Search Results (161)

Physalis pubescens L. is a seasonal fruit with high nutritional value but a short shelf life that limits its processing and utilization. This study integrated metagenomics and metabolomics to investigate the comparative effects of Lactiplantibacillus plantarum fermentation on volatile flavor metabolites and microbial community composition of P. pubescens by comparing initial (0 h) and post-fermentation (24 h) states. After 24 h of fermentation, 1316 volatile compounds were putatively identified by GC-MS, with 592 metabolites significantly changed and 501 upregulated and 91 downregulated. Key flavor compounds that impart citrus, floral, fruity, and rose notes including D-limonene, geraniol, D-carvone, and phenylethyl alcohol were markedly increased. Metagenomic analysis revealed that L. plantarum rapidly dominated the microbial community (relative abundance surged from <0.05% to ~72%) while effectively suppressing potential spoilage bacteria such as Escherichia coli. Functional gene annotation demonstrated significant enrichment of amino acid, carbohydrate, and fatty acid metabolism pathways, with key enzyme genes (L-lactate dehydrogenase, pyruvate oxidase, acetyl-CoA carboxylase) predominantly assigned to L. plantarum, suggesting their potential contribution to the generation of organic acids, ethanol, and esters. Spearman correlation analysis indicated that Lactobacillaceae genera were significantly positively correlated with terpenoids, phenols, alcohols, and aldehydes. This study provides the first metagenomics-metabolomics insight into the microbial and molecular mechanisms associated with flavor formation in LAB-fermented P. pubescens, offering a theoretical foundation for developing stable and controllable fermented fruit products. Full article

High-glucose exposure impairs intestinal metabolic homeostasis and barrier integrity in fish, but the transcriptional responses associated with high-glucose adaptation in fish intestinal epithelial cells remain incompletely understood. This study investigated whether exogenous 5-methylcytosine (5MC) alleviates high-glucose-induced metabolic and epithelial stress in grass carp (Ctenopharyngodon Idella) intestinal epithelial cells and whether these responses are associated with changes in DNA methyltransferase 3 beta (dnmt3b) expression and Caudal type homeobox 1b (cdx1b)/Sodium-glucose cotransporter 1 (sglt1)-related transcriptional responses. As exploratory in silico information, molecular docking predicted candidate complex conformations of DNMT3B with CDX1B and SGLT1, with binding energies of −37.2 and −25.9 kcal/mol, respectively. Functionally, dnmt3b knockdown significantly reduced dnmt3b, Interleukin 6 (il6), and Nuclear factor kappa B (nfκb) expression, while increasing cdx1b, sglt1, Solute carrier family 2 member 3a (slc2a3a), 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4a (pfkfb4a), and Amine oxidase copper containing 1 (aoc1) expression (p < 0.05). CDX2/CDX1B-like immunoreactive protein and SGLT1 protein levels were also increased after dnmt3b knockdown (p < 0.05). Under high-glucose stress, exogenous 5MC exerted concentration-dependent effects. Specifically, 6 mM 5MC significantly reduced residual extracellular glucose, lactate dehydrogenase and diamine oxidase activities, and malondialdehyde content, while increasing glutathione content, cell viability, and cell migration (p < 0.05). These effects remained detectable after replacement with high-glucose medium for an additional 12 h. By contrast, 24 mM 5MC markedly increased lactate dehydrogenase activity and reduced cell viability, suggesting potential cytotoxicity (p < 0.05). S-adenosylmethionine (SAM) levels were significantly lower in the NC and 6 mM groups than in the HG, 12 mM, and 24 mM groups, suggesting changes in SAM-related one-carbon metabolic status rather than direct evidence of altered DNA methylation (p < 0.05). Exogenous 5MC, particularly at 6 mM, alleviated high-glucose-induced metabolic and epithelial stress in grass carp intestinal epithelial cells. These effects were accompanied by changes in several glucose metabolism- and inflammation-related genes. However, the cellular uptake, metabolic fate, DNA incorporation, methylation consequences, and causal roles of these gene-expression changes remain to be further verified. Full article

