Biomarcadores de estrés oxidativo en las branquias del bivalvo Mactra stultorum expuesto a acrilamida

Acrylamide (ACR) is among the most deleterious pollutants in the environment and presents a serious risk to humans and ecosystems. The purpose of this study was to assess its effects when administered at different concentrations (5, 10 and 20 mg L–1) to evaluate antioxidant status in the gills of Mactra stultorum. Our results showed, after five days of treat­ment, an increase in malondialdehyde (MDA), lipid hydroperoxides (LOOH), advanced oxidation protein products (AOPP), reduced glutathione (GSH), ascorbic acid (Vit C) and metallothionein (MDA) levels in gills of treated clams compared with controls. Moreover, an increase in superoxide dismutase (SOD) and a significant decrease in glutathione peroxidase (GPx) activities were also observed. Acrylamide induced neurotoxicity, as evidenced by the inhibition of acetylcholinesterase (AChE) activity in a dose-dependent manner. Overall, our results indicated that oxidative stress may be considered one of the mechanisms behind acrylamide toxicity in bivalves, although the subject requires more research.La acrilamida (ACR) es uno de los contaminantes más perjudiciales en el medio ambiente y presenta un grave riesgo para los seres humanos y los ecosistemas. El objetivo de este estudio es evaluar los efectos del ACR administrado a diferentes concentraciones (5, 10 y 20 mg L–1) con el fin de evaluar el estado antioxidante en las branquias de Mactra stulto­rum. Nuestros resultados mostraron, después de 5 días de tratamiento, un aumento en los niveles de malondialdehído (MDA), hidroperóxidos lipídicos (LOOH), proteínas de oxidación avanzada (AOPP), glutatión reducido (GSH), ácido ascórbico (vit C) y metalotioneínas (MTs) en las branquias de las almejas tratadas en comparación con los controles. Además, también se observó un aumento en la superóxidodismutasa (SOD) y una disminución significativa en las actividades de glutatión pero­xidasa (GPx). La acrilamida indujo neurotoxicidad como lo demuestra la inhibición de la actividad de la acetilcolinesterasa (AChE) de una manera dependiente de la dosis. En general, nuestros resultados indicaron que el estrés oxidativo puede con­siderarse como uno de los mecanismos detrás de la toxicidad por ACR en los bivalvos, aunque el tópico debería beneficiarse de más investigaciones

AVALIAÇÃO DA CAPTAÇÃO DE OLIGOELEMENTOS NO CARANGUEJO INVASIVO PORTUNUS SEGNIS HEPATOPANCREAS USANDO UMA ABORDAGEM BIOQUÍMICA MULTIVARIADA

