Lycopene attenuates oxidative stress induced experimental cataract development: an in vitro and in vivo study

OBJECTIVES

Lycopene, a nutritional antioxidant, was evaluated for its anticataract potential to further establish its role in cataract prevention.

METHODS

The ability of lycopene to modulate the biochemical parameters was investigated by in vitro studies. Enucleated rat lenses were maintained in organ culture containing Dulbecco's Modified Eagles Medium alone or in addition with 100 microM selenite and served as the normal and control groups, respectively. For the test group, the control medium was supplemented with 10 microM lycopene. The lenses were incubated for 24 h at 37 degrees C. At the end of the incubation period, the lenses were examined for morphologic variation, and biochemical parameters such as reduced glutathione, the lipid peroxidation product malondialdehyde, and the antioxidant enzymes glutathione peroxidase, glutathione S-transferase, superoxide dismutase, and catalase were estimated. In vivo selenite cataract was induced in 9-d-old rats by subcutaneous injection of sodium selenite (25 micromoles/kg of body weight). The rats in the test group were injected with lycopene (200 microg/kg body weight, intraperitoneally) 4 h before the selenite challenge. The incidence of cataract was observed when the rats first opened their eyes. Galactose cataract was induced in rats by feeding 30% galactose in the diet. Rats in the test group were fed orally with 200 microg/kg of lycopene daily, and rats in the control group received only vehicle. Cataract stages were graded at regular intervals.

RESULTS

A fall (25%) in the glutathione level and a rise (32%) in the malondialdehyde content were observed in control as opposed to normal lenses. Lycopene supplementation in the medium significantly (P < 0.001) restored glutathione and malondialdehyde levels. A significant decrease in the activity of antioxidant enzymes also was observed in the control lenses. A significant restoration in the activities of superoxide dismutase (P < 0.05) and catalase and glutathione S-transferase (P < 0.01), with no effect on glutathione peroxidase, was observed in the lycopene-supplemented group. Lycopene also reduced the incidence of selenite cataract. Only 9% of the eyes in the test group developed dense nuclear opacity as opposed to 83% in the control group. A significant delay in the onset and progression of galactose cataract was observed with oral feeding of lycopene. Only 35% of the eyes developed mature cataract as opposed to 100% in the control group.

CONCLUSIONS

Lycopene protects against experimental cataract development by virtue of its antioxidant properties, and it may be useful for prophylaxis or therapy against cataracts.

Selenium nanoparticles are more efficient than sodium selenite in producing reactive oxygen species and hyper-accumulation of selenium nanoparticles in cancer cells generates potent therapeutic effects

We have previously demonstrated that selenium nanoparticles (SeNPs) administered via oral route possess similar capacities of increasing selenoenzyme activities as the extensively examined sodium selenite, selenomethionine and methylselenocysteine, and yet display the lowest toxicity among these selenium compounds in mouse models. However, the low toxicity of SeNPs found in mammalian systems would lead to the interpretation that the punctate distribution of elemental selenium found in cultured cancer cells subjected to selenite treatment that triggers marked cytotoxicity represents a detoxifying mechanism. The present study found that SeNPs could be reduced by the thioredoxin- or glutaredoxin-coupled glutathione system to generate ROS. Importantly, ROS production by SeNPs in these systems was more efficient than by selenite, which has been recognized as the most redox-active selenium compound for ROS production. This is because multiple steps of reduction from selenite to selenide anion are required; whereas only a single step reduction from the elemental selenium atom to selenide anion is needed to trigger redox cycling with oxygen to produce ROS. We thus speculated that accumulation of SeNPs in cancer cells would result in a strong therapeutic effect, rather than serves a detoxification function. Indeed, we showed herein that preformed SeNPs generated a potent therapeutic effect in a mouse model due to rapid, massive and selective accumulation of SeNPs in cancer cells. Overall, for the first time, we demonstrate that SeNPs have a stronger pro-oxidant property than selenite and hyper-accumulation of SeNPs in cancer cells can generate potent therapeutic effects.

