Evaluation of selenium on kidney function following ischemic injury in rats; protective effects and antioxidant activity

Nanoselenium attenuates renal ischemia-reperfusion injury in rats

Using selenium (Se) nanoparticles has received attention in recent years because of their therapeutic benefits due to their anticancer, antioxidant, anti-inflammatory, and anti-diabetic effects. This research was conducted to evaluate the possible protective impact of nano-Se on renal unilateral ischemia/reperfusion injury (uIRI) in adult male Wistar rats. Using clamping of the left renal pedicle within 45 min uIRI was induced. The animals were randomly divided into nine groups of control, nano-Se (0.25, 0.5, and 1 mg/kg bw/day) alone, uIRI control, and uIRI rats administrated with nano-Se. At 30 days after treatment, the animals were sacrificed to be assessed biochemically and histopathologically. Nano-Se in uIRI groups have significantly decreased serum creatinine, urea levels, renal histological damage, and increased antioxidant status. Also, our findings demonstrated that the administration of nano-Se caused a significant decrease in the immunoreactivity level of the epidermal growth factor (EGF) and EGFR expression (EGF receptor) in the renal tissue of the uIRI rats. Therefore, nano-Se possesses renoprotective effects, and this effect might be attributable to its antioxidant and free radical scavenger effects. These renoprotective effects may depend on the decreased EGF immunoreactivity level and EGFR expression in the kidney tissue and improve the structure of the kidney tissue. Thus, our research provided biochemical and histological data supporting the potential clinical use of nano-Se for the treatment of certain kidney disorders.

Selenium prevented renal tissue damage in lipopolysaccharide-treated rats

OBJECTIVES

Kidney diseases are one of the common diseases, which are one of the main causes of death in society and impose costs on the health system of the society. A growing body of evidence has well documented that inflammatory responses and oxidative damage play a significant role in the progress of various kidney diseases.

METHODS

This study examined whether selenium (Sel) could prevent the detrimental influences of lipopolysaccharide (LPS) in rats. Four groups of Wistar rats were considered: control, LPS (1 mg/kg, i.p., for 14 days), LPS-Sel 1 (0.1 mg/kg, i.p., for 14 days), and LPS-Sel 2 (0.2 mg/kg, i.p., for 14 days).

RESULTS

Sel treatment markedly attenuated oxidative stress damage in the kidney tissue in LPS-induced renal toxicity. Generally, the administration of Sel resulted in improved antioxidant indicators such as catalase (CAT) and superoxide dismutase (SOD) activities, or total thiol content, and decreased malondialdehyde (MDA) in the kidney tissue. It also decreased interleukin-6 in kidney homogenates. Furthermore, Se treatment significantly inhibited the elevation of serum biochemical markers of kidney function including serum, BUN, and creatinine.

CONCLUSIONS

Based on the findings of the current study, it seems that the administration of Sel to LPS-treated rats improves renal function by reducing oxidative damage and inflammation in kidney tissue. However, more research is needed to reveal the accurate mechanisms for the effect of Sel on renal outcomes of LPS in human subjects.

Bromide Ion Impurity-Induced Reaction between Selenium(IV) and Acidic Bromate: Prototype of a Cycle with Autocatalytic Behavior

The selenium(IV)-bromate reaction in an acidic medium using phosphoric acid/phosphate buffer was investigated by UV-vis spectroscopy monitoring the formation of bromine. In an excess of bromate, the absorbance-time curves measured at 450 nm display a characteristic sigmoidal shape having a fairly long induction period, while in the opposite case, when selenium(IV) species is used in excess, the measured data follow the rise and fall behavior. Depending on the excess of Se(IV) the final bromine-containing product is either an elementary bromine or bromide ion. Simultaneous evaluation of the measured kinetic traces clearly indicated that, surprisingly, no direct reaction takes place between the reactants. Instead of that, a trace amount of bromide ion impurity in the stock bromate solution is sufficient to drive the system via the oxidation of the bromide ion by bromate producing elementary bromine followed by the subsequent selenite-bromine reaction reestablishing the bromide ion to open a new cycle. As a result, the concentration of bromide ions increases in a sigmoidal fashion during the course of the reaction unless enough selenium(IV) species is present; hence, the overall synergetic effect observed is the autocatalytic rise of bromide ions. Therefore, the cycle mentioned above may be considered as a prototype of autocatalytic cycles. This observation prompted us to clarify the explicit difference between an autocatalytic cycle and an autocatalytic reaction.

