ObjectiveThe malaria parasites remodel the host erythrocyte structure by exporting parasite proteins that interact with the membrane skeleton proteins of red blood cells (RBCs), facilitating their intracellular survival and pathogenicity. Skeleton-binding protein 1 (SBP1) is a conserved exported protein across Plasmodium species. In Plasmodium falciparum, SBP1 has been reported to interact with erythrocyte membrane skeleton proteins 4.1R and spectrin, while its contribution to erythrocyte remodeling and parasite virulence in Plasmodium berghei (Pb) remains unclear. This study aims to determine whether PbSBP1 associates with the host cytoskeletal protein 4.1R and to investigate its role in the remodeling of host RBCs and the pathogenicity of Plasmodium berghei. MethodsIn Plasmodium berghei, the relationship between PbSBP1 and the erythrocyte cytoskeletal protein 4.1R was examined using co-immunoprecipitation. A Pbsbp1 gene knockout mutant of Plasmodium berghei (Pbsbp1∆) was generated based on the principle of double crossover homologous recombination. The deformability of erythrocytes infected with Pbsbp1∆ parasites was assessed using microfluidic methods. Microchannels with an array of cylindrical pillars were used to detect modifications in infected RBC deformability. The infected RBCs were squashed between the rows and recovered between the columns and the transit velocity (μm/s) of infected RBCs travelling through the microchannel was recorded. The component of the erythrocyte membrane skeleton junctional complex, tropomodulin (TMOD), was fluorescently labeled, and the cytoskeletal network of infected erythrocytes was imaged using super-resolution stochastic optical reconstruction microscopy (STORM) to analyze ultrastructural changes in the cytoskeleton of wild-type (WT) and Pbsbp1∆-infected erythrocytes. Actin-based junctional complexes were displayed as individual clusters by the labeled TMOD in the STORM images, and the cluster densities and distances between adjacent clusters of infected RBCs were calculated. Additionally, rodent malaria models (BALB/c mice) and experimental cerebral malaria models (C57BL/6 mice) were employed to monitor the growth of Pbsbp1∆ and WT parasites during the intraerythrocytic stage and their capacity to induce cerebral malaria in mice. ResultsPbSBP1 may participate in the remodeling of infected erythrocytes through direct or indirect interaction with the erythrocyte cytoskeletal protein 4.1R. Microfluidic assays revealed that the deformability of erythrocytes infected with Pbsbp1∆ parasites was significantly enhanced compared to those infected with WT parasites. STORM imaging further demonstrated that the ultrastructure of the erythrocyte cytoskeleton in Pbsbp1∆-infected cells was altered relative to that in WT-infected erythrocytes. The distances between nearest neighbors of clusters had a tendency to increase while the cluster densities were decreased in Pbsbp1∆-infected RBCs compared to WT-infected RBCs. Subsequent phenotypic analysis indicated that the growth rate of Pbsbp1∆ parasites during the intraerythrocytic stage was significantly slower than that of WT parasites, and their ability to induce cerebral malaria in mice was also attenuated. These findings suggest that PbSBP1 is involved in the remodeling of the erythrocyte membrane skeleton, likely through its direct or indirect interaction with protein 4.1R, thereby regulating the deformability of infected erythrocytes and influencing the pathogenicity of the blood-stage parasites. ConclusionThis study establishes a role for PbSBP1 in host erythrocyte remodeling and parasite virulence, providing new research strategies for the prevention and treatment of malaria.