The decrease of relative weight, lesions, and apoptosis of bursa of fabricius induced by excess dietary selenium in chickens

Selenium is an essential trace element possessing immune-stimulatory properties. The purpose of this 42-day study was to investigate the effects of excess dietary sodium selenite on immune function by determining morphological changes and apoptosis of bursa of Fabricius. Three hundred 1-day-old Avian broilers were fed on a basic diet (0.2 ppm selenium) or the same diet amended to contain 1, 5, 10, and 15 ppm selenium supplied as sodium selenite (n = 60/group). Relative weight of bursa was significantly decreased in the 1, 5, 10, and 15 ppm groups at 28 days of age, when compared with that of 0.2 ppm group. Pathological lesions were progressed with the dietary Se level increased. The gross lesions of bursa involved obvious atrophy with decreased volume and pale color. Histopathologically, decreased number of lymphocytes and loosely packed lymphocytes appeared in the medulla and cortex in the follicles. Ultrastructurally, mitochondria injury and increased apoptotic cells with condensed nuclei were observed. In comparison to that of control group, excess Se (5, 10, and 15 ppm) intake increased the percentage of Annexin V positive cells, as measured by flow cytometry. Terminal deoxynucleotidyl transferase 2'-deoxyuridine 5'-triphosphate nick end-labeling assay showed that there were increased frequencies of apoptotic cells in 10 and 15 ppm selenium groups. These data suggest that Se supplementation with sodium selenite should be carefully evaluated as excess selenium (more than 5 ppm) intake could cause profound immunologic inhibition.

High-dose selenium for the mitigation of radiation injury: a pilot study in a rat model

The purpose of this study was to evaluate in an animal model the safety and efficacy of dietary supplementation with high doses of selenium for the mitigation of the type of radiation injury that might be sustained during a nuclear accident or an act of radiological terrorism. Age-matched male rats were exposed to 10 Gy (single dose) of total-body irradiation (TBI) followed by a syngeneic bone marrow transplant, then randomized to standard drinking water or drinking water supplemented with sodium selenite or seleno-l-methionine. At 21 weeks after TBI, most rats on standard drinking water had severe renal failure with a mean blood urea nitrogen (BUN) level of 124 +/- 29 mg/dl (geometric mean +/- SE) whereas rats on selenium-supplemented drinking water (100 microg/day) had a mean BUN level of 67 +/- 12 mg/dl. The mitigating effect of selenium was confirmed by histopathological analyses. None of the animals on high-dose selenium showed signs of selenium toxicity. Our results suggest that dietary supplementation with high-dose selenium may provide a safe, effective and practical way to mitigate radiation injury to kidneys.

Seleno-enzymes and seleno-compounds: the two faces of selenium

Selenium protects cells and inhibits many inflammatory cell mechanisms through antioxidant seleno-enzymes. Immunity improvement is illustrated by the study of Berger and colleagues, with reduction of nosocomial pneumonia in burnt patients under multi-trace-element supplementation. As seleno-compounds (especially sodium selenite) are pro-oxidant, however, administration above 800 μg/day may be dangerous in septic shock. Paradoxically, direct reversible pro-oxidative effects of seleno-compounds may also be beneficial for reduction of inflammation (genomic action, apoptosis), and may even be bactericidal or virucidal. These facts need to be further examined, as well as the possible dramatic drop of plasma selenoprotein P in septic shock and its role in endothelium protection.

Inhibition of selenite-induced cataract by caffeine

PURPOSE

The objective of the investigation was to study possible inhibition of oxidative stress and cataract formation by caffeine in vivo.

METHODS

Oxidative stress and consequent cataract formation was induced by intraperitoneal administration of a single dose of sodium selenite (1.16 μmol) to Sprague-Dawley rat pups on day 9 postnatally. In experiments designed to inhibit such cataract formation, the pups were pretreated intraperitoneally with caffeine (5.15 μmol), starting 2 days prior to the administration of selenite and continuing such treatment till day 21, when the experiments were terminated. The extent of tissue damage caused by the selenite was assessed biochemically by measurements of the levels of GSH and ATP in the isolated lenses. Cataract formation and its prevention were monitored by examining the eye with pen light illumination and subsequent photography of the isolated lenses.

