RESUMEN
Zebrafish were exposed to 0, 2.5 and 5 µg/L cadmium (Cd) for 10 weeks, and then each group was exposed to 26 °C(control) and 32 °C (high temperature) for 7 days. 22 indicators were compared between 26 °C and 32 °C in the spleen, including body weight, LPO and NO levels, activity levels of Cu/Zn-SOD, CAT and iNOS, MTs protein levels, and mRNA levels of Nrf2, Cu/Zn-SOD, CAT, HSF1, HSF2, HSP70, MTF-1, MTs, IL-6, IL-10, IL-1ß, TNF-α, iNOS and NF-κB. Most indicators were not significantly affected by heat in fish from no Cd pollution. However, almost all of indicators were responsive to heat in fish pre-exposed to Cd. Several indicators were sensitive to heat in fish pre-exposed to 2.5 µg/L Cd such as iNOS activities, and mRNA levels of iNOS and IL-10. Most other indicators were sensitive to heat in fish pre-exposed to 5 µg/L. The mRNA levels of HSP70 and MTF-1 were up-regulated by heat in fish pre-exposed to 0, 2.5 and 5 µg/L Cd. However, the magnitude of increase was the greatest in fish pre-exposed to 5 µg/L Cd. These differences between control and high temperature would serve as biomarkers to distinguish healthy from Cd-polluted group. The findings imply that metal pollution history should be carefully considered when screening heat biomarkers in fish.
Asunto(s)
Cadmio/metabolismo , Calor/efectos adversos , Inmunidad Innata , Estrés Oxidativo , Contaminantes Químicos del Agua/metabolismo , Pez Cebra/metabolismo , Animales , Biomarcadores/metabolismo , Relación Dosis-Respuesta a Droga , Femenino , MasculinoRESUMEN
The hypothesis tested in this study was that Cu pre-acclimation would mitigate high Cu induced immunotoxic effects in large yellow croaker Pseudosciaena crocea. To the end, fish were pre-acclimation to 0 and 84µg CuL-1 for 48h and then exposed to 0 and 420µg CuL-1 for another 48h. Survival rate, Cu content, ROS, NO, activities and mRNA levels of inflammatory genes (iNOS and COX-2), and gene expressions of transcription factor NF-κB and its inhibitor IκBα were determined in spleen and head-kidney of large yellow croaker. Cu pre-acclimation significantly reduced mortality of fish exposed to 420µg CuL-1. Cu pre-acclimation triggered the up-regulation of both enzyme activities and express levels of iNOS and COX-2 in spleen under 420µg CuL-1 exposure, resulting in remarkable reduction of Cu content and ROS in this tissue. Contrast to spleen, iNOS activity remained unchanged but the mRNA level of iNOS increased, and the mRNA level of COX-2 remained constant though COX-2 activity enhanced in head-kidney, suggesting iNOS and COX-2 may be modulated by Cu at a post-transcriptional level. In this process, NF-κB/IκBα signaling molecules may play a vital role in the transcriptional activation of inflammatory genes in both spleen and head-kidney. In conclusion, low Cu pre-acclimation alleviated high Cu induced immunotoxicity in spleen and head-kidney of large yellow croaker by enhancing the activities and mRNA levels of inflammatory genes.
Asunto(s)
Aclimatación/efectos de los fármacos , Cobre/toxicidad , Riñón Cefálico/efectos de los fármacos , Perciformes/inmunología , Bazo/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Aclimatación/genética , Animales , Cobre/análisis , Relación Dosis-Respuesta a Droga , Proteínas de Peces/genética , Expresión Génica/efectos de los fármacos , Riñón Cefálico/inmunología , Perciformes/genética , Perciformes/metabolismo , ARN Mensajero/genética , Bazo/inmunología , Regulación hacia Arriba , Contaminantes Químicos del Agua/análisisRESUMEN
The present study explored the possible preventive effects of blue light emitting diodes (LEDs) on cadmium (Cd)-induced oxidative stress and immunotoxicity in zebrafish. To this end, zebrafish were exposed to a white fluorescent bulb or blue LEDs (LDB, peak at 450nm, at an irradiance of 0.9W/m2), and 0 or 30µgL-1 waterborne Cd for 5 weeks. Growth performance, survival rate, and hepatic histology, ultrastructure, antioxidant and innate immune responses were determined in zebrafish. Cd exposure alone reduced growth and survival rate, and induced oxidative damage and changes in histology and ultrastructure. However, Cd exposure in combination with LDB apparently relieved these negative effects. The alleviation of adverse effects might result from the up-regulation of antioxidant and innate immune genes at transcriptional, translational, or post-translational levels. Cd exposure alone dramatically enhanced mRNA levels of nuclear transcription factor κB (NF-κB) and E2-related factor (Nrf2). However, compared to Cd exposure alone, Cd exposure in combination with LDB apparently down-regulated both genes. Taken together, our results suggest that chronic Cd exposure induced a negative effect on zebrafish, possibly involved in NF-κB-induced immunotoxicity and Nrf2-induced oxidative stress. Finally, for the first time, our data demonstrated that LDB could protect fish against Cd toxicity.
