Effects of directional adaptation on selenium tolerance and accumulation of heterotrophic Chlorella pyrenoidosa / 生物工程学报

Selenium (Se) is an essential trace element for organisms. Se deficiency will cause diseases such as Keshan disease and Kashin-Beck in human being, and huge loss to animal husbandry. Currently available Se supplements have such problems as low Se content, poor bioavailability, and poor safety. Chlorella pyrenoidosa can produce bioavailable and safe organic Se under suitable conditions, which is thus a promising Se supplement. Therefore, in this study, we tried to improve the Se tolerance and accumulation of C. pyrenoidosa by directional adaptation. To be specific, we gradually increased the concentration of Na2SeO3 in medium to domesticate C. pyrenoidosa and optimized the adapting time and concentration gradient of Na2SeO3 during the adaptation. The results showed that the adapted C. pyrenoidosa was more tolerant to Se and had stronger Se enrichment ability. In 5 L fermenter, the adapted strains could tolerate 40 mg/L Na2SeO3 and the synthesis rate of organic Se was 175.6% higher. Then, Se addition method in the 5 L fermenter was optimized. The result demonstrated that addition of Na2SeO3 at 40 mg/L during heterotrophic culture achieved the final dry weight of C. pyrenoidosa cells at 106.4 g/L, content of organic Se at 1 227 mg/kg, and synthesis rate of organic Se at 1.36 mg/(L·h). Compared with the reported highest cell density of 75 g/L and the highest organic Se content of 560 mg/kg, the corresponding figures in this study were 41.9% and 119.1% higher, respectively. In conclusion, directional adaptation can remarkably improve the Se tolerance and enrichment of C. pyrenoidosa.

The protective role of selenium against dental amalgam-induced intracellular oxidative toxicity through the TRPV1 channel in DBTRG glioblastoma cells

Abstract Objective The exposure to mercury (Hg) from dental amalgams is a suspected causative factor in neurological diseases. This study investigated the toxic effects of two different amalgam compositions related to Hg and the protective effects of selenium against the toxic effects of Hg through the TRPV1 channel in the human DBTRG glioblastoma cell line. Methodology Six groups of the cells were organized. Analyses of cell viability, apoptosis, caspase 3 and caspase 9 activities, mitochondrial membrane depolarization, reactive oxygen species (ROS) production, and Western Blotting for protein expression levels were performed. Results Cell viability values were lower in amalgam with high copper (HCu) and low copper (LCu) groups independently of time but were increased by selenium and capsazepine (p<0.001 and p<0.05). Conversely, apoptosis rates, caspase 3 and caspase 9 expression, ROS formation, mitochondrial membrane depolarization, and protein expression levels were higher in the HCu and LCu groups but were decreased by selenium (p<0.001 and p<0.05). Conclusions Selenium combined with an amalgam of either HCu or LCu decreases the toxic effects created by Hg in human DBTRG glioblastoma cells.

Antioxidant activity of selenium on bisphenol-induced apoptosis and testicular toxicity of Albino rats / Actividad antioxidante el selenio sobre la apoptosis inducid por bisfenol y toxicidad testicular en ratas albinas

SUMMARY: Bisphenol A (BPA) is an industrial chemical widely used to make polycarbonate plastics for packaging and epoxy resins. This study sought to examine how selenium (Se) affects BPA toxicity in terms of albino rats' histological structure, antioxidant enzymes and reproductive organs (seminiferous tubules). Twenty-four adult male rats were divided into four experimental groups: Group 1: Control; Group 2: Orally administered BPA; Group 3: Orally administered sodium selenite; Group 4: Treated daily with BPA followed by selenium (Se). All experiment done for 4 weeks. BPA exposure caused changes in the testicular histological structure, which consists apoptosis, and led to changes in several biochemical markers: Malondialdehyde, catalase, superoxide dismutase, and glutathione peroxidase. However, these BPA side effects may be ameliorated in rats treated with BPA-plus-Se. These protective effects of Se may attributable to its ability to remove potentially damaging oxidizing agents in living organisms. The results may confirm that Se countered the oxidant effects and increased the BPA-induced stress response in rats. So, Se promotes the healthy growth and development of mammals by protecting them from oxidative stress. As human are greatly exposed to BPA and it can accumulate in tissues, there is concern about human reproductive functions particularly for occupational workers exposed usually to greater levels of BPA. Thus, the use of BPA in multiple industries must be restricted and the inaccurate usage of plastic containers should be avoided to decrease the health hazards. Administration of Se may protect against the adverse effects of BPA on reproductive functions and structures.

