Protein and DNA oxidation in different anatomic regions of rat brain in a mimetic ageing model

Role of mitochondrial homeostasis in D-galactose-induced cardiovascular ageing from bench to bedside

Ageing is an inevitable phenomenon which affects the cellular to the organism level in the progression of the time. Oxidative stress and inflammation are now widely regarded as the key processes involved in the aging process, which may then cause significant harm to mitochondrial DNA, leading to apoptosis. Normal circulatory function is a significant predictor of disease-free life expectancy. Indeed, disorders affecting the cardiovascular system, which are becoming more common, are the primary cause of worldwide morbidity, disability, and mortality. Cardiovascular aging may precede or possibly underpin overall, age-related health decline. Numerous studies have foundmitochondrial mechanistc approachplays a vital role in the in the onset and development of aging. The D-galactose (D-gal)-induced aging model is well recognized and commonly used in the aging study. In this review we redeposit the association of the previous and current studies on mitochondrial homeostasis and its underlying mechanisms in D-galactose cardiovascular ageing. Further we focus the novel and the treatment strategies to combat the major complication leading to the cardiovascular ageing.

The ameliorative mechanism of Lactiplantibacillus plantarum NJAU-01 against D-galactose induced oxidative stress: a hepatic proteomics and gut microbiota analysis

Probiotic intervention is an effective strategy to alleviate oxidative stress-related diseases. Our previous studies found that Lactiplantibacillus plantarum NJAU-01 (NJAU-01) exhibited antioxidant effects in a D-galactose (D-gal)-induced aging mouse model. However, the underlying mechanism remains to be unveiled. This study was aimed to investigate the ameliorative effect and mechanism of NJAU-01 against oxidative stress induced by D-gal. The results showed that NJAU-01 could reverse the tendency of a slow body weight gain induced by D-gal. NJAU-01 relieved hepatic oxidative stress via increasing the hepatic total antioxidant capacity and antioxidant enzyme activities including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT). Moreover, the malondialdehyde (MDA) level was reversed after NJAU-01 supplementation. The proteomic results showed that there were 201 differentially expressed proteins (DEPs) between NJAU-01 and D-gal groups. NJAU-01 regulated the expressions of glutathione S-transferase Mu 5 (Gstm5), glutathione S-transferase P2 (Gstp2) and NADH dehydrogenase 1α subcomplex subunit 7 (Ndufa7) related to oxidative stress, and autophagy protein 5 (Atg5) and plasma alpha-L-fucosidase (Fuca2) involved in autophagy, etc. 16S rDNA sequencing results showed that NJAU-01 supplementation could regulate the gut microbiota dysbiosis induced by D-gal via increasing the relative abundances of the phylum Firmicutes and the genus Lactobacillus and reducing the relative abundances of the phylum Bacteroidetes and the genera Lachnospiraceae_NK4A136_group as well as Prevotellaceae_UCG-001, etc.. Spearman correlation analysis results showed that the altered gut microbiota composition had a significant correlation with antioxidant enzyme activities and the DEPs related to oxidative stress. Overall, NJAU-01 alleviated hepatic oxidative stress induced by D-gal via manipulating the gut microbiota composition and hepatic protein expression profile.

Structural characterization and improves cognitive disorder in ageing mice of a glucomannan from Dendrobium huoshanense

In the present work, a neutral polysaccharide (DHP-2W) with attenuating cognitive disorder was identified from Dendrobium huoshanense and its structure was clarified. The polysaccharide was successfully purified from D. huoshanense by column chromatography and its activity was evaluated. With a molecular weight of 508.934kDa, this polysaccharide is composed of mannose and glucose at a molar ratio of 75.81: 24.19. Structural characterization revealed that DHP-2W has a backbone consisting of 4)-β-D-Manp-(1 and 4)-β-D-Glcp-(1. In vivo experiments revealed that DHP-2W improved cognitive disorder in D-galactose treated mice and relieved oxidative stress and inflammation. DHP-2W attenuates D-galactose-induced cognitive disorder by inhibiting the BCL2/BAX/CASP3 pathway and activating the AMPK/SIRT pathway, thereby inhibiting apoptosis. Furthermore, DHP-2W had a significant effect on regulating the serum levels of Flavin adenine dinucleotide, Shikimic acid, and Kynurenic acid in aged mice. These, in turn, had a positive impact on AMPK/SIRT1 and BCL2/BAX/CASP3, resulting in protective effects against cognitive disorder.

Berberine attenuates brain aging via stabilizing redox homeostasis and inflammation in an accelerated senescence model of Wistar rats

Aging is a multifaceted and progressive physiological change of the organism categorized by the accumulation of deteriorating processes, which ultimately compromise the biological functions. The objective of this study was to investigate the anti-aging potential of berberine (BBR) in D-galactose (D-Gal) induced aging in rat models. In this study, male Wistar rats were divided into four groups: The control group was given only vehicle, the BBR group was treated with berberine orally, the D-Gal group was treated with D-galactose subcutaneously and the BBR + D-Gal group was treated with D-galactose and berberine simultaneously. D-galactose exposure elevated the pro-oxidants such as malondialdehyde (MDA) level, protein carbonyl and advanced oxidation protein products (AOPP) in the brain. It decreased the anti-oxidants such as reduced glutathione (GSH) and ferric reducing antioxidant potential (FRAP) in the brain. D-galactose treatment also reduced the mitochondrial complexes (I, II, III and IV) activities and elevated the inflammatory markers such as interleukine-6 (IL-6), tumor necrosis factor- α (TNF-α) and C-reactive protein (CRP). The mRNA expressions of IL-6 and TNF-α in the brain were upregulated following D-galactose exposure. Berberine co-treatment in D-galactose induced aging rat model prevented the alteration of pro-oxidant and anti-oxidant in the brain. Berberine treatment restored the mitochondrial complex activities in the brain and also normalized the inflammatory markers. Based on these findings we conclude that berberine treatment has the potential to mitigate brain aging in rats via stabilizing the redox equilibrium and neuroinflammation.

The Biological Activity of Ganoderma lucidum on Neurodegenerative Diseases: The Interplay between Different Active Compounds and the Pathological Hallmarks

Neurodegenerative diseases represent a cluster of conditions characterized by the progressive degeneration of the structure and function of the nervous system. Despite significant advancements in understanding these diseases, therapeutic options remain limited. The medicinal mushroom Ganoderma lucidum has been recognized for its comprehensive array of bioactive compounds with anti-inflammatory and antioxidative effects, which possess potential neuroprotective properties. This literature review collates and examines the existing research on the bioactivity of active compounds and extracts from Ganoderma lucidum in modulating the pathological hallmarks of neurodegenerative diseases. The structural information and preparation processes of specific components, such as individual ganoderic acids and unique fractions of polysaccharides, are presented in detail to facilitate structure-activity relationship research and scale up the investigation of in vivo pharmacology. The mechanisms of these components against neurodegenerative diseases are discussed on multiple levels and elaborately categorized in different patterns. It is clearly presented from the patterns that most polysaccharides of Ganoderma lucidum possess neurotrophic effects, while ganoderic acids preferentially target specific pathogenic proteins as well as regulating autophagy. Further clinical trials are necessary to assess the translational potential of these components in the development of novel multi-target drugs for neurodegenerative diseases.

Trimethylamine-N-oxide aggravated the sympathetic excitation in D-galactose induced aging rats by down-regulating P2Y12 receptor in microglia

This study aimed to determine whether trimethylamine N-oxide (TMAO) was involved in sympathetic activation in aging and the underlying mechanisms. Our hypothesis is TMAO reduces P2Y12 receptor (P2Y12R) and induces microglia-mediated inflammation in the paraventricular nucleus (PVN), then leading to sympathetic activation in aging. This study involved 18 young adults and 16 old adults. Aging rats were established by injecting D-galactose (D-gal, 200 mg/kg/d) subcutaneously for 12 weeks. TMAO (120 mg/kg/d) or 1% 3, 3-dimethyl-l-butanol (DMB) was administrated via drinking water for 12 weeks to investigate their effects on neuroinflammation and sympathetic activation in aging rats. Plasma TMAO, NE and IL-1β levels were higher in old adults than in young adults. In addition, standard deviation of all normal to normal intervals (SDNN) and standard deviation of the average of normal to normal intervals (SDANN) were lower in old adults and negatively correlated with TMAO, indicating sympathetic activation in old adults, which is associated with an increase in TMAO levels. Treatment of rats with D-gal showed increased senescence-associated protein levels and microglia-mediated inflammation, as well as decreased P2Y12R protein levels in PVN. Plasma TMAO, NE and IL-1β levels were increased, accompanied by enhanced renal sympathetic nerve activity (RSNA). While TMAO treatment exacerbated the above phenomenon, DMB mitigated it. These findings suggest that TMAO contributes to sympathetic hyperactivity in aging by downregulating P2Y12R in microglia and increasing inflammation in the PVN. These results may provide promising new target for the prevention and treatment of aging and aging-related diseases.

