Approaching Sustainable Lithium-Ion Batteries through Voltage-Responsive Smart Prelithiation Separator with Surface-Engineered Sacrificial Lithium Agents.

The surge in lithium-ion batteries has heightened concerns regarding metal resource depletion and the environmental impact of spent batteries. Battery recycling has become paramount globally, but conventional techniques, while effective at extracting transition metals like cobalt and nickel from cathodes, often overlook widely used spent LiFePO4 due to its abundant and low-cost iron content. Direct regeneration, a promising approach for restoring deteriorated cathodes, is hindered by practicality and cost issues despite successful methods like solid-state sintering. Hence, a smart prelithiation separator based on surface-engineered sacrificial lithium agents is proposed. Benefiting from the synergistic anionic and cationic redox, the prelithiation separator can intelligently release or intake active lithium via voltage regulation. The staged lithium replenishment strategy was implemented, successfully restoring spent LiFePO4's capacity to 163.7 mAh g-1 and a doubled life. Simultaneously, the separator can absorb excess active lithium up to approximately 600 mAh g-1 below 2.5 V to prevent over-lithiation of the cathode This innovative, straightforward, and cost-effective strategy paves the way for the direct regeneration of spent batteries, expanding the possibilities in the realm of lithium-ion battery recycling.

Vertically Fluorinated Graphene Encapsulated SiOx Anode for Enhanced Li+ Transport and Interfacial Stability in High-Energy-Density Lithium Batteries.

Achieving high energy density has always been the goal of lithium-ion batteries (LIBs). SiOx has emerged as a compelling candidate for use as a negative electrode material due to its remarkable capacity. However, the huge volume expansion and the unstable electrode interface during (de)lithiation, hinder its further development. Herein, we report a facile strategy for the synthesis of surface fluorinated SiOx (SiOx@vG-F), and investigate their influences on battery performance. Systematic experiments investigations indicate that the reaction between Li+ and fluorine groups promotes the in situ formation of stable LiF-rich solid electrolyte interface (SEI) on the surface of SiOx@vG-F anode, which effectively suppresses the pulverization of microsized SiOx particles during the charge and discharge cycle. As a result, the SiOx@vG-F enabled a higher capacity retention of 86.4 % over 200 cycles at 1.0 C in the SiOx@vG-F||LiNi0.8Co0.1Mn0.1O2 full cell. This approach will provide insights for the advancement of alternative electrode materials in diverse energy conversion and storage systems.

Ligustrazine and liguzinediol protect against doxorubicin-induced cardiomyocytes injury by inhibiting mitochondrial apoptosis and autophagy.

Preventing or treating heart failure (HF) by blocking cardiomyocyte apoptosis is an effective strategy that improves survival and reduces ventricular remodelling and dysfunction in the chronic stage. Autophagy is a mechanism that degrades intracellular components and compensates for energy deficiency, which is commonly observed in cardiomyocytes of failed hearts. Cardiomyocytes activated by doxorubicin (DOX) exhibit strong autophagy. This study aims to investigate the potential protective effect of ligustrazine and its derivative liguzinediol on regulating DOX-induced cardiomyocyte apoptosis and explore the use of the embryonic rat heart-derived myoblast cell line H9C2 for identifying novel treatments for HF. The results indicated that it has been demonstrated to reverse myocardial infarction remodelling in failed hearts by promoting autophagy in salvaged cardiomyocytes and anti-apoptosis of cardiomyocytes in granulation tissue. Our study suggests that ligustrazine and liguzinediol can be a promising agents and autophagy is potential pathway in the management of HF.

Fault Identification and Localization of a Time-Frequency Domain Joint Impedance Spectrum of Cables Based on Deep Belief Networks.