Age-related hyperphosphatemia is increasingly recognized as a contributing factor in sarcopenia. This work studies the metabolic effects of elevated phosphate on muscle. C2C12 cells were differentiated in the absence or presence of 10 mM β-glycerophosphate (BGP), an exogenous phosphate donor. In addition, quadriceps muscles from four experimental groups of male C57BL/6J mice were analyzed: young (5 months) and old (24 months) fed with standard diet; old mice fed with hypophosphatemic diet or supplemented with the phosphate binder Velphoro^®, for the last three months of life. Mice were stratified according to sarcopenia degree based on muscle mass, strength and physical performance. Protein levels were determined by immunoblotting and mRNA expression by RT-qPCR. ATP levels were measured by luminescence and L-lactate production, citrate synthase and cytochrome c oxidase activities by colorimetric assays. Mitochondrial content, membrane potential and reactive oxygen species (ROS) were determined by fluorescence assay. BGP-treated cells showed increased glucose transporter 1 (GLUT1) and decreased NADH Dehydrogenase (CI-NDUFB8) protein expression, elevated hexokinase II (HK2), phosphoglycerate kinase 1 (PGK1) and lactate dehydrogenase A (LDHA) mRNA levels, reduced ATP levels, increased lactate production, and decreased mitochondrial enzyme activities. Moreover, BGP increased ROS, diminished mitochondrial membrane potential, and altered fusion–fission dynamics and mitophagy. In aged quadriceps, oxidative phosphorylation (OXPHOS) subunits and superoxide dismutase 2 (SOD2) expression were reduced. The hypophosphatemic diet improved all parameters, whereas Velphoro^® selectively increased Mitochondrial cytochrome C oxidase subunit 1 (CIV-MTCO1) expression. Several altered mitochondrial markers are associated with sarcopenia degree. Altogether, hyperphosphatemia induces metabolic changes that scale with the sarcopenic degree. Our findings show a relevant association between hyperphosphatemia and mitochondrial dysfunction, and they support the potential benefit of phosphate reduction as a strategy to prevent or mitigate sarcopenia. Full article

Seasonal fluctuations in open solid-state fermentation drive batch-to-batch variability in Chinese Baijiu Daqu; however, how environmental shifts reshape microbial functional expression and non-volatile flavour precursors in medium-high-temperature Daqu remains poorly resolved. In this study, data-independent acquisition (DIA)-based quantitative metaproteomics and untargeted liquid chromatography–mass spectrometry (LC-MS) metabolomics were integrated to characterise winter and summer Daqu from Luzhou, Sichuan. Among 2904 annotated non-volatile metabolites, orthogonal partial least squares discriminant analysis (OPLS-DA) revealed clear seasonal separation; 1472 differential metabolites (560 up- and 912 downregulated in winter vs. summer; variable importance in projection [VIP] > 1, p < 0.05) were enriched in glycolysis/gluconeogenesis, the tricarboxylic acid (TCA) cycle, amino acid biosynthesis, and starch/sucrose metabolism. DIA-based quantitative metaproteomics further resolved season-specific enzyme expression: summer Daqu exhibited elevated saccharolytic, glycolytic and amino-acid-converting enzymes (β-glucosidase, 6-phosphofructokinase, pyruvate dehydrogenase), whereas winter Daqu was enriched in glucose oxidase, phosphoenolpyruvate carboxykinase and aldehyde dehydrogenase, consistent with a pattern suggestive of carbon-storage prioritisation. Proteome–metabolome integration established a coherent “enzyme protein abundance–inferred metabolic tendency–metabolite accumulation” correlative framework axis: higher hydrolytic and central-carbon enzyme abundance in summer corresponded to increased maltose, lactate, acetate, L-glutamate and L-aspartate. Therefore, production season reshapes Daqu quality chiefly by corresponding to distinct patterns of in situ enzyme protein abundance, providing a DIA quantitative metaproteome-anchored mechanistic framework for screening high-expression starters and stabilising seasonal Daqu quality. Full article