Time-resolved map of serum metabolome profiling in D-galactose-induced aging rats with exercise intervention

Exercise, an intervention with wide-ranging effects on the whole body, has been shown to delay aging. Due to aging and exercise as modulator of metabolism, a picture of how exercise delayed D-galactose (D-gal)-induced aging in a time-resolved manner was presented in this paper. The mapping of molecular changes in response to exercise has become increasingly accessible with the development of omics techniques. To explore the dynamic changes during exercise, the serum of rats and D-gal-induced aging rats before, during, and after exercise was analyzed by untargeted metabolomics. The variation of metabolites was monitored to reveal the specific response to D-gal-induced senescence and exercise in multiple pathways, especially the basal amino acid metabolism, including glycine serine and threonine metabolism, cysteine and methionine metabolism, and tryptophan metabolism. The homeostasis was disturbed by D-gal and maintained by exercise. The paper was expected to provide a theoretical basis for the study of anti-aging exercise.

d-Galactose induces the senescence and phenotype switch of corpus cavernosum smooth muscle cells

Studies regarding age-related erectile dysfunction (ED) based on naturally aging models are limited by their high costs, especially for the acquisition of primary cells from the corpus cavernosum. Herein, d-galactose ( d-gal) was employed to accelerate cell senescence, and the underlying mechanism was explored. As predominant functional cells involved in the erectile response, corpus cavernosum smooth muscle cells (CCSMCs) were isolated from 2-month-old rats. Following this, d-gal was introduced to induce cell senescence, which was verified via β-galactosidase staining. The effects of d-gal on CCSMCs were evaluated by terminal deoxynucleoitidyl transferase dUTP nick-end labeling (TUNEL), immunofluorescence staining, flow cytometry, western blot, and quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, RNA interference (RNAi) was carried out for rescue experiments. Subsequently, the influence of senescence on the corpus cavernosum was determined via scanning electron microscopy, qRT-PCR, immunohistochemistry, TUNEL, and Masson stainings. The results revealed that the accelerated senescence of CCSMCs was promoted by d-gal. Simultaneously, smooth muscle alpha-actin (alpha-SMA) expression was inhibited, while that of osteopontin (OPN) and Krüppel-like factor 4 (KLF4), as well as fibrotic and apoptotic levels, were elevated. After knocking down KLF4 expression in d-gal-induced CCSMCs by RNAi, the expression level of cellular alpha-SMA increased. Contrastingly, the OPN expression, apoptotic and fibrotic levels declined. In addition, cellular senescence acquired partial remission. Accordingly, in the aged corpus cavernosum, the fibrotic and apoptotic rates were increased, followed by downregulation in the expression of alpha-SMA and the concurrent upregulation in the expression of OPN and KLF4. Overall, our results signaled that d-gal-induced accelerated senescence of CCSMCs could trigger fibrosis, apoptosis and phenotypic switch to the synthetic state, potentially attributed to the upregulation of KLF4 expression, which may be a multipotential therapeutic target of age-related ED.

Aerobic exercise enhances mitochondrial homeostasis to counteract D-galactose-induced sarcopenia in zebrafish

Sarcopenia is a common skeletal muscle degenerative disease characterized by decreased skeletal muscle mass and mitochondrial dysfunction that involves microRNAs (miR) as regulatory factors in various pathways. Exercise reduces age-related oxidative damage and chronic inflammation and increases autophagy, among others. Moreover, whether aerobic exercise can regulate mitochondrial homeostasis by modulating the miR-128/insulin-like growth factor-1 (IGF-1) signaling pathway and can improve sarcopenia requires further investigation. Interestingly, zebrafish have been used as a model for aging research for over a decade due to their many outstanding advantages. Therefore, we established a model of zebrafish sarcopenia using d-galactose immersion and observed substantial changes, including reduced skeletal muscle cross-sectional area, increased tissue fibrosis, decreased motility, increased skeletal muscle reactive oxygen species, and notable alterations in mitochondrial morphology and function. We found that miR-128 expression was considerably upregulated, where as Igf1 and peroxisome proliferator-activated receptor gamma coactivator 1-alpha were significantly downregulated; moreover, mitochondrial homeostasis was reduced. Four weeks of aerobic exercise delayed sarcopenia progression and prevented the disruption of mitochondrial function and homeostasis. The genes related to atrophy and miR-128 were downregulated, Igf1 expression was considerably upregulated, and the phosphorylation levels of Pi3k, Akt, and Foxo3a were upregulated. Furthermore, mitochondrial respiration and homeostasis were enhanced. In conclusion, aerobic exercise improved skeletal muscle quality and function via the miR-128/IGF-1 signaling pathway, consequently ameliorating mitochondrial homeostasis in aging skeletal muscle.

Combination of epigallocatechin 3 gallate and curcumin improves D-galactose and normal-aging associated memory impairment in mice

Previously, we observed curcumin improves aging-associated memory impairment in D-galactose (D-gal) and normal-aged (NA) mice. Evidence showed that multiple agents can be used in managing aging-induced memory dysfunction, drawn by the contribution of several pathways. Curcumin and Epigallocatechin 3 gallate (EGCG) combination substantially reduced the oxidative stress that commonly mediates aging. This study examined the combined effect of EGCG and curcumin on memory improvement in two recognized models, D-gal and normal-aged (NA) mice. The co-administration of EGCG and curcumin significantly (p < 0.05) increased retention time detected by passive avoidance (PA) and freezing response determined in contextual fear conditioning (CFC) compared to the discrete administration of EGCG or curcumin. Biochemical studies revealed that the combination of EGCG and curcumin remarkably ameliorated the levels (p < 0.05) of glutathione, superoxide dismutase, catalase, advanced oxidation protein products, nitric oxide, and lipid peroxidation compared to the monotherapy of EGCG or curcumin in mice hippocampi. The behavioral and biochemical studies revealed that the combination of EGCG and curcumin showed better improvement in rescuing aging-associated memory disorders in mice. EGCG and curcumin combination could serve as a better choice in managing aging-related memory disorders.

Role of hypoxia in cellular senescence

Senescent cells persist and continuously secrete proinflammatory and tissue-remodeling molecules that poison surrounding cells, leading to various age-related diseases, including diabetes, atherosclerosis, and Alzheimer's disease. The underlying mechanism of cellular senescence has not yet been fully explored. Emerging evidence indicates that hypoxia is involved in the regulation of cellular senescence. Hypoxia-inducible factor (HIF)- 1α accumulates under hypoxic conditions and regulates cellular senescence by modulating the levels of the senescence markers p16, p53, lamin B1, and cyclin D1. Hypoxia is a critical condition for maintaining tumor immune evasion, which is promoted by driving the expression of genetic factors (such as p53 and CD47) while triggering immunosenescence. Under hypoxic conditions, autophagy is activated by targeting BCL-2/adenovirus E1B 19-kDa interacting protein 3, which subsequently induces p21WAF1/CIP1 as well as p16Ink4a and increases β-galactosidase (β-gal) activity, thereby inducing cellular senescence. Deletion of the p21 gene increases the activity of the hypoxia response regulator poly (ADP-ribose) polymerase-1 (PARP-1) and the level of nonhomologous end joining (NHEJ) proteins, repairs DNA double-strand breaks, and alleviates cellular senescence. Moreover, cellular senescence is associated with intestinal dysbiosis and an accumulation of D-galactose derived from the gut microbiota. Chronic hypoxia leads to a striking reduction in the amount of Lactobacillus and D-galactose-degrading enzymes in the gut, producing excess reactive oxygen species (ROS) and inducing senescence in bone marrow mesenchymal stem cells. Exosomal microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) play important roles in cellular senescence. miR-424-5p levels are decreased under hypoxia, whereas lncRNA-MALAT1 levels are increased, both of which induce cellular senescence. The present review focuses on recent advances in understanding the role of hypoxia in cellular senescence. The effects of HIFs, immune evasion, PARP-1, gut microbiota, and exosomal mRNA in hypoxia-mediated cell senescence are specifically discussed. This review increases our understanding of the mechanism of hypoxia-mediated cellular senescence and provides new clues for anti-aging processes and the treatment of aging-related diseases.