To improve the accuracy of shallow neural networks in processing complex signals and cable fault diagnosis, and to overcome the shortage of manual dependency and cable fault feature extraction, a deep learning method is introduced, and a time-frequency domain joint impedance spectrum is proposed for cable fault identification and localization based on a deep belief network (DBN). Firstly, based on the distribution parameter model of power cables, we model and analyze the cables under normal operation and different fault types, and we obtain the headend input impedance spectrum and the headend input time-frequency domain impedance spectrum of cables under various operating conditions. The headend input impedance amplitude and phase of normal operation and different fault cables are extracted as the original input samples of the cable fault type identification model; the real part of the headend input time-frequency domain impedance of the fault cables is extracted as the original input samples of the cable fault location model. Then, the unsupervised pre-training and supervised inverse fine-tuning methods are used for automatically learning, training, and extracting the cable fault state features from the original input samples, and the DBN-based cable fault type recognition model and location model are constructed and used to realize the type recognition and location of cable faults. Finally, the proposed method is validated by simulation, and the results show that the method has good fault feature extraction capability and high fault type recognition and localization accuracy.

Potential Controllable Redox Couple for Mild and Efficient Lithium Recovery from Spent Batteries.

The prosperity of the lithium-ion battery market is dialectically accompanied by the depletion of corresponding resources and the accumulation of spent batteries. It is an urgent priority to develop green and efficient battery recycling strategies for helping ease resources and environmental pressures at the current stage. Here, we propose a mild and efficient lithium extracting strategy based on potential controllable redox couples. Active lithium in the spent battery without discharging is extracted using a series of tailored aprotic solutions comprised of polycyclic aromatic hydrocarbons and ethers. This ensures a safe yet efficient recycling process with nearly ≈100 % lithium recovery. We further investigate the Li+ -electron concerted redox reactions and the effect of solvation structure on kinetics during the extraction, and broaden the applicability of the Li-PAHs solution. This work can stimulate new inspiration for designing novel solutions to meet efficient and sustainable demands in recycling batteries.

Selective Extraction of Transition Metals from Spent LiNix Coy Mn1-x-y O2 Cathode via Regulation of Coordination Environment.

The complexity of chemical compounds in lithium-ion batteries (LIBs) results in great difficulties in the extraction of multiple transition metals, which have similar physicochemical characteristics. Here, we propose a novel strategy for selective extraction of nickel, cobalt, and manganese from spent LiNix Coy Mn1-x-y O2 (NCM) cathode through the regulation of coordination environment. Depending on adjusting the composition of ligand in transition metal complexes, a tandem leaching and separation system is designed and finally enables nickel, cobalt, and manganese to enrich in the form of NiO, Co3 O4 , and Mn3 O4 with high recovery yields of 99.1 %, 95.1 %, and 95.3 %, respectively. We further confirm that the combination of different transition metals with well-designed ligands is the key to good selectivity. Through our work, fine-tuning the coordination environment of metal ions is proved to have great prospects in the battery recycling industry.

Novel insights: Dynamic foam cells derived from the macrophage in atherosclerosis.

Atherosclerosis can be regarded as a chronic disease derived from the interaction between disordered lipoproteins and an unsuitable immune response. The evolution of foam cells is not only a significant pathological change in the early stage of atherosclerosis but also a key stage in the occurrence and development of atherosclerosis. The formation of foam cells is mainly caused by the imbalance among lipids uptake, lipids treatment, and reverse cholesterol transport. Although a large number of studies have summarized the source of foam cells and the mechanism of foam cells formation, we propose a new idea about foam cells in atherosclerosis. Rather than an isolated microenvironment, the macrophage multiple lipid uptake pathways, lipid internalization, lysosome, mitochondria, endoplasmic reticulum, neutral cholesterol ester hydrolase (NCEH), acyl-coenzyme A-cholesterol acyltransferase (ACAT), and reverse cholesterol transport are mutually influential, and form a dynamic process under multi-factor regulation. The macrophage takes on different uptake lipid statuses depending on multiple uptake pathways and intracellular lipids, lipid metabolites versus pro-inflammatory factors. Except for NCEH and ACAT, the lipid internalization of macrophages also depends on multicellular organelles including the lysosome, mitochondria, and endoplasmic reticulum, which are associated with each other. A dynamic balance between esterification and hydrolysis of cholesterol for macrophages is essential for physiology and pathology. Therefore, we propose that the foam cell in the process of atherosclerosis may be dynamic under multi-factor regulation, and collate this study to provide a holistic and dynamic idea of the foam cell.