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a globally prevalent hepatic disorder, characterized by hepatic lipid accumulation and extrahepatic complications, notably intestinal barrier injury, which further exacerbates MASLD progression. The “gut–liver axis” has been identified as a critical contributor to MASLD development, with insulin-like growth factor 1 (IGF-1) serving as a pivotal coupling factor of this axis. However, the specific role and molecular mechanism by which IGF-1 modulates intestinal barrier function in the context of MASLD remains unclear. Methods: This study analyzed the correlations between the GH/IGF-1 axis and intestinal barrier function in MASLD rats, and explored the effects of IGF-1 intervention both in vivo and in vitro. Results: Our results showed that MASLD rats exhibited intestinal barrier impairment, characterized by elevated serum Diamine oxidase (DAO) and D-Lactate (D-LAC) levels, villus damage, and downregulation of tight junction proteins and Mucin (MUC2). These changes were accompanied by suppression of the GH/IGF-1 axis. Correlation analysis uncovered a negative association between IGF-1 levels and markers of barrier dysfunction. IGF-1 intervention effectively repaired the intestinal barrier structure of MASLD rats and significantly upregulated the expressions of IGF-1R, PI3K, and AKT. In vitro, IGF-1 treatment improved transepithelial electrical resistance (TEER), enhanced barrier-related gene expression, promoted cell proliferation, and inhibited apoptosis. Conclusions: These findings suggested that GH/IGF-1 axis suppression, intestinal barrier dysfunction, and IGF-1R/PI3K/AKT signaling were interconnected within the gut–liver axis in MASLD. IGF-1 may contribute to barrier regulation through associated signaling changes, highlighting the GH/IGF-1 axis as a potential complementary target. Full article

Background: The development of Slow Transit Constipation (STC) is associated with intestinal barrier damage. Coreopsis tinctoria Nutt. (CT) is effective in treating STC, but the mechanisms are unclear. Methods: We investigated three CT extracts—traditional aqueous extract, and an aqueous extract from supercritical fluid extraction, with or without lipophilic components—on intestinal transit in a loperamide-induced STC rat model. The potential therapeutic targets of CT for STC were initially predicted using an integrated approach of network pharmacology and molecular docking. The therapeutic effect of CT was evaluated in a STC rat model by assessing defecation parameters (fecal count, water content, intestinal transit), colon histology (H&E and AB-PAS staining), inflammatory markers (ELISA), and target protein expression (Western blotting and immunohistochemistry). In parallel, an LPS-induced IEC-6 cell injury model was used to investigate intestinal barrier protection, analyzing cell viability (CCK-8), apoptosis (flow cytometry and Western blotting), migration (scratch assay), and protein expression (Western blotting). Results: Docking and enrichment analysis highlighted hub targets (TNF, AKT1, Caspase3, STAT3, and BCL-2) and the PI3K/AKT pathway. In vivo, CT treatment improved defecation function, reduced colonic damage, and decreased markers of inflammation and apoptosis in STC rats. It also up-regulated ZO-1 and Occludin, lowered serum markers of intestinal permeability D-lactate (D-LA) and Diamine oxidase (DAO), and restored intestinal barrier function. Furthermore, CT reduced Caspase3 expression and increased the expression of proteins such as BCL-2, PI3K, and P-AKT/AKT. These findings were further supported by in vitro experiments. Conclusions: CT improves STC and its associated intestinal barrier damage by activating the PI3K/AKT pathway and suppressing inflammation and apoptosis, among which the aqueous extract from supercritical fluid extraction combined with the lipophilic fraction exhibits the best efficacy. Full article