RESULTS

Injection of selenite led to a significant loss of lens clarity because of cataract formation. In the group treated with caffeine, the formation of cataract was significantly prevented. In the caffeine-untreated group, the levels of lens GSH and ATP were substantially lower than in the caffeine-treated group. The levels of GSH decreased from a value of ∼8.2 μmol to ∼2 μmol/g wet weight of the lens. The content of ATP decreased from ∼2.5 μmol to about ∼ 1 μmol. In the case of caffeine-treated group, these decreases were significantly prevented from taking place, the corresponding values of GSH and ATP being ∼5.8 and ∼1.6 μmol/g, respectively.

CONCLUSION

Over all, the results suggest that caffeine can exert a significant preventive effect against cataract formation induced by agents generating reactive oxygen species such as sodium selenite.

Differential acute effects of selenomethionine and sodium selenite on the severity of colitis

The European population is only suboptimally supplied with the essential trace element selenium. Such a selenium status is supposed to worsen colitis while colitis-suppressive effects were observed with adequate or supplemented amounts of both organic selenomethionine (SeMet) and inorganic sodium selenite. In order to better understand the effect of these selenocompounds on colitis development we examined colonic phenotypes of mice fed supplemented diets before the onset of colitis or during the acute phase. Colitis was induced by treating mice with 1% dextran sulfate sodium (DSS) for seven days. The selenium-enriched diets were either provided directly after weaning (long-term) or were given to mice with a suboptimal selenium status after DSS withdrawal (short-term). While long-term selenium supplementation had no effect on colitis development, short-term selenite supplementation, however, resulted in a more severe colitis. Colonic selenoprotein expression was maximized in all selenium-supplemented groups independent of the selenocompound or intervention time. This indicates that the short-term selenite effect appears to be independent from colonic selenoprotein expression. In conclusion, a selenite supplementation during acute colitis has no health benefits but may even aggravate the course of disease.

Long-Term Excessive Selenium Supplementation Induces Hypertension in Rats

Selenium (Se) is an essential trace element involved in several biological pathways, naturally found in rocks, soils, and food. Even though the daily requirement of Se is achieved through a balanced diet, the use of Se supplements has been frequent. Due to the risk of toxic effects of having Se in excess, supplementation is still under debate. The aim was to evaluate the effects of long-term Se supplementation upon systolic blood pressure (SBP) and redox status of rats exposed to sodium selenite. Male Wistar rats were exposed to 2 and 6 mg/L of sodium selenite in drinking water for 85 days. SBP and body weight were evaluated weekly; oxidative stress biomarkers were measured in blood or plasma; and Se levels were assessed in blood, plasma, kidney, and liver. Se supplementation (2 and 6 mg/L) induced significant increase in the SBP in rats from the 42nd day until the end of the study. This increase on SBP was not associated with significant changes in oxidative stress biomarkers. A significant increase in Se levels was found in whole blood, kidney, and liver from both groups of rats receiving Se supplementation when compared to control. Although the exact mechanisms underlying this augment in SBP are not clear, they are potentially related to other Se biological routes besides the synthesis of selenoproteins, such as GSH-Px. Due to the negative effects upon blood pressure, precautionary measures are advised, since the selling of supplements does not require a medical prescription.

Long-term selenium supplementation in HaCaT cells: importance of chemical form for antagonist (protective versus toxic) activities

The beneficial effect of selenium (Se) on cancer is known to depend on the chemical form, the dose and the duration of the supplementation. The aim of this work was to explore long term antagonist (antioxidant versus toxic) effects of an inorganic (sodium selenite, Na2SeO3) and an organic (seleno-L-methionine, SeMet) forms in human immortalized keratinocytes HaCaT cells. HaCaT cells were supplemented with Na2SeO3 or SeMet at micromolar concentrations for 144 h, followed or not by UVA radiation. Se absorption, effects of UVA radiation, cell morphology, antioxidant profile, cell cycle processing, DNA fragmentation, cell death triggered and caspase-3 activity were determined. At non-toxic doses (10 μM SeMet and 1 μM Na2SeO3), SeMet was better absorbed than Na2SeO3. The protection of HaCaT from UVA-induced cell death was observed only with SeMet despite both forms increased glutathione peroxidase-1 (GPX1) activities and selenoprotein-1 (SEPW1) transcript expression. After UVA irradiation, malondialdehyde (MDA) and SH groups were not modulated whatever Se chemical form. At toxic doses (100 μM SeMet and 5 μM Na2SeO3), Na2SeO3 and SeMet inhibited cell proliferation associated with S-G2 blockage and DNA fragmentation leading to apoptosis caspase-3 dependant. SeMet only led to hydrogen peroxide production and to a decrease in mitochondrial transmembrane potential. Our study of the effects of selenium on HaCaT cells reaffirm the necessity to take into account the chemical form in experimental and intervention studies.