RESUMEN: El bisfenol A (BPA) es un químico industrial ampliamente utilizado para fabricar plásticos de policarbonato para envases y resinas epoxi. Este estudio examinó el efecto de selenio (Se) en la toxicidad del BPA en términos de la estructura histológica, enzimas antioxidantes y los órganos reproductivos (túbulos seminíferos) de ratas albinas. Se dividieron veinticuatro ratas macho adultas en cuatro grupos experimentales: Grupo 1: control; Grupo 2: BPA administrado por vía oral; Grupo 3: BPA administrado por vía oral para; Grupo 4: tratado diariamente con BPA seguido de selenio (Se). El experimento se realizó durante cuatro semanas y se observó que la exposición al BPA provocó cambios en la estructura histológica testicular, incluyendo apoptosis, y alteraciones en varios marcadores bioquímicos:malondialdehído, catalasa, superóxido dismutasa y glutatión peroxidasa. Sin embargo, estos efectos secundarios del BPA pueden mejorar en ratas tratadas con BPA-plus-Se. Estos efectos protectores del Se pueden ser atribuidos a la capacidad de eliminar agentes oxidantes potencialmente dañinos en organismos vivos. Los resultados indicaron que se contrarrestaron los efectos oxidantes y aumentó la respuesta al estrés inducido por BPA en ratas, y favorece el crecimiento y desarrollo en los mamíferos al protegerlos del estrés oxidativo. Debido a la exposición al BPA en el ser humano, se puede acumular en los tejidos, por lo que existe una preocupación por el daño a las funciones reproductivas en particular de los trabajadores que generalmente están expuestos a niveles más altos de BPA. Por lo tanto, se debe restringir el uso de BPA en las industrias y evitar el uso incorrecto de envases de plástico para así disminuir los riesgos para la salud. La administración correcta de Se puede proteger contra los efectos adversos del BPA en las funciones y estructuras reproductivas.

Efeito do consumo de castanhas-do-brasil (Bertholettia excelsa H.B.K. ) sobre os biomarcadores inflamatórios e o estado nutricional relativo ao selênio de mulheres obesas / Effect of Brazil nut (Bertholettia excelsa H.B.K. ) consumption on inflammatory biomarkers and nutritional status of selenium in obese women

A inflamação e o estresse oxidativo são processos que ocorrem simultaneamente na obesidade e contribuem para o aumento da síntese de mediadores inflamatórios e de espécies reativas de oxigênio e nitrogênio. O mineral selênio (Se), cuja principal fonte alimentar é a castanha-do-brasil, possui propriedades antioxidantes e anti-inflamatórias. Considerando a importância do processo inflamatório na obesidade e o potencial papel do Se como anti-inflamatório por meio da atuação de selenoproteínas, o estudo da influência deste micronutriente neste contexto é de grande relevância. Desse modo, o objetivo deste estudo foi avaliar o efeito do consumo da castanha-do-brasil sobre os biomarcadores inflamatórios e o estado nutricional relativo ao Se de mulheres obesas. No total, foram recrutadas 72 participantes alocadas randomicamente no grupo que consumiu a castanha-dobrasil (BN) ou no grupo controle (CO) e, acompanhadas por um período de 2 meses. O grupo BN consumiu 1 unidade de castanha-do-brasil (~409,5 µg/Se) por dia e o grupo CO não recebeu nenhum tipo de intervenção. Antes e após o período da intervenção, foram realizadas as avaliações antropométrica e do consumo alimentar, e dos parâmetros bioquímicos relacionados ao Se, estresse oxidativo, perfil lipídico e biomarcadores inflamatórios. Completaram o estudo 29 participantes do grupo BN e 26 do grupo CO com idade média de 40,3 (9,0) e 39,4 (9,5) anos (p=0,714), respectivamente. No baseline do estudo, observou-se que a população estudada não apresentava deficiência de Se. No grupo BN, verificou-se um aumento de todos biomarcadores de Se avaliados. Após 8 semanas de intervenção, um aumento significativo foi observado na expressão gênica de diversos parâmetros pró-inflamatórios no grupo BN (IL-6, TNF-α, TLR2 e TLR4). Apesar de não ter havido mudanças nas concentrações plasmáticas referentes a estes parâmetros, o aumento significativo da expressão gênica pode ser um indicativo de estímulo pró-inflamatório induzido pelo consumo da castanha-do-brasil com altas concentrações de Se