The direct involvement of the phosphatidylinositol 3-kinase (PI3K)/serine threonine kinase (AKT) signaling pathway in the alleviation of the heat stress (HS)-induced damage to the integrity and barrier function of broiler jejunal organoids (JOs) by supplemental zinc (Zn) has not been confirmed. To verify it, two experiments were conducted in the present study. In experiment 1, the optimal concentrations of PI3K/AKT inhibitor (PI3K-IN-1) or agonist (YS-49) were screened. In experiment 2, the role of PI3K/AKT in Zn alleviation of HS-induced damage to JOs was evaluated with three JO types as control groups under baseline incubation temperature (40 °C) plus a 3 (JOs types) × 3 (Zn sources) factorial design under high temperature (44 °C). The results showed that the optimal concentrations of the PI3K-IN-1 and YS-49 for effectively inhibiting and promoting (p < 0.001) phosphorylation of PI3K and AKT were 16 μmol/L and 9 μmol/L, respectively. Adding Zn, especially Zn proteinate with moderate chelation strength (Zn-Prot M), alleviated (p < 0.001) the HS-induced increases in diamine oxidase content and lactate dehydrogenase activity in the media and the HS-induced decreases in JOs budding percentage, proportions of 5-ethynyl-2′-deoxyuridine and proliferating cell nuclear antigen positive cells, and the phosphorylation of PI3K and AKT. PI3K/AKT inhibition or activation reduced or enhanced (p < 0.05) the above alleviating effect of Zn, especially Zn-Prot M. These results indicate that the PI3K/AKT signaling pathway mediated the alleviation of HS-induced damage to integrity and barrier function of broiler JOs by supplemental Zn, particularly Zn-Prot M via promotion of cell proliferation. Full article

This study compared intestinal polyamine metabolism and barrier function between Ningxiang (NX) and Duroc × Landrace × Yorkshire (DLY) piglets under baseline conditions and following ETEC challenge. Experiment 1 (baseline, n = 12/breed) assessed colonic barrier integrity, immune status, polyamines, and microbiota. Experiment 2 (ETEC challenge, n = 8/group/breed) evaluated responses to oral ETEC (10⁹ CFU) over 3 days. Under baseline conditions, NX piglets showed superior barrier integrity, higher goblet cell numbers and mucin 2 (MUC2) protein expression, and lower plasma levels of intestinal permeability markers—diamine oxidase (DAO), D-lactate (DLA), and endotoxin (ET)—compared with DLY piglets. NX piglets also exhibited reduced colonic pro-inflammatory cytokine levels (IL-6 and IL-1β) and higher expression of immune-related markers (CD3, CD68, and IgA) versus DLY piglets. In contrast, DLY piglets displayed more active microbial polyamine metabolism in the colon, with higher concentrations of putrescine, spermidine, and spermine, as well as increased ornithine decarboxylase (ODC) expression. 16S rRNA sequencing revealed greater microbial diversity and enrichment of taxa (Muribaculaceae_unclassified, Prevotella) in NX piglets, whereas DLY piglets showed enrichment of polyamine-associated genera (Collinsella, Veillonella). Following the ETEC challenge, DLY piglets displayed pronounced polyamine upregulation, including elevated polyamine levels and ODC1 expression. Conversely, NX piglets maintained more stable polyamine metabolism, higher expression of tight junction proteins (ZO-1 and occludin), lower plasma permeability markers, reduced pro-inflammatory cytokine expression (IL-6, IL-1β, IL-22), and increased anti-inflammatory IL-10 expression. Collectively, these findings demonstrate that NX piglets possess superior intestinal barrier integrity and immune maturity, while DLY piglets exhibit a more active but stress-responsive polyamine metabolic phenotype. The divergent metabolic and immune responses to ETEC challenge underscore the distinct strategies employed by these two breeds in maintaining gut homeostasis. These findings provide preliminary insights that may inform future breeding strategies aimed at enhancing intestinal health and disease resistance in pigs, pending validation in broader genetic backgrounds and mechanistic studies. Full article

