RESUMO
EGCG, a major component of green tea, has a number of properties which includes it being a powerful antioxidant. The purpose of this investigation was to deduce whether inclusion of EGCG in the drinking water of albino rats attenuates the effect of a light insult (2200lx, for 24h) to the retina. TUNEL-positive cells were detected in the outer nuclear layer of the retina, indicating the efficacy of the light insult in inducing photoreceptor degeneration. Moreover, Ret-P1 and the mRNA for rhodopsin located at photoreceptors were also significantly reduced as well as the amplitude of both the a- and b-waves of the electroretinogram was also reduced showing that photoreceptors in particular are affected by light. An increase in protein/mRNA of GFAP located primarily to Müller cells caused by light shows that other retinal components are also influenced by the light insult. However, antigens associated with bipolar (alpha-PKC), ganglion (Thy-1) and amacrine (GABA) cells, in contrast, appeared unaffected. The light insult also caused a change in the content of various proteins (caspase-3, caspase-8, PARP, Bad, and Bcl-2) involved in apoptosis. A number of the changes to the retina caused by a light insult were significantly attenuated when EGCG was in the drinking water. The reduction of the a- and b-waves and photoreceptor specific mRNAs/protein caused by light were significantly less. In addition, EGCG attenuated the changes caused by light to certain apoptotic proteins (especially at after 2 days) but did not appear to significantly influence the light-induced up-regulation of GFAP protein/mRNA. It is concluded that orally administered EGCG blunts the detrimental effect of light to the retina of albino rats where the photoreceptors are primarily affected.
Assuntos
Antioxidantes/farmacologia , Catequina/análogos & derivados , Células Fotorreceptoras/efeitos dos fármacos , Retina/efeitos dos fármacos , Degeneração Retiniana/tratamento farmacológico , Administração Oral , Animais , Antioxidantes/uso terapêutico , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Apoptose/efeitos da radiação , Proteínas Reguladoras de Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas Reguladoras de Apoptose/efeitos da radiação , Catequina/farmacologia , Catequina/uso terapêutico , Proteína Glial Fibrilar Ácida/genética , Proteína Glial Fibrilar Ácida/metabolismo , Luz/efeitos adversos , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/efeitos da radiação , Neuroglia/efeitos dos fármacos , Neuroglia/metabolismo , Neuroglia/efeitos da radiação , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Estresse Oxidativo/efeitos da radiação , Células Fotorreceptoras/fisiologia , Células Fotorreceptoras/efeitos da radiação , RNA Mensageiro/efeitos dos fármacos , RNA Mensageiro/metabolismo , RNA Mensageiro/efeitos da radiação , Ratos , Ratos Wistar , Retina/fisiopatologia , Retina/efeitos da radiação , Degeneração Retiniana/etiologia , Degeneração Retiniana/fisiopatologia , Rodopsina/genéticaRESUMO
BACKGROUND AND OBJECTIVE: Low-level laser therapy (LLLT) is a known modulator of inflammatory process. Herein we studied the effect of 660 nm diode laser on mRNA levels of neutrophils anti-apoptotic factors in lipopolysaccharide (LPS)-induced lung inflammation. STUDY DESIGN/METHODOLOGY: Mice were divided into 8 groups (n=7 for each group) and irradiated with energy dosage of 7.5 J/cm(2). The Bcl-xL and A1 mRNA levels in neutrophils were evaluated by Real Time-PCR (RT-PCR). The animals were irradiated after exposure time of LPS. RESULTS: LLLT and an inhibitor of NF-kappaB nuclear translocation (BMS 205820) attenuated the mRNA levels of Bcl-xL and A1 mRNA in lung neutrophils obtained from mice subjected to LPS-induced inflammation. CONCLUSION: LLLT reduced the levels of anti-apoptotic factors in LPS inflamed mice lung neutrophils by an action mechanism in which the NF-kappaB seems to be involved.