Berberine may provide redox homeostasis during aging in rats

Aging is a natural phenomenon, which is characterised by progressive physiological changes at cellular and organ level. During aging, the defence mechanism of an organism declines over the period of time. The aim of this study was to investigate the biological efficacy of berberine in D-galactose induced aging rat models. For the study, rats were divided into four groups: Control received only vehicle, BBR received berberine orally, D-Gal received D-galactose subcutaneously and BBR + D-Gal received D-galactose and berberine simultaneously. D-galactose treatment increased the pro-oxidants such as malondialdehyde (MDA) level, protein carbonyl, plasma membrane redox system (PMRS) and advanced oxidation protein products (AOPP) in the erythrocytes or plasma. It reduced the anti-oxidant level such as reduced glutathione (GSH), ferric reducing ability of plasma (FRAP), plasma thiols, sialic acid and membrane transporters like Na+/K+ ATPase and Ca2+ ATPase activity in the erythrocyte membrane. Co-treatment of berberine in D-galactose induced aging rat models restored pro-oxidants and anti-oxidants in erythrocytes. Berberine also restored the activity of Na+/K+ ATPase and Ca2+ ATPase in the erythrocyte membrane. On the basis of these findings, we suggest that berberine treatment could attenuate erythrocyte aging in rats through stabilisation of the redox equilibrium.

Curcumin displays a potent caloric restriction mimetic effect in an accelerated senescent model of rat

Curcumin, a strong natural compound with numerous health benefits, is extracted from the Curcuma longa. According to recent research findings, it also acts as a calorie restriction mimetic. We examined established aging biomarkers in erythrocytes and plasma and tested a persistent oral dietary dose of curcumin in young and D-galactose-induced accelerated rat aging models. For four weeks, D-gal (300 mg/kg b.w. subcutaneously) and curcumin (200 mg/kg b.w. oral) were administered simultaneously to test the protective effects of curcumin against D-galactose-induced accelerated aging and oxidative stress. In the accelerated senescent rat model, we discovered a significant rise in protein carbonyl, malonaldehyde (MDA), and advanced oxidation protein products. Increased levels of catalase, superoxide dismutase, ferric-reducing antioxidant potential, and reduced glutathione (GSH) were observed. Our findings reveal that curcumin has characteristics resembling a calorie restriction mimic and can successfully maintain redox equilibrium throughout the aging process in rat erythrocytes and plasma.

Chronic D-Galactose Administration Induces Natural Aging Characteristics, in Rat's Brain and Heart

We aimed to investigate the effect of chronic D-galactose exposure on the mimicking of natural aging processes based upon the hallmarks of aging. Seven-week-old male Wistar rats (n = 12) were randomly assigned to receive either normal saline solution as a vehicle (n = 6) or 150mg/kg/day of D-galactose subcutaneously for 28 weeks. Seventeen-month-old rats (n = 6) were also included as the chronologically aged controls. At the end of week 28 of the experiment (when the rats reach 35 weeks old and 24 months old), all rats were sacrificed for brain and heart collection. Our results showed that chronic D-galactose exposure mimicked natural aging characteristics of the brain and the heart in terms of deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, and functional impairment. All of which highlight the potential of D-galactose as a substance for inducing brain and cardiac aging in animal experiments. DATA AVAILABILITY: The data that support the findings of this study are available from the corresponding author upon reasonable request.

Characterization and anti-aging effects of Opuntia ficus-indica (L.) Miller extracts in a D-galactose-induced skin aging model

Opuntia ficus-indica (L.) Miller (OFI), belonging to the family Cactaceae, is widely cultivated not only for its delicious fruits but also for its health-promoting effects, which enhance the role of OFI as a potential functional food. In this study, the in vitro collagenase and elastase enzyme inhibitory effects of extracts from different parts of OFI were evaluated. The most promising extracts were formulated as creams at two concentrations (3 and 5%) to investigate their effects on a D-galactose (D-gal)-induced skin-aging mouse model. The ethanolic extracts of the peel and cladodes exhibited the highest enzyme inhibitory effects. Cream made from the extract of OFI peel (OP) (5%) and cream from OFI cladodes extract (OC) (5%) significantly decreased the macroscopic aging of skin scores. Only a higher concentration (5%) of OC showed the normalization of superoxide dismutase (SOD) and malondialdehyde (MDA) skin levels and achieved significant improvements as compared to the vitamin E group. Both OC and OP (5%) showed complete restoration of the normal skin structure and nearly normal collagen fibres upon histopathological examination. The Ultra-Performance Liquid Chromatography High Resolution Mass Spectrometry (UHPLC-ESI-TOF-MS) metabolite profiles revealed the presence of organic acids, phenolic acids, flavonoids, betalains, and fatty acids. Flavonoids were the predominant phytochemical class (23 and 22 compounds), followed by phenolic acids (14 and 17 compounds) in the ethanolic extracts from the peel and cladodes, respectively. The anti-skin-aging effects could be attributed to the synergism of different phytochemicals in both extracts. From these findings, the OFI peel and cladodes as agro-waste products are good candidates for anti-skin-aging phytocosmetics.

Hydrogen Sulfide Inhibited Sympathetic Activation in D-Galactose-Induced Aging Rats by Upregulating Klotho and Inhibiting Inflammation in the Paraventricular Nucleus

The present study aimed to explore the central relationship between cardiovascular conditions and aging. D-galactose (D-gal) was utilized to induce an accelerated aging model and to evaluate the effects of hydrogen sulfide (H₂S) on aging-related cardiovascular risk factors and mechanisms. Eight-week-old Sprague Dawley rats were given an intraperitoneal injection of 250 mg/kg D-gal every day with or without H₂S (56 μmol/kg) for 12 weeks. We found that D-gal treatment induced a noticeably aging-related increase in p16, p53 and p21 protein levels and senescence-associated beta-galactosidase staining. In addition, the level of noradrenalin was increased, accompanied by enhanced blood pressure and renal sympathetic nerve activity in aged rats. The greater sympathetic responses were related with the increased level of inflammation. The decreased level of klotho in the paraventricular nucleus neuron also contributed to sympathetic activation in D-gal-induced aged rats. However, the exogenous administration of H₂S attenuated the sympathetic activity in aged rats, as evidenced by the decreased blood pressure, renal sympathetic nerve activity and noradrenalin level. The ameliorated cellular senescence, inflammation and heightened klotho in the paraventricular nucleus were attributed to the protective effects of H₂S. The present study provides further evidence for the drug development of H₂S for the prevention or treatment of the aging-associated cardiovascular diseases.

Dietary methionine restriction improves gut microbiota composition and prevents cognitive impairment in D-galactose-induced aging mice

Dietary methionine restriction (MR) has been shown to delay aging and ameliorate age-related cognitive impairments. We hypothesized that changes in the gut microbiota may mediate these effects. To test this hypothesis, ICR mice subcutaneously injected with 150 mg kg^-1 day^-1D-galactose were fed a normal (0.86% methionine) or an MR (0.17% methionine) diet for 2 months. Multiple behavioral experiments were performed, and the gut microbiota composition, metabolite profiles related to short-chain fatty acids (SCFAs) in the feces, and indicators related to the redox and inflammatory states in the hippocampus were further analyzed. Our results indicated that MR alleviated cognitive impairment (including non-spatial memory deficits, working memory deficits, and hippocampus-dependent spatial memory deficits) and anxiety-like behavior in D-Gal-induced aging mice. Furthermore, MR increased the abundance of putative SCFA-producing bacteria such as Lachnospiraceae, Turicibacter, Roseburia, Ruminococcaceae_UCG-014, Intestinimonas, Rikenellaceae, Tyzzerella, and H₂S-producing bacteria such as Desulfovibrio in feces. Moreover, MR reversed and normalized the levels of intestinal SCFAs (acetate, propionate, and butyrate) and important intermediate metabolites of the SCFAs (pyruvate, lactate, malate, fumarate, and succinate), abolished aging-induced oxidative stress and inflammatory responses, increased the levels of H₂S in the plasma and hippocampus, and selectively modulated the expression of multiple learning- and memory-related genes in the hippocampus. These findings suggest that MR improved the gut microbiota composition and SCFA production and alleviated oxidative stress and inflammatory responses in the hippocampus, which might prevent cognitive impairment in D-galactose-induced aging mice.