To address cryodamage in Culter alburnus sperm, this study evaluated the effects of trehalose supplementation in a conventional cryomedium (D-15 + 10% ethylene glycol). Six experimental groups were established: fresh sperm (G1), a conventional cryomedium (G2), groups supplemented with 10, 100, or 200 mmol/L trehalose (G3–G5), and a control group with extender only (G6). The group with 100 mmol/L trehalose (G4) was associated with improved post-thaw motility parameters (activation rate, movement time, and lifespan) and higher antioxidant (superoxide dismutase and catalase) and energy metabolism (ATPase, succinate dehydrogenase, lactate dehydrogenase) enzyme activities. Ultrastructural damage in G4 included partial plasma membrane rupture and mitochondrial swelling, while G6 exhibited additional damage features including membrane disintegration, mitochondrial disruption, and flagellar fracture. Proteomic analysis revealed that, compared to G1, G4 exhibited higher abundance of proteins (e.g., Histone H2A, cytochrome c oxidase, profilin) involved in structural integrity and energy homeostasis, whereas G6 showed signatures of oxidative stress and metabolic dysfunction (lower abundance of NADH dehydrogenase and higher abundance of calcium-transporting ATPase and glutathione S-transferase). In conclusion, 100 mmol/L trehalose was associated with improved cryopreservation outcomes, and the proteins identified provide a basis for further investigation. This approach offers a framework for refining germplasm conservation strategies in aquaculture. Full article

The increasing demand for continuous physiological monitoring has accelerated the development of high-sensitivity wearable electrochemical platforms. This study reports the fabrication of a multi-analyte electrochemical sensor based on single-walled carbon nanotubes (SWCNTs) for the detection of sweat-associated metabolites. To facilitate efficient heterogeneous electron transfer, glucose oxidase (Gox), lactate oxidase (Lox), and urease (Ure) were immobilized onto the SWCNT network through π–π interaction using 1-pyrenebutanoic acid succinimidyl ester (PBSE), followed by additional stabilization via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS) coupling. The developed platform exhibited concentration-dependent resistance responses within the ranges of 0.02–0.20 mM for glucose, 20–100 mM for lactate, and 50–400 mM for urea under controlled experimental conditions. The resistance-based configuration enabled stable and reproducible signal modulation across these concentration intervals. Although direct testing with human sweat was not performed, the electrochemical behavior of key sweat-related metabolites was systematically evaluated as a preparatory step toward future wearable integration. Full article

This study aims to systematically assess the comprehensive, dose-dependent effects of substituting soybean meal with cottonseed protein at various ratios on weaned piglets. In total, 28-day-old weaned piglets (Duroc × Landrace × Large White crossbred; n = 45) were selected and then randomly categorized into three groups: 100% soybean meal (CON), 50% soybean meal +50% cottonseed protein (CSP50), and 100% CSP (CSP100) groups. After a 7-day adaptation period, the experiment continued for an additional 28 days. The results showed no significant differences among groups in growth performance, organ indices, most carcass traits, or meat quality indicators. The CSP50 group showed significantly reduced levels of diamine oxidase (DAO) and D-lactate and increased complexity of the colonic microbial network, with improved abundance of beneficial bacterial genera such as g_Blautia and g_Eubacterium. The CSP100 group showed elevated intestinal permeability, a decreased villus height, a villus-to-crypt ratio, specific digestive enzymes, a reduced Firmicutes/Bacteroidetes (F/B) ratio and abundant inflammation-associated bacteria, including g_Streptococcus. Furthermore, correlation analysis suggested that specific gut microorganisms and metabolic pathways may be potentially related to average daily gain (ADG), average daily feed intake (ADFI), the feed conversion ratio (F/G), DAO, and D-lactic acid. These findings suggest that dietary inclusion of 50% cottonseed protein (CSP50) is associated with sustained growth performance and enhanced gut health in weaned piglets, concurrent with shifts in the composition and predicted function of the gut microbiota. Full article