In the current investigation, we evaluated the biological consequences of trace elements contamination in the two Tunisian gulfs (Gabes gulf and Tunis gulf) on the blue swimming crabs hepatopancreas (Portunus segnis). The concentrations of three trace elements (cadmium, copper, and lead) in the hepatopancreas P.segnis were evaluated. Additionally, acetylcholinesterase (AChE), metallothioneins (MTs), hydroxide peroxidase (H2O2) and advanced oxidation protein products (AOPP) levels, were chosen as measurements to evaluate the environmental effects on the two crabs’ populations from different gulfs. Macromolecular (lipids, proteins, and DNA) were also determined in P.segnis hepatopancreas. The results of trace elements bioaccumulation in soft P. segnis hepatopancreas showed a high pollution in the Gabes gulf as evidence by significant accumulation of cadmium, cooper, and lead. These findings were confirmed by significant increases of metal pollution index (MPI) and metallothioneins (MTs) levels in the hepatopancreas of P. segnis from Gabes gulf than these from Tunis gulf. Consequently, the trace elements accumulation in P.segnis from Gabes gulf conduct to the generation of lipid peroxidation processes as documented by the high levels of H2O2and LOOH. A significant decrease of AChE activity was recorded in crabs collected from Gabes gulf as compared to these from Tunis gulf. The present study revealed depletion of proteins and lipids contents, while DNA showed significant degradation on crab hepatopancreas collected from Gabes gulf comparing to Tunis gulf. These evidences must be taken in consideration when using P. segnis as an ecological indicator species in the biomonitoring programs.Na investigação atual, avaliamos as consequências biológicas da contaminação por oligoelementos nos dois golfos tunisinos (Golfo de Gabes e Golfo de Tunísia) sobre os caranguejos nados azuis hepatopâncreas (Portunus segnis). Foram avaliadas as concentrações de três oligoelementos (cádmio, cobre e chumbo) no hepatopâncreas P.segnis. Além disso, os níveis de acetilcolinesterase (AChE), metalotioninas (MTs), peroxidase hidróxida (H2O2) e produtos de proteína de oxidação avançada (AOPP) foram escolhidos como medidas para avaliar os efeitos ambientais nas populações dos dois caranguejos de diferentes golfos. Macromoleculares (lipídios, proteínas e DNA) também foram determinados em P.segnis hepatopâncreas. Os resultados da bioacumulação de elementos vestigiais em P. segnis hepatopancreas mole mostraram uma alta poluição no Golfo de Gabes como evidência pelo acúmulo significativo de cádmio, cobre e chumbo. Estes resultados foram confirmados por aumentos significativos do índice de poluição de metais (MPI) e dos níveis de metalotioninas (MTs) no hepatopâncreas de P. segnis do Golfo de Gabes do que estes do Golfo de Tunísia. Consequentemente, o acúmulo de elementos vestigiais em P.segnis do Golfo de Gabes conduz à geração de processos de peroxidação lipídica, como documentado pelos altos níveis de H2O2e LOOH. Uma diminuição significativa da atividade de AChE foi registrada em caranguejos coletados do Golfo de Gabes em comparação com estes do Golfo de Tunísia. O presente estudo revelou esgotamento de proteínas e conteúdo de lipídios, enquanto o DNA mostrou degradação significativa no hepatopâncreas de caranguejo coletado do Golfo de Gabes em comparação com o Golfo de Tunísia. Estas evidências devem ser levadas em consideração ao utilizar P. segnis como uma espécie indicadora ecológica nos programas de biomonitoramento

Evaluación del estrés oxidativo, genotoxicidad y respuestas histopatológicas en la glándula digestiva Ruditapes decussatus recolectada de las lagunas del norte de Túnez

The aim of the present study was to investigate the combined effects of seasonality and anthropogenic pressure on a battery of oxidative stress, lipid peroxidation, protein oxidation, DNA damage and histological alterations in the native clam Ruditapes decussatus collected from a less contaminated area (LCA), Ghar El Melh, a moderately contaminated area (MCA), the North Lake, and a highly contaminated area (HCA), the South Lake, all located in the southern Mediterranean Sea. The accumulation of cadmium, lead, copper, iron and zinc was higher in the digestive glandsof clams collected from the MCA and the HCAthan in those from the LCA, particularly during the warm season. Our results reveal that metallothionein, lipid peroxidation, protein oxidation levels and antioxidant defence systems were higher, while acetylcholinesterase activity was lower, in clams from the MCAand HCAthan in those from the LCA. The results also indicate that clams from the MCA and the HCAare characterized by histological alterations and DNA damage. In conclusion, the evident changes of antioxidant defence systems and macromolecules between the studied lagoons reveal the perturbation of the physiological states of clams from polluted sites thatcope with seasonal changes and trace element accumulations.El objetivo del presente estudio es investigar los efectos combinados de la estacionalidad y la presión antropogénica en una batería de estrés oxidativo, peroxidación lipídica, oxidación de proteínas, daños en el DNA y alteraciones histológicas en la almeja nativa Ruditapes decussata recolectada de un área menos contaminada (Ghar El Melh «LCA») y de dos sitios con diferentes niveles de contaminación (la laguna norte «MCA» y la laguna sur «HCA» de Túnez) en el sur del mar Mediterráneo. La acumulación de cadmio, plomo, cobre, hierro y zinc fue mayor en la glándula digestiva de las almejas recolectadas de la MCA y la HCA en comparación con las de la LCA, particularmente durante la estación cálida. Nuestros resultados revelan que la metalotioneína, la peroxidación lipídica, los niveles de oxidación de proteínas y los sistemas de defensa antioxidante aumentaron, mientras que la actividad de la acetilcolinesterasa disminuyó en las almejas del área moderadamente y altamente contaminada en comparación con la menos contaminada. Los resultados también indican que las almejas del MCA y el HCA se caracterizan por varias alteraciones histológicas y daños en el ADN. En conclusión, los cambios evidentes de los sistemas de defensa antioxidante y las macromoléculas entre las lagunas estudiadas revelan la perturbación de los estados fisiológicos de las almejas de los sitios contaminados que hacen frente a los cambios estacionales y las acumulaciones de metales