Asunto(s)
Antioxidantes , Cadmio/toxicidad , Inmunidad Innata , Luz , Hígado/efectos de los fármacos , Estrés Oxidativo , Pez Cebra/metabolismo , Animales , Antioxidantes/metabolismo , Regulación hacia Abajo , Exposición a Riesgos Ambientales , Inmunidad Innata/efectos de los fármacos , Inmunidad Innata/genética , Hígado/metabolismo , Hígado/patología , Hígado/ultraestructura , Factor 2 Relacionado con NF-E2/genética , Factor 2 Relacionado con NF-E2/metabolismo , FN-kappa B/genética , FN-kappa B/metabolismo , ARN Mensajero/metabolismo , Regulación hacia Arriba , Pez Cebra/genética , Pez Cebra/crecimiento & desarrollo , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismoRESUMEN
The study was carried out to evaluate the effects of low-dose zinc (Zn) pre-exposure on survival rate, new Zn accumulation, and mitochondrial bioenergetics in the liver and spleen of large yellow croaker exposed to high-dose Zn. To the end, fish were pre-exposed to 0 and 2 mg L-1 Zn for 48 h and post-exposed to 0 and 12 mg L-1 Zn for 48 h. Twelve milligrams Zn per liter exposure alone reduced survival rate, but the effect did not appear in the 2 mg L-1 Zn pre-exposure groups. Two milligrams per liter Zn pre-exposure also ameliorated 12 mg Zn L-1 induced new Zn accumulation, reactive oxygen species (ROS) levels, and mitochondrial swelling in the liver. However, these effects did not appear in the spleen. In the liver, 2 mg L-1 Zn pre-exposure apparently relieved 12 mg L-1 Zn induced down-regulation of activities of ATP synthase (F-ATPase), succinate dehydrogenase (SDH), and malate dehydrogenase (MDH). The mRNA levels of these genes remained relatively stable in fish exposed to 12 mg L-1 Zn alone, but increased in fish exposed to 12 mg L-1 Zn with 2 mg L-1 Zn pre-treatment. In the spleen, 2 mg Zn L-1 pre-exposure did not mitigate the down-regulation of mRNA levels of genes and activities of relative enzymes induced by 12 mg L-1 Zn. In conclusion, our study demonstrated low-dose zinc pre-exposure ameliorated high-dose zinc induced mitochondrial dysfunction in the liver but not in the spleen of large yellow croaker, indicating an organ-specific effect.
Asunto(s)
Mitocondrias/efectos de los fármacos , Perciformes/metabolismo , Zinc/farmacología , Animales , Regulación hacia Abajo , Proteínas de Peces/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/metabolismo , Malato Deshidrogenasa , Mitocondrias/metabolismo , ATPasas de Translocación de Protón Mitocondriales/metabolismo , ARN Mensajero/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Bazo/efectos de los fármacos , Bazo/metabolismo , Succinato Deshidrogenasa/metabolismo , Zinc/farmacocinéticaRESUMEN
The aim of the present study was to assess survival rate, Zn accumulation, reactive oxygen species (ROS) levels, oxidative damage and antioxidant responses after Zn exposure (2 and 8 mg L-1 Zn) at different exposure times (6, 12, 24, 48 and 96 h) in the liver of large yellow croaker. Survival rate was reduced at 96 h, and hepatic Zn content increased during 24-96 by 8 mg L-1 Zn. In the 2 mg L-1 Zn group, no fish died and the increase in Zn content merely occurred at 96 h. Exposure to 8 mg L-1 Zn induced accumulation of ROS, lipid peroxidation and protein carbonylation during the late stage of exposure. In contrast, exposure to 2 mg L-1 Zn did not result in oxidative damage, which may result from the up-regulation of antioxidant defenses. Although exposure to 8 mg L-1 Zn increased activities and mRNA levels of antioxidant enzymes during the early stage of exposure, including Cu/Zn-SOD, Mn-SOD, CAT, GPx and GR, the activities of these enzymes except Cu/Zn-SOD were inhibited at 96 h. Furthermore, a sharp increase in Nrf2 expression was observed in fish exposed to 8 mg L-1 at 6 and 12 h, and 2 mg L-1 at 12 h and 24 h, suggesting that Nrf2 was required for the protracted induction of these genes. The late increase in Keap1 expression may support its role in switching off the Nrf2 response. In conclusion, the present study demonstrated different effects of low- and high-dose waterborne Zn on antioxidant responses, which could contribute to the understanding of antioxidant and toxic roles of zinc on a molecular level.
