The SARS-CoV-2 pandemic has affected millions worldwide, with aging being a key risk factor for severe disease outcomes. This study examines the rate of epigenetic aging, as measured by DNA methylation-based aging markers, in COVID-19 patients versus healthy individuals. We found that PCGrimAge, a next-generation epigenetic clock associated with immune dysregulation and inflammation, showed the strongest correlation with the chronological age of the European COVID-19 patients. Several other next-generation epigenetic clocks, including PCGrimAge, DunedinPACE, and ZhangY2017, also exhibited accelerated aging in both older and female COVID-19 patients. Interestingly, first-generation clocks, such as Hannum2013, indicated a significant reduction in epigenetic aging, likely reflecting limitations in their sensitivity to infection-related biological changes rather than an actual deceleration of the aging process. Our results also showed that immune dysregulation, rather than intrinsic cellular aging, may be the primary driver of accelerated epigenetic aging in COVID-19. This is supported by stronger associations observed in Age Acceleration (AA) and Extrinsic Epigenetic Age Acceleration (EEAA) compared to Intrinsic Epigenetic Age Acceleration (IEAA). Furthermore, immune dysregulation may be linked to CpG site demethylation, which in turn influences epigenetic clock dynamics. We also identified disparities between European and non-European populations, characterized by significantly higher IEAA for PCPhenoAge and DunedinPACE among non-European patients with COVID-19. In summary, our results underscore the differential sensitivity of epigenetic clocks to COVID-19-related biological changes.

Age-related functional decline has emerged as a major challenge to human health and societal development. Safe and effective anti-aging interventions, particularly those involving natural products, offer promising strategies to delay aging and promote healthy longevity. In this study, we used Caenorhabditis elegans (C. elegans) models to investigate the anti-aging effects and underlying mechanisms of Liu Jun Zi Decoction (LJZD), a traditional Chinese herbal formula. The results showed that LJZD extended lifespan and enhanced stress resistance and locomotion in C. elegans. Serum pharmacochemistry, network pharmacology, and molecular docking identified key bioactive compounds that target the IIS/mTOR and p16/p21 pathways. Furthermore, we found that LJZD promoted longevity by improving mitochondrial function via the IIS-mTOR axis. Notably, LJZD also conferred neuroprotection in Aβ-/tau-expressing models. These findings provide mechanistic insights into multi-target herbal interventions for aging and neurodegeneration.

The mechanisms underlying skeletal muscle ageing, whilst poorly understood, are thought to involve dysregulated micro (mi)RNA expression. Using young and aged rat skeletal muscle tissue, we applied high-throughput RNA sequencing to comprehensively study alterations in miRNA expression occurring with age, as well as the impact of caloric restriction (CR) on these changes. Furthermore, the function of the proteins targeted by these age- and CR-associated miRNAs was ascertained. Numerous known and novel age-associated miRNAs were identified of which CR normalised > 35% to youthful levels. Our results suggest miRNAs upregulated with age to downregulate proteins involved in muscle tissue development and metabolism, as well as longevity pathways, such as AMPK and autophagy. Furthermore, our results suggest miRNAs downregulated with age to upregulate pro-inflammatory proteins, particularly those involved in innate immunity as well as the complement and coagulation cascades. Interestingly, CR was particularly effective at normalising miRNAs upregulated with age, rescuing their associated protein-coding genes but was less effective at rescuing anti-inflammatory miRNAs downregulated with age. Lastly, the effects of a specific miRNA, miR-96-5p, identified by our analysis to be upregulated with age, were studied in cultured C2C12 myoblasts. We demonstrated miR-96-5p to decrease cell viability and markers of mitochondrial biogenesis, myogenic differentiation and autophagy. Overall, our results provide novel information regarding how miRNA expression changes in skeletal muscle, as well as the potential functional consequences of these changes and how they are ameliorated by CR.