Kinetics and Mechanism of Selenium(IV) Oxidation by Aqueous Bromine Solution

The bromine-selenite reaction at strongly acidic conditions was investigated by monitoring the absorbance-time traces at the isosbestic point of the bromine-tribromide system at a constant ionic strength (0.5 M adjusted by sodium perchlorate) and temperature. Despite the simplicity of the stoichiometry, the kinetics was found to be very complex. Although the formal kinetic orders of the reactants bromine and selenite are strictly 1, that of the hydrogen ion varies from -2 to less than -3 and notably depends on the initial bromide concentration as well. The bromide ion also inhibits the reaction, making the whole system as a sound example of efficient autoinhibition. We have clearly shown that the inhibitory effect of the bromide ion cannot be explained quantitatively by either exclusively considering the unreactivity of the tribromide ion over elemental bromine or driving the reaction via hypobromous acid formed from the well-known hydrolysis of bromine in aqueous solutions. Instead of that, bromonium ion transfer initiating equilibrium is suggested between the selenium(IV) and bromine species to produce bromide ion and SeO₃Br^- followed by the hydrolysis of this short-lived intermediate. This hydrolytic transformation was found to be catalytic with respect to hydroxide and bromide ions as well. We have also demonstrated that, among the wide variety of selenium species present in the acidic aqueous solution, the best result can be obtained by considering HSeO₃ ^- as the kinetically active species toward bromine. The proposed mechanism containing 10 acid-base equilibria with known equilibrium constants, the above-mentioned initiating equilibrium, and the hydrolysis of SeO₃Br^- is able to fit all 49 kinetic absorbance-traces simultaneously, taking into account properly the most important characteristics of the measured data at strongly acidic conditions. Furthermore, this kinetic model was further extended by the direct reactions of hypobromous acid with selenium(IV) species suggested previously with reasonably modified rate coefficients to describe the pH dependence of the apparent second-order rate coefficients over the pH = 1-13 range, providing a useful tool to predict more accurately the kinetic behavior of selenium(IV) species in water treatment process conditions.

Antitumor effect of selenium-rich Brazil nuts and selenomethionine dietary supplementation on pre-existing 4T1 mammary tumor growth in mice

Selenium (Se) is an essential micronutrient known to play an important role in the antioxidant system that can potentially influence tumor growth. We aimed to investigate the effects of dietary Se supplementation after detection of 4T1 mammary tumor growth in BALB/c mice. Thirty female mice received subcutaneous inoculation of 4T1 cells. After five days, all animals presenting palpable tumors were randomly assigned to three groups: a control group (Se-control) receiving a diet with adequate Se (0.15 mg/kg) and two other groups that received Se-supplemented diets (1.4 mg/kg of total Se) with either Brazilian nuts (Se-Nuts) or selenomethionine (SeMet). Data were assessed by either One or Two-way ANOVA followed by Tukey's HSD or Bonferroni's post hoc tests, respectively. Both Se-supplemented diets reduced tumor volume from the thirteenth day of feeding compared with the Se-adequate (control) diet (p < 0.05). The SeMet group presented a higher Se blood concentration (p < 0.05) than the Se-control group, with the Se-Nuts group presenting intermediate values. Selenoprotein P gene expression in the liver was higher in the Se-Nuts group than in the Se-control group (p < 0.05), while the SeMet group presented intermediate expression. Dietary Se supplementation, starting after detection of 4T1 palpable lesions, reduced tumor volume in mice.

Cross talk of vasopressin conditioned cell therapy in ischemic heart disease: Role of oxidative stress markers

Objectives

Background: Impaired coronary blood flow causes cardiac ischemia. Cellular therapy is a new approach to the treatment of myocardial ischemia. This study aimed to investigate the effect of adipose tissue-derived mesenchymal stem cells (AD-MSCs) conditioned with vasopressin on oxidative stress, perivascular collagen, and angiogenesis caused by myocardial infarction (MI) in rats.

Materials and Methods

We divided 40 male albino Wistar rats into 4 groups; Control group; No intervention; in experimental groups, after it generated induced MI on models, it divided into three groups: Vehicle group (150 μl of cell-free culture medium received); ASC-MI group (6× 10⁶ AD-MSC received) and AVP-ASC-MI group (received 6 × 10⁶ AD-MSC conditioned with 10 nM vasopressin). Then, histologic parameters and anti-oxidant enzymes were evaluated 7 days post-MI cell injection.

