásicos/toxicidade , Análise Citogenética/métodos , Dano ao DNA/fisiologia , Relação Dose-Resposta a Droga , Expressão Gênica , Mediadores da Inflamação/metabolismo , Masculino , Substâncias Protetoras/farmacologia , Ratos , Ratos Wistar , Zearalenona/farmacologia
8.
J Anim Sci ; 93(6): 2796-805, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26115267

RESUMO

Two experiments were designed to evaluate the impact of puberty status and the administration of melengestrol acetate (MGA) before onset of the breeding period on ovulatory responses (Exp. 1) and conception rate after AI performed on estrus detection during 10 d and the pregnancy rate through 80 d of breeding period (Exp. 2) of pasture-grazed beef heifers. In Exp. 1, heifers (15 pubertal and 15 prepubertal) received 0.5 mg per heifer/d -1 of MGA over 14 d. No differences in the ovulatory responses were found 10 d after the MGA administration (pubertal = 46.7% vs. prepubertal P = 53.3%; P = 0.72). In Exp. 2, 368 heifers were randomly assigned to groups according to pubertal status and the MGA treatment. All heifers were inseminated on estrus detection for up 10 d after MGA administration and following exposure to bulls between 20 and 80 d. The MGA-treated heifers exhibited a greater AI service rate than control heifers (72.1 vs. 41.6%;P < 0.01); however, heifers receiving MGA had lower conception results following AI (51.6 vs. 71.4%; P = 0.01). In addition, MGA-treated heifers were more likely to have a corpus luteum in the middle of the breeding period (95.3 vs. 87.5%;P < 0.01), although the Cox proportional hazard of pregnancy rate was similar (P = 0.29) at the end of the breeding period. At onset of the breeding period, pubertal heifers presented a greater pregnancy rate following AI (pubertal P = 42.2% vs. prepubertal P = 24.9%; P = 0.01). Therefore, pubertal heifers seem to have greater overall reproductive efficiency than prepubertal heifers, particularly at the beginning of the breeding period. Interestingly, administration of MGA before the onset of the breeding period increased AI service rate but did not alter the rate of pregnancy throughout the breeding period of pasture-grazed beef heifers.


Assuntos
Cruzamento/métodos , Suplementos Nutricionais , Acetato de Melengestrol/farmacologia , Puberdade/fisiologia , Reprodução/efeitos dos fármacos , Animais , Bovinos , Detecção do Estro/métodos , Sincronização do Estro/métodos , Feminino , Fertilização/efeitos dos fármacos , Inseminação Artificial/veterinária , Masculino , Acetato de Melengestrol/administração & dosagem , Ovulação/efeitos dos fármacos , Gravidez , Taxa de Gravidez
9.
Exp Toxicol Pathol ; 67(2): 179-87, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25541063

RESUMO

Immunosuppressive drugs are used to suppress immune system activity in transplant patients and reduce the risk of organ rejection. The present study evaluated the potential cytotoxic, genotoxic and mutagenic of the immunosuppressive drugs cyclosporine (CsA) and tacrolimus (FK-506) on normal human fibroblasts (MRC-5 cells). Based on plasma concentrations of the immunosuppressive drugs, which were obtained from the records of kidney transplant patients at the Kidney Institute of Londrina, Brazil, 11 concentrations of each immunosuppressive were chosen to evaluate cell viability using the MTT assay. From these results, CsA and FK-506 concentrations of 135, 300, 675, and 1520 ng/ml and 8, 16, 24, and 32 ng/ml, respectively, were evaluated using (i) the comet assay, (ii) the nuclear division index (NDI), (iii) the micronucleus test (CBMN) and (iv) cell proliferation curves generated by quantifying cell numbers and protein levels. In this study, 1520 to 3420 ng/ml CsA decreased cell viability after 48 h of exposure. Genotoxic effects were observed only with a concentration of 1520 ng/ml after 3h of exposure and with concentrations of 675 and 1520 ng/ml after 24h of exposure. Mutagenic effects were observed only for the concentration of 1520 ng/ml. FK-506 decreased cell viability after 72 h of exposure for concentrations up to 20 ng/ml; genotoxic effects were observed with concentrations up to 8 ng/ml for both treatment times (3 and 24h) and mutagenic effects were observed with concentrations of 24 and 32 ng/ml after 24h of treatment. The cell proliferation curves demonstrated the absence of cytostatic effects of these drugs, and these data were confirmed by the NDI analysis. Our results suggest that concentrations lower than 300 ng/ml of CsA and 16 ng/ml of FK-506 are safe for use, as they did not induce genotoxic and mutagenic damage or affect MRC-5 cell viability and proliferation.