Healthspan, the disease-free period of life, has become a central focus in aging research. Cuscuta chinensis seed and Eucommia ulmoides bark extracts, two traditional Chinese medicine (TCM) remedies, have shown promising healthspan-extending effects in Caenorhabditis elegans. In this study, RNA-seq analysis of aged worms treated with these extracts revealed significant transcriptomic alterations. Gene ontology and KEGG pathway analyses indicated upregulation of genes involved in immune defense, lysosomal function, and protein homeostasis, which may underlie the shared phenotype of enhanced stress resistance and lifespan extension. Beyond these effects, C. chinensis further improved multiple health parameters. Consistent with its broad spectrum of phenotypes, C. chinensis induced extensive transcriptomic remodeling involving over 3000 differentially expressed genes. Modulating collagen-, unc-, and muscle-related genes may explain improved locomotion, while upregulation of mec genes could contribute to enhanced mechanosensation. Notably, far-3, encoding a fatty acid- and retinol-binding protein, was upregulated more than 150-fold, and RNA interference assays demonstrated that FAR-3 is necessary for C. chinensis-induced healthspan improvement. Furthermore, C. chinensis influenced genes linked to antagonistic pleiotropy and insulin-like signaling, suggesting a systemic, hormesis-driven reprogramming of aging processes. Together, these findings uncover both shared and distinct molecular mechanisms through which C. chinensis and E. ulmoides promote healthspan in C. elegans.

Homeostatic systems (nervous, immune, and endocrine) are crucial for maintaining health throughout life and, consequently, relevant for the rate of aging and the longevity achieved. In many species, male and female mammals show different lifespans, attributed to distinct redox states, but it is scarcely known whether sex differences in the functioning of these systems are involved. This study investigated, in an integrative view, sex differences in the nervous and immune systems of Swiss strain mice by analyzing behavior, immune function, and redox biomarkers across aging, to determine whether possible sex differences in homeostatic systems affect longevity. A longitudinal study was conducted on 20 female and male Swiss mice. At their young (2 mon), adult (7 mon), and old (18 mon) ages, subjects were subjected to a battery of behavioral tests, and peritoneal leukocytes were extracted to assess immune function and redox biomarkers. The natural deaths of animals were recorded for a longevity study. Our results indicate that sexual differences begin at a young age, and several are maintained until old age. Females, in general, show better behavior, immune function, and redox biomarkers, contributing to their higher longevity compared to males. The enhanced longevity in females may be attributable, in part, to the preservation of robust immune competence, with emphasis on innate immune functions and lower oxidative stress. The integration of behavioral and immunological profiles, together with redox biomarkers, underscores the critical importance of incorporating both sex as a biological variable in the design of aging-related research.

While immune system involvement in aging is increasingly recognized, causal relationships between specific immune cell populations and biological aging indicators remain unclear. We aimed to identify immune targets influencing aging trajectories to inform future immunomodulatory interventions. We conducted two-sample Mendelian randomization (MR) analysis using immunophenotype GWAS data (3,757 Sardinian participants) and aging phenotype statistics (PhenoAgeAccel: n = 107,460; BioAgeAccel: n = 98,446). Analysis employed IVW methodology with sensitivity analyses including weighted median estimation, MR-Egger regression, MR-PRESSO, and Cochran's Q statistic. Significance was determined using False Discovery Rate (FDR) correction (P < 0.05). After FDR correction, seventeen immune cell phenotypes showed significant associations with PhenoAgeAccel: two cDCs, one monocyte subtype, ten myeloid cells, three TBNK cells, and one Treg population. Key findings included protective effects of FSC-A on granulocyte (β = -0.24, 95% CI:-0.37 to -0.10, P = 1.81 × 10) and risk associations of CD14 CD16 monocyte (β = 0.41, 95% CI:0.24-0.58, P = 6.84 × 10). Among TBNK cells, CD8 T cell (β = 0.32, 95% CI: 0.16-0.47, P = 6.44 × 10) and CD28 CD8 T cell (β = 0.40, 95% CI: 0.23-0.58, P = 8.14 × 10) emerged as risk factors. For BioAgeAccel, four phenotypes showed suggestive relationships, with Unswitched Memory B Cell showing the strongest protective effect (β =  - 0.32, 95% CI:-0.52 to-0.12, p = 1.75 × 10). Our study revealed causal relationships between specific immune cell phenotypes and biological aging acceleration, identifying potential therapeutic targets for age-modulation and suggesting immune signatures as crucial regulators in aging-related processes.

