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Fish Physiol Biochem ; 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31811578


Light is an essential factor for organisms and affects the endocrine and stress regulation of fish in nature. However, sudden changes in light and dark conditions in artificial environments can negatively impact fish. In the present study, to evaluate the physiological and oxidative stress responses of goldfish (Carassius auratus) exposed to two different light conditions, sudden light changes and slowly dimming light changes for 24 h, we analyzed the mRNA expression and activity of stress indicators [corticotropin-releasing hormone (CRH) and pro-opiomelanocortin (POMC)], levels of plasma cortisol and glucose, mRNA expression of glucocorticoid receptor (GR), and activity of plasma oxidative stress indicators (superoxide dismutase and catalase). Consequently, the mRNA expressions and activities of CRH and POMC, plasma levels of cortisol and glucose, and mRNA expression of GR were found to be significantly increased during the light changes, particularly in the control group. Additionally, plasma levels of cortisol and glucose in the control group were significantly higher than those in the dimming group during the light changes. However, no significant differences in mRNA expression levels and activities of antioxidant enzymes both in the control and dimming groups were observed. These results indicate that dimming light induces less stress than sudden changes in light.

Fish Physiol Biochem ; 45(1): 391-400, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30269261


There have been a number of studies on the negative effects of blue light exposure in various species; however, little information is available on the impacts of blue light intensity and duration on fish. We investigated the effects of blue light spectra on stress in the retinas of goldfish, using a blue (460 nm) light-emitting diode (LED) at three intensities (0.5, 1.0, and 1.5 W/m2). The experiment was conducted for 4 weeks, and sampling was performed at intervals of 1 week. We measured changes in the expression of cortisol, and the concentrations of hydrogen peroxide (H2O2), melanin-concentrating hormone receptor (MCH-R), and caspase-3 in the retinas of goldfish. In addition, we measured histological changes in the retina. We used a transferase dUTP nick end labeling (TUNEL) assay to evaluate the apoptotic response to blue LED spectra. Levels of cortisol, H2O2, MCH-R, and caspase-3 increased with exposure time and light intensity. Histological analysis revealed that the thickness of melanin granules increased with exposure time and light intensity. The progressive TUNEL assay revealed many apoptotic cells after exposure to blue LED light, increasing with exposure time and light intensity. Irradiation with blue light for longer than 1 week induced increased retinal stress and may induce apoptosis in the retinas of goldfish, even at a low intensity.

Cor , Carpa Dourada , Luz/efeitos adversos , Retina/efeitos da radiação , Degeneração Retiniana/veterinária , Animais , Caspase 3/genética , Caspase 3/metabolismo , Proteínas de Peixes , Regulação da Expressão Gênica/efeitos da radiação , Hidrocortisona/metabolismo , Peróxido de Hidrogênio , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Lesões Experimentais por Radiação , Reação em Cadeia da Polimerase em Tempo Real , Retina/metabolismo
Biochem Biophys Res Commun ; 476(4): 541-545, 2016 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-27255995


We determined the molecular mechanism underlying the environmental (photoperiodic) regulation of sexual maturation in fish, we examined the expression of sexual maturation-related hormones and vertebrate ancient long opsin (VAL-opsin) in goldfish (Carassius auratus) exposed to different light spectra (red and green light-emitting diodes). We further evaluated the effect of exogenous gonadotropin hormone (GTH) on the expression of VAL-opsin under different light conditions. Our results demonstrated that the expression of GTHs was higher in the fish exposed to green light, and VAL-opsin levels were increased in the fish receiving GTH injection. Therefore, we have uncovered a molecular mechanism underlying the environmental (light)-induced trigger for sexual maturation: VAL-opsin is activated by green light and GTH, which promotes the expression of sexual maturation genes.

Proteínas de Peixes/metabolismo , Carpa Dourada/crescimento & desenvolvimento , Carpa Dourada/metabolismo , Gonadotropinas Hipofisárias/metabolismo , Opsinas/metabolismo , Maturidade Sexual/efeitos da radiação , Animais , Proteínas de Peixes/genética , Expressão Gênica/efeitos da radiação , Carpa Dourada/genética , Gonadotropinas Hipofisárias/genética , Luz , Opsinas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Maturidade Sexual/genética , Maturidade Sexual/fisiologia
Biochem Biophys Res Commun ; 476(2): 96-101, 2016 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-27181352


We investigated the effect of light spectra on retinal damage and stress in goldfish using green (530 nm) and red (620 nm) light emitting diodes (LEDs) at three intensities each (0.5, 1.0, and 1.5 W/m(2)). We measured the change in the levels of plasma cortisol and H2O2 and expression and levels of caspase-3. The apoptotic response of green and red LED spectra was assessed using the terminal transferase dUTP nick end labeling (TUNEL) assay. Stress indicator (cortisol and H2O2) and apoptosis-related genes (caspase-3) decreased in green light, but increased in red light with higher light intensities over time. The TUNEL assay revealed that more apoptotic cells were detected in outer nuclear layers after exposure to red LED over time with the increase in light intensity, than the other spectra. These results indicate that green light efficiently reduces retinal damage and stress, whereas red light induces it. Therefore, red light-induced retina damage may induce apoptosis in goldfish retina.

Apoptose/efeitos da radiação , Carpa Dourada/fisiologia , Retina/efeitos da radiação , Estresse Fisiológico/efeitos da radiação , Animais , Caspase 3/genética , Regulação da Expressão Gênica/efeitos da radiação , Carpa Dourada/sangue , Hidrocortisona/sangue , Peróxido de Hidrogênio/sangue , Luz , Retina/citologia , Retina/metabolismo , Retina/patologia