Results

Arterial muscle diameter improved and collagen deposition around the coronary arteries decreased in cell-received groups compared with the vehicle group. Malondialdehyde (MDA), catalase (CAT), (GSH) Glutathione, and Total Anti-oxidant Capacity (TAC) parameters were not significantly different between the cells received groups compared with the vehicle group. But the Catalase (CAT) parameter in the ASC-MI group had a significant increase from the control group.

Conclusion

We prepared direct evidence that intramyocardial injection of AD-MSCs reveals the positive cardiac remodeling post-MI in rats, and these useful effects can be more enhanced by administrating injection of conditioned ADSCs with vasopressin.

Inhibiting Metastasis and Improving Chemosensitivity via Chitosan-Coated Selenium Nanoparticles for Brain Cancer Therapy

Selenium nanoparticles (SeNPs) were synthesized to overcome the limitations of selenium, such as its narrow safe range and low water solubility. SeNPs reduce the toxicity and improve the bioavailability of selenium. Chitosan-coated SeNPs (Cs-SeNPs) were developed to further stabilize SeNPs and to test their effects against glioma cells. The effects of Cs-SeNPs on cell growth were evaluated in monolayer and 3D-tumor spheroid culture. Cell migration and cell invasion were determined using a trans-well assay. The effect of Cs-SeNPs on chemotherapeutic drug 5-fluorouracil (5-FU) sensitivity of glioma cells was determined in tumor spheroids. An in vitro blood–brain barrier (BBB) model was established to test the permeability of Cs-SeNPs. SeNPs and Cs-SeNPs can reduce the cell viability of glioma cells in a dose-dependent manner. Compared with SeNPs, Cs-SeNPs more strongly inhibited 3D-tumor spheroid growth. Cs-SeNPs exhibited stronger effects in inhibiting cell migration and cell invasion than SeNPs. Improved 5-FU sensitivity was observed in Cs-SeNP-treated cells. Cellular uptake in glioma cells indicated a higher uptake rate of coumarin-6-labeled Cs-SeNPs than SeNPs. The capability of coumarin-6 associated Cs-SeNPs to pass through the BBB was confirmed. Taken together, Cs-SeNPs provide exceptional performance and are a potential alternative therapeutic strategy for future glioma treatment.

Selenomethionine Alleviates Intestinal Ischemia-Reperfusion Injury in Mice Through the Bax-Caspase Pathway

Selenomethionine (SeMet) is known to alleviate ischemia-reperfusion (I/R) injury. However, its details of action have not been thoroughly elucidated in mice with intestinal I/R injury. In this study, intestinal I/R injury mice models were established, and ELISAs were performed to determine the levels of redox factors, including glutathione peroxidase (GSH-Px), catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA), in mice intestinal tissues. Furthermore, several apoptosis-related markers, such as cytochrome c (Cyt-c), Bcl-2, and Bax, were detected using qPCR and Western blotting, while caspase-3 was detected using Western blotting alone. The results showed that SeMet alleviated I/R damage by increasing GSH-Px, CAT, and SOD levels and reducing MDA levels. Our data demonstrated that SeMet reduced I/R injury and inhibited the expression of Cyt-c, Bax, and caspase-3. SeMet also increased the expression of Bcl-2 in the intestinal tissues of mice. In addition, the TUNEL assay results showed that SeMet mitigated apoptosis in the villi cells of the intestinal mucosa. The findings also revealed that I/R could lead to increased apoptosis levels and that SeMet alleviated I/R-induced apoptosis by mediating the Bax/cytochrome C/caspase-3 apoptotic signaling pathways in the intestinal I/R injury mice models. Thus, SeMet inhibited apoptosis and resulted in an increase of Bcl-2 levels; downregulated the expression of Bax, Cyt-c, and caspase-3; and alleviated the intestinal ischemia injury in mice. The I/R injury increased the cytosolic Bax, Cyt-c, and caspase-3 levels and significantly decreased Bcl-2 expression levels in the I/R group, compared to the Sham group. However, the levels of all markers were reversed post-SeMet pre-treatment.