Amyloid-β (Aβ) plaques are one of the primary biomarkers of Alzheimer's Disease (AD). Other publications have reported various mechanisms regarding the clearance of Aβ, and recent studies have also investigated the relationship between daily rhythms of Aβ and AD. The intent of this study was to determine if the circadian rhythm of Aβ differed between a region that was more vulnerable to AD-related pathology (the olfactory bulbs; OB) compared to a region that is less vulnerable (the cerebellum; CER). We chose to utilize an APPxPS1 knock-in (KI) mouse strain as this strain expresses amyloid precursor protein (APP) and Aβ under control of its normal promoter as opposed to AD transgenic models that overexpress APP and, as a consequence, Aβ. Mice (N = 128, equally divided between male and female, wild type and KI) were acclimated to a 12:12 light cycle for two weeks, and tissue was collected over a 24-h period in constant darkness. Using a unique immunoassay designed to measure human or rodent Aβ side-by-side, we confirmed a robust circadian Aβ rhythm in the mouse brain and that the OB contains more overall Aβ accumulation than the CER. The circadian Aβ rhythm was not present in the OB of the KI as compared to the WT mice. In contrast, the Aβ rhythm in the CER did not differ between genotypes. These results suggest that the loss of Aβ rhythm in disease-affected brain regions may be associated with the development of AD pathology and could have important implications for therapy.

An accumulation of senescent cells within tissues is a hallmark of the aging process. Cellular senescence is associated with an increased level of cytosolic dsDNA which primarily originates from a leakage of mitochondrial DNA (mtDNA) and a loss of genomic DNA integrity. Cytosolic dsDNA is an important alarming factor for cytosolic dsDNA sensors which trigger the remodeling of the immune system through diverse signaling pathways. The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) (cGAS-STING) signaling is a major defence mechanism induced by an accumulation of cytosolic dsDNA in senescent cells. The cGAS-STING pathway stimulates immune responses via the interferon regulatory factor 3 (IRF3) and nuclear factor-κB (NF-κB)-driven pathways. The activation of cGAS-STING signaling in senescent cells generates pleiotropic immune responses in a context-dependent manner. For instance, cGAS-STING signaling induces proinflammatory responses by enhancing the secretion of cytokines, chemokines, and colony-stimulating factors. The secretion of many chemokines and colony-stimulating factors can remodel hematopoiesis and enhance thymic involution with aging. Moreover, cGAS-STING signaling promotes proinflammatory responses by stimulating the NLRP3 inflammasomes. On the other hand, cGAS-STING signaling aids in the resolution of inflammation by recruiting immunosuppressive cells into tissues and suppressing the pathogenic activity of T helper 17 cells. In addition, an increased cGAS-STING signaling in senescent cells stimulates the expression of inhibitory immune checkpoint ligands, such as PD-L1, and thus prevents their elimination by immune cells. Recent studies have clearly revealed that cGAS-STING signaling not only induces cellular senescence but it can also promote the aging process.