Olfactory receptors (ORs) form the largest superfamily of G protein-coupled receptors (GPCRs). Traditionally recognized for their role in the nasal olfactory epithelium, where they mediate the sense of smell, accumulating evidence has firmly established their ectopic expression in non-olfactory tissues, including the intestine, lungs, and kidneys. The intestine, as the primary site for nutrient digestion and absorption, harbors a highly complex chemical environment. To adapt to this environment, the gut employs a sophisticated network of “chemosensors” to monitor luminal contents and maintain homeostasis. Among these sensors, intestinal ORs have emerged as crucial functional components, serving as a molecular bridge that connects environmental chemical signals—such as food-derived odorants—to specific physiological responses. This discovery has significantly deepened our understanding of how dietary flavors and compounds influence intestinal physiology at the molecular level. This review systematically summarizes the expression profiles, ligand classification, and biological functions of ORs within the gastrointestinal tract. Studies indicate that intestinal ORs exhibit distinct spatial distribution patterns across different gut segments and display cell-type specificity, particularly within enterocytes and enteroendocrine cells. These receptors function as versatile sensors capable of recognizing a wide variety of ligands, including exogenous dietary components, gut microbiota metabolites such as short-chain fatty acids, and endogenous small molecules like azelaic acid. Upon activation by specific ligands, intestinal ORs trigger intracellular signaling cascades, primarily involving the AC-cAMP-PKA pathway or calcium influx channels. A major focus of this review is to elucidate the molecular mechanisms by which these receptors regulate the secretion of gut hormones. Activation of specific ORs in enteroendocrine cells has been shown to stimulate the release of hormones such as glucagon-like peptide-1 (GLP-1), peptide YY (PYY), and serotonin (5-HT), thereby modulating systemic energy metabolism, glucose homeostasis, and gastrointestinal motility. Furthermore, the review addresses the critical roles of ORs in immune regulation and pathology. Evidence suggests that specific ORs contribute to the maintenance of intestinal immune homeostasis and may offer protection against inflammation. Beyond their involvement in inflammatory responses, ORs such as Olfr78 have been shown to regulate the differentiation and function of intestinal endocrine cells. Similarly, Olfr544 has been demonstrated to alleviate intestinal inflammation by remodeling the gut microbiome and metabolome. These findings collectively suggest that specific ORs hold promise as therapeutic targets for mitigating intestinal inflammation and maintaining gut homeostasis. Additionally, the review explores the emerging role of ORs in cancer. Although OR expression is often downregulated in tumor tissues compared to normal mucosa, activation of specific ORs by certain ligands can inhibit tumor cell proliferation and migration and induce apoptosis via pathways such as MEK/ERK and p38 MAPK. Conversely, other receptors, such as OR7C1, may serve as biomarkers for cancer-initiating cells. In conclusion, intestinal ORs represent a vital component of the gut’s sensory network. The review also discusses the translational potential of these findings. By elucidating the precise pairing relationships between dietary components and specific ORs, novel therapeutic strategies could be developed. Intestinal ORs may thus emerge as promising targets for nutritional and pharmacological interventions in metabolic diseases, inflammatory bowel diseases, and malignancies.