Antioxidant and antitumor activities of selenium- and zinc-enriched oyster mushroom in mice

Selenium and zinc are well-known essential trace elements with potent biological functions. However, the possible health benefits of the combined administration of dietary selenium and zinc have not been studied extensively. In this study, we prepared selenium- and zinc-enriched mushrooms (SZMs) containing increased levels of selenium and zinc. The effects of SZMs on antioxidant and antitumor activities were evaluated. Mice were fed with either a control diet or a diet supplemented with SZMs or sodium selenite and zinc sulfate for 6 weeks. Antioxidant capacity was investigated by measuring the activities of antioxidant enzymes and the levels of lipid peroxide products. Results showed that treatment with SZMs significantly increased the activities of glutathione peroxidase (GPx) and superoxide dismutase and decreased the levels of malondialdehyde and lipofuscin. Furthermore, using a mouse model of lung tumors, we found that SZMs significantly decreased the number of tumor nodes with an increase in the activity of GPx. SZMs had a greater effect on the increase in both antioxidant and antitumor activities than did sodium selenite and zinc sulfate. These findings suggest that SZMs may be effective for improving antioxidant capacity and preventing tumors.

Jun N-terminal kinase activation and upregulation of p53 and p21(WAF1/CIP1) in selenite-induced apoptosis of regenerating liver

To investigate apoptosis induced by selenite in hepatocytes in vivo, rats received a single injection of sodium selenite immediately after partial hepatectomy. Characteristic DNA fragmentation in gel electrophoresis and in situ end-labeling and the increase in caspase-3 activity were observed at 4 h after partial hepatectomy with selenite injection. The activation of Jun N-terminal kinase (JNK) was observed as early as 15 min and increased to about 10-fold the maximal level of the control at 1 and 2 h after partial hepatectomy in selenite-injected rats, while a transient increase was observed at 1 h in the control. Western blot analysis revealed that the c-Jun and the phosphorylated c-Jun protein markedly increased after 30 min and reached a maximal level at 1 and 2 h after partial hepatectomy with selenite injection, although c-Jun and a faint band of the phosphorylated c-Jun were observed after 1 h in the control. The levels of c-jun mRNA and c-Fos protein and mRNA in selenite-injected rats also increased more than in the control. The rise in the p53 protein level after partial hepatectomy with selenite injection was followed by the upregulation of p21(WAF1/CIP1) mRNA and protein expression. These results suggested that selenite induced apoptosis accompanied by the activation of caspase-3 and JNK and the upregulation of c-jun, c-fos, p53 and p21(WAF1/CIP1) at the early stage of liver regeneration.

[Significance of selenium in intensive care medicine. Clinical studies of patients with SIRS/sepsis syndrome]

Selenium is an essential component of the intracellular antioxidant system as a structural component of the active center of the glutathione peroxidase enzymes. These selenoenzymes play a major role in protecting cells against peroxidation, especially lipid peroxidation and selenium seems to play a direct role in the regulation of inflammatory processes. In conditions of systemic inflammatory response or sepsis, patients are exposed to severe oxidative stress. These patients already have both, a decreased plasma selenium and glutathione peroxidase activity at admission to the ICU as has been shown in several studies. The degree of selenium deficiency is correlated with the severity of disease and the incidence of mortality. The reason for the low plasma selenium levels is unknown. Especially it would be of interest a) if the low plasma selenium is the consequence of the systemic inflammatory response with distribution of selenium in other compartments of the body, b) most important, whether the substitution of selenium might improve the outcome and decrease the mortality rate of these patients. In 2 independently performed intention-to-treat studies including patients with systemic inflammatory response syndrome or sepsis a beneficial effect of selenium supplementation on multiple organ function and outcome could already be demonstrated as well as a tendency of an improved mortality rate. A prospective analytical study clearly could demonstrate the inverse relationship between low plasma selenium and morbidity and mortality of patients with SIRS/sepsis. The results of these studies are so convincing, that we propose a randomized, prospective, double blind multicenter phase-III study including patients with systemic inflammatory response syndrome or sepsis to investigate, whether a high-dose selenium substitution in addition to the recommended treatment strategies for patients with sepsis improves outcome and mortality rate of these patients.