Macromolecules Influence Cellular Competence and Expression Level of IGFs Genes in Bovine Oocytes In Vitro

In vitro maturation (IVM) of mammalian oocytes, which influences subsequent in vitro development of embryos, is affected by the macromolecule content in culture media for the success of oocyte maturation competence, in which the cytoplasmic and nuclear reprogramming events occur. The insulin-like growth factor family (IGFs) promotes the maturation of bovine oocytes and the expansion of cumulus cells and also inhibits apoptosis. This study was, therefore, designed to examine the effects of macromolecules (bovine serum albumin, BSA; fetal calf serum, FCS; and polyvinyl alcohol, PVA) on in vitro nuclear maturation, total cellular protein, glutathione peroxidase (GPx) enzyme activity, and the gene expression level of IGF1, IGF2, and their receptor in bovine oocytes. Oocytes obtained from bovine ovaries were cultured in bicarbonate-buffered medium 199 supplemented with 4 mg/mL BSA, 10% FCS, 1 mg/mL PVA, and without macromolecule supplement (control) during 22 h in the air with a humidified atmosphere and 5% CO2 at 38.5 °C temperature. Supplementation of BSA and FCS increased (χ2 = 9.84; p < 0.05) the percentages of oocytes that reached metaphase II compared to the control and PVA. The amount of protein per ml of cell extracts of oocytes matured in FCS supplemented culture media was higher (p < 0.05) than the oocytes in the PVA and control. The levels of GPx enzyme activity in cell extracts isolated from oocytes in each experimental group did not change over time, but the GPx enzyme activity in oocytes matured in PVA-supplemented culture media was lower (p < 0.05) than in oocytes in the other experimental groups. Transcript for the IGF1 gene was not detected in all experimental groups, but the supplementation of BSA and FCS significantly elevated the transcript level of the IGF2 gene. In addition, the maturation of oocytes with BSA-supplemented media increased the transcript level of the IGF1R gene, whereas the transcript level of the IGF2R gene was similar among macromolecule supplementation groups. The current study concluded that BSA and FCS could improve in vitro bovine oocyte development due to supporting nuclear maturation and increasing the total cellular protein content, GPx enzyme, and transcript activity.

Oxidation Stress as a Mechanism of Aging in Human Erythrocytes: Protective Effect of Quercetin

Aging is a multi-factorial process developing through a complex net of interactions between biological and cellular mechanisms and it involves oxidative stress (OS) as well as protein glycation. The aim of the present work was to verify the protective role of Quercetin (Q), a polyphenolic flavonoid compound, in a d-Galactose (d-Gal)-induced model of aging in human erythrocytes. The anion-exchange capability through the Band 3 protein (B3p) measured by the rate constant of the SO₄²⁻ uptake, thiobarbituric acid reactive substances (TBARS) levels—a marker of lipid peroxidation—total sulfhydryl (-SH) groups, glycated hemoglobin (A1c), and a reduced glutathione/oxidized glutathione (GSH-GSSG) ratio were determined following the exposure of erythrocytes to 100 mM d-Gal for 24 h, with or without pre-incubation with 10 µM Q. The results confirmed that d-Gal activated OS pathways in human erythrocytes, affecting both membrane lipids and proteins, as denoted by increased TBARS levels and decreased total sulfhydryl groups, respectively. In addition, d-Gal led to an acceleration of the rate constant of the SO₄²⁻ uptake through the B3p. Both the alteration of the B3p function and oxidative damage have been improved by pre-treatment with Q, which preferentially ameliorated lipid peroxidation rather than protein oxidation. Moreover, Q prevented glycated A1c formation, while no protective effect on the endogenous antioxidant system (GSH-GSSG) was observed. These findings suggest that the B3p could be a novel potential target of antioxidant treatments to counteract aging-related disturbances. Further studies are needed to confirm the possible role of Q in pharmacological strategies against aging.

Antioxidative potential of Lactobacillus sp. in ameliorating D-galactose-induced aging

Aging is a progressive, unalterable physiological degradation process of living organisms, which leads to deterioration of biological function and eventually to senescence. The most prevalent factor responsible for aging is the accumulation of damages resulting from oxidative stress and dysbiosis. D-galactose-induced aging has become a hot topic, and extensive research is being conducted in this area. Published literature has reported that the continuous administration of D-galactose leads to the deterioration of motor and cognitive skills, resembling symptoms of aging. Hence, this procedure is employed as a model for accelerated aging. This review aims to emphasize the effect of D-galactose on various bodily organs and underline the role of the Lactobacillus sp. in the aging process, along with its anti-oxidative potential. A critical consideration to the literature describing animal models that have used the Lactobacillus sp. in amending D-galactose-induced aging is also given. KEY POINTS: • D-Galactose induces the aging process via decreasing the respiratory chain enzyme activity as well as ATP synthesis, mitochondrial dysfunction, and increased ROS production. • D-Galactose induced aging primarily affects the brain, heart, lung, liver, kidney, and skin. • The anti-oxidative potential of Lactobacillus sp. in improving D-galactose-induced aging in animal models via direct feeding and feeding of Lactobacillus-fermented food.

Curcumin improves D-galactose and normal-aging associated memory impairment in mice: In vivo and in silico-based studies

Aging-induced memory impairment is closely associated with oxidative stress. D-Galactose (D-gal) evokes severe oxidative stress and mimics normal aging in animals. Curcumin, a natural flavonoid, has potent antioxidant and anti-aging properties. There are several proteins like glutathione S-transferase A1 (GSTA1), glutathione S-transferase omega-1 (GSTO1), kelch-like ECH-associated protein 1 (KEAP1), beta-secretase 1 (BACE1), and amine oxidase [flavin-containing] A (MAOA) are commonly involved in oxidative stress and aging. This study aimed to investigate the interaction of curcumin to these proteins and their subsequent effect on aging-associated memory impairment in two robust animal models: D-Gal and normal aged (NA) mice. The aging mice model was developed by administering D-gal intraperitoneally (i.p). Mice (n = 64) were divided into the eight groups (8 mice in each group): Vehicle, Curcumin-Control, D-gal (100mg/kg; i.p), Curcumin + D-gal, Astaxanthin (Ast) + D-gal, Normal Aged (NA), Curcumin (30mg/kg Orally) + NA, Ast (20mg/kg Orally) + NA. Retention and freezing memories were assessed by passive avoidance (PA) and contextual fear conditioning (CFC). Molecular docking was performed to predict curcumin binding with potential molecular targets. Curcumin significantly increased retention time (p < 0.05) and freezing response (p < 0.05) in PA and CFC, respectively. Curcumin profoundly ameliorated the levels of glutathione, superoxide dismutase, catalase, advanced oxidation protein products, nitric oxide, and lipid peroxidation in mice hippocampi. In silico studies revealed favorable binding energies of curcumin with GSTA1, GSTO1, KEAP1, BACE1, and MAOA. Curcumin improves retention and freezing memory in D-gal and nature-induced aging mice. Curcumin ameliorates the levels of oxidative stress biomarkers in mice. Anti-aging effects of curcumin could be attributed to, at least partially, the upregulation of antioxidant enzymes through binding with GSTA1, GSTO1, KEAP1, and inhibition of oxidative damage through binding with BACE1 and MAOA.

Fisetin, a potential caloric restriction mimetic, modulates ionic homeostasis in senescence induced and naturally aged rats

CONTEXT

Fisetin as a caloric restriction mimetic (CRM) exerts numerous beneficial effects on different aging model systems. The effect of fisetin on erythrocyte membrane functions against induced aging is not very clear.

OBJECTIVES

The potential role of fisetin in the modulation of erythrocytes membrane-bound transporters during natural and induced aging in rats was assessed.

MATERIALS AND METHODS

Male Wistar rats were used for natural and D-galactose (D-gal) induced aging model. After supplementation with fisetin, the activities of different membrane transporters and biomarkers of oxidative stress were evaluated.

RESULTS

Fisetin modulated membrane transporters such as calcium-ATPase, sodium potassium-ATPase and sodium hydrogen exchanger during senescence-induced as well as in natural aging. Fisetin also protected oxidative modifications in rat aging.

DISCUSSION AND CONCLUSION

Fisetin supplementation improves the ionic homeostasis, a factor that is involved in the aetiology of several age-associated diseases, in naturally old as well as D-gal induced aged rats.

The Effect of Acute Oral Galactose Administration on the Redox System of the Rat Small Intestine

Galactose is a ubiquitous monosaccharide with important yet incompletely understood nutritive and physiological roles. Chronic parenteral d-galactose administration is used for modeling aging-related pathophysiological processes in rodents due to its ability to induce oxidative stress (OS). Conversely, chronic oral d-galactose administration prevents and alleviates cognitive decline in a rat model of sporadic Alzheimer's disease, indicating that galactose may exert beneficial health effects by acting in the gut. The present aim was to explore the acute time-response of intestinal redox homeostasis following oral administration of d-galactose. Male Wistar rats were euthanized at baseline (n = 6), 30 (n = 6), 60 (n = 6), and 120 (n = 6) minutes following orogastric administration of d-galactose (200 mg/kg). The overall reductive capacity, lipid peroxidation, the concentration of low-molecular-weight thiols (LMWT) and protein sulfhydryls (SH), the activity of Mn and Cu/Zn superoxide dismutases (SOD), reduced and oxidized fractions of nicotinamide adenine dinucleotide phosphates (NADPH/NADP), and the hydrogen peroxide dissociation rate were analyzed in duodenum and ileum. Acute oral administration of d-galactose increased the activity of SODs and decreased intestinal lipid peroxidation and nucleophilic substrates (LMWT, SH, NADPH), indicating activation of peroxidative damage defense pathways. The redox system of the small intestine can acutely tolerate even high luminal concentrations of galactose (0.55 M), and oral galactose treatment is associated with a reduction rather than the increment of the intestinal OS. The ability of oral d-galactose to modulate intestinal OS should be further explored in the context of intestinal barrier maintenance, and beneficial cognitive effects associated with long-term administration of low doses of d-galactose.