Association between Selenium Status and Chronic Kidney Disease in Middle-Aged and Older Chinese Based on CHNS Data

Background: The association between selenium and chronic kidney disease (CKD) remains controversial. Population studies with large samples facilitate the reliability of conclusions. Objective: In this study, we aimed to describe the prevalence of a CKD association with selenium intake in middle-aged and older Chinese. Methods: Data for this study were obtained from the China Health and Nutrition Survey (CHNS). A total of 5381 participants (aged ≥ 45) with biochemical test data were included in the study. Logistic regression models were used to examine the association between diet selenium intake (quartile) and the prevalence of CKD. Results: A total of 942 (17.01%) participants had CKD. The prevalence of CKD was 23.33%, 20.32%, 14.98%, and 9.25% among participants with average selenium intakes of 21.5 ± 4.82, 33.1 ± 2.79, 43.8 ± 3.70, and 67.0 ± 13.97 µg/day, respectively. In the fully adjusted model (Model 3), across the quartiles of selenium intake, the ORs for the prevalence of CKD were 1.00, 1.09 (95% CI 0.69–1.73), 0.82 (95% CI 0.49–1.38), and 0.43 (95% CI 0.22–0.85). The protein intake had a certain diagnostic significance for the selenium intake. Conclusions: An adequate selenium intake may have a positive effect on CKD. The influence of individual weight and location on the effect of selenium on CKD needs to be further explored.

Sub-Flap Use of Nano-Selenium Oxide Solution Enhances Skin Flap Viability in Rats: Study the Novel Role of mTOR and p-mTOR Expression

BACKGROUND

Nano-selenium oxide (NSeO) particles are highly noticeable due to their tissue-protective and antioxidant properties. For this purpose, the effect of NSeO was evaluated on skin flap survival and flap oxidative stress markers in rats. Also, another effect of NSeO was investigated on the expression of mTOR and p-mTOR.

MATERIALS AND METHODS

Fifty rats were divided into five groups of ten. Skin flap size was 3×8 cm in all groups. Groups were: (1) Sham, (2) Flap Surgery group, (3) Flap Surgery + NSeO, (4) Flap Surgery + Rapamycin (mTOR inhibitor), (5) Flap Surgery + Rapamycin + NSeO. The flap necrosis rate was computed using the paper pattern method on day seven after surgery. After day seven, flap tissues were collected for histological evaluations. Then, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were measured. Furthermore, the expression levels of mTOR and p-mTOR were measured using the Western blot method.

RESULTS

Treatment with NSeO significantly reduced necrosis (P<0.05). It also resulted in a decrease in MDA level (P<0.05). Histologically, NSeO reduced inflammation and increased positive signs of tissue healing (epithelialization, neovascularization, fibroblast migration, and granulation tissue). NSeO increased SOD activity significantly (P<0.05), whereas, using rapamycin reversed these effects. Also, in all groups, mTOR changes were not significant. Additionally, p-mTOR expression was significantly reduced in groups that rapamycin was injected.

CONCLUSION

NSeO can reduce flap necrosis and enhance tissue healing in rats. So, it can potentially be used clinically to promote tissue repair significantly, and its effects are independent of the mTOR pathway.

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Supplementation with selenium nanoparticles alleviates diabetic nephropathy during pregnancy in the diabetic female rats

The bioactivity of nanoparticles has engendered a promise in scientific communities for developing novel therapeutic strategies. This study investigated the protective effects of selenium nanoparticles (SeNPs) against kidney injury in streptozocin-induced diabetes during pregnant (DDP) rats. The female rats were separated into three groups (n = 8). Group 1 received the vehicle, normal saline. Group 2 received a single intraperitoneal dose of 50 mg/kg of streptozocin. Group 3 received a single intraperitoneal injection of 50 mg/kg of streptozocin, followed by treatment with SeNPs at a dose of 2.5 mg/kg twice a week for 6 weeks (1 week before gestation and continuing for 5 additional weeks). The structure formed by the fabricated SeNPs with citric acid in the presence of ascorbic acid indicated that nano-Se was associated with a carbon matrix. The diabetic group suffered from polyuria, a reduction in body weight, delayed gestation, and only 40% successful pregnancy compared with the control rats. Interestingly, SeNPs significantly reduced the rate of urination, accelerated the start of gestation, and increased the percentage of successful pregnancy in females with DM. Severe changes were observed in the pancreatic β-cells of the diabetic rats, with darkly stained and fragmented chromatin in nuclei, while SeNPs partially restored the normal morphological features of the pancreatic β-cells. The concentrations of urea, creatinine, MDA, and glucose were significantly increased in the diabetic rats, while GSH was significantly reduced compared with controls. Interestingly, SeNPs restored all of these parameters to values at or near control levels. SeNPs were capable of improving the histological structure of the kidney in mothers with DDP. Hence, the present work is relevant to GDM demonstrating SeNPs shielding the kidney structure and function in vivo.