Sodium selenite and Se-enriched yeast supplementation in atherosclerotic patients: Effects on the expression of pyroptosis-related genes and oxidative stress status

BACKGROUND AND AIMS

Atherosclerosis as a chronic inflammatory disorder of the arterial wall is the main leading cause of the cardiovascular disease (CVD). Caspase-dependent pyroptosis plays a pivotal role in the pathogenesis of CVD. Selenium (Se) is an important component of the antioxidant defense and plays a crucial role in cardiovascular health. This study aimed to investigate the effects of daily consumption of sodium selenite and Se-enriched yeast on the expression of pyroptosis-related genes, and biomarkers of oxidative stress in patients with atherosclerosis.

METHODS AND RESULTS

In this randomized, double-blinded, placebo-controlled clinical trial, 60 patients with atherosclerosis were recruited. Participants received 200 μg/day of sodium selenite, Se-enriched yeast, or placebo for 8 following weeks. The pyroptosis-related genes' mRNA expression in peripheral blood mononuclear cells (PBMCs) was assessed before and after the intervention. Also, the levels of superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO), and glutathione peroxidases (GPX) were measured at baseline and following the intervention. Following sodium selenite and Se-enriched yeast supplementation, the relative expression levels of TLR4, ASC, NLRP3, and NF-κB1 were significantly downregulated (p < 0.05). Furthermore, the changes in GPX were significantly increased after selenite and yeast supplementation (p < 0.05). Also, selenite and yeast consumption caused a statistically significant decrease in the change of MDA level (p < 0.05).

CONCLUSION

In summary, these findings showed that Se supplementation may reduce inflammation through down-regulation of some pro-inflammatory genes, improving antioxidant defenses in atherosclerosis patients. Further research is required to come to a definite conclusion of selenium supplementation on the CVD risk. This study was registered on the Iranian Registry of Clinical Trials website (identifier: RCT20110123005670N28; https://www.irct.ir/).

Cassia tora leaves modulates selenite cataract by enhancing antioxidant status and preventing cytoskeletal protein loss in lenses of Sprague Dawley rat pups

ETHNOPHARMACOLOGICAL RELEVANCE

Cataract is the clouding or opacity that develops in the eye's lens and is considered to be an unavoidable consequence of aging due to irreversible lens damage. Free radicals and oxidant species are reported to be the major factor responsible for the onset and pathology of cataract. No pharmacological measures are formulated to treat cataract blindness and surgical removal of the opaque lens is the only remedy till date. Boosting of antioxidant potential of the lens is proved to prevent cataract and many indigenous plants have been screened for anticataractogenic potential in the last decades. The objective of the present study was to determine whether Cassia tora leaves; the plant employed in traditional medicine for eye rejuvenation and ailments, can prevent cataract in neonatal rats.

MATERIALS AND METHODS

Cataract was induced by a single subcutaneous injection of sodium selenite at a dose of 4 μg/g body weight on the 10th day and Cassia tora leaves was administered orally from 8th day upto 12th day at a concentration of 5 μg/g body weight. After 30 days; lens morphology, oxidant-antioxidant equilibrium, glutathione metabolism, cytoskeletal protein/gene expressions were monitored.

RESULTS

Lens morphology, biochemical analysis and expression studies supported the anticataractogenic effect of Cassia tora leaves.

CONCLUSION

In summary, it can be suggested that the consumption of these leaves afford protection to the lens with its antioxidant action and seems to be a new therapeutic approach against cataract by preventive protection.