Is Galactose a Hormetic Sugar? An Exploratory Study of the Rat Hippocampal Redox Regulatory Network

SCOPE

Galactose, a ubiquitous monosaccharide with incompletely understood physiology is often exploited for inducing oxidative-stress mediated aging in animals. Recent research demonstrates that galactose can conserve cellular function during periods of starvation and prevent/alleviate cognitive deficits in a rat model of sporadic Alzheimer's disease. The present aim is to examine the acute effects of oral galactose on the redox regulatory network (RRN).

METHODS AND RESULTS

Rat plasma and hippocampal RRNs are analyzed upon acute orogastric gavage of galactose (200 mg kg^-1 ). No systemic RRN disbalance is observed; however, a mild pro-oxidative shift accompanied by a paradoxical increment in tissue reductive capacity suggesting overcompensation of endogenous antioxidant systems is observed in the hippocampus. Galactose-induced increment of reductive capacity is accompanied by inflation of the hippocampal pool of nicotinamide adenine dinucleotide phosphates indicating ROS detoxification through disinhibition of the oxidative pentose phosphate pathway flux, reduced neuronal activity, and upregulation of Leloir pathway gatekeeper enzyme galactokinase-1.

CONCLUSION

Based on the observed findings, and in the context of previous work on galactose, a hormetic hypothesis of galactose is proposed suggesting that the protective effects may be inseparable from its pro-oxidative action at the biochemical level.

Exercise renovates H2S and Nrf2-related antioxidant pathways to suppress apoptosis in the natural ageing process of male rat cortex

Ageing is a complex biological process that increases the probability of disease and death, which affects the organs of all species. The accumulation of oxidative damage in the brain contributes to a progressive loss of cognitive functions or even declined the energy metabolism. In this study, we tested the effects of exercise training on the apoptosis, survival, and antioxidant signaling pathways in the cerebral cortex of three age groups of male rats; 3, 12, and 18 months. We observed that H₂S and the expression of Nrf2-related antioxidant pathways declined with age and increased after exercise training. IGF1R survival pathway was less increased in middle-aged rats; however, significantly increased after exercise training. The expression of mitochondrial-dependent apoptotic pathway components, such as Bak, cytochrome C, and caspase 3 in the ageing control group, were much higher than those of the exercise training groups. This study demonstrated that exercise training could reduce the apoptosis and oxidative stress that accrues throughout ageing, which causes brain damage.

A novel strategy based on targeted cellular metabolomics for quantitatively evaluating anti-aging effect and screening effective extracts of Erzhi Wan

The complexity of ingredients in traditional Chinese medicine (TCM) makes it challenging to clarify its efficacy in an acceptable and scientific approach. The present study was aimed to use quantification results from targeted cellular metabolomics to evaluate anti-aging efficacy of a famous Chinese medicine formula, Erzhi Wan (EZW), and screen possible effective extracts, depending on the developed strategy integrating multivariate receiver operating characteristic (ROC) curve and analytic hierarchy process (AHP). In this study, senescent NRK cells induced by D-galactose were treated with drug-containing serum of EZW and four kinds of extracts (petroleum ether, ethyl acetate, butanol and water). Intermediates of two major metabolic pathways for energy synthesis, tricarboxylic acid (TCA) cycle and glycolysis, were accurately quantified by GC-MS/MS to identify discriminate metabolites for clarifying therapeutic mechanism of EZW based on multivariate statistical analysis. Senescent and non-senescent cells were successfully distinguished using these metabolites by ROC curve analysis. Next, these metabolites were used as evaluation indexes to quantitatively reflect different effect of EZW and its extracts, according to the role of them in distinguishing groups and in conjunction with AHP. In vitro detection of senescence-associated β-galactosidase (SA-β-gal) activity was used to verify the reliability of evaluation results. The reversal after treatment of drug-containing serum of EZW and extracts was observed, and the petroleum ether extract might be the potential active extract responsible for the major anti-aging effect of EZW, which was in agreement with in vitro experiments. Altogether, metabolomics was a powerful approach for evaluation efficacy and elucidation action mechanisms of TCM. The integrated evaluation strategy in this paper with properties of high practicality, feasibility and effectivity was expected to provide a new insight into comprehensive and quantitative efficacy evaluation.

17β-Estradiol alleviates cardiac aging induced by d-galactose by downregulating the methylation of autophagy-related genes

Intrinsic cardiac aging increases cardiovascular mortality and morbidity in the elderly. Estrogen helps reduce the risk of cardiovascular disease in women, with 17β-estradiol (17β-E2) activating the autophagy pathway and inhibiting vascular aging, mainly through estrogen receptor alpha (ER α) to prevent atherosclerosis. Abnormal methylation of autophagy-related genes can impact autophagic regulation. We hypothesized that 17β-E2, specifically 17β-E2 α, downregulates the methylation of autophagy factors and delays cardiac aging. Here, we used d-galactose, 17β-E2, and ER α receptor antagonist methyl-piperidino-pyrazole (MPP) to establish different aging models in mice divided into four groups, namely negative control, D.gal, D.gal + 17β-E2, and D.gal + 17β-E2 + MPP groups. Echocardiography showed that compared with the D.gal group group, the D.gal + 17β-E2 showed substantially increased cardiac function. The level of cardiac aging markers in mice in the D.gal + 17β-E2 group was lower than that in mice in the D.gal group. Beclin1, LC3, and Atg5 mRNA and protein expression levels in mice in the D.gal + 17β-E2 group were significantly increased compared with those in the D.gal group. Additionally, Beclin1, LC3, and Atg5 methylation levels were significantly decreased in the D.gal + 17β-E2 group. All the above values of the D.gal + 17β-E2 + MPP group were between those of the D.gal and D.gal + 17β-E2 groups. The expression of Dnmt1, Dnmt2, and Dnmt3A genes was the highest in the D.gal group. In summary, our results suggest that 17β-E2, specifically 17β-E2 α, promotes autophagy by downregulating the methylation of autophagy factors, thereby inhibiting galactose-induced cardiac aging in mice. 17β-E2 may be a potential therapeutic target to mitigate the effects of cardiac aging.

Pasteurized non-fermented cow's milk but not fermented milk is a promoter of mTORC1-driven aging and increased mortality

Recent epidemiological studies in Sweden, a country with traditionally high milk consumption, revealed that the intake of non-fermented pasteurized milk increased all-cause mortality in a dose-dependent manner. In contrast, the majority of epidemiological and clinical studies report beneficial health effects of fermented milk products, especially of yogurt. It is the intention of this review to delineate potential molecular aging mechanisms related to the intake of non-fermented milk versus yogurt on the basis of mechanistic target of rapamycin complex 1 (mTORC1) signaling. Non-fermented pasteurized milk via its high bioavailability of insulinotropic branched-chain amino acids (BCAAs), abundance of lactose (glucosyl-galactose) and bioactive exosomal microRNAs (miRs) enhances mTORC1 signaling, which shortens lifespan and increases all-cause mortality. In contrast, fermentation-associated lactic acid bacteria metabolize BCAAs and degrade galactose and milk exosomes including their mTORC1-activating microRNAs. The Industrial Revolution, with the introduction of pasteurization and refrigeration of milk, restricted the action of beneficial milk-fermenting bacteria, which degrade milk's BCAAs, galactose and bioactive miRs that synergistically activate mTORC1. This unrecognized behavior change in humans after the Neolithic revolution increased aging-related over-activation of mTORC1 signaling in humans, who persistently consume large quantities of non-fermented pasteurized cow's milk, a potential risk factor for aging and all-cause mortality.