Inflammation and oxidative stress are processes that occur simultaneously in obesity and contribute to an increase in the synthesis of inflammatory mediators and reactive oxygen and nitrogen species. The mineral selenium (Se), whose main food source is the Brazil nut, has antioxidant and anti-inflammatory properties. Considering the importance of the inflammatory process in obesity and the potential role of Se as an anti-inflammatory by means of selenoproteins, the study of the influence of this micronutrient in this context is of great relevance. Thus, the aim of this study was to evaluate the effect of Brazil nut intake on inflammatory biomarkers and nutritional status of Se in obese women. In total, 72 participants randomly assigned to Brazil nut group (BN) or control group (CO) were recruited and followed up for 2 months. The BN group consumed 1 unit of Brazil nut (~ 409.5 µg/Se) per day and the CO group did not received any intervention. On baseline and after two months of follow-up, the evaluation of anthropometry and food consumption, and of the biochemical parameters related to Se, oxidative stress, lipid profile and inflammatory biomarkers were performed. Twenty-nine participants of BN group and twenty-six of the CO group completed the trial, with a mean age of 40.3 (9.0) and 39.4 (9.5) years (p= 0.714), respectively. At the baseline of the study, it was observed that this population did not present Se deficiency. In BN group, there was an increase in all Se biomarkers evaluated. After 8 weeks of intervention, a significant increase was observed in gene expression of several pro-inflammatory parameters in BN group (IL-6, TNF-α, TLR2 and TLR4). Although there have been no changes in plasma concentrations related to these parameters, a significant increase in gene expression may be an indicative of a pro-inflammatory stimulus induced by the intake of Brazil nuts with high Se concentrations

Experimental furcal perforation treated with mineral trioxide aggregate plus selenium: immune response

Abstract The aim of this study is to evaluate the expression of cytokines in response to mineral trioxide aggregate (MTA) plus selenium in germ-free mice with experimental furcal perforation. The first left maxillary molar was opened, and the furcal area was perforated and treated with post-MTA-Se (experimental group). The same surgical intervention was performed for the maxillary right first molar, which was treated with MTA (control group). Fifteen mice were sacrificed 7, 14, and 21 days after furcal perforation, and periapical tissue samples were collected. The mRNA expression levels of the cytokines TGF-β, TNF-α, IFN-γ, HPRT, IL-10, IL-4, RANK, RANKL, IL-1, and IL-17 were assessed by using real-time polymerase chain reaction. In the experimental group, at 21-days post-MTA-Se sealing, the mRNA levels of TNF-α and IL-10 were upregulated compared with those in the control group (p < 0.05). Futher assessment revealed basal mRNA expression levels of IL-1α, IFN-γ, RANK, RANKL, IL-17A, IL-4, and TGF-β, over long experimental times, in both the experimental and control groups (p > 0.05). In conclusion, MTA+Se sealing favoured increased expression of IL-10 and TNF-α at later time points (day 21).