Supplementation With Vitamin E, Zinc, Selenium, and Copper Re-Establishes T-Cell Function and Improves Motor Recovery in a Rat Model of Spinal Cord Injury

Spinal cord injury (SCI) causes a dysfunction of sympathetic nervous system innervation that affects the immune system, leading to immunosuppression syndrome (ISS) and contributing to patient degeneration and increased risk of several infections. A possible therapeutic strategy that could avoid further patient deterioration is the supplementation with Vitamin E or trace elements, such as Zinc, Selenium, and Copper, which individually promotes T-cell differentiation and proliferative responses. For this reason, the aim of the present study was to evaluate whether Vitamin E, Zinc, Selenium, and Copper supplementation preserves the number of T-lymphocytes and improves their proliferative function after traumatic SCI. Sprague–Dawley female rats were subjected to moderate SCI and then randomly allocated into three groups: (1) SCI + supplements; (2) SCI + vehicle (olive oil and phosphate-buffered saline); and (3) sham-operated rats. In all rats, the intervention was initiated 15 min after SCI and then administered daily until the end of study. Locomotor recovery was assessed at 7 and 15 days after SCI. At 15 days after supplementation, the quantification of the number of T-cells and its proliferation function were examined. Our results showed that the SCI + supplements group presented a significant improvement in motor recovery at 7 and 15 days after SCI. In addition, this group showed a better T-cell number and proliferation rate than that observed in the group with SCI + vehicle. Our findings suggest that Vitamin E, Zinc, Selenium, and Copper supplementation could be part of a therapy for patients suffering from acute SCI, helping to preserve T-cell function, avoiding complications, and promoting a better motor recovery. All procedures were approved by the Animal Bioethics and Welfare Committee (Approval No. 201870; CSNBTBIBAJ 090812960).

Metabolic syndrome during gestation and lactation: An important renal problem in dams. selenium renal clearance

BACKGROUND

Metabolic syndrome (MS) in lactating dams leads to several cardiometabolic changes related to selenium (Se) status and selenoproteins expression which produce hypertension. However, little is known about the state of these dams' kidney functions and their Se deposits.

METHODS

Two experimental groups of dam rats were used: control (Se: 0.1 ppm) and MS (Fructose 65 % and Se: 0.1 ppm). At the end of lactation (21d postpartum) kidney weight and protein content, Se deposits, and the activity of the antioxidant selenoprotein glutathione peroxidase (GPx) were measured in dams. Kidney functional parameters: albuminuria, creatinine clearance, serum aldosterone and uric acid levels and water and electrolyte (Na⁺ and K⁺) balance were also evaluated. Systolic blood pressure (SBP) was measured.

RESULTS

In MS dams at the end of lactation Se deposits and GPx activity are higher in the kidney; however, lipid renal peroxidation appears, relative Se clearance increases, and the dams have lost Se by urine. MS dams have polyuria and polydipsia, high uric acid serum levels, albuminuria and high creatinine clearance, implying glomerular renal malfunction with protein loss. They also present hypernatremia, hypokalemia and hyperaldosteronemia, leading to high SBP; however, a natriuretic process is taking place.

CONCLUSION

Since these alterations appear, at least in part, to be related to oxidative stress in renal cells, Se supplementation could be beneficial to avoiding greater lipid renal oxidation during lactation.