ObjectiveType I interferon (IFN-I) signaling is essential for antiviral innate immunity, yet its sustained or excessive activation contributes to the pathogenesis of several autoimmune diseases and interferonopathies, such as systemic lupus erythematosus and Aicardi-Goutières syndrome. Current strategies targeting this pathway, exemplified by JAK inhibitors, act mainly on downstream signal transduction and provide limited direct control over upstream IFN-I production, while also carrying the risk of broad immunosuppression. Phyllanthus emblica L. has long been used in traditional medicine for inflammatory disorders, but the bioactive constituent responsible for its regulation of IFN-I signaling and the underlying molecular mechanism have not been clearly defined. This study aimed to identify the active anti-inflammatory component of P. emblica and to characterize its mechanism of action on the IFN-I pathway in macrophages. MethodsActive components ofP. emblica and their candidate targets were screened by network pharmacology using the TCMSP and DrugBank databases (oral bioavailability≥30%, drug-likeness≥0.18) and intersected with inflammation-related genes retrieved from public databases. The predicted interaction between EGCG and IFN-I pathway proteins (TBK1, IRF3, STAT1) was evaluated by molecular docking, with BX795 and GSK8612 used as reference TBK1 inhibitors. Mechanistic experiments were performed in THP-1-derived macrophages and primary bone marrow-derived macrophages (BMDM). Upstream signaling was activated by transfection of the nucleic acid analogs poly(I∶C) and poly(dA∶dT) or by lipopolysaccharide (LPS) stimulation, whereas downstream signaling was activated by exogenous IFN-β. An siRNA-mediated TREX1 knockdown model was used to mimic endogenous nucleic acid-driven interferonopathy. Expression of IFN-β1 and interferon-stimulated genes (ISGs) was measured by RT-qPCR, protein phosphorylation by Western blot, and IFN-β secretion by ELISA. Cellular thermal shift assay (CETSA) and drug affinity responsive target stability (DARTS) were used to probe the interactionbetween EGCG and IRF3. ResultsNetwork pharmacology identified (-)-epigallocatechin-3-gallate (EGCG) as a candidate IFN-I-suppressive constituent of P. emblica, with predicted binding to TBK1, IRF3, and STAT1. Molecular docking yielded binding energies of -9.2, -7.2, and -8.2 kcal/mol for TBK1, IRF3, and STAT1, respectively, indicating an affinity for TBK1 comparable to that of the reference inhibitors BX795 (-5.7 kcal/mol) and GSK8612 (-6.4 kcal/mol). EGCG suppressed IFN-β1 and ISG mRNA expression under poly (I∶C), poly (dA∶dT), and LPS stimulation in both THP-1 macrophages and BMDM. At the protein level, EGCG reduced the phosphorylation of TBK1 and IRF3 without affecting the levels of the upstream sensors cGAS and RIG-I, and lowered IFN-β secretion in a concentration-dependent manner. CETSA and DARTS showed that EGCG did not enhance the thermal stability or protease resistance of IRF3, indicating that its effect on IRF3 is indirect. Following IFN-β stimulation, prolonged EGCG treatment reduced STAT1 phosphorylation in a time-dependent manner without an apparent change in IRF9, and partially attenuated ISG transcription; this effect was not monotonicly concentration-dependent, and CXCL10 showed the most consistent suppression. In TREX1-knockdown cells, the elevated mRNA levels of ISG15, ISG56, and CXCL10 were reduced by EGCG. ConclusionEGCG suppresses IFN-I responses by concurrently inhibiting TBK1-IRF3-dependent IFN‑β production and JAK-STAT1-mediated downstream transcription. These in vitro findings provide a mechanistic basis for the anti-inflammatory use of P. emblica in traditional medicine and identify EGCG as a candidate for further evaluation in interferon-driven autoimmune disease models.

ObjectiveTo observe the clinical efficacy and safety of Tianmeng Lingjiao Formula（天礞羚角方， TLF） as an adjunctive therapy for paroxysmal atrial fibrillation （PAF） with phlegm-heat harassing the interior syndrome. MethodsNinety patients with PAF and phlegm-heat harassing the interior syndrome were enrolled and randomly assigned in a 2∶1 ratio to test group （60 cases） and control group （30 cases）. The control group received conventional western medicine， while the test group received TLF in addition to the conventional treatment， with one dose administered daily. The treatment course for both groups was 4 weeks. The efficacy of traditional Chinese medicine （TCM） syndrome and the rate of atrial fibrillation （AF） conversion were compared between groups. Assessments included AF burden， frequency and duration of AF episodes， TCM syndrome scores， and European Heart Rhythm Association （EHRA） AF symptom classification before and after treatment. Safety indicators such as blood routine， urine routine， stool routine， liver function， kidney function， and electrolytes were also monitored. Adverse events were recorded. ResultsA total of 82 patients completed the study （54 in the test group and 28 in the control group）. After treatment， AF burden， the frequency and duration of AF episodes， and TCM syndrome scores were significantly reduced in both groups， and the test group showed lower indicators than the control group （P＜0.01 or P＜0.05）. The AF conversion rate was 25.93% （14/54） in the test group， significantly higher than 3.57% （1/28） in the control group （P＜0.05）. The total effective rate for TCM syndrome efficacy was 83.33% （45/54） in the test group， which was significantly higher than 67.86% （19/28） in the control group （P＜0.05）. After treatment， the EHRA atrial fibrillation symptom severity in the test group showed significant improvement， and the improvement in atrial fibrillation symptoms was superior to that in the control group （P＜0.01or P＜0.05）. No significant abnormalities were observed in safety indicators， and no adverse events occurred during the trial. ConclusionTLF as an adjunctive therapy can reduce AF burden， enhance the conversion rate of AF， decrease the frequency and duration of episodes， and improve clinical symptoms in patients with paroxysmal atrial fibrillation presenting with phlegm-heat harassing the interior syndrome， with a favorable safety profile.