Antioxidant effect of quinoline derivatives containing or not selenium: Relationship with antinociceptive action quinolines are antioxidant and antinociceptive

ABSTRACT The present study investigated the antioxidant effect of a new class of quinoline derivatives (a-d) on assays in vitro. Lipid peroxidation, thiol peroxidase-like and free radical scavenging activities were determined to evaluate antioxidant activity of compounds. Thiol oxidase-like and δ-aminolevulinate dehydratase activities were performed as a toxicological parameter. A second objective of this study was to evaluate the in vivo antinociceptive effect of the compound with better antioxidant effect and without toxic effects in a model of nociception induced by formalin in mice. In liver, at 100 µM, compound a reduced the lipid peroxidation to the control levels, while compounds c and d partially reduced it. In brain, only compound d partially reduced the lipid peroxidation at 50 and 100 µM. Compound b did not have an effect on the lipid peroxidation. Thiol peroxidase-like and free radical scavenging activities are not involved in the antioxidant mechanisms of these compounds. Compounds did not present thiol oxidase-like activity and effect on the δ-aminolevulinate dehydratase. In vivo experiments showed that compound a caused an inhibition of licking time in the first and second phases, and edema formation induced by formalin. In conclusion, quinoline derivative without selenium presented better in vitro antioxidant effect and in vivo antinociceptive activity.

[Assessment of aerobic training with selenium nanoparticles supplementation effects on cytokines levels of liver tissue in 4T1 breast cancer mice]

Introduction: The liver is known as a tissue highly sensitive to immunological changes such as cytokines activity. It has been shown that using selenium nanoparticle supplementation and exercise training separately can effectively decrease tumor volume and improve immune responses. The aim of this study was to examine the effects of aerobic interval training and supplementation of selenium nanoparticles on protein expression of cytokines in liver tissue in mice with breast cancer

Materials and Methods: Sixty-four Balbc mice were divided into eight groups. Experimental groups received aerobic interval training and selenium nanoparticles supplementation orally for 6 weeks, before and after cancer induction. At the end of the sixth week, after tumor injection, proteins levels of IL-6, IL-4, TNF-alpha and INF-gamma were measured in liver tissue by the enzyme-linked immunosorbent assay [ELISA] method

Results: Results of the current study showed that IL-6, TNF-alpha and IL-4 protein levels decreased in liver tissue of the breast cancer tumor [P<0.05]. Aerobic interval training caused significant increase in IL-6 and TNF-alpha protein levels in liver tissue [P<0.05]. Increase in INF-gamma cytokine levels in liver tissue was also observed, following selenium nanoparticle supplementation [P<0.05]. Results also showed that tumor volume decreased following exercise training and administration of selenium nanoparticles administration

Conclusion: Cytokines changes in liver tissue occurred in conjunction with decrease in tumor volume. It is possible that simultaneously using selenium nanoparticles and exercise training with immune system reinforcement could help in reducing tumor volume and modulating cytokine levels in liver

Selenium protects cerebral cells by cisplatin induced neurotoxicity

PURPOSE: To evaluate the central nervous system toxicity of cisplatin and neuroprotective effect of selenium. METHODS: Twenty-one male Wistar albino rats were divided into three groups: control (C), cisplatin (CS), cisplatin and selenium (CSE, n=7 in each group). Cisplatin (12 mg/kg/day, i.p.) was administered to CS and CSE groups for three days. Furthermore, CSE group received 3mg/kg/day (twice-a-day as 1.5 mg/kg) selenium via oral gavage five days before cisplatin injection and continued for 11 consecutive days. The same volumes of saline were administered to C group intraperitoneally and orally at same time. RESULTS: Heterochromatic and vacuolated neurons and dilated capillary vessels in the brain were observed in the histochemical examinations of cisplatin treated group. Rats that were given a dose of 3mg/kg/day selenium decreased the cisplatin induced histopathological changes in the brain, indicating a protective effect. In addition, cytoplasmic staining of the cell for bcl-2, both cytoplasmic and nuclear staining for bax were determined to be positive in the all groups. Bax positive cells were increased in the CS group compared to C group, in contrast to decreased bcl-2 positivity. CONCLUSION: Selenium limited apototic activity and histological changes due to the cisplatin related central neurotoxicity. .