This two part study on the afferent connectivity of lumbar spinal motor neurons in normal ageing mice investigates; Study 1: time course analysis of age-related changes in the synaptic coverage of lumbar spinal cords of male C57BL/BJ mice at 4,15,18 and 24 months of age and Study 2: the effect of long term 8-month resistance wheel exercise (RWE) on lumbar spinal cords of male C57BL/6J mice exercised from 15 to 23 months of age. Uniquely, each study used spinal cords obtained from the same mice that had previously been analysed for changes in skeletal muscles and sciatic nerves in a parallel series of time course and exercise studies. Input to presumed alpha motor neurons was investigated by quantifying VGLUT1 immunoreactive synaptic contacts known to be derived from proprioceptive muscle afferents. Here we found no significant changes in the percentage of synaptic VGLUT1 coverage of motor neurons from 4 to 24 months. Importantly, this differs from our previous results (Krishnan et al., Biogerontology 19:385-399, 2018) where there was about 50% decrease in VGLUT1 innervation of motor neurons in older mice aged 27 months, indicating a rapid deterioration in proprioceptive feedback in late ageing. In the exercise study, 8 months of voluntary wheel running (beginning at 15 months), had no impact on VGLUT1 synaptic connectivity in spinal cords, consistent with our previous report of no effect on peripheral nerves obtained from this same ageing and exercised cohort of mice. Nonetheless there was a significant amount of sarcopenia in these animals. Overall, these studies highlight the variable impact of ageing on different motor-related tissues.

Aging not only significantly reduces the quality of life for the elderly but also poses multifaceted challenges to society. Its progression involves the synergistic interaction of multidimensional, multipathway molecular mechanisms, including mitochondrial dysfunction, oxidative stress accumulation, chronic inflammation, and genomic damage. Quercetagetin (QG), as a natural flavanol monomer, exhibits significant potential in anti-aging due to its simultaneous targeting of key aging pathways such as oxidative stress and chronic inflammation. We first evaluated QG's safety profile, finding that 0.02 mg/ml QG did not adversely affect motility, feeding, growth, and reproductive capacity in Caenorhabditis elegans (C. elegans). At this concentration, in vivo experiments using wild-type C. elegans confirmed QG's ability to extend lifespan and enhance oxidative stress resistance. The antioxidant and anti-aging effects of QG were further validated using the daf-16 mutant C. elegans DR26. Subsequently, observation of QG's impact on C. elegans mitochondrial morphology revealed significant reductions in area/perimeter and mitochondria coverage ratio following treatment. This indicates that QG treatment shifts the mitochondrial network from fusion toward fission and reduces overall mitochondrial content. QG can also improve age-related dopaminergic, 5-hydroxytryptaminergic and cholinergic neuron degeneration. Mass spectrometry metabolome analysis revealed that QG significantly affected citrate cycle and glycerophospholipid metabolism. Collectively, QG extends C. elegans lifespan by regulating redox homeostasis, DAF-16/FOXO pathways, mitochondrial homeostasis and metabolic reprogramming. This multi-target regulatory capacity positions QG as an ideal candidate molecule for anti-aging drug development.

Vocal fold fibroblasts play an important role in the production of the extracellular matrix in the vocal folds. Myofibroblasts increase in the aging vocal fold lamina propria with increased alpha-smooth muscle actin. In addition to alpha-smooth muscle actin, various sarcomeric genes are expressed in myofibroblasts. However, there have been no studies on sarcomeric genes with myofibroblast differentiation in aging vocal folds. The purpose of this study was to analyze the changes and functions of sarcomeric genes related to myofibroblast differentiation in aging vocal folds using next-generation sequencing (NGS). Young (6-month-old, 22 rats) and old (22-month-old, 22 rats) male Sprague-Dawley rats were used for this study. NGS was performed on the harvested lamina propria of the vocal folds in each group. NGS data were analyzed using functional annotation, gene ontology, network pathways, and network analysis methods. After identifying the increased expression of sarcomeric genes in aging vocal folds, we evaluated the expression of sarcomeric genes in the normal human vocal fold lamina propria removed after surgery for various vocal fold lesions. The functions of sarcomeric genes in fibroblast senescence, proliferation, differentiation, contraction, and stiffness were investigated. Among the four sarcomeric genes identified through network cluster analysis of the NGS results, the expression levels of myosin light chain kinase 2 (Mylk2) and myomesin 2 (Myom2) were significantly higher in the lamina propria of old rats than in young rats. The increase in Mylk2 and Myom2 expression was associated with cellular senescence but not with the proliferative ability of fibroblasts. However, the expression of Mylk2 and Myom2 increased with myofibroblast differentiation. Inhibition of Mylk2 and Myom2 affects cellular contraction, leading to reduced stiffness. Our results suggest that Mylk2 and Myom2 are novel biomarkers of vocal fold myofibroblasts and are involved in the regulation of vocal fold stiffness in aging rats and humans.