Citrus aurantium L. peel extract mitigates hexavalent chromium-induced oxidative stress and cardiotoxicity in adult rats

In the present study, we aimed to examine the potential protective effect of C. aurantinum L. peel extract against oxidative damage induced by hexavalent chromium in the heart of adult rats. Rats were divided into six groups. Group I served as controls and received standard diet. Group II received via drinking water potassium dichromate (K2Cr2O7) alone (700 ppm) during 3 weeks. Groups III and IV were pre-treated for 10 days by gavage with the ethanolic extract of C. aurantium peels at doses of 100 and 300 mg/kg body weight/day, respectively, and then K2Cr2O7 was administrated during 3 weeks. Groups V and VI received by gavage only C. aurantium peel ethanolic extract at doses of 100 and 300 mg/kg body weight/day, respectively, during 10 days. K2Cr2O7 treatment increased the cardiac levels of malondialdehyde (MDA), protein carbonyls (PCO), advanced oxidation protein products (AOPP), non-protein thiols, glutathione and vitamin C, as well as the activities of catalase, superoxide dismutase and glutathione peroxidase. Cardiac histological alterations, manifested by hemorrhage and cytoplasmic vacuolization, were also observed. Pre-treatment with C. aurantium peel extract (300 mg/kg) attenuated significantly the biochemical and histopathological changes observed following K2Cr2O7 exposure in rat’s heart. Our findings indicated that C. aurantium peel extract was able to hamper K2Cr2O7-induced myocardial injury, which could be attributed to its antioxidant activity

Fenthion, an organophosphorus pesticide, induces alterations in oxidant/antioxidant status and histopathological disorders in cerebrum and cerebellum of suckling rats

293-301Fenthion (FEN) is an organophosphorus pesticide known for its wide toxic manifestations. In this study, the effects of FEN were evaluated on the cerebrum and cerebellum oxidant/antioxidant status and histopathological disorders in the suckling rats. Pregnant rats were divided into two groups: control group received pure water, while FEN group received daily by their drinking water 551 ppm of FEN from the 14th day of pregnancy until day 14 after delivery. Acetylcholine esterase (AChE) activity was inhibited in both the cerebrum and cerebellum of suckling rats whose mothers were treated with FEN. The cerebrum and cerebellum oxidative damage was demonstrated by a significant increase of malondialdehyde (MDA), advanced oxidation protein product and glutathione (GSH) levels and disturbance in the antioxidant enzyme activities. A significant decline of non-protein thiol and vitamin C levels was also observed. These changes were confirmed by histopathological observations which were marked by pyknotic neurons in the cerebrum and apoptotic cells in the cerebellum of FEN-treated rats. In the cerebellum of <span style="mso-ansi-language: EN-US" lang="EN-US">FEN-treated rats, the most conspicuous damage was the absence of external granular layer, indicating growth retardation. These data suggested that exposure of pregnant and lactating rats to FEN induced oxidative stress and histopathological disorders in the cerebrum and cerebellum of their pups. Thus, the use of FEN must be under strict control, especially for pregnant and lactating mothers. </span