Participação do selênio no diabetes mellitus tipo 2 / Participation of selenium in type 2 diabetes mellitus

OBJECTIVE: This review aims to bring updated information on the relationship between oxidative stress and the role of selenium as antioxidant nutrient in mechanisms involved in the pathogenesis of type 2 diabetes mellitus. Data source: The bibliographic survey was conducted in PubMed, SciELO and Lilacs, considering the 2002-2014 period, and included the following types of studies: randomized or quasi-randomized controlled trials, cohort, case-control study, case series and case report. Forty-nine pertinent scientific studies were selected. Data synthesis: Several studies have demonstrated the contribution of acute and/or chronic hyperglycemia to the manifestation of oxidative stress in type 2 diabetic patients. Accordingly, selenium has an important participation in controlling this disease due to its antioxidant role in the elimination of free radicals, present in excess, and because it blocks the activation of nuclear transcription factor kappa B, a regulator sensitive to oxidants that stimulates the production of inflammatory mediators (cytokines) and adhesion molecules. CONCLUSIONS: There is convincing experimental evidence demonstrating the involvement of selenium in glycemic control. However, current information is still scarce and inconsistent, and it is necessary to conduct further studies on the subject to determine the selenium intake safety range as well as clarify the influence of this mineral on the manifestation of type 2 diabetes mellitus and its associated disorders

OBJETIVO: Esta revisão visa trazer informações atualizadas sobre a relação entre o estresse oxidativo e o papel do selênio como nutriente antioxidante em mecanismos envolvidos na patogênese do diabetes mellitus tipo 2. Fonte de dados: O levantamento bibliográfico foi realizado nas bases de dados Pubmed, SciELO e Lilacs considerando o período de 2002 a 2014 e abrangeu os seguintes tipos de estudos: ensaios clínicos controlados randomizados ou quase-randomizados, coorte, estudo caso-controle, série de casos e relato de caso. Foram selecionados 49 que se relacionavam com esta pesquisa bibliográfica. Síntese dos dados: Várias pesquisas têm demonstrado a contribuição do estado hiperglicêmico agudo e/ou crônico na manifestação do estresse oxidativo em pacientes diabéticos tipo 2. Nesse sentido, o selênio possui participação importante no controle dessa doença, devido ao seu papel antioxidante na eliminação dos radicais livres, presentes em excesso, e por bloquear a ativação do fator de transcrição nuclear kappa B, um regulador sensível a oxidantes que estimula a produção de mediadores inflamatórios (citocinas) e de moléculas de adesão. CONCLUSÕES: Existem evidências experimentais convincentes que demonstram a participação do selênio no controle glicêmico. No entanto, as informações atuais ainda são bastante escassas e inconsistentes e faz-se necessária a realização de novos estudos sobre o tema a fim de determinar a faixa de segurança de ingestão de selênio, além de obter esclarecimentos acerca da influência do mineral sobre a manifestação do diabetes mellitus tipo 2 e das desordens a ele associadas

Inhibitory effect of zinc, copper and selenium on telomerase activity in tumor tissues and t47d breast cancer cell line

The present study was performed to investigate the effects of trace elements particularity Se, Zn and Cu on tumor genesis in breast cancer. The inhibitory effect of Se, Zn and Cu, on telomerase activity was analyzed in human breast tumor tissues and breast cancer [T47D] cells. Tissue specimens from 24 women with benign breast disease and 32 women with breast cancer specimens [ductal carcinoma, lobular carcinoma] were collected during surgery. In addition venous blood samples were obtained for assessing the trace elements. T47D cell line was cultured and treated with trace elements. Telomerase activity then was measured with TRAP assay in cell line and tissue extracts. There was a significant difference between tissue and serum levels of Cu, Se and the ratio of Cu/Zn in patients and controls [P<0.001]. After treating with 100 microm/L Zn So4, 10 um /L Cu So4 for 6 hours, telomerase activity of T47D cells was markedly increased. But after treating with 10, and 30 um /L selenium-L- methionin, telomerase activity was markedly inhibited. Telomerase activity of T47D cells for 24 hours were 0.93, 0.60 and for 48 hours were 0.76, 0.12 respectively [control 49.2%]. There were variations in serum level of Zn and Cu in breast cancer patients. Association between trace elements level and telomerase activity level can be exploited as prognostic and diagnostic marker for breast cancer