Tumor angiogenesis is a core pathological driver of malignant growth, invasion, and metastasis, and represents a major obstacle to effective anticancer therapy. Conventional antiangiogenic agents, including neutralizing monoclonal antibodies and small-molecule tyrosine kinase inhibitors, are constrained by drug resistance, on-target toxicity, and the compensatory activation of alternative pro-angiogenic pathways. Targeted protein degradation (TPD) has emerged as a promising strategy that may overcome these limitations. Unlike traditional inhibitors that operate through an occupancy-driven mechanism, degraders function through an event-driven catalytic mechanism in which a single degrader molecule can catalytically promote the ubiquitination and subsequent proteasomal or lysosomal degradation of multiple molecules of the same target protein, thereby eliminating the target protein together with all of its functions rather than merely blocking a single active site. This review systematically delineates the pathophysiological basis of tumor angiogenesis, encompassing the angiogenic switch driven by hypoxia-inducible factor-1α (HIF-1α), the aberrant structural and functional features of the tumor vasculature, and the self-reinforcing vicious cycles that sustain malignant progression. We then categorize the principal TPD modalities, with particular emphasis on proteolysis-targeting chimeras (PROTACs) and lysosome-targeting chimeras (LYTACs), and describe their design principles and mechanisms of action. PROTACs recruit E3 ubiquitin ligases to direct intracellular targets to the ubiquitin-proteasome system for degradation, whereas LYTACs engage lysosome-targeting receptors to route extracellular and membrane proteins to the lysosome, thereby expanding the degradable target space beyond the intracellular proteome. We further summarize recent advances in the application of TPD to antiangiogenic intervention at four distinct levels. First, at the signaling initiation level, degradation of vascular endothelial growth factor (VEGF) and its receptor vascular endothelial growth factor receptor 2 (VEGFR2) by aptamer-engineered PROTACs, antibody-based LYTACs, and small-molecule VEGFR2 degraders blocks the upstream trigger of the angiogenic cascade. Second, at the signal transduction level, degradation of focal adhesion kinase (FAK), B-Raf proto-oncogene serine/threonine kinase (BRAF), phosphodiesterase 4 (PDE4), and bromodomain-containing protein 4 (BRD4) interrupts intracellular signaling cascades and transcriptional responses. Third, at the microenvironment level, degradation of proviral integration site for Moloney murine leukemia virus (PIM) kinases curtails the pro-angiogenic signals secreted by tumor-associated macrophages. Fourth, multi-target synergistic strategies, exemplified by bispecific degraders that simultaneously target human epidermal growth factor receptor 2 (HER2) and VEGF-A, represent a preliminary exploration of cooperative intervention. Representative degraders reviewed herein elicit diverse antiangiogenic phenotypes, ranging from the direct inhibition of endothelial cell proliferation, migration, and tube formation to reductions in microvessel density and the suppression of vasculogenic mimicry. Finally, we discuss the major challenges that remain, including the precise matching of degradation kinetics with the vascular normalization window, target selectivity and tissue specificity, and the activation of compensatory networks and the emergence of resistance. Since the application of TPD in this setting remains at an early stage, the clinical translation of these approaches will require careful optimization of degradation efficiency, spatiotemporal control, and delivery strategies. We also envision future directions toward immunotherapy-based combination regimens and precision-degradation approaches guided by single-cell and spatial transcriptomics. In our view, TPD should not be regarded merely as a substitute for conventional antiangiogenic drugs, but rather as a molecular tool capable of systematically remodeling the tumor vascular microenvironment. When precise control of degradation efficiency and spatiotemporal regulation are integrated with a thorough understanding of the heterogeneity and compensatory capacity of tumor vessels, the full clinical potential of this strategy can be realized.