Reproductive cycle and gonad development of the commercial clam Donax trunculus from the Bay of Tunis (Northern Tunisia, South Mediterranean coast): Effects of environmental variability

In Tunisia the commercial exploitation of Donax trunculus is limited to the unregulated catches which threaten the biological sustainability of this species. Knowledge of the gametogenic development of a species is a prerequisite for proper management and sustainable exploitation of this fishery. The reproductive cycle of D. trunculus from the Bay of Tunis was carried out between November 2006 and January 2008, using the dry weight changes, the histological examination of the gonad and the measurement of oocyte size. Results showed that, sex ratio were in favor of males without any hermaphroditism. The gametogenesis activity of both sexes, started with decreasing seawater temperature during late autumn and the main spawning event took place from June to October when temperatures rose. During this time, clams loose, gradually, their weights and condition and maturity indices reached their lowest values immediately after spawning period. The mean oocyte diameter varied significantly between 12.1 ± 9.8 urn in early gametogenesis and 45.9 ±13.6 um during maturity. Considering these data, a closed season from May to July coinciding with the most intensive gamete release should be considered for the preservation and the management of the natural stock of D. trunculus from the Bay of Tunis.Peer Reviewe

Effect of Freezing Process on the Chemical Properties of Blue Swimming Crab Portunus segnis: Storage Stability and Acceptability

peer reviewedThe effect of frozen storage at a commercial temperature (−30°C) on the nutritional characteristics of the blue swimming crab Portunus segnis for a period of 120 days was investigated. Lipid and protein oxidation was investigated by analyses of peroxide value, thiobarbituric acid reactive substances, free fatty acids, and advanced oxidation protein products. Results showed significant lipid deterioration with extended storage time and changes in fatty acids composition and lipid classes. From a nutritional standpoint, it would be preferable for human consumption to eat frozen crabs for no more than 30 days as they retain a higher nutritional value

Metal body burden and tissue oxidative status in the bivalve Venerupis decussata from Tunisian coastal lagoons

Coastal transitional waters are exposed to many anthropogenic threats. This study aims to assess the trace metals' pollution status of transitional waters by evaluating its biological effects in the clam Venerupis decussata. Among the studied sites along the Tunisian littoral, South Tunis and Boughrara were the most impacted, since clams from these two lagoons presented significant differences in: (i) trace metal contents, (ii) in-cell hydrogen peroxide, (iii) enzymatic and non-enzymatic defenses, (iv) damage to lipids and proteins, and (v) protein post-translational modifications. These changes related to evident histopathological traits. PCA showed a clear separation between the digestive gland and gills tissues and illustrated an impact gradient in Tunisian coastal lagoons. Water temperature was revealed as an added natural stressor that, when concurring with high pollution, may jeopardize an ecosystem's health and contribute to the accumulation of hazardous metals in organisms.This study was supported by the Spanish Ministry of Economy and Competitiveness -CTM2016-75908-R-, by the Andalusian Plan of Research, Development, and Innovation, and by the University of Cordoba “Plan Propio” program to group BIO187 (Spain). Safa Bejaoui stay in Cordoba was funded by the Tunisian government, Ministry of Higher Education and Scientific Research, University of Tunis EL Manar, Laboratory of Ecology, Biology and Physiology of Aquatic Organisms -EBPAO, LR18ES41- (Tunisia). Pedro M. Costa acknowledges Fundação para a Ciência e Tecnologia -FCT-MCES- for the grant IF/00265/2015 and for the support to UCIBIO, Applied Molecular Biosciences Unit -UID/Multi/04378/2019- (Portugal).Peer reviewe

Nitraria retusa fruit prevents penconazole-induced kidney injury in adult rats through modulation of oxidative stress and histopathological changes

