Oxidative damage parameters in renal tissues of aged and young rats based on gender

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.

Empagliflozin improves kidney senescence induced by D-galactose by reducing sirt1-mediated oxidative stress

Sodium-glucose cotransporter-2 (SGLT-2) inhibitors have received widespread attention because of their significant protective effects on the kidney. Previous studies have shown that Sirt1, as which is an antiaging protein, is closely related to the maintenance of redox homeostasis. The goal of this study was to determine whether empagliflozin could ameliorate D-galactose-induced renal senescence in mice, and examine the possible mechanisms of Sirt1. We constructed a rapid ageing model in mice by administering D-galactose. An ageing model was constructed by treating cells with high glucose. Treadmill and Y-maze tests were used to assess exercise tolerance and learning memory ability. Pathologically stained sections were used to assess kidney injury. Tissue and cell senescence were evaluated by senescence-associated β-galactosidase staining. The expression levels of P16, SOD1, SOD2 and Sirt1 were detected by immunoblotting. D-gal-treated mice exhibited significant age-related changes, as measured by behavioural tests and ageing marker protein levels. empagliflozin alleviated these ageing manifestations. In addition, Sirt1, SOD1 and SOD2 levels were downregulated in model mice and upregulated by empagliflozin treatment. Empagliflozin had similar protective effects at the cellular level, and these effects were reduced by the Sirt1 inhibitor. Empagliflozin has an antiaging effect, which may be related to reducing Sirt1-mediated oxidative stress.

Stereological study and analysis of oxidative stress during renal aging in rats

PURPOSE

To evaluate renal histological changes by stereology and morphometry and analyze the main markers of oxidative stress in rats undergoing natural aging.

METHODS

Seventy two Wistar rats were divided into six groups of 12 rats each, which were euthanized at 3, 6, 9, 12, 18, and 24 months of age. Right kidney was stereologically and morphometrically analyzed to calculate the volumetric density (Vv[glom]), numerical density (Nv[glom]) and glomerular volume (Vol[glom]). Left kidney was used to determine the levels of nonprotein thiols, lipid peroxidation, and protein carbonylation, as well as the activities of superoxide-dismutase and catalase enzymes.

RESULTS

Both Vv[glom] and Nv[glom] values showed gradual decreases between groups. Activity of superoxide-dismutase was elevated at 24 months of age, and the levels of nonprotein thiols were higher in older animals. Greater catalase activity and protein carbonylation were observed in animals between 6 and 12 months of age but lessened in older rats. Lipid peroxidation decreased in the older groups.

CONCLUSIONS

Morphometric and stereological analyses revealed a gradual decrease in the volume and density of renal glomeruli during aging, as well as kidney atrophy. These findings related to oxidative stress clarify many changes occurring in kidney tissues during senescence in rats.

Effects of Aging and Methionine Restriction on Rat Kidney Metabolome

Methionine restriction (MetR) in animal models extends maximum longevity and seems to promote renoprotection by attenuating kidney injury. MetR has also been proven to affect several metabolic pathways including lipid metabolism. However, there is a lack of studies about the effect of MetR at old age on the kidney metabolome. In view of this, a mass spectrometry-based high-throughput metabolomic and lipidomic profiling was undertaken of renal cortex samples of three groups of male rats-An 8-month-old Adult group, a 26-month-old Aged group, and a MetR group that also comprised of 26-month-old rats but were subjected to an 80% MetR diet for 7 weeks. Additionally, markers of mitochondrial stress and protein oxidative damage were analyzed by mass spectrometry. Our results showed minor changes during aging in the renal cortex metabolome, with less than 59 differential metabolites between the Adult and Aged groups, which represents about 4% of changes in the kidney metabolome. Among the compounds identified are glycerolipids and lipid species derived from arachidonic acid metabolism. MetR at old age preferentially induces lipid changes affecting glycerophospholipids, docosanoids, and eicosanoids. No significant differences were observed between the experimental groups in the markers of mitochondrial stress and tissue protein damage. More than rejuvenation, MetR seems to induce a metabolic reprogramming.

Effects of d-galactose-induced ageing on the heart and its potential interventions

Ageing is a strong independent risk factor for disability, morbidity and mortality. Post-mitotic cells including those in the heart are a particular risk to age-related deterioration. As the occurrence of heart disease is increasing rapidly with an ageing population, knowledge regarding the mechanisms of age-related cardiac susceptibility and possible therapeutic interventions needs to be acquired to prevent advancing levels of heart disease. To understand more about the ageing heart, numerous aged animal models are being used to explore the underlying mechanisms. Due to time-consuming for investigations involving naturally aged animals, mimetic ageing models are being utilized to assess the related effects of ageing on disease occurrence. d-galactose is one of the substances used to instigate ageing in various models, and techniques involving this have been widely used since 1991. However, the mechanism through which d-galactose induces ageing in the heart remains unclear. The aim of this review was to comprehensively summarize the current findings from in vitro and in vivo studies on the effects of d-galactose-induced ageing on the heart, and possible therapeutic interventions against ageing heart models. From this review, we hope to provide invaluable information for future studies and based on the findings from experiments involving animals, we can inform possible therapeutic strategies for the prevention of age-related heart diseases in clinical settings.