Assuntos
Terapia com Luz de Baixa Intensidade , Pulmão/imunologia , Pulmão/efeitos da radiação , NF-kappa B/metabolismo , Neutrófilos/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteína bcl-X/metabolismo , Animais , Inflamação , Lipopolissacarídeos/imunologia , Masculino , Camundongos , Antígenos de Histocompatibilidade Menor , Neutrófilos/efeitos da radiação , Peptídeos/farmacologia , RNA Mensageiro/metabolismo , RNA Mensageiro/efeitos da radiaçãoRESUMO
The hypothalamic suprachiasmatic nuclei (SCN) comprise the main site in the brain involved in the control of the homeostatic mechanism which respond to environmental daily light changes. The sympathetic nervous system and hypothalamic releasing or inhibiting factors mediate the SCN control of a number of peripheral organs and tissues. In this work we analyzed the involvement of two environmental light conditions, constant light (LL) and constant dark (DD) for 20 days, on the expression of mRNAs for catecholamines biosynthetic enzymes and neuropeptide Y (NPY) genes in rat superior cervical ganglia (SCG) and adrenal gland. The results of Northern blot analysis show that LL exposure reduces mRNA levels for tyrosine hydroxylase (TH) the rate limiting catecholamine biosynthetic enzyme and also of dopamine beta-hydroxylase (DBH) as well as for NPY in SCG to about half the levels in control animals. In contrast, exposure of the rats to DD did not elicit any change in the SCG. In the adrenal gland, both, LL and DD conditions increased the TH, DBH as well as phenylethanolamine N-methyltransferase (PNMT) mRNA levels. Under the same conditions, adrenal NPY mRNA levels were decreased by either LL or DD. The results show, for the first time, that prolonged changes in environmental light can alter the gene expression of catecholamine biosynthetic enzymes and of NPY. There was differential response in SCG and adrenal gland.
Assuntos
Glândulas Suprarrenais/metabolismo , Catecolaminas/biossíntese , Ritmo Circadiano/genética , Luz , Neuropeptídeo Y/biossíntese , Gânglio Cervical Superior/metabolismo , Adaptação Fisiológica/genética , Glândulas Suprarrenais/citologia , Animais , Catecol O-Metiltransferase/genética , Escuridão , Dopamina beta-Hidroxilase/genética , Regulação para Baixo/genética , Regulação para Baixo/efeitos da radiação , Ambiente Controlado , Masculino , Neuropeptídeo Y/genética , Estimulação Luminosa , RNA Mensageiro/metabolismo , RNA Mensageiro/efeitos da radiação , Ratos , Ratos Wistar , Gânglio Cervical Superior/citologia , Tirosina 3-Mono-Oxigenase/genética , Regulação para Cima/genética , Regulação para Cima/efeitos da radiaçãoRESUMO
PURPOSE: To examine the influence of dose, dose-rate and radiation quality on telomerase activity (TA) in the KG1a hematopoietic cell line. MATERIALS AND METHODS: KG1a cells were irradiated with gamma-rays (0.5-5 Gy) at 0.025 Gy/min, 0.30 Gy/min and 1.57 Gy/min and with a neutron/gamma-ray field (5 Gy). Cell viability was determined by trypan blue exclusion. Apoptosis and cell cycle distribution were evaluated by flow cytometry. Proliferative capacity was studied by MTS assay and TA by PCR. Following 3Gy gamma-irradiation, the expression of hTERT, hTR and TP1 genes was evaluated by RT-PCR. RESULTS: Dose- and dose-rate-dependent telomerase activation with an increase in hTERT mRNA and a drop in hTP1 mRNA were observed after irradiation. Down-regulation of telomerase activity occurred in a dose-dependent manner. Although non-significant changes in short-term survival were observed after irradiation, late apoptosis became evident after G2/M arrest. Early repression of TA preceded telomerase activation in samples irradiated with a neutron/gamma-ray field, in which short-term survival was affected. CONCLUSIONS: Radiation-induced telomerase activation depends on dose-rate. High-LET and low-LET irradiations induce similar changes in TA that differ mainly in their kinetics and their magnitude. Changes in TA are not related to cell-cycle redistribution nor to the induction of cell death; they are the consequence of specific regulatory responses to ionizing radiation. Mechanisms including both transcriptional and post-translational control may be involved in this regulation.
Assuntos
RNA Mensageiro/efeitos da radiação , Telomerase/biossíntese , Regulação para Cima , Apoptose , Ciclo Celular/efeitos da radiação , Sobrevivência Celular , Relação Dose-Resposta à Radiação , Regulação para Baixo , Humanos , Cinética , Biossíntese de Proteínas , RNA Mensageiro/metabolismo , Telomerase/metabolismo , Fatores de Tempo , Transcrição GênicaRESUMO
Malignant transformation is frequently accompanied by changes in the cytoarchitecture of adherent cells, which may be influenced by fluctuations in actin gene expression. We now show that normal melanocytes express a 5 fold higher level of actin mRNA than their melanoma counterparts. Induction of terminal melanogenesis did not increase actin in melanoma cells. However, culture with the thymidine analog, Bromodeoxyuridine, increased actin expression in undifferentiated but not in differentiating melanoma. Cell detachment assays and cell shape comparisons revealed a direct correlation of actin mRNA with increased melanoma cell adhesion rather than with differentiation-mediated suppression of tumor growth.