Context: Nitraria retusa (Forssk.) Asch. (Nitrariaceae) is a medicinal plant which produces edible fruits whose antioxidant activity has been demonstrated. Objective: The current study elucidates the potential protective effect of N. retusa fruit aqueous extract against nephrotoxicity induced by penconazole, a triazole fungicide, in the kidney of adult rats. Materials and methods: Adult Wistar rats were exposed either to penconazole (67 mg/kg body weight), or to N. retusa extract (300 mg/kg body weight) or to their combination. Penconazole was administered by intra-peritoneal injection every 2 days from day 7 until day 15, the sacrifice day, while N. retusa extract was administered daily by gavage during 15 days. Oxidative stress parameters, kidney biomarkers and histopathological examination were determined. Results: Nitraria retusa extract administration to penconazole treated rats decreased kidney levels of malondialdehyde (−10%), hydrogen peroxide (−12%), protein carbonyls (PCOs, −11%) and advanced oxidation protein products (AOPP, −16%); antioxidant enzyme activities: catalase (−13%), superoxide dismutase (−8%) and glutathione peroxidase (GPx, −14%), and the levels of non-enzymatic antioxidants: non-protein thiols (−9%), glutathione (−7%) and metallothionein (−12%). Furthermore, this plant extract prevented kidney biomarker changes by reducing plasma levels of creatinine, urea, uric acid and LDH and increasing those of ALP and GGT. Histopathological alterations induced by penconazole (glomeruli fragmentation, Bowman’s space enlargement, tubular epithelial cells necrosis and infiltration of inflammatory leucocytes) were attenuated following N. retusa administration. Discussion and conclusion: Our results indicated that N. retusa fruit extract had protective effects against penconazole-induced kidney injury, which could be attributed to its phenolic compounds

Potential antioxidant effects of Narcissus tazetta phenolic compounds against cadmium chloride–induced hepatotoxicity in Swiss albino mice

3 Figuras.-- 5 TablasNarcissus tazetta (Amaryllidaceae) is a medicinal plant widely used for cut flowers and potted ornamental plant in Tunisia flora. The current study evaluated the phenolic composition and antioxidant properties of its flower extracts and investigated its potential protective activity against cadmium chloride (CdCl)–induced hepatotoxicity in mice. Mice were divided into six groups of six each: group 1, serving as negative controls, received by intraperitoneal way only distilled water; group 2 received by intraperitoneal way CdCl (0.16 mg/kg bw); groups 3 and 4 received CdCl at the same dose of group 2 and 100 or 200 mg/kg bw of Narcissus tazetta flower extracts via oral route; groups 5 and 6, serving as positive controls, received only Narcissus tazetta flower extracts. Polyphenolic compounds of the extract were analyzed by colorimetric and high-performance liquid chromatography-mass spectrometry (HPLC-MS) methods. Total antioxidant activity and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging potential of the extract were estimated using colorimetric method. Results indicated that ethanolic flower extract contained high levels of total phenolic and flavonoid along with a strong total antioxidant and DPPH free radical scavenging activities. HPLC-MS analysis identified eight phenolic compounds, including rutin, kaempferol glycosides, and chlorogenic acids. The extract also exhibited marked hepatoprotective effects against CdCl toxicity by reducing hepatic levels of malondialdehyde, advanced oxidation protein products, hydrogen peroxide, metallothioneins, and DNA degradation. Additionally, co-administration of Narcissus tazetta flower extracts lowered the plasma activities of transaminases, gamma glutamyl transpeptidase, and lactate dehydrogenase and increased hepatic levels of reduced glutathione, nonprotein thiols, vitamin C, and catalase activity. The hepatoprotective effects of the extract were demonstrated by histopathological improvement of liver disorders. The current study provided ethnopharmacological application of Narcissus tazetta flower extracts against CdCl-induced oxidative stress suggesting its chemoprevention role of its phenolic compounds as a natural antioxidant.This work received financial assistance from the Ministry of Higher Education and Scientific Research of Tunisi