Efeitos antioxidantes do selênio e seu elo com a inflamação e síndrome metabólica / Selenium antioxidant effects and its link with inflammation and metabolic syndrome

O estado inflamatório crônico e de baixo grau bem como o estresse oxidativo associados à síndrome metabólica são fatores de risco relevantes para o desenvolvimento de doenças cardiovasculares. Neste contexto, o selênio é um mineral essencial que se encontra associado com o correto funcionamento dos principais processos metabólicos celulares. Estudos in vitro e in vivo em modelos experimentais de síndrome metabólica, bem como em humanos, tem investigado o efeito do selênio sobre a expressão e secreção de biomarcadores de inflamação e de estresse oxidativo. Para obtenção dos artigos sobre efeitos antioxidantes do selênio foram feitas pesquisas nos websites científicos. Na literatura encontramos numerosos artigos sobre os diferentes parâmetros modulados pelas concentrações plasmáticas de selênio, incluindo a proteína-C reativa, a interleucina-6, o fator de necrose tumoral-α, a interleucina-1β e a proteína transportadora de retinol-4. Esta revisão teve por objetivo discutir o papel do selênio nos processos inflamatórios e de estresse oxidativo, associados à síndrome metabólica.

The mild chronic inflammation and oxidative stress associated with metabolic syndrome are relevant risk factors for the development of cardiovascular diseases. In this context, selenium is an essential mineral associated with the correct functioning of the main metabolic processes of the cell. In vitro and in vivo studies in experimental metabolic syndrome models as well as in humans have investigated the effect of selenium on the expression and secretion of inflammation and oxidative stress biomarkers. Articles on the antioxidant effects of selenium were sought in scientific websites. There are a great number of studies in the literature on the different parameters modulated by blood selenium levels, such as C-reactive protein, interleukin-6, tumor necrosis factor-alpha, interleukin-1 beta and retinol binding protein 4. The objective of this review is to discuss the role of selenium in inflammatory and oxidative stress processes associated with the metabolic syndrome.

[Antioxidant effects of selenium on sperm parameters and testicular structure in young and aged mice]

Selenium, as an antioxidant, is essential for normal testicular function and spermatogenesis. It can reduce free oxidative radicals as a cofactor for antioxidant enzymes; therefore, it is expected to increase fertility. This experimental study was conducted to determine the effects of different doses of selenium on sperm parameters and testicular structure of aged and young mice. In this study, twenty 10 to 12-month and twenty 2 to 3-month old male mice were randomly divided into three control, sham and experimental groups. The control group received no injection but the sham and the experimental groups received daily intraperitoneal injectins of selenium solvent [Normal saline] and selenium, 0.2 mg/kg [Based on dose/response data], respectively over 5 weeks. Histological examinations as well as sperm analyses were performed on days 21, 28, 35 and 42 following the initiation of injections. Sperm analyses showed improvements especially in terms of normal morphology and viability rates in the experimental group [P<0.05]. Decreased sperm counts were evident in the aged mice at histological examination and some vacuoles were observable in the epithelium of seminiferous tubules. The results indicated that administration of 0.2 mg/kg selenium, improves some sperm parameters in the aged mice; thus, it seems that selenium effects are dose-dependent and appropriate amounts of the element can probably improve testicular function and sperm quality in the aged subjects

Selenium acts as an insulin-like molecule for the down-regulation of diabetic symptoms via endoplasmic reticulum stress and insulin signalling proteins in diabetes-induced non-obese diabetic mice.