A Competing-Risks Nomogram in Patients with Metastatic Pancreatic Duct Adenocarcinoma.

BACKGROUND The primary objective of this study was to assess the cumulative incidence of cause-specific mortality (CSM) and other causes of mortality (OCM) for patients with metastatic pancreatic duct adenocarcinoma (mPDAC). The secondary objective was to calculate the probability of CSM and build a competing risk nomogram to predict CSM for mPDAC. MATERIAL AND METHODS We identified patients with mPDAC between 2010 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database. We assessed the cumulative incidence function (CIF) for cause-specific mortality and other causes of mortality. We used Gray's test to investigate the differences. The Fine and Gray proportional subdistribution hazard model was applied to model CIF. And a competing risk nomogram was built to predict the probability of CSM for mPDAC. RESULTS There were 10 527 eligible patients diagnosed with mPDAC from 2010 to 2015 who were included in our formal analysis. The 6-month cumulative incidence of CSM was 60.3% and 5.9% for other causes. Predictors of SCM for mPDAC included surgery, age, tumor size, chemotherapy, radiation therapy, bone metastasis, and liver metastasis. The nomogram was proven to be well calibrated, and had good model discriminative ability. CONCLUSIONS We assessed the CIF of CSM and competing risk mortality in patients with mPDAC using the SEER database. The Fine and Gray proportional subdistribution hazard model performance was good, with a concordance index of 0.74, and the competing-risks nomogram was built, which can be a helpful predictive tool for cases with mPDAC. However, a validation sample data set and further verification are still needed to assess a profile for prognostic use in a prospective study.

CD21int CD23+ follicular B cells express antigen-specific secretory IgM mRNA as primary and memory responses.

CD21int CD23+ IgM+ mouse follicular B cells comprise the bulk of the mature B-cell compartment, but it is not known whether these cells contribute to the humoral antibody response. We show using a direct RT-PCR method for antigen-specific VH, that FACS-sorted mouse CD21int CD23+ B cells express specific secretory IgM VH transcripts in response to immunization and also exhibit a memory response. The secretory IgM expressed is distinct from the IgG expressed by cells of this phenotype, which we also analyse here, having a distinct broader distribution of CDR-H3 sequences and zero or low levels of somatic mutation in the region analysed. These results imply that cells of the CD21int CD23+ phenotype have distinct IgM+ and IgG+ populations that contribute directly to the humoral antibody and memory responses by expressing antigen-specific secretory immunoglobulin. We also argue that the more diverse CDR-H3 sequences expressed by antigen-experienced IgM+ CD21int CD23+ follicular B cells would place them at the bottom of a recently hypothesized memory B-cell hierarchy.

miR-155 contributes to the progression of glioma by enhancing Wnt/ß-catenin pathway.

As the most common brain tumor, glioma is featured with poor prognosis due to its resistance to current therapeutic strategies. The elucidation of etiology is believed to facilitate the development of novel effective anti-glioma treatment modalities. As a confirmed oncogenic microRNA (miRNA) in many other types of cancers, the role of miR-155 in glioma is still unknown. This study is aimed to study the role of miR-155 in the progression of glioma. Our results revealed that miR-155 was overexpressed in the collected glioma specimen, compared with noncancerous brain tissues. The suppression of miR-155 attenuated the proliferation of glioma cells and the activation of Wnt pathway. Silencing miR-155 was also able to suppress the growth of U-87 MG glioma xenografts in mice. Pearson analysis indicated that miR-155 level was inversely correlated with the abundance of HMG-box transcription factor 1 (HBP1), a strong Wnt pathway inhibitor, in glioma samples. Further experiments confirmed that miR-155 suppressed the expression of HBP1 by targeting the putative miRNA recognition elements (MREs) within its messenger RNA (mRNA) 3' untranslated region (UTR). Furthermore, HBP1 small interfering RNA (siRNA) abolished the effect of miR-155 suppression on the proliferation of glioma and the activation of Wnt pathway. Taken together, miR-155 promoted the progression of glioma by enhancing the activation of Wnt pathway. Thus, targeting miR-155 may be an effective strategy for glioma treatment.