Aging may be conceptualized as a wound that fails to heal, characterized by persistent, unresolved inflammation. Building on Ogrodnik's "unhealed wound" model, this Perspective extends the Exposure-Related Malnutrition (ERM) framework to propose a bioenergetic interpretation of aging. ERM links chronic stress adaptation, nutrient misallocation, and mitochondrial insufficiency to sustained bioenergetic debt that impedes the transition from catabolic containment to anabolic repair. Across tissues, this energetic shortfall manifests as metabolic inflexibility, lipid-droplet accumulation, and a continuum of adaptive mitochondrial dysfunction that remains reversible until the threshold of senescence-the terminal stage of unresolved adaptation. Recognizing bioenergetic availability as the principal determinant of regenerative success reframes mitochondrial dysfunction and senescence not as primary causes of aging but as downstream consequences of chronic energetic exhaustion. Within this continuum, aging reflects a progressive loss of rhythmic catabolic-anabolic cycling that supports metabolic adaptation. Transient metabolic stress normally induces hormetic activation followed by anabolic recovery, but when this oscillation fails, adaptive hormesis gives way to maladaptive exhaustion. Aging thus emerges from the erosion of bioenergetic rhythm-a transition from recovery with renewal to endurance without repair.

Aging involves progressive accumulation of molecular and cellular damage, leading to functional decline and increased susceptibility to age-related diseases. Natural low-molecular-weight geroprotectors are substances of plant and food origin capable of modulating key mechanisms of aging. Based on current scientific data, sixteen fundamental mechanisms of aging are analyzed, and compounds from food that demonstrate potential in slowing age-related changes are presented. Special attention is paid to the mechanisms of action of these substances at the molecular and cellular levels, as well as their availability in common food products. This review summarizes the current understanding of the interaction between natural nutrients and fundamental aging processes and opens perspectives for developing dietary strategies for healthy longevity.

High-intensity interval training (HIIT) is capable of reversing many aging-related metabolic differences in the proteome, but studies using proteomics to investigate the mechanism of the effects of HIIT on hepatic metabolic function in aged rats have not been reported. In this study, we investigated the effects of 8 months of HIIT on mitochondrial oxidative function, oxidative stress, and inflammation in the liver of aged rats, and further explored the possible mechanisms of the metabolic effects of HIIT in aged rats by proteomics. The results of the study revealed that HIIT improved liver morphology, enhanced mitochondrial oxidative function, decreased inflammation and apoptosis levels, increased intrahepatic antioxidant function and inhibited ferroptosis in aged rats. Proteomics showed that HIIT altered changes in glycine, serine and threonine metabolic pathways in the liver, and further use of targeted amino acid metabolomics revealed that HIIT markedly increased glycine and serine content in aged livers. In vitro cells demonstrated that exogenous glycine supplementation significantly enhanced the intracellular antioxidant capacity of oxidatively stressed hepatocytes, while decreasing the level of inflammatory factor expression and significantly inhibiting the occurrence of ferroptosis. Our findings suggest that the improvement of metabolic function in aged liver tissue by HIIT may be associated with elevated glycine content, and that glycine within aged livers elevated by HIIT may mediate the maintenance of metabolic homeostasis within liver tissue.