Efficient preparation of selenium/glutathione-enriched Candida utilis and its biological effects on rats

The main purpose of this study was to prepare selenium/glutathione-enriched Candida utilis and investigate its effect on growth performance, antioxidant capacity, and immune response in rats. The preparation of the selenium/glutathione-enriched yeast was conducted using fed-batch culture for high cell density. The optimal culture conditions for increased intracellular organic selenium and glutathione contents were as follows: the concentrated medium was fed beginning at 12 h using a polynomial feeding strategy until a total glucose concentration of 150 g/l was reached, and sodium selenite was continuously added together with glucose to a total concentration of 60 mg/l. As a result, 81 % of sodium selenite was assimilated and transformed into organic selenium by C. utilis under optimal conditions, which in turn resulted in greater glutathione accumulation and lower malondialdehyde cellular content in the yeast. To investigate and compare the effects of the prepared selenized C. utilis and other dietary supplements, 40 female rats were divided into five groups of eight rats each, following a randomized block design. Experimental feeding was conducted for a period of 6 weeks. Selenium supplementation with inorganic selenium (sodium selenite) and organic selenium (selenized C. utilis) showed better results than the control and other groups supplemented with yeast with or without glutathione. The body mass of rats, selenium deposition, and oxidative enzymes activities in both serum and liver samples, and immunity responses were all significantly improved by selenium supplementation, and between the two sources, organic selenium was more effective than inorganic selenium.

Ultrastructural changes in the mycelium of Hericium erinaceum (Bull.; Fr.) Pers. under selenium-induced oxidative stress

BACKGROUND

In this study we examined the influence of various forms of selenium (organic and inorganic) on the vivacity of Hericium erinaceum mycelium and structural changes and ultrastructure occurring during its development in submerged culture.

RESULTS

The mycelium was grown on sodium selenite (Na₂SeO₃), Selol (with 20 and 50 g kg⁻¹ Se, respectively) and a mixture of Na₂SeO₃ and Selol. Samples of the mycelium were collected on day 3 and day 24 of the incubation and viewed under an electron microscope. Selol at concentration 20 g kg⁻¹ did not cause any damage to the cell ultrastructure, but it contributed to the thickening of the cell wall, which implied an influence on polysaccharide production. In the other cases, degradation changes appeared in the protoplasm and the thickness of the cell wall did not increase.

CONCLUSION

The nature of the effect exerted by various sources of selenium in the culture medium on the formation of polysaccharides probably results from the differences in their chemical composition and differences in the toxicity of these compounds towards the cells, but is also connected with the decomposition of the wall surrounding degraded fungal cells.

[Molecular biology studies of a multicenter phase III study (SIC Study)]

Transcription factors adjust the up- and downregulation of inflammatory genes. Within the bounds of the SIC-study (Selenium in Intensive Care) the authors will investigate the role of transcription factors NF-kappa B and AP-1 in S.I.R.S/septic patients. The goal of these investigations is the corroboration of therapy of septic patients with sodium selenite at the molecular biological level.

[Effect of selenium on the side effect profile of adjuvant chemotherapy/radiotherapy in patients with breast carcinoma. Design for a clinical study]

Selenium is a very important component of the antioxidative protective mechanism which belong to every cell. By chemotherapy and radiotherapy a strong increase of free oxygen radicals is induced leading to a damage also of normal tissue. This phenomenon is registered as adverse drug reactions. Since, in addition, tumor patients frequently have low selenium blood levels the application of higher doses of selenium in connection with chemo- and radiotherapy will induce the toxicity of the treatment without lowering the efficiency. Within the presented prospective randomized placebo-controlled double-blind phase-III study we intend to answer the question whether the application of higher doses of sodium selenite will reduce the toxicity of chemotherapy and radiotherapy. Primary targets of the study are therefore the evaluation of toxicity according to CTC-criteria and of life quality.

[Potential of selenium in gynecologic oncology]

BACKGROUND

Studies on potential benefits of selenite in cancers of the female genital tract and breast cancer have concentrated on 2 fields: prevention on one side, complementary oncological therapy on the other side. Big studies have been realized in the past which have shown no clear effect of selenium supplementation in prevention of female cancers and breast cancer in the industrialized nations of Europe and Northern America. Few investigations exist on the therapeutic effects of selenium therapy in the clinical field of gyneco-oncology.