miR-30 overexpression promotes glioma stem cells by regulating Jak/STAT3 signaling pathway.

Malignant glioma is the most common intracranial tumor with poor prognosis. It is well believed that glioma stem cells (GSCs) are responsible for the initiation and progression of glioma. Janus kinase/signal transducer and activator of transcription (Jak/STAT3) pathway plays a key role in the functions of GSCs. However, the regulatory mechanism of Jak/STAT3 pathway has not been completely elucidated. This study employed multidisciplinary approaches to investigate the upstream regulators of Jak/STAT3 signaling in GSCs. miR-30 was found to be overexpressed in the GSCs derived from U-87 MG and primary glioma cells, compared with non-stem-cell-like glioma cells and normal cells. Downregulation of miR-30 was able to suppress Jak/STAT3 pathway and reduce the tumorigenecity of GSCs. miR-30 decreased the expression of suppressor of cytokine signaling 3 (SOCS3) expression by targeting 3'UTR of its mRNA. The silencing of SOCS3 abolished the effect of miR-30 downregulation on GSCs. Collectively, there is a regulatory pathway consisting of miR-30, SOCS3, and Jak/STAT3 in GSCs, and targeting this pathway may be a promising strategy to treat glioma.

Thread-like supercapacitors based on one-step spun nanocomposite yarns.

Thread-like electronic devices have attracted great interest because of their potential applications in wearable electronics. To produce high-performance, thread-like supercapacitors, a mixture of stable dispersions of single-walled carbon nanotubes and conducting polyaniline nanowires are prepared. Then, the mixture is spun into flexible yarns with a polyvinyl alcohol outer sheath by a one-step spinning process. The composite yarns show excellent mechanical properties and high electrical conductivities after sufficient washing to remove surfactants. After applying a further coating layer of gel electrolyte, two flexible yarns are twisted together to form a thread-like supercapacitor. The supercapacitor based on these two yarns (SWCNTs and PAniNWs) possesses a much higher specific capacitance than that based only on pure SWCNTs yarns, making it an ideal energy-storage device for wearable electronics.

Recruitment of a distinct but related set of VH sequences into the murine CD21hi/CD23- marginal zone B cell repertoire to that seen in the class-switched antibody response.

Development and maintenance of cells in the murine follicular and marginal zone compartments is thought to involve differing levels of stimulation of the BCR, although it is still not clear which BCR ligands mediate these events. How the delineation between naive and Ag experienced B cell populations relates to cell phenotype and how precise or blurred this delineation is, is also not well understood. In this study, using PCR to analyze the Ab response to phenyl-oxazolone in the mouse, we show that the Ab repertoire of CD21(hi)/CD23(-) marginal zone B cells shows persistent increase in levels of particular IgM after immunization with foreign Ag. Further, we show that these IgMs have different but related VH/CDR3 sequences from those seen in the class-switched response to oxazolone that we have also analyzed. We also detect an effect of Ag on the follicular B cell repertoire that is less persisting. These results provide evidence consistent with the signal-strength model of mature B cell development being extended to include stimulation by foreign Ag, and also further the known zone of influence of foreign Ag on the B cell compartment.

[Construction of recombinant adenovirus vector co-expressing VEGF165 and SDF-1 genes and its expression in ischemic cerebral tissue of rats].