Bone marrow exhibits functional decline, yet cellular heterogeneity and molecular mechanisms remain unclear due to limitations of traditional research methods. This study aims to characterize age-related changes and identify key drivers in bone marrow. Integrated multi-omics analysis was performed using scRNA-seq, proteomics, pseudo-bulk transcriptomics, weighted gene co-expression network analysis (WGCNA)-based transcription factor (TF) network modeling, and CellChat analysis. Samples included 6 young and aged bone marrow specimens. Statistical validation involved differential expression analysis, Cox regression modeling, and receiver operating characteristic (ROC) curve analysis. A novel hematopoietic subpopulation (3.19% of aged samples) was identified, activating the cellular senescence pathway (KEGG) and enhancing inflammatory crosstalk with CD8⁺ T cells via NMU signaling (|avg_log2FC|> 0.58, p < 0.001). Pseudo-bulk and proteomic analyses identified CAPN1, MAP2K1, and JUND as potential signal modules. Immunohistochemistry and Western blot confirmed their co-expression, while molecular docking revealed interaction interfaces. In two independent bulk-RNA cohorts (n = 58), a Cox model based on the CAPN1-MAP2K1-JUND module showed robust predictive value for aging, with AUCs of 0.7507 (p = 0.0154) and 0.90 (p = 0.0274). This study identifies a pivotal molecular module linking single-cell dynamics to tissue-level senescence in bone marrow, providing new insights into aging mechanisms and potential therapeutic targets.

Cellular and molecular mechanisms that drive a perturbed wound microenvironment and impaired healing in aged skin have not been fully delineated. To obtain a comprehensive understanding of cell-intrinsic changes acquired during ageing that impact early responses to injury, we performed single-cell RNA sequencing in young and aged intact female murine skin and wounds 3 days post-injury. We observed that substantial changes in the mean proportional distribution and transcriptomic state of skin resident subpopulations in aged, but not young, tissues accompany a global increase in basal inflammation. This is driven by an altered signalling environment leading to impaired keratinocyte differentiation, loss of fibroblast identity and defective macrophage function. Further, we show that ageing-induced changes in skin resident cells persist after injury, resulting in increased expression of senescence-related genes in wound fibroblasts and aberrant monocyte-to-macrophage transitioning coupled to an enhanced inflammatory signature and defective intercellular signalling in comparison to wounds in young mice. In summary, our data highlights a contribution of both cell-intrinsic changes and an altered tissue microenvironment to poor wound healing responses in aged mice.

To verify whether DNA repair is regulated by FOXO3a, a tet-on flag-h-FOXO3a transgenic mice were used. RT-q-PCR and western blot analysis showed that the mRNA and protein levels of flag-h-FOXO3a, XRCC4, XPC, APE1 and MSH2 increased dose dependently by doxycycline. DNA repair activities like non-homologous end joining (NHEJ), nucleotide excision repair (NER), base excision repair (BER), mismatch repair (MMR) also increased in a doxycycline dose dependent manner. MEF (mouse embryonic fibroblast) cells of the transgenic mouse were transfected with human XRCC4/XPC/APE1/MSH2 promoter-pGL3 basic vectors. Promoter assay and ChIP (chromatin immunoprecipitation) assay showed increased promoter activity and interactions of FOXO3a to FOXO consensus sites. The results indicate that XRCC4, XPC, APE1, and MSH2 are transcriptional target genes of FOXO3a and activities of NHEJ, NER, BER and MMR are regulated probably via transcriptional activation of XRCC4, XPC, APE1 and MSH2 by FOXO3a. FOXO3a overexpression in MEF cells and tet-on flag-h-FOXO3a transgenic mouse exhibited high resistance to gamma radiation. Small intestine showed less damage and apoptosis in doxycycline-treated mice. The median and maximum lifespan of the doxycycline-treated transgenic mice increased by about 30%. The results suggest that FOXO3a overexpression provide protection against gamma radiation and lifespan extension possibly via activation of DNA repair.