Kidney diseases and COVID-19 infection: causes and effect, supportive therapeutics and nutritional perspectives

Recently, the novel coronavirus disease 2019 (COVID-19), has attracted the attention of scientists where it has a high mortality rate among older adults and individuals suffering from chronic diseases, such as chronic kidney diseases (CKD). It is important to elucidate molecular mechanisms by which COVID-19 affects the kidneys and accordingly develop proper nutritional and pharmacological strategies. Although numerous studies have recently recommended several approaches for the management of COVID-19 in CKD, its impact on patients with renal diseases remains the biggest challenge worldwide. In this paper, we review the most recent evidence regarding causality, potential nutritional supplements, therapeutic options, and management of COVID-19 infection in vulnerable individuals and patients with CKD. To date, there is no effective treatment for COVID-19-induced kidney dysfunction, and current treatments are yet limited to anti-inflammatory (e.g. ibuprofen) and anti-viral medications (e.g. Remdesivir, and Chloroquine/Hydroxychloroquine) that may increase the chance of treatment. In conclusion, the knowledge about kidney damage in COVID-19 is very limited, and this review improves our ability to introduce novel approaches for future clinical trials for this contiguous disease.

Selenium and Coenzyme Q10 Supplementation Improves Renal Function in Elderly Deficient in Selenium: Observational Results and Results from a Subgroup Analysis of a Prospective Randomised Double-Blind Placebo-Controlled Trial

A low selenium intake is found in European countries, and is associated with increased cardiovascular mortality. There is an association between selenium level and the severity of kidney disease. An association between inflammation and selenium intake is also reported. The coenzyme Q10 level is decreased in kidney disease. The aim of this study was to examine a possible association between selenium and renal function in an elderly population low in selenium and coenzyme Q₁₀, and the impact of intervention with selenium and coenzyme Q₁₀ on the renal function. The association between selenium status and creatinine was studied in 589 elderly persons. In 215 of these (mean age 71 years) a randomised double-blind placebo-controlled prospective trial with selenium yeast (200 µg/day) and coenzyme Q₁₀ (200 mg/day) (n = 117) or placebo (n = 98) was conducted. Renal function was determined using measures of glomerular function at the start and after 48 months. The follow-up time was 5.1 years. All individuals were low on selenium (mean 67 μg/L (SD 16.8)). The changes in renal function were evaluated by measurement of creatinine, cystatin-C, and the use of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) algorithm, and by the use of T-tests, repeated measures of variance and ANCOVA analyses. An association between low selenium status and impaired renal function was observed. Intervention causes a significantly lower serum creatinine, and cystatin-C concentration in the active treatment group compared with those on placebo (p = 0.0002 and p = 0.001 resp.). The evaluation with CKD-EPI based on both creatinine and cystatin-C showed a corresponding significant difference (p < 0.0001). All validations showed corresponding significant differences. In individuals with a deficiency of selenium and coenzyme Q_10, low selenium status is related to impaired renal function, and thus supplementation with selenium and coenzyme Q10 results in significantly improved renal function as seen from creatinine and cystatin-C and through the CKD-EPI algorithm. The explanation could be related to positive effects on inflammation and oxidative stress as a result of the supplementation.

Therapeutic Potential of Selenium as a Component of Preservation Solutions for Kidney Transplantation

Selenium has strong antioxidant properties and diverse effects on the immune system. The aim of the study was to analyse the protective effect of selenium as a component of a kidney preservation solution on the prevention of ischemia-reperfusion injury of nephrons. The solution was modified by the addition of Se (1 µg/L), prolactin (0.1 µg/L) and Se with prolactin (1 µg/L Se + 0.1 µg/L PRL). The study used a model for storing isolated porcine kidneys in Biolasol^® (modified Biolasol^®), which minimizes ischemia-reperfusion injury of grafts. The introduction of Se⁴⁺ ions at a dose of 1 µg/L into the Biolasol^® preservation solution in the form of Na₂SeO₃ caused an increase in the activity/concentration of the analysed biochemical parameters: aspartate transaminase, alanine transaminase, urea and protein. This suggests an adverse effect of Se⁴⁺ on nephron function during ischemia-reperfusion. The best graft protection was obtained by using Biolasol^® modified with the addition of selenium (IV) at a dose of 1 µg/L and prolactin at a concentration of 0.1 µg/L. We proposed the mechanism of prolactin action in the metabolic reduction of selenite (SO₃²⁻) during ischemia/reperfusion.

A Stereological Study of the Toxic Effects of Cerium Oxide during Pregnancy on Kidney Tissues in Neonatal NMRI Mice

Background

Both antioxidant and prooxidant activities have been previously reported for cerium oxide (CeO₂). The aim of this study was to investigate the effects of CeO₂ at different doses on changes in kidney tissues and markers in neonatal mice.