Enteropathogenic Escherichia coli (EPEC) disrupts intestinal barrier integrity, induces inflammation, and alters gut microbial balance, leading to diarrhea and growth impairment. Probiotics are considered promising alternatives to antibiotics for managing enteric infections, yet the functional properties and underlying mechanisms of feline-derived strains remain unclear. This study evaluated the protective effects of Ligilactobacillus (L.) agilis ZY25 and L. salivarius ZY35, isolated from healthy cats, against EPEC-induced intestinal injury in C57BL/6 mice, with a focus on barrier function, immune modulation, and microbial homeostasis. In this 21-day experiment, 48 mice were assigned to six groups (n = 8/group): control, EPEC model (MOD), chlortetracycline treatment (CTC), probiotic treatment (PRO-T; post-infection only), probiotic pre-treatment (PRO-P; pre-infection only), and continuous probiotic supplementation (PRO; pre- and post-infection). EPEC challenge (0.2 mL; 1 × 10⁹ CFU/mL) was performed daily during experimental days 8–14. EPEC challenge resulted in weight loss (p < 0.05), increased (p < 0.05) diarrhea incidence, elevated (p < 0.05) serum D-lactate, diamine oxidase, and lipopolysaccharide levels, impaired intestinal morphology, immune imbalance, and microbial dysbiosis. Probiotic administration alleviated these alterations, as evidenced by restored intestinal morphology, reduced serum markers of barrier permeability (D-lactate, DAO, LPS), enhanced systemic immunoglobulins (IgA, IgG, IgM), a balanced cytokine profile (increased IL-4, IL-10; decreased TNF-α, IL-6, IL-1β, IFN-γ, CRP), and modulation of the gut microbiota (enrichment of beneficial taxa such as Lachnospiraceae_NK4A136_group and suppression of pro-inflammatory Desulfovibrio). The continuous supplementation regimen (PRO) produced the most consistent improvements among the three intervention strategies tested. These findings suggest that feline-derived probiotics mitigate EPEC-induced intestinal dysfunction, accompanied by improved barrier-related indices, immune rebalancing, and microbial stabilization, thereby providing proof-of-concept evidence for their further evaluation in feline gastrointestinal health. Full article

Background: Inonotus obliquus (Chaga), a medicinal and edible macrofungus abundant in bioactive polyphenols, is a potential source of natural antioxidants and anti-inflammatory agents for functional foods. This study aimed to evaluate the antioxidant capacity of three key polyphenols (osmundacetone [OS], protocatechuic aldehyde [PAH], protocatechuic acid [PA]) from I. obliquus and decipher their anti-inflammatory mechanisms via the MyD88/TLR4/NF-κB pathway in a gout-related model. Methods: Antioxidant activity was assessed by xanthine oxidase (XO) inhibition (IC₅₀), superoxide anion (O₂⁻) scavenging, and structure–activity relationship (SAR) analysis; in a monosodium urate (MSU)-induced acute gout cell model, reactive oxygen species (ROS), nitric oxide (NO), lactate dehydrogenase (LDH), superoxide dismutase (SOD), pro-inflammatory cytokines (TNF-α, IL-1β) were quantified, and MyD88/TLR4/NF-κB pathway proteins were analyzed by Western blot. Results: OS showed the strongest XO inhibition (IC₅₀ = 4.91 mM), followed by PAH (IC₅₀ = 5.92 mM) and PA (IC₅₀ = 26.53 mM); OS exerted dual redox effects by scavenging O₂⁻ and suppressing XO-mediated O₂⁻ generation, with its conjugated C=C-carbonyl system and PAH’s aldehyde group enhancing XO binding. All polyphenols and I. obliquus crude extract significantly reduced ROS, NO, LDH, and cytokines (p < 0.05), increased SOD, and downregulated TLR4, MyD88, and NF-κB expression. Conclusions: I. obliquus-derived polyphenols exhibit obvious antioxidant and xanthine oxidase inhibitory effects, and regulate oxidative stress, pro-inflammatory mediators, and the MyD88/TLR4/NF-κB signaling pathway in monosodium urate-stimulated RAW 264.7 inflammatory macrophages, supporting their development as natural functional food ingredients and potential candidates for gout-related and oxidative stress-associated inflammatory cellular disorders. Full article