Objective To analyze the characteristics of methadone-related poisoning cases and provide a reference for forensic identification.Methods A total of 71 cases of methadone-related poisoning re-ported from 1998 to 2023 in China and 26 cases of methadone-related deaths reported from 2013 to 2018 in Italy were retrieved from databases including PubMed,Wanfang and CNKI.The general infor-mation,forensic pathological and toxicological characteristics were analyzed.Results Among the 71 methadone-related poisoning cases in China,there were 54 cases(76.06%)of poisoning without death and 17 cases(23.94%)of death from poisoning.There were 54 male cases(76.06%),and 51 cases(71.83%)aged 19 to 39 years old.There were 35 cases(49.30%)of poisoning caused by methadone alone,and 32 cases(45.07%)were poisoning caused by methadone combined with other substances or drugs including heroin and benzodiazepines.Most of the poisoned showed coma,respiratory depres-sion and miosis.Signs of asphyxia were often found by autopsy.The mass concentration of methadone detected in the blood of 6 deceased ranged from 0.112 to 3.000 mg/L.Among the 26 methadone-related deaths in Italy,22 cases were male(84.62%).There were 6 cases(23.08%)caused by methadone alone,and 20 cases(76.92%)died from methadone combined with other substances or drugs.The mass concentration of methadone in blood ranged from 0.181 to 4.059 mg/L.Conclusion The propor-tions of poisoning cases caused by methadone alone and methadone combined with other substances or drugs are comparable in China.The majority of deceased caused by methadone poisoning shows typi-cal triad of coma,respiratory depression and miosis,which helps forensic experts determine the cause of death related to methadone.Additionally,it is necessary to increase the routine testing of the con-centration of methadone and its combined substances or drugs in deceased,and collect data for the in-terpretation of the results of related cases.

Objective To investigate the genetic differences among different populations based on 13 autosomal STR loci in CODIS core.Methods Data of 13 autosomal STR loci(CSF1PO,FGA,THO1,TPOX,vWA,D3S1358,D5S818,D7S820,D8S1179,D13S317,D16S539,D18S51,D21S11)were collected from 95 populations in scientific journals between 1999 and 2021,soursed from the PubMed database,which had been published.Allele frequencies of loci were sorted out and forensic genetic parameters including gene differentiation coefficient(Gst),total heterozygosity(Ht),subpopula-tion heterozygosity(Hs)values,and Nei's DA genetic distance were calculated.Principal component analysis,phylogenetic tree,and multidimensional scale analysis were conducted to assess population ge-netic structure.Results A total of 265 alleles were detected at the 13 STR loci in these 95 popula-tions.The mean values of Gst,Ht,and Hs were 0.023 247,0.797 915 and 0.779 365.Population genetic analyses reflected significant differences among populations from Asia,Africa and Europe.In Asian populations,there was a certain degree of distinction between mainland and island populations;the Han population showed a certain degree of distinction with surrounding populations in mainland;while within the Han population,there were two distinct clusters formed by the northern Han and the south-ern Han.Conclusion The 13 autosomal STR loci in CODIS core demonstrate potential value for popu-lation identification across different groups,and may be used for the differentiation of ethnic groups,among different continental populations.