OBJECTIVE: To construct a recombinant adenoviral vector carrying and co-expressing vascular endothelial growth factor 165 (VEGF165) and stromal cell derived factor 1 (SDF-1) and explore its co-expression in ischemic brain tissue in rats. METHODS: The VEGF165 and SDF-1 genes were directionally connected with internal ribosome entry site (IRES). And the double gene co-expression recombinant shuttle plasmid pDC316-VEGF165-IRES-SDF-1 was built with homologous recombination. The resultant plasmid pDC316-VEGF165-IRES-SDF-1 and backbone plasmid pBHGlox_E1, 3Cre were transfected into HEK293 cells by liposome and the recombinant adenoviral particles capable of infection were acquired. With the rounds of amplification, the purified adenoviral vector Ad5-VEGF165-IRES-SDF-1 was obtained with a titer of up to 1×10(10) IU/ml. The rat model of middle cerebral artery occlusion (MCAO) was established by intra-luminal suturing. And the viral vectors were transfused into the lateral ventricle by a stereotactic microinjection. The expressions of VEGF165 and SDF-1 in ischemic brain tissue were examined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. RESULTS: The results of PCR, double enzyme digestion and gene sequencing showed that both the recombinant plasmid and the constructed adenoviral vector were expressed. And the adenoviral vector Ad5-VEGF165-IRES-SDF-1 could mediate a co-expression of VEGF165 and SDF-1 in ischemic cerebral tissue. CONCLUSION: The recombinant adenoviral vector carrying VEGF165 and SDF-1 are successfully constructed. And Ad5-VEGF165-IRES-SDF-1 may mediate a co-expression of VEGF165 and SDF-1 in ischemic cerebral tissue of rats.

[Study of effect of tongsaimai tablets on experimental diabetic foot model rats].

OBJECTIVE: To observe the effect of Tongsaimai (TSM) tablets in treating foot trauma of diabetic foot (DF) model rats, and discuss its potential mechanism. METHOD: Male SD rats were selected to duplicate the diabetic foot ulcer model and randomly divided into the blank control group, the model group, the metformin treatment group, and TSM 12.44, 6.22, 3.11 g x kg(-1) groups (n = 10). The healing of ulcer wounds were observed on day 1, 4, 8, 13 and 18. After 18 days, a histopathologic examination was conducted for ulcer tissues. The contents of superoxide dismutase (SOD) and malondialdehyde (MDA) were detected by hydroxylamine and TBA methods. The content of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were determined with the radioimmunoassay. The immunohistochemical method was used to observe the expression of vascular endothelial growth factor (VEGF) in ulcer tissues and the number of capillary vessels. RESULT: TSM could alleviate the pathological changes of diabetic foot rats, accelerate the ulcer healing on 4, 8, 13, 18 d, reduce MDA, IL-6, TNF-alpha, VEGF content in rat serum at 18 d (after the rehabilitation period), and enhance the SOD content. Specifically, the TSM 12.44 g x kg(-1) group showed significant differences compared with the model group (P < 0.05, P < 0.01). At 18 d after the treatment (the late rehabilitation period), the VEGF expression of TSM 12.44, 6.22 g x kg(-1) groups and the number of blood capillaries of the TSM 12.44 g x kg(-1) group were significantly lower than that of the model group (P < 0.05, P < 0.01). CONCLUSION: TSM could promote the foot wound healing of DF model rats, reduce MDA, IL-6 and TNF-alpha levels in serum, increase the SOD content and decrease the VEGF expression and the number of blood capillaries in the late rehabilitation period. Its action mechanism may be related to the inhibition of oxidative stress injury and the inflammatory cell infiltration.

High-Strength and High-Temperature-Resistant Structural Battery Integrated Composites via Polymeric Bi-Continuous Electrolyte Engineering.