Aging is a complex process that includes chronological aging and cellular aging. Although chronological aging is irreversible, cellular aging, which is reversible, is closely associated with chronological aging. Understanding the complexity of the impact and mechanisms of aging on the male reproductive function is crucial in maintaining male fertility. This study reviews the effects and mechanisms associated with aging in males on male reproductive health. It also provides potential therapeutic strategies for alleviating the reproductive consequences of aging in males. Evidence from the literature revealed that aging suppresses testicular steroidogenesis and circulating testosterone, lowers spermatogenesis and sperm quality, and induces erectile dysfunction. These adverse events are mediated by mitochondrial dysfunction and reduced ATP production, oxidative stress, inflammation, apoptosis, and DNA damage. More so, telomere shortening, cellular senescence, and epigenetic modification play crucial roles. Modulation of these processes with antioxidants such as vitamin C, vitamin E, CoQ10, and zinc attenuates cellular aging and promotes male reproductive health.

Aging reduces testicular function by lowering sperm quality and testosterone, worsened by diseases. Morphine addiction harms male reproduction by disrupting hormonal balance and increasing testicular oxidative stress and inflammation. Regular physical exercise can help counteract these effects by boosting antioxidants and supporting sperm production. This study explores how exercise mitigates inflammaging and testosterone decline by modulating the NF-κB signaling pathway in aged male rats with morphine addiction. A total of 56 male Wistar rats were divided into eight groups, with four groups for each age category (young and old). The experimental groups were as follows: 1) Control, 2) Trained, 3) Addicted, and 4) Trained + Addicted. Rats in the addicted groups received morphine treatment for 28 days, while the trained groups underwent treadmill exercise sessions for 4 weeks. The gene expression levels of NF-κB and Nrf2 in testis tissue were quantified using RT-PCR. Additionally, the concentrations of the cytokines TNF-α and IL-10 were measured in testis tissue by ELISA. Furthermore, the levels of MDA, TAC, and testosterone were assessed using specific assay kits. Our results demonstrated that morphine exposure in both young and old rats significantly decreased IL-10, TAC, and testosterone levels, while it increased TNF-α, MDA, and NF-κB gene expression. Exercise in both young and old groups resulted in a reduction of NF-κB gene expression, as well as decreased levels of TNF-α and MDA. Additionally, exercise increased testosterone, interleukin-10, and total antioxidant capacity in both serum and testicular tissue. Our results demonstrated that exercise mitigates testicular impairments following morphine exposure in young and old rats via reducing inflammation and oxidative stress while increasing testosterone levels and modulating NF-κB expression.

One of the key hallmarks of aging is the breakdown of proteostasis-the finely tuned balance of protein synthesis, folding, trafficking, and degradation that maintains proteome integrity and cellular function. In this study, we employed N metabolic labeling to assess protein turnover in young and aged mice. Among the proteins examined, cystatin C exhibited the largest age-related reduction in turnover, alongside decreases in other proteins involved in neuroprotection, structural stability, and neurotransmission, including transthyretin, proteolipid protein 1, and the astrocytic glutamate transporter SLC1A3. Reduced proteostatic capacity is likely to increase neuronal susceptibility to proteotoxic stress, protein aggregation, and excitotoxic injury. Immunohistochemical analysis revealed a punctate accumulation of cystatin C in cortical layer IV, a region particularly vulnerable to age-related pathology. Moreover, gene expression profiling showed region-specific upregulation of inflammatory markers (Cd11b, Fcgr1, and Cr3), suggesting enhanced degradation of brain structures through phagocytic activity. Together, these findings demonstrate that aging disrupts proteostasis in a protein- and region-specific manner, with cystatin C emerging as a central mediator linking impaired clearance to neuroinflammation and cortical vulnerability. Interventions aimed at enhancing autophagy, proteasome function, or chaperone activity may represent promising strategies to counteract proteostasis collapse and mitigate neurodegeneration in the aging brain.