D-galactose-induced liver aging model: Its underlying mechanisms and potential therapeutic interventions

Aging is associated with a variety of morphological and functional changes in the liver. Oxidative stress and inflammation are now widely accepted as the main mechanisms involved in the aging process that may subsequently cause severe injury to mitochondrial DNA which leads to apoptosis. As aging may increase the risks for various liver diseases and plays as an adverse prognostic factor increasing the mortality rate, knowledge regarding the mechanisms of age-related liver susceptibility and the possible therapeutic interventions is imperative. Due to cost and time constraints, a mimetic aging model is generally preferred to naturally aged animals to study the underlying mechanisms of aging liver. The use of D-galactose in aging research is dated back to 1962 and has since been used widely. This review aims to comprehensively summarize the effects of D-galactose-induced aging on the liver and the underlying mechanisms involved. Its potential therapeutic interventions are also discussed. It is hoped that this invaluable information may facilitate researchers in choosing the appropriate aging model and provide a valuable platform for testing potential therapeutic strategies for the prevention and treatment of age-related liver diseases.

Characterization of murine mammary stem/progenitor cells in a D-galactose-induced aging model

Aging plays an important role in many diseases, including breast cancer. Aged mammary stem/progenitor cells are perceived to be the cells of origin in breast tumorigenesis; however, the extensive use of mice who have aged naturally for research is hampered by cost, time, disease complications, and high mortality. In this study, we characterized murine mammary stem/progenitor cells in a D-galactose-induced accelerated aging model and compared them with findings from our earlier study on mice from natural aging. Our results showed that mammary glands in the D-galactose-induced aging model mimic natural aging in terms of pathological changes, epithelial cell composition, and mammary stem/progenitor cell function. These changes are accompanied by elevated inflammatory responses both systemically in the blood and locally in the mammary glands, which is similar in mice who age naturally. Our study for the first time evaluated the mammary glands and mammary stem/progenitor function in a D-galactose-induced aging model in rodents, and our findings suggest that D-galactose treatment can be used as a surrogate to study the role aged stem/progenitor cells play in breast tumorigenesis.

Spectroscopic Signature of Red Blood Cells in a D-Galactose-Induced Accelerated Aging Model

This work presents a semi-quantitative spectroscopic approach, including FTIR-ATR and Raman spectroscopies, for the biochemical analysis of red blood cells (RBCs) supported by the biochemical, morphological and rheological reference techniques. This multi-modal approach provided the description of the RBC alterations at the molecular level in a model of accelerated aging induced by administration of D-galactose (D-gal), in comparison to natural aging. Such an approach allowed to conclude that most age-related biochemical RBC membrane changes (a decrease in lipid unsaturation and the level of phospholipids, or an increase in acyl chain shortening) as well as alterations in the morphological parameters and RBC deformability are well reflected in the D-gal model of accelerated aging. Similarly, as in natural aging, a decrease in LDL level in blood plasma and no changes in the fraction of glucose, creatinine, total cholesterol, HDL, iron, or triglycerides were observed during the course of accelerated aging. Contrary to natural aging, the D-gal model led to an increase in cholesterol esters and the fraction of total esterified lipids in RBC membranes, and evoked significant changes in the secondary structure of the membrane proteins. Moreover, a significant decrease in the phosphorous level of blood plasma was specific for the D-gal model. On the other hand, natural aging induced stronger changes in the secondary structures of the proteins of the RBCs' interior. This work proves that research on the aging mechanism, especially in circulation-related diseases, should employ the D-gal model with caution. Nonetheless, the D-gal model enables to imitate age-related rheological alterations in RBCs, although they are partially derived from different changes observed in the RBC membrane at the molecular level.

Middle age as a turning point in mouse cerebral cortex energy and redox metabolism: Modulation by every-other-day fasting

Normal brain aging is accompanied by intensification of free radical processes and compromised bioenergetics. Caloric restriction is expected to counteract these changes but the underlying protective mechanisms remain poorly understood. The present work aimed to investigate the intensity of oxidative stress and energy metabolism in the cerebral cortex comparing mice of different ages as well as comparing mice given one of two regimens of food availability: ad libitum versus every-other-day fasting (EODF). Levels of oxidative stress markers, ketone bodies, glycolytic intermediates, mitochondrial respiration, and activities of antioxidant and glycolytic enzymes were assessed in cortex from 6-, 12- and 18-month old C57BL/6J mice. The greatest increase in oxidative stress markers and the sharpest decline in key glycolytic enzyme activities was observed in mice upon the transition from young (6 months) to middle (12 months) age, with smaller changes occurring upon transition to old-age (18 months). Brain mitochondrial respiration showed no significant changes with age. A decrease in the activities of key glycolytic enzymes was accompanied by an increase in the activity of glucose-6-phosphate dehydrogenase suggesting that during normal brain aging glucose metabolism is altered to lower glycolytic activity and increase dependence on the pentose-phosphate pathway. Interestingly, levels of ketone bodies and antioxidant capacity showed a greater decrease in the brain cortex of females as compared with males. The EODF regimen further suppressed glycolytic enzyme activities in the cortex of old mice, and partially enhanced oxygen consumption and respiratory control in the cortex of middle aged and old males. Thus, in the mammalian cortex the major aging-induced metabolic changes are already seen in middle age and are slightly alleviated by an intermittent fasting mode of feeding.

Receptor for Advanced Glycation End Products Acts as a Fuel to Colorectal Cancer Development

Receptor for advanced glycation end-products (RAGE) is a multiligand binding and single-pass transmembrane protein taken in diverse chronic inflammatory conditions. RAGE behaves as a pattern recognition receptor, which binds and is engaged in the cellular response to a variety of damage-associated molecular pattern molecules, as well as HMGB1, S100 proteins, and AGEs (advanced glycation end-products). The RAGE activation turns out to a formation of numerous intracellular signaling mechanisms, resulting in the progression and prolongation of colorectal carcinoma (CRC). The RAGE expression correlates well with the survival of colon cancer cells. RAGE is involved in the tumorigenesis, which increases and develops well in the stressed tumor microenvironment. In this review, we summarized downstream signaling cascade activated by the multiligand activation of RAGE, as well as RAGE ligands and their sources, clinical studies, and tumor markers related to RAGE particularly in the inflammatory tumor microenvironment in CRC. Furthermore, the role of RAGE signaling pathway in CRC patients with diabetic mellitus is investigated. RAGE has been reported to drive assorted signaling pathways, including activator protein 1, nuclear factor-κB, signal transducer and activator of transcription 3, SMAD family member 4 (Smad4), mitogen-activated protein kinases, mammalian target of rapamycin, phosphoinositide 3-kinases, reticular activating system, Wnt/β-catenin pathway, and Glycogen synthase kinase 3β, and even microRNAs.

Spermidine, a caloric restriction mimetic, provides neuroprotection against normal and D-galactose-induced oxidative stress and apoptosis through activation of autophagy in male rats during aging

Spermidine (SPD) is a natural polyamine present in all living organisms and is involved in the maintenance of cellular homeostasis by inducing autophagy in different model organisms. Its role as a caloric restriction mimetic (CRM) is still being investigated. We have undertaken this study to investigate whether SPD, acting as a CRM, can confer neuroprotection in D-galactose induced accelerated senescence model rat and naturally aged rats through modulation of autophagy and inflammation. Young male rats (4 months), D-gal induced (500 mg/kg b.w., subcutaneously) aging and naturally aged (22 months) male rats were supplemented with SPD (10 mg/kg b.w., orally) for 6 weeks. Standard protocols were employed to measure prooxidants, antioxidants, apoptotic cell death and electron transport chain complexes in brain tissues. Gene expression analysis with reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to assess the expression of autophagy and inflammatory marker genes. Our data demonstrate that SPD significantly (p ≤ 0.05) decreased the level of pro-oxidants and increased the level of antioxidants. SPD supplementation also augmented the activities of electron transport chain complexes in aged brain mitochondria thus proving its antioxidant potential at the level of mitochondria. RT-PCR data revealed that SPD up-regulated the expression of autophagy genes (ATG-3, Beclin-1, ULK-1 and LC3B) and down-regulated the expression of the inflammatory gene (IL-6) in aging brain. Our results provide first line of evidence that SPD provides neuroprotection against aging-induced oxidative stress by regulating autophagy, antioxidants level and also reduces neuroinflammation. These results suggest that SPD may be beneficial for neuroprotection during aging and age-related disorders.