Asunto(s)
Hígado/efectos de los fármacos , Perciformes/metabolismo , Contaminantes Químicos del Agua/toxicidad , Zinc/toxicidad , Animales , Catalasa/genética , Proteínas de Peces/metabolismo , Expresión Génica/efectos de los fármacos , Glutatión Peroxidasa/metabolismo , Glutatión Reductasa/metabolismo , Hígado/metabolismo , Factor 2 Relacionado con NF-E2/genética , Estrés Oxidativo/efectos de los fármacos , ARN Mensajero/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Superóxido Dismutasa/genética , Contaminantes Químicos del Agua/farmacocinética , Zinc/farmacocinéticaRESUMEN
The present study assessed the effects of a white fluorescent bulb (the control) and two different light-emitting diodes (blue LEDs, LDB; red, LDR) on growth, morphology, and oxidative stress in the liver and ovary of zebrafish for 5 weeks. Growth maintained relatively constant under LDB condition, but was reduced under LDR condition. In the liver, hepatosomatic index (HSI) and protein carbonylation (PC) increased under LDR condition, whereas lipid peroxidation (LPO) declined and HSI remained unchanged under LDB condition. The decrease in oxidative damage by LDB could be attributed to the up-regulated levels of mRNA, protein, and activity of Cu/Zn-SOD and CAT. A failure to activate the activity of both enzymes may result in the enhanced PC levels under LDR condition, though both genes were up-regulated at transcriptional and translational levels. In the ovary, although gonadosomatic index sharply increased under LDR condition, LPO and PC dramatically accumulated. The increase in oxidative damage by LDR might result from the down-regulated levels of protein and activity of Cu/Zn-SOD and CAT, though both genes were up-regulated at a transcriptional level. Furthermore, a sharp increase in expression of transcription factor Nrf2 that targets antioxidant genes was observed in the liver but not in the ovary under LDB and LDR conditions. In conclusion, our data demonstrated a positive effect of LDB and negative effect of LDR on fish antioxidant defenses, emphasizing the potentials of LDB as an effective light source in fish farming.
Asunto(s)
Luz , Hígado/efectos de la radiación , Ovario/efectos de la radiación , Pez Cebra , Animales , Peso Corporal/efectos de la radiación , Catalasa/genética , Catalasa/metabolismo , Femenino , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Peroxidación de Lípido/efectos de la radiación , Hígado/crecimiento & desarrollo , Hígado/metabolismo , Factor 2 Relacionado con NF-E2/genética , Tamaño de los Órganos/efectos de la radiación , Ovario/crecimiento & desarrollo , Ovario/metabolismo , Carbonilación Proteica/efectos de la radiación , ARN Mensajero/metabolismo , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo , Pez Cebra/crecimiento & desarrollo , Pez Cebra/metabolismoRESUMEN
Certain light emitting diodes (LEDs) have become popular in fish farming beacause of a promoting effect on growth and reproduction. However, little information is available on innate immune responses in related tissues under LEDs conditions. The present study assessed the effects of a white fluorescent bulb (the control) and two different light-emitting diodes (LEDs: blue, LDB, peak at 450 nm; red, LDR, 630 nm) on growth and innate immune responses in the serum, liver and ovary of zebrafish for 8 weeks. LDB significantly enhanced specific growth rate (SGR), food intake (FI), and serum globulin levels. In contrast, LDR sharply inhibited SGR, FI, and the levels of albumin and globulin. Under LDB condition, there was an increase in protein levels of alkaline phophatase (AKP) and protein and activity levels of lysozyme (LZM) in the liver, and the levels of mRNA, protein, and activity of LZM in the ovary. Under LDR condition, LZM was dramatically down-regulated at mRNA, protein and activity levels in the ovary, suggesting that LZM was regulated at a transcriptional level. In the liver of the LDR group, though AKP mRNA levels sharply increased, its protein and activity levels significantly declined, indicating that AKP was regulated at translational level. Furthermore, a positive correlation between transcription factor NF-κB RelA mRNA levels and expression levels of AKP and LZM was observed in the liver and ovary, implying a transcriptional regulation of NF-κB RelA. In conclusion, the present study demonstrated a positive effect of LDB and negative effect of LDR on fish growth and innate immune responses, possibly associated with modifications at transcriptional, translational, and post-translational levels, and the transcriptional regulation of the NF-κB signaling molecule.