Methods

We randomly divided 30 pregnant NMRI mice into five groups (n = 6 per group)-a control group and four groups treated with intraperitoneal (i.p.) administration of different doses of CeO₂ (10, 25, 80, or 250 mg/kg body weight (bw)) on gestation days (GD) 7 and GD14. At the end of the treatment period, we analyzed the kidney tissues and serum samples. The levels of two serum redox markers, malondialdehyde (MDA) and ferric reducing/antioxidant power (FRAP), were determined. Data were analyzed using one-way ANOVA and Tukey's test, and a P value of <0.05 was considered significant.

Results

The mean total volumes of the renal corpuscle, glomeruli, and Bowman's capsule membranes significantly increased, and there was a significant decrease in the mean total volume of Bowman's space in the high-dose CeO₂ group compared to that in the control group. No statistically significant differences existed in the serum levels of MDA and FRAP in the treated and control groups.

Conclusion

Our results suggest that high doses of CeO₂ impair fetal renal development in pregnant mice, which results in kidney damage. Therefore, CeO₂ administration during pregnancy could have dose-dependent adverse effects on the developing kidneys in neonates.

Selenoproteins and renal programming in metabolic syndrome-exposed rat offspring

Maternal metabolic syndrome (MS) during gestation and lactation leads to several cardiometabolic changes related to selenium (Se) status and selenoprotein expression in offspring. However, little is known about kidney programming and antioxidant selenoprotein status in MS pups. To gain more knowledge on this subject, two experimental groups of dam rats were used: Control (Se: 0.1 ppm) and MS (fructose 65% and Se: 0.1 ppm). At the end of lactation, Se deposits in kidneys, selenoprotein expression (GPx1, GPx3, GPx4 and selenoprotein P), oxidative balance and AMP-activated protein kinase (AMPK) and activated transcriptional factor NF-κB expression were measured. Kidney functional parameters, albuminuria, creatinine clearance, aldosteronemia, and water and electrolyte balance, were also evaluated. One week later systolic blood pressure was measured. Lipid peroxidation takes place in the kidneys of MS pups and Se, selenoproteins and NF-κB expression increased, while AMPK activation decreased. MS pups have albuminuria and low creatinine clearance which implies glomerular renal impairment with protein loss. They also present hypernatremia and hyperaldosteronemia, together with a high renal Na⁺ reabsorption, leading to a hypertensive status, which was detected in these animals one week later. Since these alterations seem to be related, at least in part, to oxidative stress, the increase in Se and selenoproteins found in the kidneys of these pups seems to be beneficial, avoiding a higher lipid oxidation. However, in order to analyze the possible global beneficial role of Se in kidneys during MS exposure, more data are necessary to document the relationships between GPx4 and NF-κB, and SelP and AMPK in kidneys.

Protective Effects of Selenium on Cyclophosphamide-Induced Oxidative Stress and Kidney Injury

Cyclophosphamide (CP) is a common anticancer drug, but its use in cancer treatment is limited due to its severe toxicities induced mainly by oxidative stress in normal cells. Reactive oxygen species (ROS) lead to multiple organ injuries, including the kidneys. Selenium (Se) is a nutritionally essential trace element with antioxidant properties. In the present study, the possible protective effect of Se on CP-induced acute nephrotoxicity was investigated. Forty-two Sprague-Dawley rats were equally divided into six groups of seven rats in each. The control group received saline, and other groups were injected with CP (150 mg/kg), Se (0.5 or 1 mg/kg), or CP + Se intraperitoneally. Total antioxidant capacity (TAC), total oxidant state (TOS), oxidative stress index (OSI), creatinine, and cystatin C (Cys C) levels were measured in the sera. In addition, kidney tissues were examined histologically. In the CP alone treated rats, creatinine, Cys C, TOS, and OSI levels increased, while TAC level decreased. CP-induced histological damages were decreased by co-treatment of Se and biochemical results supported the microscopic observations. In conclusion, our study points to the therapeutic potential of Se and indicates a significant role of ROS in CP-induced kidney toxicity.