Structural battery integrated composites (SBICs) combining outstanding strength and heat resistance are highly desirable candidates for next generation high speed aircraft. Here, a novel high-temperature-resistant bi-continuous electrolyte based on phthalonitrile resin is presented, allowing the construction of SBICs capable of stable operation across a wide temperature range. Excellent mechanical strength and high ionic conductivity can coexist in a bi-continuous structure electrolyte (PL50) where the phthalonitrile resin serves as the matrix phase and the ionic liquid electrolyte serves as the conductive phase. Benefiting from the thermal stability of the phthalonitrile resin, SBICs assembled with a PL50 bi-continuous electrolyte deliver excellent mechanical performance even at temperatures exceeding 200 °C, with a flexural strength of 299 MPa and a flexural modulus of 31.8 GPa. Additionally, with an increase in operating temperature, PL50@SBICs demonstrated enhanced rate performance while maintaining good cycling stability. The demonstration of resisting mechanical abuse at high temperatures and flame retardance further suggests the promise of SBICs with PL50 bi-continuous electrolytes operating under extreme conditions.

Potential targets for the treatment of MI: GRP75-mediated Ca2+ transfer in MAM.

After myocardial infarction (MI), there is a notable disruption in cellular calcium ion homeostasis and mitochondrial function, which is believed to be intricately linked to endoplasmic reticulum (ER) stress. This research endeavors to elucidate the involvement of glucose regulated protein 75 (GRP75) in post-MI calcium ion homeostasis and mitochondrial function. In MI rats, symptoms of myocardial injury were accompanied by an increase in the activation of ER stress. Moreover, in oxygen-glucose deprivation (OGD)-induced cardiomyocytes, it was confirmed that inhibiting ER stress exacerbated intracellular Ca2+ disruption and cell apoptosis. Concurrently, the co-localization of GRP75 with IP3R and VDAC1 increased under ER stress in cardiomyocytes. In OGD-induced cardiomyocytes, knockdown of GRP75 not only reduced the Ca2+ levels in both the ER and mitochondria and improved the ultrastructure of cardiomyocytes, but it also increased the number of contact points between the ER and mitochondria, reducing mitochondria associated endoplasmic reticulum membrane (MAM) formation, and decreased cell apoptosis. Significantly, knockdown of GRP75 did not affect the protein expression of PERK and hypoxia-inducible factor 1α (HIF-1α). Transcriptome analysis of cardiomyocytes revealed that knockdown of GRP75 mainly influenced the molecular functions of sialyltransferase and IP3R, as well as the biosynthesis of glycosphingolipids and lactate metabolism. The complex interaction between the ER and mitochondria, driven by the GRP75 and its associated IP3R1-GRP75-VDAC1 complex, is crucial for calcium homeostasis and cardiomyocyte's adaptive response to ER stress. Modulating GRP75 could offer a strategy to regulate calcium dynamics, diminish glycolysis, and thereby mitigate cardiomyocyte apoptosis.

Lactiplantibacillus plantarum ATCC8014 Alleviates Postmenopausal Hypercholesterolemia in Mice by Remodeling Intestinal Microbiota to Increase Secondary Bile Acid Excretion.

Hypercholesterolemia poses a significant cardiovascular risk, particularly in postmenopausal women. The anti-hypercholesterolemic properties of Lactiplantibacillus plantarum ATCC8014 (LP) are well recognized; however, its improving symptoms on postmenopausal hypercholesterolemia and the possible mechanisms have yet to be elucidated. Here, we utilized female ApoE-deficient (ApoE-/-) mice undergoing bilateral ovariectomy, fed a high-fat diet, and administered 109 colony-forming units (CFU) of LP for 13 consecutive weeks. LP intervention reduces total cholesterol (TC) and triglyceride (TG) accumulation in the serum and liver and accelerates their fecal excretion, which is mainly accomplished by increasing the excretion of fecal secondary bile acids (BAs), thereby facilitating cholesterol conversion. Correlation analysis revealed that lithocholic acid (LCA) is an important regulator of postmenopausal lipid abnormalities. LP can reduce LCA accumulation in the liver and serum while enhancing its fecal excretion, accomplished by elevating the relative abundances of Allobaculum and Olsenella in the ileum. Our findings demonstrate that postmenopausal lipid dysfunction is accompanied by abnormalities in BA metabolism and dysbiosis of the intestinal microbiota. LP holds therapeutic potential for postmenopausal hypercholesterolemia. Its effectiveness in ameliorating lipid dysregulation is primarily achieved through reshaping the diversity and abundance of the intestinal microbiota to correct BA abnormalities.