Assuntos
Proliferação de Células/efeitos dos fármacos , Ciclosporina/toxicidade , Dano ao DNA , Imunossupressores/toxicidade , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Tacrolimo/toxicidade , Técnicas de Cultura de Células , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Ensaio Cometa , Ciclosporina/sangue , Relação Dose-Resposta a Droga , Fibroblastos/efeitos dos fármacos , Fibroblastos/patologia , Humanos , Imunossupressores/sangue , Transplante de Rim , Testes para Micronúcleos , Tacrolimo/sangue
10.
Cell Tissue Res ; 358(1): 257-69, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24988912

RESUMO

This study presents a comprehensive view of the histological and functional status of the prostate of adult rat offspring of mothers subjected to gestational diabetes induced by alloxan. The ventral prostate of male adult offspring of diabetic (DP) or normal (CP) mothers was evaluated for collagen fibres, cell death, fibroblasts, smooth muscle cells, cell proliferation, matrix metalloproteinases (MMPs), androgen receptors (AR), transforming growth factor ß1 (TGFß-1), catalase and total antioxidant activity. The prostates of DP animals were lower in weight than those of the CP group. The DP group also exhibited hyperglycaemia and hypotestosteronemia, higher cell proliferation and AR expression, a reduction in α-actin (possibly interfering with the reproductive function of the prostate), and enhanced activity of MMP-2, although the absolute content of MMP-2 was lower in this group. These findings were associated with increased TGFß-1 and decreased collagen distribution. The prostates of DP rats additionally exhibited reductions in catalase and total antioxidant activity. Thus, rats developing in a diabetic intrauterine environment have glycaemic and hormonal changes that impact on the structure and physiology of the prostate in adulthood. The increased AR expression possibly leads to elevated cell proliferation. Stromal remodelling was characterized by enhanced activity of MMP-2 and collagen degradation, even with increased TGFß-1 activation. These changes associated with increased oxidative stress might interfere with tissue architecture and glandular homeostasis.


Assuntos
Diabetes Mellitus Experimental , Diabetes Gestacional , Metaloproteinase 2 da Matriz/biossíntese , Gravidez em Diabéticas , Efeitos Tardios da Exposição Pré-Natal/enzimologia , Próstata/enzimologia , Animais , Colágeno/metabolismo , Feminino , Regulação da Expressão Gênica , Hiperglicemia/enzimologia , Hiperglicemia/etiologia , Hiperglicemia/patologia , Masculino , Estresse Oxidativo , Gravidez , Efeitos Tardios da Exposição Pré-Natal/patologia , Próstata/patologia , Ratos , Ratos Wistar , Receptores Androgênicos/biossíntese , Fator de Crescimento Transformador beta1/biossíntese
11.
Horm Metab Res ; 46(7): 471-6, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24799027

RESUMO

Considering the increasing consumption of saturated fat and glucose in diets worldwide and its possible association to carcinogenesis, this investigation analysed the proliferation profile of nonmalignant human prostate epithelial cells after exposure to elevated levels of fat and glucose. PNT1A cells were cultured with palmitate (100 or 200 µM) and/or glucose (450 mg/dl) for 24 or 48 h. Treated cells were evaluated for viability test and cell proliferation (MTS assay). AKT and AMPK phosphorylation status were analysed by Western blotting. After 24 h of high-fat alone or associated with high-glucose treatment, there was an increase in AMPK and AKT activation associated to unchanged MTS-cell proliferation. Following 48 h of high-fat but not high-glucose alone, cells decreased AMPK activation and maintained elevated AKT levels. These data were associated to increased cell proliferation after further high-fat treatment. After longer high-fat exposure, MTS revealed that cells remained proliferating. High-glucose alone or associated to high-fat treatment was not able to increase cell proliferation and AKT activation. A high-fat medium containing 100 µM of palmitate stimulates proliferation in PNT1A cells by decreasing the activation of AMPK and increasing activation of AKT after longer exposure time. These findings improve the knowledge about the negative effect of high levels of this saturated fatty acid on proliferative disorders of prostate.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Células Epiteliais/enzimologia , Glucose/farmacologia , Próstata/citologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Western Blotting , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Dieta Hiperlipídica , Ativação Enzimática/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Humanos , Masculino , Palmitatos/farmacologia , Fosforilação/efeitos dos fármacos , Fatores de Tempo
12.
Horm Metab Res ; 43(4): 275-81, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21225543