Asunto(s)
Inmunidad Innata/efectos de la radiación , Luz , Pez Cebra/crecimiento & desarrollo , Pez Cebra/inmunología , Animales , Femenino , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Hígado/inmunología , FN-kappa B/genética , FN-kappa B/metabolismo , Ovario/inmunología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Pez Cebra/sangreRESUMEN
We evaluated the effects of acute Zn exposure (4 and 8 mg L(-1) Zn) on lipid peroxidation, and activities and mRNA levels of antioxidant enzyme genes (Cu/Zn-SOD, CAT, GPx, and GR), and gene expression of the Nrf2-Keap1 signaling molecule at different exposure times (0, 6, 12, 24, 48, and 96 h) in the spleen of large yellow croaker. Lipid peroxidation remained relatively constant during 6-48 h and 6-24 h and sharply increased at 96 h and during 48-96 h in fish exposed to 4 and 8 mg L(-1) Zn, respectively. Activities of all tested enzymes increased during the early stage of exposure and decreased towards the end of the exposure in both groups. However, mRNA levels of antioxidant enzyme genes were dramatically up-regulated by 4 and 8 mg L(-1) Zn during the late stage of exposure. During the early stage of exposure for 6 h, the 8 mg L(-1) Zn exposure sharply increased mRNA levels of Cu/Zn-SOD, CAT, GPx1b, Nrf2, and Keap1, whereas, the 4 mg L(-1) Zn exposure did not significantly affect the expression of these genes. Our data also showed positive relationships between Nrf2 expression and mRNA levels of its target genes, suggesting that Nrf2 was required for the protracted induction of these genes. Furthermore, a sharp increase in Keap1 expression levels was observed in fish exposed to 4 mg L(-1) at 96 h, and 8 mg L(-1) at 6, 48, and 96 h. In conclusion, the present study demonstrated that Zn-induced antioxidant defenses were involved in modifications at enzymatic and transcriptional levels and the transcriptional regulation of the Nrf2-Keap1 signaling molecule; these results may contribute to the understanding of mechanisms that maintain the correct redox balance in the immune organ of the large yellow croaker.
Asunto(s)
Proteínas de Peces/genética , Regulación de la Expresión Génica/efectos de los fármacos , Proteína 1 Asociada A ECH Tipo Kelch/genética , Factor 2 Relacionado con NF-E2/genética , Perciformes/genética , Bazo/efectos de los fármacos , Zinc/toxicidad , Animales , Antioxidantes/metabolismo , Proteínas de Peces/metabolismo , Perfilación de la Expresión Génica , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Peroxidación de Lípido , Factor 2 Relacionado con NF-E2/metabolismo , Perciformes/inmunología , Perciformes/metabolismo , Bazo/metabolismo , Contaminantes Químicos del Agua/toxicidadRESUMEN
The aim of the present study was to evaluate the effects of acute inorganic Hg exposure (0, 32 and 64µgHgL(-1)) on lipid peroxidation, activities and gene expression of antioxidant enzymes (Cu/Zn-SOD, CAT, GPx, GR and GST), and mRNA levels of the Keap1-Nrf2 signaling molecules at different exposure times (6h, 12h, 24h, 48h, and 96h) in the liver of large yellow croaker Pseudosciaena crocea. The results showed that lipid peroxidation was sharply reduced by 32µg Hg L(-1) during 6-12h before returning to control levels. Similarly, lipid peroxidation was significantly reduced during 6-12h followed by a sharp increase towards the end of the exposure in the 64µgHgL(-1) group. There was a negative relationship between lipid peroxidation and antioxidant enzyme activities, and positive relationship between activities and gene expression of antioxidant enzymes, suggesting that the changes at a molecular level may underlie enzymatic level and accordingly affect hepatic lipid peroxidation. Obtained results also showed a coordinated transcriptional regulation of antioxidant genes, suggesting that Nrf2 is required for the protracted induction of these genes. Furthermore, a negative relationship between the mRNA levels of Nrf2 and Keap1 indicated that Keap1 may play an important role in switching off the Nrf2 response. In conclusion, this is the first study to elucidate effects of waterborne Hg on antioxidant system in large yellow croaker through the Keap1-Nrf2 pathway, which will aid our understanding of the molecular mechanisms of waterborne heavy metal on antioxidant responses in fish.
Asunto(s)
Mercurio/toxicidad , Factor 2 Relacionado con NF-E2/fisiología , Estrés Oxidativo/efectos de los fármacos , Perciformes/metabolismo , Animales , Antioxidantes/metabolismo , Regulación de la Expresión Génica , Peroxidación de Lípido/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/metabolismo , Mercurio/metabolismo , Compuestos de Mercurio/metabolismo , Compuestos de Mercurio/toxicidad , Factor 2 Relacionado con NF-E2/genética , Oxidación-Reducción/efectos de los fármacos , Distribución Aleatoria , Transducción de Señal/efectos de los fármacosRESUMEN
The aim of the present study was to evaluate the effect of ß-glucan on acute hypoxia-induced oxidative stress and the changes in energy metabolism by determining ROS production, activities and mRNA levels of energy metabolism enzyme (PK, F-ATPase, SDH and MDH), and in gene expression of HIF-1α in the liver of large yellow croaker. Fish were injected with ß-glucan at a dose of 0 or 5 mg kg(-1) body weight on 6, 4 and 2 days before exposed to 1.5 and 7.0 mg DO L(-1) for 48 h. The results showed that ß-glucan enhanced survival rate and reduced ROS during the lethal hypoxic stress, indicating that ß-glucan could ameliorate hypoxia-induced oxidative stress. Obtained results also showed that ß-glucan could up-regulate activities and mRNA levels of PK, demonstrating that ß-glucan increased anaerobic glycolysis capacity. Furthermore, a coordinated transcriptional regulation of energy metabolism enzyme genes was observed, suggesting that HIF-1α is required for regulating these genes. In conclusion, ß-glucan could alleviate cute hypoxia-induced oxidative stress in large yellow croker by enhancing anaerobic glycolysis capacity, emphasizing a central role of transcription factor HIF-1α in the process.