Background/Objectives: Mitochondrial dysfunction is a major cause of brain injury in patients with primary mitochondrial disease. New mitochondrial therapeutics and non-invasive tools for efficacy monitoring are urgently needed. To these ends, succinate prodrug NV354 (methyl 3-[(2-acetylaminoethylthio)carbonyl]propionate) and diffuse optical techniques are promising. In this proof-of-concept study, we characterize NV354’s effects on microdialysis metrics of cerebral metabolism in a swine model of mitochondrial dysfunction and assess the associations of diffuse optical metrics with mitochondrial dysfunction and metabolic improvement. Methods: One-month-old swine received a four-hour co-infusion of rotenone with either the succinate prodrug NV354 (n = 5) or placebo (n = 5). Rotenone is a mitochondrial complex I inhibitor. Before and during co-infusion, cerebral metabolism was probed with microdialysis and diffuse optics. Microdialysis acquired interstitial lactate and pyruvate levels invasively, while diffuse optics measured changes in oxygen extraction fraction (OEF) and oxidized cytochrome-c-oxidase concentration (oxCCO). Results: Interstitial lactate continually increased in the placebo group (p < 0.01), but lactate levels plateaued in the NV354 group (p = 0.90). oxCCO also increased in the placebo group (p = 0.05), but OEF remained constant (p = 0.80). In the NV354 group, oxCCO increased (p < 0.01) while OEF decreased (p < 0.01). Conclusions: Microdialysis results suggest that NV354 treatment can increase oxygen metabolism in large animals with mitochondrial dysfunction. The optical oxCCO metric was also sensitive to metabolic changes induced by rotenone and NV354 administration. Full article

Cadmium (Cd) is a typical pollutant with strong toxicity even at low concentrations. In the marine environment, Cd is a problem of magnitude and ecological significance due to its high toxicity and accumulation in living organisms. The clam Meretrix meretrix is a useful bioindicator species for evaluating heavy-metal stress. This study investigated the extent of recovery from Cd²⁺-induced oxidative and immune impairments in M. meretrix gills achieved by short-term depuration. Clams were exposed to 3 mg/L Cd²⁺ for six days or three days followed by three days of depuration, and the Cd contents, morphological structure, osmoregulation, oxidative stress, and immune responses in the gills were evaluated. The results showed that gill Cd contents increased with exposure, reaching 9.857 ± 0.074 mg·kg⁻¹ on day 3 but decreased slightly to 8.294 ± 0.056 mg·kg⁻¹ after depuration, while reaching 18.665 ± 0.040 mg·kg⁻¹ on day 6 after continuous exposure. Histological lesions, including lamellar fusion, hemolymphatic sinus dilation, and ciliary degeneration, partially recovered after depuration. Reactive oxygen species (ROS) and malondialdehyde (MDA) levels decreased significantly, while DNA-protein crosslinking rate (DPC) and protein carbonyl (PCO) showed minor reductions. Total antioxidant capacity (T-AOC) and the activities of Ca²⁺/Mg²⁺-ATPase (CMA), cytochrome c oxidase (COX), succinate dehydrogenase (SDH), and lactate dehydrogenase (LDH) increased by over 10% during depuration, though these changes were not statistically significant. Lysozyme (LZM) activity and MT transcript levels increased progressively with Cd exposure, indicating their suitability as biomarkers of Cd stress. Acid and alkaline phosphatase (ACP, AKP) activities and Hsp70 and Nrf2 mRNA transcripts exhibited inverted U-shaped response consistent with hormetic response. ACP and AKP activity levels rose by more than 20% after depuration, suggesting partial restoration of immune capacity. Overall, Cd exposure induced oxidative damage, metabolic disruption, and immune suppression in M. meretrix gills, yet short-term depuration allowed partial recovery. These findings enhance understanding of Cd toxicity and reversibility in marine bivalves and reinforce the usage of biochemical and molecular markers for monitoring Cd contamination and assessing depuration efficiency in aquaculture environments. Full article