RESUMO

Long-term dexamethasone therapy may induce peripheral insulin resistance (IR), which in turn elicits increased beta-cell function and proliferation. However, whether such adaptive compensations occur during short-term treatment with dexamethasone is unclear. Here, we compared morphofunctional parameters in endocrine pancreas after short- and long-term dexamethasone administration. Groups of rats received daily i. p. injection of 1 mg/kg b. w. dexamethasone for 1 (DEX-1), 3 (DEX-3), or 5 consecutive days (DEX-5), whilst control rats were saline-treated (CTL). Despite the absence of apparent IR in DEX-1 rats, this group exhibited increased circulating insulin levels and glucose-stimulated insulin secretion (GSIS), compared to the CTL group (p<0.05). Evident IR as well as marked hyperinsulinemia and GSIS, as judged by the static and dynamic insulin secretion values, were observed in DEX-3 and DEX-5 rats (p<0.05). GSIS in islets cultured with 1 µM dexamethasone was lower compared to the control (p<0.05). Marked increases in beta-cell proliferation were observed in DEX-3 and DEX-5 rats, compared to CTL and DEX-1 rats (p<0.05). The alterations observed in DEX-3 rats were more pronounced in DEX-5 rats, which also exhibited a higher content of islet Cdk4 and Cd2 proteins, compared to the CTL group (p<0.05). We conclude that short-term dexamethasone treatment (DEX-1) induces an increase in beta-cell function that does not require the presence of discernible IR. As the treatment continues, the IR develops rapidly, and increased insulin secretion as well as beta-cell hyperplasia is demanded for the appropriate maintenance of glucose homeostasis.


Assuntos
Dexametasona/efeitos adversos , Ilhotas Pancreáticas/efeitos dos fármacos , Animais , Proliferação de Células/efeitos dos fármacos , Dexametasona/administração & dosagem , Glucose/metabolismo , Insulina/metabolismo , Resistência à Insulina , Secreção de Insulina , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/anatomia & histologia , Ilhotas Pancreáticas/metabolismo , Masculino , Ratos , Ratos Wistar , Tempo
13.
Acta Physiol (Oxf) ; 200(3): 223-35, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20456283

RESUMO

AIM: Glucocorticoid administration induces insulin resistance (IR) and enhances islet mass and insulin secretion in rodents and humans. Here, we analysed whether these effects are still present after the interruption of dexamethasone treatment. METHODS: Adult Wistar rats were distributed into CTL (daily injection of saline for five consecutive days), DEX (daily injection of 1 mg kg(-1) body wt of dexamethasone for five consecutive days) and DEX(10) (5 days of dexamethasone treatment, followed by a period of 10 days without dexamethasone). RESULTS: In vivo experiments indicated that the marked hyperinsulinemia found in DEX rats during fasting and fed states was normalized in the DEX(10) group. Furthermore, the IR and glucose intolerance observed in DEX were restored in DEX(10) rats. Islets from DEX rats secreted more insulin in response to increasing concentrations of glucose and other metabolic and non-metabolic stimuli, compared with that in the CTL group. The insulin secretion for the most compounds studied returned to CTL values in DEX(10) islets. Increased insulin secretion correlated well with the augmentation in ß-cell proliferation and mass in DEX rats, and these morphological alterations were normalized in islets from DEX(10) rats. In parallel, the increased levels of proteins involved in ß-cell proliferation such as Cd2 and Cdk4 observed in DEX islets were also normalized in DEX(10) islets. CONCLUSION: These data strongly support the view that almost all the morphophysiological alterations induced by dexamethasone in the endocrine pancreas are reverted after discontinuation of the treatment. This information is important, considering the frequent use of glucocorticoids in humans.