Reviving Fatigue Surface for Solid-State Upcycling of Highly Degraded Polycrystalline LiNi1-x-yCoxMnyO2 Cathodes.

The ongoing tide of spent lithium-ion batteries (LIBs) urgently calls for high-value output in efficient recycling. Recently, direct regeneration has emerged as a novel recycling strategy but fails to repair the irreversible morphology and structure damage of the highly degraded polycrystalline layered oxide materials. Here, this work carries out a solid-state upcycling study for the severely cracked LiNi1-x-yCoxMnyO2 cathodes. The specific single-crystallization process during calcination is investigated and the surface rock salt phase is recognized as the intrinsic obstacle to the crystal growth of the degraded cathodes due to sluggish diffusion in the heterogeneous grain boundary. Accordingly, this work revives the fatigue rock salt phase by restoring a layered surface and successfully reshapes severely broken cathodes into the high-performance single-crystalline particles. Benefiting from morphological and structural integrity, the upcycled single-crystalline cathode materials exhibit an enhanced capacity retention rate of 93.5% after 150 cycles at 1C compared with 61.7% of the regenerated polycrystalline materials. The performance is also beyond that of the commercial cathodes even under a high cut-off voltage (4.5 V) or high operating temperature (45 °C). This work provides scientific insights for the upcycling of the highly degraded cathodes in spent LIBs.

Activation of estrogen receptor α inhibits TLR4 signaling in macrophages and alleviates the instability of atherosclerotic plaques in the postmenopausal stage.

Acute cardiovascular events increase significantly in postmenopausal women. The relationship between estrogen receptor (ER) and plaque stability in the postmenopausal stage remains to be elucidated. We aimed to explore whether ERα activation improves plaque instability in the postmenopausal stage. Here, we report that postmenopausal women showed increased macrophage activation and plaque instability with increased MCP-1, MMP9, TLR4, MYD88 and NF-κB p65 and decreased ERα and TIMP1 expression in the vascular endothelium. Moreover, ovariectomy in LDLR-/- mice resulted in a significant increase in plaque area and necrotic core area, as well as a significant decrease in collagen content and an increase in macrophage accumulation in the artery. Ovariectomy also reduced serum estrogen levels and ERα expression and upregulated TLR4 and MMP9 expression in arteries in LDLR-/- mice. Estrogen or phytoestrogen therapy upregulated the expression level of ERα in ovariectomized mice and increased plaque stability by inhibiting macrophage accumulation and TLR4 signaling. In vitro, LPS incubation of RAW264.7 cells resulted in a significant decrease in ERα and TIMP1 expression and an increase in TLR4 activation, and estrogen or phytoestrogen treatment increased ERα and TIMP1 expression and inhibited TLR4 activation and MMP9 expression in LPS-treated RAW264.7 cells. Compared to control siRNA transfected RAW264.7 cells, TLR4 siRNA promoted TIMP1 expression in RAW264.7 cells with LPS incubation, but did not affect ERα expression in RAW264.7 cells with or without LPS treatment. The ERα inhibitor MPP abolished the regulatory effect of estrogen or phytoestrogen on LPS-induced RAW264.7 cells. In conclusion, the present study demonstrates that decreased ERα expression promotes macrophage infiltration and plaque instability in the postmenopausal stage, and activation of ERα in the postmenopausal stage alleviates atherosclerotic plaque instability by inhibiting TLR4 signaling and macrophage-related inflammation.