Asunto(s)
Metabolismo Energético/efectos de los fármacos , Hipoxia/metabolismo , Perciformes/metabolismo , Especies Reactivas de Oxígeno/metabolismo , beta-Glucanos/farmacología , Animales , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Hígado/metabolismo , Malato Deshidrogenasa/genética , Malato Deshidrogenasa/metabolismo , ATPasas de Translocación de Protón Mitocondriales/genética , ATPasas de Translocación de Protón Mitocondriales/metabolismo , Estrés Oxidativo/efectos de los fármacos , Perciformes/genética , Piruvato Quinasa/genética , Piruvato Quinasa/metabolismo , ARN Mensajero/metabolismo , Succinato Deshidrogenasa/genética , Succinato Deshidrogenasa/metabolismoRESUMEN
The aim of the present study was to explore the effect of waterborne zinc (control, 0.85, 2.20, 3.10 mg/l, respectively) exposure on lipid deposition and metabolism in the hepatopancreas and muscle of grass carp Ctenopharyngodon idella. The lipid content, Zn accumulation, and the activities and expression levels of several enzymes involved in lipid metabolism were determined in hepatopancreas and muscle. Waterborne Zn exposure reduced growth performance and increased Zn accumulation in both tested tissues. In hepatopancreas, Zn exposure increased lipid content, the activities of lipogenic enzymes, such as 6PGD, G6PD, ME, ICDH and FAS, as well as the mRNA expression level of G6PD, 6PGD, ICDH, FAS and SREBP-1. But the activity of CPT I and the mRNA expression of HSL, CPT Iα1a, CPT Iα2a and PPARα were down-regulated by Zn exposure. In contrast, in muscle, waterborne Zn exposure decreased lipid deposition, activities of 6GPD, ICDH and ME, as well as the mRNA expression level of G6PD, ICDH, ME, FAS and SREBP-1. However, the activity of CPT I as well as the mRNA expression level of PPARα, HSL, CPT Iα2a, CPT Iα1b and CPT Iß were up-regulated by Zn exposure. Our results indicate that waterborne Zn increases lipid content by up-regulating lipogenesis and down-regulating lipolysis in hepatopancreas. But, in muscle, waterborne Zn reduces lipid accumulation by up-regulating lipolysis and down-regulating lipogenesis. Differential patterns of lipid deposition, enzymatic activities and genes' expression indicate the tissue-specific regulatory mechanism in fish.
Asunto(s)
Carpas/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Zinc/toxicidad , Animales , Carpas/crecimiento & desarrollo , Hepatopáncreas/efectos de los fármacos , Hepatopáncreas/metabolismo , Metabolismo de los Lípidos/genética , Músculos/efectos de los fármacos , Músculos/metabolismo , Contaminantes Químicos del Agua/farmacocinética , Zinc/farmacocinéticaRESUMEN
Peroxisome proliferator-activated receptor gamma (PPARγ) is ligand-inducible transcription factor and has important roles in lipid metabolism, cell proliferation and inflammation. In the present study, yellow catfish Pelteobagrus fulvidraco PPARγ cDNA was isolated from liver by RT-PCR and RACE, and its molecular characterization and transcriptional regulation by insulin in vivo and in vitro were determined. The generation of PPARγ1 and PPARγ2 was due to alternative promoter of PPARγ gene. PPARγ1 and PPARγ2 mRNA covered 2426 bp and 2537 bp, respectively, with an open reading frame (ORF) of 1584 bp encoding 527 amino acid residues. Yellow catfish PPARγ gene was organized in a manner similar to that of their mammalian homologs, implying a modular organization of the protein's domains. A comparison between the yellow catfish PPARγ amino acid sequence and the correspondent sequences of several other species revealed the identity of 55-76.2%. Two PPARγ transcripts (PPARγ1 and PPARγ2) mRNAs were expressed in a wide range of tissues, but the abundance of each PPARγ mRNA showed the tissue- and developmental stage-dependent expression patterns. Intraperitoneal injection of insulin in vivo significantly stimulated the mRNA expression of total PPARγ and PPARγ1, but not PPARγ2 in the liver of yellow catfish. In contrast, incubation of hepatocytes with insulin in vitro increased the mRNA levels of PPARγ1, PPARγ2 and total PPARγ. To our knowledge, for the first time, the present study provides evidence that PPARγ1 and PPARγ2 are differentially expressed with and among tissues during different developmental stages and also regulated by insulin both in vivo and in vitro, which serves to increase our understanding on PPARγ physiological function in fish.