Acute kidney injury and inflammatory response of sepsis following cecal ligation and puncture in d-galactose-induced aging rats

Background

Recently, the d-galactose (d-gal)-induced mimetic aging rat model has been widely used in studies of age-associated diseases, which have shown that chronic d-gal exposure induces premature aging similar to natural aging in rats. With the increasing rate of sepsis in the geriatric population, an easy-access animal model for preclinical studies of elderly sepsis is urgently needed. This study investigates whether a sepsis model that is established in d-gal-induced aging rats can serve as a suitable model for preclinical studies of elderly patients with sepsis.

Objective

To investigate the acute kidney injury (AKI) and inflammatory response of sepsis following cecal ligation and puncture (CLP) in d-gal-induced aging rats.

Methods

Twelve-week-old male Sprague Dawley rats were divided into low-dose d-gal (L d-gal, 125 mg/kg/d), high-dose d-gal (H d-gal, 500 mg/kg/d), and control groups. After daily subcutaneous injection of d-gal for 6 weeks, the CLP method was used to establish a sepsis model.

Results

The mortality was 73.3%, 40%, and 33.3% in the H d-gal, L d-gal, and control groups, respectively. Blood urea nitrogen, creatinine, plasma neutrophil gelatinase-associated lipocalin, interleukin-6, interleukin-10, and tumor necrosis factor-α were markedly increased in the H d-gal group after establishment of the sepsis model (H d-gal vs control, P<0.05 at 12 h and 24 h post-CLP). The rate of severe AKI (RIFLE-F) at 24 h post-CLP was 43% for both the control and L d-gal groups and 80% for the H d-gal group.

Conclusion

High-dose- d-gal-induced aging rats are more likely to die from sepsis than are young rats, and probably this is associated with increased severity of septic AKI and an increased inflammatory response. Therefore, use of the high-dose- d-gal-induced aging rat model of sepsis for preclinical studies can provide more useful information for the treatment of sepsis in elderly patients.

Hyperoxic oxidative stress during abdominal surgery: a randomized trial

PURPOSE

The hypothesis of our study is that during anesthesia, administration of 80 % oxygen concentration increases oxidative stress more than 40 % oxygen.

METHODS

Forty ASA I-II patients were included in a randomized, single-blind study. Expiratory tidal volumes (ETV) were measured before induction and after extubation. After ventilation with 0.8 FiO2 and intubation, mini-bronchoalveolar lavage (mini-BAL), arterial blood gas (ABG), and blood samples were taken. Patients were randomly assigned to receive 0.8 (group I) or 0.4 (group II) FiO2 during management. Before extubation, mini-BAL, ABG, blood samples were taken. PaO2/FiO2, lactate, malondialdehyde (MDA), protein carbonyl (PCO), superoxide dismutase (SOD), total sulfhydryl (T-SH), non-protein sulfhydryl (NPSH), and protein sulfhydryl (PSH) were measured. In both groups, mean arterial pressure and heart rate values were recorded with 30-min intervals.

RESULTS

ETV values were higher in group II after extubation. PaO2/FiO2 values were higher in group II after extubation compared to group I. In both groups, plasma PCO, SOD, and T-SH levels increased significantly before extubation, whereas the increase in MDA was not significant between groups. Plasma PCO, T-SH, and lactate levels were higher in group I, and plasma SOD, and PSH were higher in group I before extubation. In both groups, MDA, SOD, T-SH, and NPSH levels in mini-BAL increased significantly before extubation. Between-group comparisons, PCO, T-SH, PSH, and NPSH were significantly higher in the BAL samples of group II, and MDA levels were higher in group I.

CONCLUSIONS

We found that 80 % FiO2 decreased ETV and PaO2/FiO2 and increased lactate levels and oxidative stress more, inhibiting antioxidant response compared to 40 % FiO2.

A comprehensive study of myocardial redox homeostasis in naturally and mimetically aged rats

Age-related myocardial dysfunction has important implications with impaired redox homeostasis. Current study focused on investigation of redox homeostasis and histopathological changes in the myocardium of mimetically (MA), naturally aged (NA), and young control (YC) rats. Chronic D-galactose administration to young male Wistar rats (5 months old) was used to set up experimental aging models. We investigated 16 different oxidative damage biomarkers which have evaluated redox homeostasis of cellular macromolecules such as protein, lipid, and DNA. As a protein oxidation biomarker, advanced oxidation end products, protein carbonyl groups, protein-bound advanced glycation end products, dityrosine, kynurenine, and N-formylkynurenine concentrations in MA and NA rats were found to be significantly higher compared to those in YC rats. On the other hand, the levels of protein thiol groups were not significantly different between groups, whereas lipid peroxidation biomarkers such as conjugated diens, lipid hydroperoxides, and malondialdehyde in MA and NA rats were found to be significantly higher in comparison to those in YCs. For the assessment of oxidative DNA damage, we analyzed eight hydroxy-5'-deoxyguanosine concentrations of MA and NA groups which were higher than YCs. As an antioxidant status in the MA and NA groups, Cu-Zn superoxide dismutase, ferric reducing antioxidant power, and total thiol levels were lower than those in the YCs. Only nonprotein thiol levels were not significantly different. We also observed similar histopathological changes in MA and NA rats. We concluded that the mimetic aging model could be considered as a reliable experimental model for myocardial senescence.