Protective Effects of Selenium Against Sodium Fluoride Induced Behavioral, Anti-Oxidant and Neurohistological Alterations in Wistar Rats

Fluoride naturally occurs in the earth’s crust and ground water and it causes fluorosis when it is consumed in high levels. The fluorosis also affects soft tissues like liver, kidney, heart, brain etc., in addition to skeletal and dental systems. The present study reports the protective effects of selenium against sodium fluoride induced neurotoxic effects. Three months old (around 250 – 280 g weight) wistar rats were randomly categorized into four groups viz. Group I (control) which received normal tap water, Group II (sodium fluoride, NaF) treated with 20 ppm of fluoride through IP, Group III treated with (NaF 20 ppm) + Selenium (5 mgkg-1 body wt./day/rat) and Group IV treated with Selenium (5 mgkg-1 body wt./day/rat) alone. The doses were continued for a period of 15 days and after that they were used for recording behavioral (rota rod, hot plate), anti-oxidant (LPO, SOD, CAT and GSH-Px) and histological (Golgi cox staining) observations. The rats treated with NaF showed the decreased motor coordination, thermal pain response, decreased CAT and SOD activity and increased LPO levels and GSH-Px activity with compared to control group. Moreover, NaF received rats also showed the decreased number of dendrites, synaptic connections and neural networks. These all alterations were reversed on administration of selenium towards fluoride toxicity and the results were significant (p<0.01). The results of selenium alone treated group of rats is comparable to control group. Based on these observed results, the present study evidenced the protective role of selenium against fluoride induced neurotoxicity.

Silibinin Improves TNF-α and M30 Expression and Histological Parameters in Rat Kidneys After Hepatic Ischemia/Reperfusion

BACKGROUND

Remote kidney damage is a sequel of hepatic ischemia-reperfusion (I/R) injury. Silibinin is the main ingredient of the milk thistle plant seed extract with known antioxidant and hepatoprotective activity. Our study investigates the nephroprotective potential of intravenously administered silibinin, as a lyophilized SLB-hydoxypropyl-beta-cyclodextrin product, in hepatic I/R injury.

MATERIAL AND METHODS

63 Wistar rats were divided into three groups: Sham (virtual intervention); Control (45 min ischemia and reperfusion); and Silibinin (200 μL intravenous silibinin administration after 45 min of ischemia). Kidney tissues were collected to determine TNF-α, M30 and histopathological changes at predetermined time intervals.

RESULTS

Comparing Sham vs. Control groups, proved that hepatic I/R injury increased renal TNF-α and M30 expression. Deterioration was observed in hyperemia/filtration of renal parenchyma and tubules, cortical filtration, tubular necrosis and edema (tissue swelling index). Intravenous silibinin administration and comparison of the Control vs. Silibinin groups showed a statistically significant decrease in TNF-α levels at 240 min following I/R (p < 0.0001), and in M30 at 180 min (p = 0.03) and 240 min (p < 0.0001). Renal parameters have significantly decreased in: hyperemia/filtration of renal parenchyma at 120 min (p = 0.003), 180 min (p = 0.0001) and 240 min (p = 0.0002); hyperemia/filtration of renal tubules at 120 min (p = 0.02), 180 min (p = 0.0001) and 240 min (p = 0.0005); cortical filtration (240 min - p = 0.005); tubular necrosis (240 min - p = 0.021); and edema (240 min - p = 0.001).

CONCLUSION

Our study confirms that hepatic I/R injury causes remote renal damage while the intravenous administration of silibinin leads to statistically significant nephroprotective action.

A Summary of New Findings on the Biological Effects of Selenium in Selected Animal Species-A Critical Review

Selenium is an essential trace element important for many physiological processes, especially for the functions of immune and reproductive systems, metabolism of thyroid hormones, as well as antioxidant defense. Selenium deficiency is usually manifested by an increased incidence of retention of placenta, metritis, mastitis, aborts, lowering fertility and increased susceptibility to infections. In calves, lambs and kids, the selenium deficiency demonstrates by WMD (white muscle disease), in foals and donkey foals, it is associated with incidence of WMD and yellow fat disease, and in pigs it causes VESD (vitamin E/selenium deficiency) syndrome. The prevention of these health disorders can be achieved by an adequate selenium supplementation to the diet. The review summarizes the survey of knowledge on selenium, its biological significance in the organism, the impact of its deficiency in mammalian livestock (comparison of ruminants vs. non-ruminants, herbivore vs. omnivore) and possibilities of its peroral administration. The databases employed were as follows: Web of Science, PubMed, MEDLINE and Google Scholar.