Asunto(s)
Bagres/metabolismo , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Insulina/farmacología , PPAR gamma/genética , ARN Mensajero/metabolismo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Bagres/crecimiento & desarrollo , Células Cultivadas , Hepatocitos/citología , Hepatocitos/metabolismo , Hipoglucemiantes/farmacología , Técnicas In Vitro , Hígado/citología , Hígado/metabolismo , Datos de Secuencia Molecular , PPAR gamma/química , PPAR gamma/metabolismo , Filogenia , Regiones Promotoras Genéticas/genética , Conformación Proteica , ARN Mensajero/genética , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido NucleicoRESUMEN
The ontogeny and kinetics of carnitine palmitoyltransferase I (CPT I) were investigated in hepatopancreas and muscle throughout four developmental stages (newly hatched larvae, 1-month-old juvenile, 3-month-old, and 6-month-old, respectively) of grass carp Ctenopharyngodon idella. In hepatopancreas, the maximal velocity (Vmax) significantly increased from hatching to 1-month-old grass carp and then gradually declined at 6-month-old grass carp. In muscle, CPT I activity was the highest at 1-month-old grass carp, nearly twofold higher than that at hatching (P < 0.05). The Michaelis constant (Km) value was also the highest for 1-month-old in both tested tissues. Carnitine concentrations (FC, AC and TC) were the lowest for 3-month-old grass carp and remained relatively constant in both tissues from fish under the other developmental stages. The FC concentration in hepatopancreas and muscle at four developmental stages were less than the respective Km, indicating that grass carp required supplemental carnitine in their food to ensure that CPT I activity was not constrained by carnitine availability.
Asunto(s)
Carnitina O-Palmitoiltransferasa/metabolismo , Carpas/metabolismo , Hepatopáncreas/enzimología , Músculo Esquelético/enzimología , Animales , Carnitina/metabolismo , Cinética , Larva/metabolismo , Metabolismo de los LípidosRESUMEN
Carnitine has been reported to improve growth performance and reduce body lipid content in fish. Thus, we hypothesised that carnitine supplementation can improve growth performance and reduce lipid content in the liver and muscle of yellow catfish (Pelteobagrus fulvidraco), a commonly cultured freshwater fish in inland China, and tested this hypothesis in the present study. Diets containing l-carnitine at three different concentrations of 47 mg/kg (control, without extra carnitine addition), 331 mg/kg (low carnitine) and 3495 mg/kg (high carnitine) diet were fed to yellow catfish for 8 weeks. The low-carnitine diet significantly improved weight gain (WG) and reduced the feed conversion ratio (FCR). In contrast, the high-carnitine diet did not affect WG and FCR. Compared with the control diet, the low-carnitine and high-carnitine diets increased lipid and carnitine contents in the liver and muscle. The increased lipid content in the liver could be attributed to the up-regulation of the mRNA levels of SREBP, PPARγ, fatty acid synthase (FAS) and ACCa and the increased activities of lipogenic enzymes (such as FAS, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and malic enzyme) and to the down-regulation of the mRNA levels of the lipolytic gene CPT1A. The increased lipid content in muscle could be attributed to the down-regulation of the mRNA levels of the lipolytic genes CPT1A and ATGL and the increased activity of lipoprotein lipase. In conclusion, in contrast to our hypothesis, dietary carnitine supplementation increased body lipid content in yellow catfish.
Asunto(s)
Carnitina/administración & dosificación , Bagres/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , Hígado/metabolismo , Músculos/metabolismo , Animales , Carnitina/análisis , China , Suplementos Dietéticos , Ácido Graso Sintasas/genética , Expresión Génica/efectos de los fármacos , Lípidos/análisis , Lipogénesis/genética , Lipólisis/genética , Hígado/química , Músculos/química , PPAR gamma/genética , ARN Mensajero/análisis , Proteínas de Unión a los Elementos Reguladores de Esteroles/genéticaRESUMEN
Up to date, only limited information is available on genetically and functionally different isoforms of CPT I enzyme in fish. In the study, molecular characterization and their tissue expression profile of three CPT Iα isoforms (CPT Iα1a, CPT Iα1b and CPT Iα2a) and a CPT Iß isoform from yellow catfish Pelteobagrus fulvidraco is determined. The activities and kinetic features of CPT I from several tissues have also been analyzed. The four CPT I isoforms in yellow catfish present distinct differences in amino acid sequences and structure. They are widely expressed in liver, heart, white muscle, spleen, intestine and mesenteric adipose tissue of yellow catfish at the mRNA level, but with the varying levels. CPT I activity and kinetics show tissue-specific differences stemming from co-expression of different isoforms, indicating more complex pathways of lipid utilization in fish than in mammals, allowing for precise control of lipid oxidation in individual tissue.