EXPERIENCES

Many patients with malignant disease of the female breast and genital tract are strongly demanding additional therapeutical concepts in natural medicine in addition to adjuvant or palliative chemo- or hormonal therapy and supportive medication. In pilot studies with low-dose natrium selenite (up to 300 micrograms/day) they report a better quality of life. Side effects were not reported. Analysis of the immune system reveal a stimulation of B19 lymphocytes and natural killer cells.

CONCLUSION

In Germany, a country with selenium deficiency, clinical studies are now carried out on the effects of selenium as a drug to reduce side effects of chemo- and radiotherapy, enhance quality of life by reducing toxic side effects and help to restore immune function.

Preclinical Evaluation of Sodium Selenite in Mice: Toxicological and Tumor Regression Studies after Striatum Implantation of Human Glioblastoma Stem Cells

Glioblastoma (GBM) is the most aggressive malignant glioma, with a very poor prognosis; as such, efforts to explore new treatments and GBM’s etiology are a priority. We previously described human GBM cells (R2J-GS) as exhibiting the properties of cancer stem cells (growing in serum-free medium and proliferating into nude mice when orthotopically grafted). Sodium selenite (SS)—an in vitro attractive agent for cancer therapy against GBM—was evaluated in R2J-GS cells. To go further, we launched a preclinical study: SS was given orally, in an escalation-dose study (2.25 to 10.125 mg/kg/day, 5 days on, 2 days off, and 5 days on), to evaluate (1) the absorption of selenium in plasma and organs (brain, kidney, liver, and lung) and (2) the SS toxicity. A 6.75 mg/kg SS dose was chosen to perform a tumor regression assay, followed by MRI, in R2J-GS cells orthotopically implanted in nude mice, as this dose was nontoxic and increased brain selenium concentration. A group receiving TMZ (5 mg/kg) was led in parallel. Although not reaching statistical significance, the group of mice treated with SS showed a slower tumor growth vs. the control group (p = 0.08). No difference was observed between the TMZ and control groups. We provide new insights of the mechanisms of SS and its possible use in chemotherapy.

[The early biochemical changes of cataractous lenses of rats cultured in vitro]

OBJECTIVE

To study the mechanism of cataractogenesis.

METHODS

Tissue culture was used to study the cataractous lenses of rats induced by sodium selenite or galactose. At the early stage, the content of nonprotein sulfhydryl (NP-SH), protein sulfhydryl (P-SH), non-soluble disulfide bond, malonaldehyde (MDA) and the activities of glutathione peroxidase (GSH-PX), glutathione reductase (GSSG-R) and glutathione-S-transferase (GSH-S) were measured in the cataractous lenses, and they were compared with that of the normal lenses.

RESULTS

The two kinds of material could all induce cataract in rats, sodium selenite being more potent. In the early period of culture (lenses were transparent), NP-SH and P-SH were decreased, while disulfide and MDA were increased, the activity of GSH-PX rose obviously, that of GSH-S also had a tendency of rise, however, the activity of GSSG-R had no obvious changes.

CONCLUSIONS

Rat lens opacity may occur after the lens is cultured in vitro with the addition of sodium selenite or galactose, and biochemical changes may develop in the lens at the early period of culture (lenses are transparent).

[Decreasing mortality in acute pancreatitis with sodium selenite. Clinical results of 4 years antioxidant therapy]

Results obtained from pancreatitis research prove the genesis if free radicals in acute pancreatitis. Xenobiotics, ethanol as well as biliary diseases will induce a deficiency in antioxidants. In antioxidative treatment sodium selenite as a water soluble redox substance represented an alternative. In the middle of the year 1990 the therapy regime was introduced in Rostock, a short time later in Dresden too. The diagnosis was made by CT enhanced by a contrast medium as well as by clinical and paraclinical parameters. CT was repeated after a week. Up to May 31, 1994 there were 245 patients treated in Rostock and 85 patients in Dresden (n = 330). Immediately after making the diagnosis 200 micrograms were given as a bolus, 800 micrograms in the following 24 hours. From the second day on 500 micrograms of selenite were administered daily. In addition, infusions of carbohydrates, electrolytes (no calcium), fluid and analgetics were given. Lavation of the intestine was made three times daily. With a well-timed selenium therapy the rates of letality, complications and operation dropped drastically. In spite of a constant number of patients no patient has died in Rostock since 1993, in Dresden 8 of 85 patients came ad exitum. Complications occurred if the therapy began too late (if patients were administered too late) and in biliary forms.