To investigate whether selenium (Sel) treatment would impact on the onset of diabetes,we examined serum biochemical components including glucose and insulin,endoplasmic reticulum (ER) stress and insulin signalling proteins, hepatic C/EBP-homologous protein (CHOP) expression and DNA fragmentation in diabetic and non- diabetic conditions of non-obese diabetic (NOD) mice. We conclude that (i) Sel treatment induced insulin-like effects in lowering serum glucose level in Sel-treated NOD mice, (ii) Sel-treated mice had significantly decreased serum biochemical components associated with liver damage and lipid metabolism, (iii) Sel treatment led to the activation of the ER stress signal through the phosphorylation of JNK and eIF2 protein and insulin signal mechanisms through the phosphorylation of Akt and PI3 kinase, and (iv) Sel-treated mice were significantly relieved apoptosis of liver tissues indicated by DNA fragmentation assay in the diabetic NOD group. These results suggest that Sel compounds not only serve as insulin-like molecules for the downregulation of glucose level and the incidence of liver damage, but may also have the potential for the development of new drugs for the relief of diabetes by activating the ER stress and insulin signalling pathways.

Co-operative effect of glutathione depletion and selenium induced oxidative stress on API and NFkB expression in testicular cells in vitro: insights to regulation of spermatogenesis

Previous studies have shown that transcription factors, API and NFkB exert important roles in the process by which selenium regulates spermatogenesis. Glutathione, an intracellular thiol, acts as a source of reducing power and aids in maintenance of the cellular redox status. The activities of selenium are closely related to the availability of glutathione. Presently, mouse testicular cells were cultured in the presence of BSO, a known glutathione depletor, to generate oxidative stress. Selenium (Se) was added as sodium selenite to these cells at concentrations of 0.5 µM and 1.5 µM. It was observed that at 1.5 µM, Se acted as a pro-oxidant and significantly decreased the redox ratio. RT PCR analysis revealed that cjun, cfos expression increased in testicular cells cultured with Se compared to control. However, the major outcome was that the combined effect of Se supplementation and GSH depletion resulted in reduced expression of cjun and cfos while p65 expression increased. This suggests that selenium affects both these transcription factors differently. Our study indicates that though low levels of oxidative stress generated by moderate doses of selenium augments the expression of cjun and cfos, a robust increase in the ROS generation caused by the dual effect high levels of selenium and glutathione depletion leads to decrease in the expression of these genes. The present work substantiates our in vivo experiments and indicates the detrimental effect of excess selenium supplementation on male fertility.

Effect of exogenous selenium on the testicular toxicity induced by ethanol in rats.

The effects of supplementation of selenium at a dose of 10 microg/ kg body weight were investigated on ethanol induced testicular toxicity in rats. In the present study, four groups of male albino rats were maintained for 60 days, as follows: (1) Control group (normal diet) (2) Ethanol group (4g/kg body weight) (3) Selenium (10 microg/kg body weight) (4) Ethanol + Selenium (4g/kg body weight + 10 microg/kg body weight). Results revealed that ethanol intake caused drastic changes in the sperm count, sperm motility and sperm morphology. It also reduced the levels of testosterone and fructose. The activities of 3betaHSD, 17betaHSD in the testis and SDH in the seminal plasma were also reduced. Lipid peroxidation was also enhanced as the lipid peroxidation products were increased and the activities of the scavenging enzymes were reduced. But on coadministration of selenium along with alcohol all the biochemical parameters were altered to near normal levels indicating a protective effect of selenium. These results were reinforced by the histopathological studies.

Antioxidant effect of curcumin in selenium induced cataract of Wistar rats.

Wistar rat pups treated with curcumin, a natural constituent of Curcuma longa before being administered with selenium showed no opacities in the lens. The lipid peroxidation, xanthine oxidase enzyme levels in the lenses of curcumin and selenium co-treated animals were significantly less when compared to selenium treated animals. The superoxidase dismutase and catalase enzyme activities of curcumin and selenium co-treated animal lenses showed an enhancement. Curcumin co-treatment seems to prevent oxidative damage and found to delay the development of cataract.