The Effect of a Rat Diet Without Added Cu on Redox Status in Tissues and Epigenetic Changes in the Brain

The aim of the study was to determine whether feeding rats a diet without added Cu increases oxidation of macromolecules in tissues, as well as epigenetic changes in the brain. The rats were divided into two groups: the Cu-6.5 group which was fed a diet with a standard content of Cu in mineral mixture – 6.5 mg Cu from CuCO3 per kg of diet; and the Cu-0 group which was fed a diet with a mineral mix without Cu supplementation. At the end of the experiment the rats were weighed and blood samples were collected. Finally, the rats were euthanized and then the liver, small intestine, spleen, kidneys, heart, brain, lung, testes and leg muscles were removed and weighed. In the blood of Cu-0 rats the lower Cp activity and greater GPx and CAT activity than in Cu-6.5 rats were noticed. In the liver, lungs, heart and testes of Cu-0 rats, a decreased content of Cu were noticed. Application of Cu-0 diets resulted in increased LOOH level in the small intestine, liver, and heart, as well as increased MDA content in the liver, spleen, lungs, brain and testes. The Cu-0 treatment caused a decrease in SOD activity in the heart, lungs and testes of the rats and a decrease in CAT activity in the small intestine. In the brain and testes of rats from the Cu-0 treatment, lower content of GSH + GSSG was observed. The brain of rats from the Cu-0 treatment showed an increase in the level of PCs, 8-OHdG, Casp 8 and DNA methylation. The research has shown that a deficiency of Cu in the diet impairs the body’s antioxidant defences, which in turn leads to increased lipid oxidation in the liver, small intestinal wall, heart, spleen, lungs, brain and testes, as well as to oxidation of proteins and DNA in the brain. A deficiency of Cu in the diet also increases methylation of cytosine in the brain.

Esculetin and idebenone ameliorate galactose-induced cataract in a rat model

Cataract is the principal cause of blindness. The enzyme, aldose reductase (AR) is a key player in polyol pathway. Buildup of polyols and oxidative stress are the main causes of cataractogenesis. This study investigated the cytoprotective properties of esculetin and idebenone in galactose-induced cataract. Rats were partitioned into four groups each of ten rats. Control group was fed with normal diet; group 2 rats were fed with galactose diet (50%); groups 3, 4 rats were fed with galactose diet concurrently with either esculetin (50 mg/kg BW) or idebenone (100 mg/kg BW), for 20 days. The study revealed that esculetin and idebenone significantly reduced the elevated levels of Bax/Bcl-2 ratio, malondialdehyde, and DNA fragmentation and increased total antioxidant capacity level in lenses compared to the cataract-induced group. Only esculetin decreased AR, galactitol, and advanced glycated end products levels in lenses. Histopathological examinations supported the biochemical findings. Esculetin and idebenone may have chemopreventive effects for sugar cataract. PRACTICAL APPLICATIONS: Cataract is an age-related disease that might cause blindness in older adult people. Presently, no absolute pharmacological treatment is accessible for cataract. The use of natural products or their derivatives attract particular attention in modern medicines as they are believed to be safer with few or no side effects. Esculetin is a polyphenolic compound found in many medicinal plants. Idebenone is a synthetic analogue of coenzyme Q10. The current study is an approach to explore the anticataract effects of esculetin and idebenone in galactose-induced cataract in rats. Our study proved that both agents have anticataractogenic potentials due to their antioxidant and antiapoptotic properties.

The need to incorporate aged animals into the preclinical modeling of neurological conditions

Neurological conditions such as traumatic brain injury, stroke, Parkinson's disease, epilepsy, multiple sclerosis, and Alzheimer's disease are serious clinical problems that affect millions of people worldwide. The majority of clinical trials for these common conditions have failed, and there is a critical need to understand why treatments in preclinical animal models do not translate to patients. Many patients with these conditions are middle-aged or older, however, the majority of preclinical studies have used only young-adult animals. Considering that aging involves biological changes that are relevant to the pathobiology of neurological diseases, the lack of aged subjects in preclinical research could contribute to translational failures. This paper details how aging affects biological processes involved in neurological conditions, and reviews aging research in the context of traumatic brain injury, stroke, Parkinson's disease, epilepsy, multiple sclerosis, and Alzheimer's disease. We conclude that aging is an important, but often overlooked, factor that influences biology and outcomes in neurological conditions, and provide suggestions to improve our understanding and treatment of these diseases in aged patients.

Goat milk attenuates mimetic aging related memory impairment via suppressing brain oxidative stress, neurodegeneration and modulating neurotrophic factors in D-galactose-induced aging model

One of the most significant hallmarks of aging is cognitive decline. D-galactose administration may impair memory and mimic the effects of natural aging. In this study, the efficiency of goat milk to protect against memory decline was tested. Fifty-two male Sprague-Dawley rats were randomly divided into four groups: (i) control group, (ii) goat milk treated group, (iii) D-galactose treated group, and (iv) goat milk plus D-galactose treated group. Subcutaneous injections of D-galactose at 120 mg/kg and oral administrations of goat milk at 1 g/kg were chosen for the study. Goat milk and D-galactose were administered concomitantly for 6 weeks, while the control group received saline. After 6 weeks, novel object recognition and T-maze tests were performed to evaluate memory of rats. Following behavioral tests, the animals were sacrificed, and right brain homogenates were analyzed for levels of lipid peroxidation, antioxidant enzymes and neurotrophic factors. The left brain hemisphere was used for histological study of prefrontal cortex and hippocampus. There was a significant memory impairment, an increase in oxidative stress and neurodegeneration and a reduction in antioxidant enzymes and neurotrophic factors levels in the brain of D-galactose treated rats compared to controls. Goat milk treatment attenuated memory impairment induced by D-galactose via suppressing oxidative stress and neuronal damage and increasing neurotrophic factors levels, thereby suggesting its potential role as a geroprotective food.

Aging induced by D-galactose aggravates cardiac dysfunction via exacerbating mitochondrial dysfunction in obese insulin-resistant rats

The prevalence of obesity and an aging population are increasing worldwide. Both obesity and aging are independently known to be associated with cardiac dysfunction. However, in obese insulin-resistant subjects, the effects of aging on metabolic status and cardiac and mitochondrial functions are not completely understood. We hypothesized that in the obese insulin-resistant condition, aging induced by D-galactose increases cardiac senescence markers and aggravates the impairment of metabolic parameters, cardiac and mitochondrial function, and increases oxidative stress, inflammation, apoptosis, and autophagy. Sixty-four male Wistar rats were fed with either normal diet (ND) or high-fat diet (HFD) for 12 weeks. Then, rats were divided into vehicle groups (0.9% NSS, subcutaneous injection (SC)) or D-galactose groups (150 mg/kg/day, SC). After 0.9%NSS or D-galactose treatment for 4 weeks and 8 weeks, metabolic and cardiac functions were determined. The heart was then removed to determine mitochondrial functions and enable biochemical studies. After 4 weeks of D-galactose injection, ND rats treated with D-galactose (NDD4), HFD rats treated with vehicle (HFV4), and HFD rats treated with D-galactose (HFD4) had reduced cardiac function, impaired cardiac mitochondrial function and autophagy, and increased oxidative stress, inflammation, and apoptosis. Interestingly, after 8 weeks, HFD rats treated with D-galactose (HFD8) had the worst impairment of cardiac and mitochondrial function, autophagy, and apoptosis in comparison to the other groups. Aging induced by D-galactose aggravated cardiac dysfunction in obese insulin-resistant rats through the worsening of cardiac mitochondrial function, autophagy, and increased apoptosis in a time-dependent manner.

D-Galactose-induced accelerated aging model: an overview

To facilitate the process of aging healthily and prevent age-related health problems, efforts to properly understand aging mechanisms and develop effective and affordable anti-aging interventions are deemed necessary. Systemic administration of D-galactose has been established to artificially induce senescence in vitro and in vivo as well as for anti-aging therapeutic interventions studies. The aim of this article is to comprehensively discuss the use of D-galactose to generate a model of accelerated aging and its possible underlying mechanisms involved in different tissues/organs.

Is D-Galactose a Useful Agent for Accelerated Aging Model of Gastrocnemius and Soleus Muscle of Sprague-Dawley Rats?

Elderly population and age-related diseases are on the rise. On the contrary, aging studies are technically hard to conduct, because they require elderly animals, the maintenance of which requires ample effort and is expensive. To tackle this problem, D-galactose is used to hasten the aging process in various tissues in rodent models and it has been shown to successfully mimic the oxidative alterations that take place in the natural aging process in various tissues both by our group and others. In the present study, the validity of D-galactose aging model in skeletal muscles was tested both on predominantly slow-twitch (soleus) and rather fast-twitch (gastrocnemius) muscle in male Sprague-Dawley rats and the results are compared with young littermate controls and naturally aged rats. Redox-related modifications in soleus and gastrocnemius were assessed by measurement of protein carbonyl groups, advanced oxidation protein products, lipid hydroperoxides, total thiol, and Cu, Zn-superoxide dismutase activities. In the present study, we provide biochemical evidence demonstrating that D-galactose-induced mimetic aging does result in oxidative stress-related redox alterations that are comparable with the alterations that occur in natural aging in soleus. On the contrary, in the D-galactose-induced mimetic aging of gastrocnemius, even though the oxidative stress markers were significantly increased, the endpoint redox homeostasis markers were not statistically comparable with the redox status of naturally aged group.