AIM:This study aims to investigate the sensitizing effects of lycorine(Lyc)in combination with cisplatin(Cis)on human osteosarcoma cells and to explore the underlying mechanisms of action.METHODS:Human osteosarcoma cell lines MG63,HOS,and cisplatin-resistant HOS/DDP cells were utilized to evaluate the effects of Lyc and cisplatin,both alone and in combination,on cell viability using the CCK8 assay.The clonogenic assay was performed to assess cell proliferation capacity,while the scratch assay evaluated the drugs' effects on cell migration.Reactive oxygen species(ROS)levels were measured using a ROS assay kit,and changes in intracellular glutathione(GSH)levels were assessed with a GSH/oxidized glutathione(GSSG)assay kit.The mitochondrial membrane potential was analyzed via JC-1 staining to determine the drugs' effects on mitochondrial function.Intracellular iron(Ⅱ)content changes were detected us-ing FerrOrange,a fluorescence probe,and cellular malondialdehyde(MDA)levels were measured using an MDA assay kit.RT-qPCR was employed to evaluate the expression levels of key genes related to ferroptosis,and Western blot analysis was conducted to detect changes in the protein expression levels of Yes-associated protein 1(YAP1),acyl-CoA synthetase long-chain family member 4(ACSL4),glutathione peroxidase 4(GPX4),heme oxygenase-1(HO-1),and transferrin re-ceptor(TFRC).RESULTS:Both Lyc and cisplatin effectively inhibited the proliferation of human osteosarcoma cells.Notably,the combination of Lyc and cisplatin led to a more substantial reduction in cell viability,proliferation,and migra-tion abilities in MG63,HOS,and HOS/DDP cells compared to cisplatin alone.Additionally,this combination significant-ly increased ROS levels while decreasing GSH content,indicating mitochondrial damage and elevated iron(Ⅱ)and MDA levels.RT-qPCR results revealed that the combination treatment more significantly downregulated ferroptosis-promoting genes and upregulated ferroptosis-inhibiting genes compared to cisplatin treatment alone(P<0.05).Western blot results showed a slight decrease in GPX4 protein expression following Lyc and cisplatin treatment,while expression levels of YAP1,TFRC,ACSL4,and HO-1 were significantly increased(P<0.05).CONCLUSION:Lyc enhances the sensitivi-ty of MG63,HOS,and HOS/DDP cells to cisplatin by promoting ferroptosis through the YAP1/TFRC signaling pathway.

Objective:To evaluate the relationship between sevoflurane preconditioning-induced reduction of cognitive impairment and hippocampal necroptosis after cardiopulmonary bypass (CPB) in rats.Methods:Sixty SPF healthy male Sprague-Dawley rats, aged 6 months, weighing 400-450 g, were divided into 4 groups ( n=15 each) using the random number table method: control group (group C), sevoflurane group (Sev group), CPB group and CPB+ sevoflurane preconditioning group (CPB+ Sev group). The rats were exposed to 0.4% sevoflurane for 2 h in CPB+ Sev group and Sev group. The CPB model was established at 30 min after the end of sevoflurane preconditioning in CPB+ Sev group. The open field test was performed to assess the autonomic movement ability on the 2nd day after CPB. The Morris water maze test was used to assess the cognitive function on the 3rd day after CPB. The hippocampal tissues were removed after the end of the Morris water maze test for determination of the necroptosis rate and cytosolic calcium concentration of hippocampal neuron ([Ca 2+ ] i) (by flow cytometry) and the expression of phosphorylated receptor-interacting protein kinase 1 (p-RIPK1), phosphorylated RIPK3 and phosphorylated mixed-lineage kinase-like domain (p-MLKL) (by Western blot) and for microscopic examination of the ultrastructure of hippocampal neurons (by transmission electron microscopy). Results:There was no statistically significant difference in the parameters of the open field test among the four groups ( P>0.05). Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was decreased, the time of staying at the original platform quadrant was shortened, the hippocampal necroptosis rate and [Ca 2+ ] i were increased, the expression of p-RIPK1, p-RIPK3 and p-MLKL was up-regulated ( P<0.05), the organelles of hippocampal neurons swelled, lysosomes broke, and some chromatin in nuclei dissoluted in CPB group. Compared with CPB group, the escape latency was significantly shortened, the number of crossing the original platform was increased, the time of staying at the original platform quadrant was prolonged, the hippocampal necroptosis rate and [Ca 2+ ] i were decreased, the expression of p-RIPK1, p-RIPK3 and p-MLKL was down-regulated ( P<0.05), and the damage to the ultrastructure of hippocampal neurons was sinificantly reduced in CPB+ Sev group ( P<0.05). Conclusions:The mechanism by which sevoflurane preconditioning attenuates cognitive impairment may be related to the inhibition of calcium overload-mediated hippocampal necroptosis in a rat model of CPB.