Asunto(s)
Carnitina O-Palmitoiltransferasa/genética , Isoformas de Proteínas/genética , Secuencia de Aminoácidos , Carnitina O-Palmitoiltransferasa/química , Carnitina O-Palmitoiltransferasa/metabolismo , Regulación Enzimológica de la Expresión Génica , Peroxidación de Lípido/genética , Hígado/metabolismo , Mitocondrias Cardíacas/metabolismo , Datos de Secuencia Molecular , Oxidación-Reducción , Isoformas de Proteínas/metabolismo , Distribución TisularRESUMEN
The present study was performed to evaluate the in vitro effects of selenium (Se) supplementation to prevent copper (Cu)-induced changes in lipid metabolism of hepatocytes from grass carp (Ctenopharyngodon idellus). Four groups (control and 100 µM Cu in combination with 0, 5, and 10 µM Se, respectively) were chosen. Compared with the control, activities of glucose 6-phosphatedehydrogenase, 6-phosphogluconate dehydrogenase, malic enzyme, and carnitine palmitoyltransferase I (CPT I) of all three Cu-exposed groups at 24 and 48 h were significantly greater. However, among three Cu-exposed groups, increasing Se concentration tended to increase activities of G6PD and ME at 24 h and 6PGD activity at 24 and 48 h but decreased CPT I activity at 24 h. Compared with the control, Cu exposure alone, or in combination with Se, downregulated mRNA levels of sterol regulatory element-binding protein-1 (SREBP-1c), fatty acid synthase (FAS), acetyl-CoA carboxylase, peroxisome proliferator activated receptor alpha (PPARα), CPT I, and hormone-sensitive lipase (HSL) at 24 h as well as SREBP-1c, FAS, and ACC mRNA levels at 48 h. However, upregulated mRNA levels of PPARα, CPT I, and HSL, as well as decreased triglyceride content, were recorded at 48 h. Thus, although toxic at greater levels, lower levels of Se provided significant protection against Cu-induced changes in lipid metabolism. For the first time, our study indicates the dose- and time-dependent effects of Se addition on changes in lipid metabolism induced by Cu in fish hepatocytes and provides new insights into Se-Cu interaction at both enzymatic and molecular levels.
Asunto(s)
Antioxidantes/metabolismo , Carpas/fisiología , Cobre/toxicidad , Selenio/metabolismo , Contaminantes Químicos del Agua/toxicidad , Animales , Hepatocitos/efectos de los fármacos , Técnicas In Vitro , Metabolismo de los Lípidos/efectos de los fármacos , ARN Mensajero/metabolismoRESUMEN
The aim of this study was to determine the potential mechanisms of exposure to waterborne zinc (Zn) on lipid metabolism in three extrahepatic tissues (ovary, muscle and mesenteric adipose tissue) of female yellow catfish Pelteobagrus fulvidraco. Female yellow catfish were chronically exposed to Zn (0.05, 0.35 or 0.86 mg Zn/l; duration of treatment 8 weeks) or acutely exposed to a high level of Zn (4.71 mg Zn/l for 96 h). Following the respective treatment, lipid deposition and mRNA levels of 11 genes (CPT IA, CPT IB, PPARα, PPARγ, SREBP-1, G6PD, 6PGD, FAS, ACCa, ACCb and LPL) involved in lipid metabolism were determined. Waterborne Zn exposure significantly reduced growth performance and lipid content in muscle but had no significant effect on lipid content in ovary and mesenteric adipose tissue. The change in the levels of the mRNA genes under study was Zn concentration-dependent and tissue-dependent. Pearson correlations between the mRNA levels of three transcriptional factors and enzymes in these tissues revealed that variations in gene expression as a result of the different Zn treatments underlay the patterns of lipid metabolism, which in turn affected fat storage and mobilization. To our knowledge, this is the first study to demonstrate the effect of waterborne Zn exposure on lipid metabolism in extrahepatic tissues at the molecular level. These results therefore contribute to our understanding of Zn-induced toxicity in fish.