Assuntos
Dexametasona/análogos & derivados , Glucocorticoides/administração & dosagem , Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Adaptação Fisiológica , Animais , Glicemia/metabolismo , Proteínas de Ciclo Celular/metabolismo , Morte Celular , Proliferação de Células , Dexametasona/administração & dosagem , Dexametasona/toxicidade , Esquema de Medicação , Glucocorticoides/toxicidade , Intolerância à Glucose/induzido quimicamente , Intolerância à Glucose/metabolismo , Hiperinsulinismo/induzido quimicamente , Hiperinsulinismo/metabolismo , Insulina/sangue , Resistência à Insulina , Secreção de Insulina , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Masculino , Ratos , Ratos Wistar , Fatores de Tempo
14.
Cell Tissue Res ; 332(3): 499-508, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18379825

RESUMO

Glucocorticoid hormones (GCs) have been widely used for the treatment of prostate cancer because of their inhibitory property against tumour growth. However, their mechanism of action in the prostate has received little attention. Excess GCs can lead to peripheral insulin resistance resulting in hyperglycaemia and hyperinsulinaemia. Insulin plays an important role as a cellular stimulant and high levels are related to low levels of androgens. Our objective has been to describe the effects of insulin resistance induced by dexamethasone treatment on the morphology of rat ventral prostate. Male adult Wistar rats received daily intraperitoneal injections of dexamethasone or saline for five consecutive days after which the rats were killed and the ventral prostate was removed, weighed and prepared for conventional and transmission electron microscopy (TEM). Dexamethasone treatment resulted in atrophy and decreased proliferative activity of prostatic epithelial cells. TEM analysis revealed changes in the epithelium-stroma interface, with some interruptions in the basement membrane. Fibroblasts showed a secretory phenotype with dilated endoplasmic reticulum. Smooth muscle cells exhibited a contractile pattern with 50% atrophy, an irregular membrane and twisted nuclei. Mitochondrial alterations, such as enlarged size and high electron density in the mitochondrial matrix, were also detected in smooth muscle cells. Insulin resistance induced by dexamethasone is thus associated with epithelial atrophy similar to that described for diabetic rats. However, GCs are responsible for morphological changes in the stromal cell population suggesting the activation of fibroblasts and atrophy of the smooth muscle cells.


Assuntos
Dexametasona/farmacologia , Glucocorticoides/farmacologia , Próstata/anatomia & histologia , Próstata/efeitos dos fármacos , Animais , Resistência à Insulina , Masculino , Microscopia Eletrônica de Transmissão , Próstata/ultraestrutura , Ratos , Ratos Wistar
15.
Eur J Histochem ; 50(1): 51-60, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16584985

RESUMO

The diabetes causes alterations in various organ systems, including the male accessory sex glands. The prostate is very important in the reproductive process and it is a frequent target of malignant changes. The aim of this work was to demonstrate the histochemical and ultrastructural alterations in the prostate of diabetic animals. Two groups of animals were utilized: control and non-obese diabetic mice (NOD). Twelve days after the characterization of diabetic status the ventral prostate was collected, fixed in Karnovsky and paraformaldehyde, processed for histochemistry and TEM associated to stereology. The results showed reduction of the epithelial area and increasing of the stromal area with muscular and collagen hypertrophy in the prostatic gland. It was characterized the development of prostatic intraepithelial neoplasia, inflammatory processes and dilation of the organelles involved in the secretory process. It was concluded that diabetes besides damaging the reproductive process, affects the glandular homeostasis favoring the development of prostatic pathologies.


Assuntos
Diabetes Mellitus Tipo 1/patologia , Próstata/patologia , Células Estromais/patologia , Animais , Comunicação Celular , Diabetes Mellitus Tipo 1/fisiopatologia , Células Epiteliais/patologia , Células Epiteliais/ultraestrutura , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos NOD , Microscopia Eletrônica de Transmissão , Tamanho do Órgão , Próstata/fisiopatologia , Doenças Prostáticas/etiologia , Doenças Prostáticas/patologia , Neoplasia Prostática Intraepitelial/etiologia , Neoplasia Prostática Intraepitelial/patologia , Neoplasias da Próstata/etiologia , Neoplasias da Próstata/patologia , Células Estromais/ultraestrutura
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