Objective:To evaluate the role of RhoA/ROCK2 pathway in electroacupuncture (EA) preconditioning-induced reduction of the perioperative neurocognitive disorder (PND) in aged rats.Methods:Eighty SPF healthy male Sprague-Dawley rats, aged 20 months, weighing 600-650 g, were divided into 4 groups ( n=20 each) using the random number table method: sham operation group (group S), PND group, EA preconditioning group and EA preconditioning plus RhoA agonist arachidonic acid group (EA+ AA group). The PND model was prepared using exploratory laparotomy performed under 3% sevoflurane anesthesia. In PND, EA and EA+ AA groups, EA preconditioning was initiated 5 days before operation as follows: Bilateral acupoints Zusanli, Hegu and Neiguan were stimulated with sparse-dense waves at 2/15 Hz and an electric current intensity of 1 mA, applied for 30 min a day for 5 consecutive days. Arachidonic acidin 10 mg/kg was intraperitoneally injected at 30 min before surgery in group AA. The open field test was conducted at 3 days postoperatively to measure the autonomous motor function, and the Morris water maze test was conducted at 3-7 days postoperatively to evaluate the cognitive function. After the end of Morris water maze test, the rats were sacrificed, and the hippocampal tissue in CA1 region was obtained for determination of the apoptosis rate of cells and concentrations of cytoplasmic calcium ion ([Ca 2+ ] i) (by flow cytometry) and the expression of phosphorylated RhoA (p-RhoA), ROCK2, and cleaved caspase-3 (by Western blot) and for examination of the ultrastructure of hippocampal neurons (with a transmission electron microscope). Results:There was no statistically significant difference in each parameter of the open field test among the four groups ( P>0.05). Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the apoptosis rate of hippocampal cells and [Ca 2+ ] i were increased, the expression of p-RhoA, ROCK2 and cleaved-caspase-3 was up-regulated ( P<0.05), and the pathological damage to hippocampal neurons was marked in PND group. Compared with PND group, the escape latency was significantly shortened, the number of crossing the original platform was reduced, the apoptosis rate of hippocampal cells and [Ca 2+ ] i were increased, the expression of p-RhoA, ROCK2 and cleaved-caspase-3 was up-regulated ( P<0.05), and the pathological damage to hippocampal neurons was significantly attenuated in EA group. Compared with EA group, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the apoptosis rate of hippocampal cells and [Ca 2+ ] i were increased, the expression of p-RhoA, ROCK2 and cleaved-caspase-3 was up-regulated ( P<0.05), and the pathological damage to hippocampal neurons was aggravated in EA+ AA group. Conclusions:The mechanism by which EA preconditioning reduces PND is related to inhibiting the activation of hippocampal RhoA/ROCK2 signaling pathway and reducing calcium overload-mediated apoptosis in cells of aged rats.