CONCLUSION

An improvement in the prognosis of acute pancreatitis can be achieved if antioxidative selenium therapy with sodium selenite is introduced in time. In rare cases total necroses and complications in organs only occurred in those patients who were admitted to this therapy too late.

[Effects of L-carnosine in preventing and treating rat cataract induced by sodium selenite]

OBJECTIVE

To explore the effect of L-carnosine in preventing and treating rat cataract induced by sodium selenite.

METHODS

This was an experimental study. Cataract was induced in the rats by sodium selenite. Rats were divided into 3 groups and each group has 3 ones. L-carnosine eye drops (50 g/L or 20 g/L ) and 0.9% normal saline were respectively instilled to the rat eye for 3 weeks and examined. L-carnosine was added to the medium of cultured rat cataract lens at 1.00, 0.10 and 0.01 g/L for 1 week and then examined. Cataract lens were studied by using two-dimensional electrophoresis.

RESULTS

One week after instillation of L-carnosine, the scores of rat cataract were 2.22 +/- 0.65, 2.39 +/- 0.98 and 2.83 +/- 0.38 in 50 g/L, 20 g/L L-carnosine and control groups, respectively. The lesion in 50 g/L L-carnosine group was lighter than that of the control group. There was significant difference between these two groups (P = 0.013). On the 2nd and 3rd weeks, there was no difference among these three groups. After 1 week for culturing cataract lens, there was no difference between these three groups. The results of two-dimensional electrophoresis showed that the protein number was 182 and 161 in the L-carnosine and control groups, respectively. High molecular weight protein decreased and low molecular weight protein increased in L-carnosine group.

CONCLUSIONS

L-carnosine at 50 g/L could restrain the development of early stage rat cataract. L-carnosine could modulate the rat lens protein in vitro, but could not affect lens cataract scores.

[The value of selenotherapy in patients with mucoviscidosis]

In cystic fibrosis (CF) patients the antioxidative-oxidative balance is chronically disturbed. Free radicals were generated by bronchial-pulmonal infection and additional exist a deficiency of antioxidative substances by enteral malabsorption especially vitamin E and selenium. Because selenium is an essential content of glutathione peroxidase, which is acting in cytosol and cell membranes, for the present we tested a selenium therapy (peroral sodium selenite 155 micrograms (Se/m2 BSA/d i. e. 4 micrograms Se/kg/d; 4 fold of recommended supply) in 32 CF patients. After three months of this therapy we have seen positive metabolic (normalized content of plasma-selenium, -glutathione peroxidase), endocrine (enhanced efficacy of thyroid hormones, mild increased IgF-I reduced LDL-chol) and clinical consequences (enhanced left ventricular cardiac output), but in three patients side effects (anorexia, nausea, mild hair loss) were observed. Longtime sodium selenite therapy only with 60 micrograms Se/m2 BSA/d over 1 year, stabilized the favourable influences without side effects. For CF patients therefore we recommend a sodium selenite substitution therapy, the best in combination with vitamin E.

[In to the question of selenium using in case of foodstuffs enrichment]

The analysis of different selenium compounds toxicity and level of selenium intake in different countries are given in the article. It showed that population of Russian Federation have not defined selenodeficiency. Thus there is no need in wide-ranging fortification of foodstuff by selenium. For increasing of selenium level in particularized foodstuffs (biology activity supplements, specialized foodstuff for pregnant, children, dietetic, medicinal and prophylactic foodstuff) are preferred the organic forms of selenium. Inorganic forms of selenium (selenites and selenates) could use only in the composition of biology activity supplements. However in this case the organic form is more preferably too.