The effects of delta-9-tetrahydrocannabinol on Krüppel-like factor-4 expression, redox homeostasis, and inflammation in the kidney of diabetic rat

Diabetes mellitus is a complex, multifactorial disorder that is attributed to pancreatic β cell dysfunction. Pancreatic β cell dysfunction results in declining utilization of glucose by peripheral tissues as kidney and it leads to nephropathy. Excessive production and accumulation of free radicals and incapable antioxidant defense system lead to impaired redox status. Macromolecular damage may occur due to impaired redox status and also immune imbalance. Δ9-Tetrahydrocannabinol (THC) is the main active ingredient in cannabis. THC acts as an immunomodulator and an antioxidant agent. Our aim was to evaluate the effects of THC in the diabetic kidney. We analyzed macromolecular damage biomarkers as protein carbonyl (PCO), lipid hydroperoxide (LHP), malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OHdG), and antioxidant defense system biomarkers as thiol fractions (T-SH, NP-SH, P-SH) and Cu/Zn-superoxide dismutase activity for the antioxidative effects of THC. Furthermore, mRNA expression of Krüppel-like factor-4, secreted immunopositive cell number changes of interleukin-6, nuclear factor κβ (NF-κβ), and peroxisome proliferator-activated receptor-γ and tumor necrosis factor α (TNF-α) levels were analyzed for the immunomodulatory activity of THC. Diabetic rats showed significantly increased levels of PCO, LHP, MDA, and 8-OHdG when compared with controls (P < 0.05 for each parameter). THC significantly reduced the elevated levels of PCO and 8-OHdG (P < 0.05 for both parameters) and also LHP and MDA levels were insignificantly reduced by THC. Also, thiol fractions insignificantly increased in THC administered diabetic kidney when compared with diabetic rats. The NF-κβ cell number significantly decreased in the diabetic rats treated with THC compared with the diabetic group. According to our data, THC has ameliorative effects on the impaired redox status of diabetic kidney and also it acts as an immunomodulator. Therefore, THC might be used as a therapeutic agent for diabetic kidneys but its usage in the healthy kidney may show adverse effects.

How various concentrations of nutrients affect basal redox homeostasis of fruit flies according to gender and aging

We evaluated the effects of type of nutrients on redox status according to age and gender in Drosophila melanogaster. Flies were raised on different dose of sucrose and fixed concentration of protein containing media and separated according to their gender and age. Redox status biomarkers such as protein carbonyl groups, dityrosine, kynurenine, lipid hydroperoxides, advanced glycation end products, and Cu,Zn superoxide dismutase were assessed. We found that all of the males had higher levels of basal oxidative stress biomarkers except protein carbonyl. On the other hand, Cu,Zn-superoxide dismutase activity was elevated. We found that high concentration of sucrose leads to impaired redox status. We also observed that high protein content in sucrose-based media fecundity rate was increased and also transition to adult flies and survival ratio were decreased. Further studies are needed to focus on evaluation of the relation between median life span, nutritional mechanisms, and redox status biomarkers. PRACTICAL APPLICATIONS: Aging is characterized by functional decline in whole body system. Unfortunately, many of the life span extension strategies may lead to age-related disorders. It is widely accepted that impaired redox homeostasis is one of the signs of age-related pathophysiological changes. Due to difficulties in the establishment and validation of mimetic aging models in rodents, D. melanogaster is becoming/getting widely used model organism in gerontological studies. Currently, high protein and low carbohydrate-based nutrition regimes have become one of the most popular nutritional choice in aging population. Favorable nutrition type is considered one of the important factors for preventing age-related pathologies and promote healthy aging. In this study, we aimed to evaluate redox modulatory effects of different nutrition types as combination of various sucrose and constant protein concentration on basal redox status in D. melanogaster. Due to evolutionally conservation, we hypothesize that similar findings may be observed in aging population. Favorable nutrition type may ameliorate or postpone age-related degenerative processes and promote healthy aging.

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.

Role of D-galactose-induced brain aging and its potential used for therapeutic interventions

Aging is a phenomenon that all living organisms inevitably face. Every year, 9.9million people, globally, suffer from dementia, an indicator of the aging brain. Brain aging is significantly associated with mitochondrial dysfunction. This is characterized by a decrease in the activity of respiratory chain enzymes and ATP production, and increased free radical generation, mitochondrial deoxyribonucleic acid (DNA) mutations, and impaired mitochondrial structures. To get a better understanding of aging and to prevent its effects on many organs, chronic systemic administration of D-galactose was used to artificially create brain senescence in animal models and established to be beneficial for studies of anti-aging therapeutic interventions. Several studies have shown that D-galactose-induced brain aging which does so not only by causing mitochondrial dysfunction, but also by increasing oxidative stress, inflammation, and apoptosis, as well as lowering brain-derived neurotrophic factors. All of these defects finally lead to cognitive decline. Various therapeutic approaches which act on mitochondria and cognition were evaluated to assess their effectiveness in the battle to reverse brain aging. The aim of this article is to comprehensively summarize and discuss the underlying mechanisms involved in D-galactose-induced brain aging, particularly as regards alterations in brain mitochondria and cognitive function. In addition, the aim is to summarize the different therapeutic approaches which have been utilized to address D-galactose-induced brain aging.

Evidence of oxidative stress in brain and liver of young rats submitted to experimental galactosemia

Galactosemia is a disorder of galactose metabolism, leading to the accumulation of this carbohydrate. Galactosemic patients present brain and liver damage. For evaluated oxidative stress, 30-day-old males Wistar rats were divided into two groups: galactose group, that received a single injection of this carbohydrate (5 μmol/g), and control group, that received saline 0.9 % in the same conditions. One, twelve or twenty-four hours after the administration, animals were euthanized and cerebral cortex, cerebellum, and liver were isolated. After one hour, it was found a significant increase in TBA-RS levels, nitrate and nitrite and protein carbonyl contents in cerebral cortex, as well as protein carbonyl content in the cerebellum and in hepatic level of TBA-RS, and a significant decrease in nitrate and nitrite contents in cerebellum. TBA-RS levels were also found increased in all studied tissues, as well as nitrate and nitrite contents in cerebral cortex and cerebellum, that also present increased protein carbonyl content and impairments in the activity of antioxidant enzymes of rats euthanized at twelve hours. Finally, animals euthanized after twenty-four hours present an increase of TBA-RS levels in studied tissues, as well as the protein carbonyl content in cerebellum and liver. These animals also present an increased nitrate and nitrite content and impairment of antioxidant enzymes activities. Taken together, our data suggest that acute galactose administration impairs redox homeostasis in brain and liver of rats.

D-Galactose High-Dose Administration Failed to Induce Accelerated Aging Changes in Neurogenesis, Anxiety, and Spatial Memory on Young Male Wistar Rats

The model of accelerated senescence with the prolonged administration of d-galactose is used in anti-aging studies because it mimics several aging-associated alterations such as increase of oxidative stress and decline of cognition. However, there is no standardized protocol for this aging model, and recently some reports have questioned its effectiveness. To clarify this issue, we used a model of high-dose d-galactose on 1-month-old male Wistar rats and studied the hippocampus, one of the most affected brain regions. In one group (n = 10), d-galactose was daily administered intraperitoneally (300 mg/kg) during 8 weeks whereas age-matched controls (n = 10) were injected intraperitoneally with saline. A third group (n = 10) was treated with the same dose of d-galactose and with oral epigallocatechin-3-gallate (EGCG) (2 grams/L), a green tea catechin with anti-oxidant and neuroprotective properties. After treatments, animals were submitted to open-field, elevated plus-maze and Morris water maze tests, and neurogenesis in the dentate gyrus subgranular layer was quantified. There were no significant alterations when the three groups were compared in the number of doublecortin- and Ki-67-immunoreactive cells, and also on anxiety levels, spatial learning, and memory. Therefore, d-galactose was not effective in the induction of accelerated aging, and EGCG administered to d-galactose-treated animals did not improve behavior and had no effects on neurogenesis. We conclude that daily 300 mg/kg of d-galactose administered intraperitoneally may not be a suitable model for inducing age-related neurobehavioral alterations in young male Wistar rats. More studies are necessary to obtain a reliable and reproducible model of accelerated senescence in rodents using d-galactose.

Yulangsan polysaccharide improves redox homeostasis and immune impairment in d-galactose-induced mimetic aging

Yulangsan polysaccharide (YLSP) is a traditional Chinese medicine used in long-term treatment as a modulator of brain dysfunction and immunity.