Involvement of ROS and JNK1 in selenite-induced a poptosisin Chang liver cells

Selenium is a dietary essential trace nutrient with important biological roles. Selenocompounds were reported to induce apoptosis in many types of tumor cells. In this study, we investigated the signaling pathway involved in the selenite-induced apoptosis using Chang liver cells as a non-malignant cell model. The Chang liver cell apoptosis induced by selenite (10 mM) was confirmed by DNA fragmentation and typical apoptotic nuclear changes. Treatment of selenite increased intracellular reactive oxygen species (ROS) level and c-Jun N-terminal kinase1 (JNK1) phosphorylation. The selenite-induced cell death was attenuated by SP600125, a specific inhibitor of JNK, and by dominant negative JNK1 (DN-JNK1). Antioxidants such as glutathione (GSH), N-acetyl cysteine (NAC), curcumin, epigallocatechin gallate (EGCG) and epicatechin (EC) inhibited selenite-induced intracellular ROS elevation and JNK1 phosphorylation. Our results suggest that selenite-induced apoptosis in Chang liver cells was preceded by the ROS generation and JNK1 activation.

Effects of Combination Dietary Conjugated Linoleic Acid with Vitamin A (Retinol) and Selenium on the Response of the Immunoglobulin Production in Mice

The dietary effect of conjugated linoleic acid (CLA) on the response of the immunoglobulin (serum and tissue) production in Balb/C mice was examined at three doses: 0 %(control), 0.5% and 1.5%. The combination effects of CLA with vitamin ADE or selenium also were investigated. CLA at 0.5% increased serum immunoglobulin A, G, mesenteric lymp node (MHN) and gut luminal IgA (secretory IgA) levels. However, 1.5% CLA decreased SIgG slightly. CLA both alone and combined with vitamin ADE and selenium did not affect serum IgE. The levels of immunoglobulin concentration in the 0.5% CLA group were higher than those in the1.5% CLA group. The level of serum IgG in 1.5% CLA combined with selenium was maintained at the same level as that of control. It is considered that over- doses of CLA (1.5%) even depressed the production of immunoglobulin but selenium and/or vitamin inhibited this activity to a certain extent.In this study, dietary CLA increased immunoglobulin production in a dose-dependent manner. Vitamin ADE and Selenium combined with CLA also increased the immunoglobulin production response except serum IgE.

In vivo and in vitro influence of selenium on DNA/RNA synthesis in spleen and lymphocytes in culture--possible mediation of changes in GSH/GSSG ratio.

Effect of superanutritional levels of selenium (Se) as sodium selenite (0.5 and 1.5 ppm) given orally to Balb/c mice for one and two weeks was observed on the rate of DNA/RNA synthesis, levels of reduced as well as oxidized glutathione (GSH and GSSG) and glutathione peroxidase (GSH-Px)/glutathione-S-transferase (GSH-S-transferase) activities in spleen. Similar effect of three different concentrations of Se (10(-7), 10(-5) and 10(-3) M) in culture media was also observed on the rate of DNA/RNA synthesis in proliferating lymphocytes taken from mice spleen. The results of the present study indicated that with increasing concentration and duration of Se treatment in vivo and in vitro, a marked inhibition of the rate of DNA/RNA synthesis was observed. Levels of total glutathione and GSSG in spleen were elevated significantly only after two weeks in 1.5 ppm treatments. Glutathione peroxidase activities in spleen decreased (p < 0.05) in 1.5 ppm group at one week and in 0.5 ppm group at two week treatment. At higher Se treatment, the activity recovered towards control. However, GSH-S-transferase in spleen remained unchanged at all treatment intervals. The results indicated that changes in glutathione system by increasing Se concentration might account for inhibition of rate of DNA/RNA synthesis.

Effects of dietary selenium on biochemical composition of rat testis.

Treatment of rats with selenium (6 and 8 ppm in diet) for 6 and 9 weeks resulted in decrease in testicular protein, phospholipid content and LDH activity and an increase in the lipid, cholesterol content and activity of ACP and ALP. These alterations have been discussed in relation to interference of selenium in various metabolic processes of testis. It seems that selenium affects the oxido-reductase activity of glutathione and resulting in oxidative damage to testis.