Asunto(s)
Bagres/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , ARN Mensajero/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Zinc/toxicidad , Tejido Adiposo/metabolismo , Animales , Femenino , Metabolismo de los Lípidos/genética , Músculo Esquelético/metabolismo , Ovario/metabolismo , ARN Mensajero/genética , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Estadísticas no ParamétricasRESUMEN
In the present study, three different copper (Cu) concentrations (control, 10 and 100 lM, respectively) and three incubation times (24, 48 and 96 h) were chosen to assess in vitro effect of Cu on lipid metabolism in hepatocytes of grass carp Ctenopharyngodon idellus. Increased glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and carnitine palmitoyltransferase I activities were observed in hepatocytes with increasing Cu concentration and exposure duration. Cu decreased mRNA levels of several lipogenic and lipolytic genes at 24 h. However, at 48 h, Cu down-regulated the process of lipogenesis but up-regulated that of lipolysis. The Cudriven up-regulation of lipolytic genes was maintained after 96 h and accompanied by a decreased intracellular triglyceride accumulation, while no effect on lipogenic genes was shown. Thus, 96-h Cu exposure induced lipid depletion, possibly due to the upregulation of lipolysis. Although in this process, lipogenesis might be up-regulated, it was not enough to compensate lipid consumption. Our study represents the first approach to concentration- and time-dependent in vitro effects of Cu on lipid metabolism of fish hepatocytes and provides new insights into Cu toxicity in fish at both enzymatic and molecular levels.
Asunto(s)
Carpas/metabolismo , Cobre/toxicidad , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Acetil-CoA Carboxilasa/genética , Animales , Carnitina O-Palmitoiltransferasa/genética , Carnitina O-Palmitoiltransferasa/metabolismo , Carpas/genética , Línea Celular , China , Cobre/administración & dosificación , Acido Graso Sintasa Tipo I/genética , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Explotaciones Pesqueras , Expresión Génica/efectos de los fármacos , Glucosafosfato Deshidrogenasa/metabolismo , Lipogénesis/efectos de los fármacos , Lipogénesis/genética , Lipólisis/efectos de los fármacos , Lipólisis/genética , PPAR alfa/genética , Fosfogluconato Deshidrogenasa/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/genética , Contaminantes Químicos del Agua/administración & dosificaciónRESUMEN
In the present study, full-length cDNA sequences of leptin (LEP), leptin receptor (LEPR) and leptin receptor overlapping transcript (LEPROT) were cloned from yellow catfish Pelteobagrus fulvidraco, and their tissue distribution profiles were determined. The validated cDNA of yellow catfish leptin (ycLEP), leptin receptor (ycLEPR) and LEPROT were 1119, 4195 and 827bp in length, encoding the peptide of 172, 1086 and 130 amino acid residues, respectively. The phylogenetic analysis revealed that fish LEP, LEPR and LEPROT were separated from tetrapod, and also ycLEPS were separated from other fish species. The ycLEP mRNA expression levels were highest in liver, followed by ovary, mesenteric fat and spleen, and lowest in intestine, heart, muscle, pituitary and testis. The ycLEPR mRNA levels were highest in pituitary, intermediate in mesenteric fat, liver, ovary, muscle and spleen, and lowest in heart, intestine and testis. The ycLEPROT mRNA levels were highest in pituitary, followed by spleen, mesenteric fat, heart, ovary, liver, muscle, testis and intestine. Identification and tissue distribution of yellow catfish LEP, LEPR and LEPROT genes provided initial step towards understanding their biological roles in yellow catfish.
Asunto(s)
Bagres/metabolismo , Proteínas de Peces/genética , Leptina/genética , Receptores de Leptina/genética , Animales , ADN Complementario/genética , Leptina/clasificación , Filogenia , Receptores de Leptina/clasificaciónRESUMEN
The present study was performed to evaluate the effects of calcium (Ca) pre-exposure and then waterborne cadmium (Cd) exposure on metal element accumulation, enzymatic activities, histology, and ultrastructure in Synechogobius hasta and test the hypothesis that Ca could protect against Cd-induced toxicity in the fish species. Three hundred sixty fish [initial mean weight 25.5 ± 0.1 g (mean ± SEM)] were stocked in 18 circular fiberglass tanks (water volume: 300 l), 9 of which were pre-exposed to Ca at a rate of 400 mg Ca/l for 9 days and then exposed to concentrations of 0, 79.3, and 158.6 µg Cd/l for 9 days. Another 9 tanks were cultured in natural seawater (no extra Ca addition) for 9 days and then exposed to concentrations of 0, 79.3, and 158.6 µg Cd/l for 9 days. Both Ca pre-exposure and then waterborne Cd exposure influenced the accumulation of metal elements [cadmium (Cd), copper, zinc, and iron] in several tissues (muscle, gill, liver, spleen, and intestine), changed hepatic intermediary metabolism, and induced histological and ultrastructural alterations in tissues. In general, Ca pre-exposure seemed to mitigate the severity of Cd-induced mortality and histopathological injuries indicating that Ca pre-exposure had the capacity to decrease Cd toxicity in S. hasta.