ObjectiveTo investigate the mechanism by which adrenoceptor alpha 2A (Adra2a) regulates lipopolysaccharide (LPS)-induced inflammation in primary hepatocytes from lipopolysaccharide-binding protein (LBP) knockout mice (Lbp^-/-). MethodsPrimary hepatocytes from C57BL/6J and Lbp^-/- mice were isolated using a two-step perfusion method. An in vitro inflammatory model was established by LPS stimulation, and an in vivo inflammatory mouse model was established by intraperitoneal injection of LPS. The in vitro experiments were grouped as follows: Control group, LPS group, BRL+LPS group, OE-NC+LPS group, and OE-Adra2a+LPS group. The Control group served as the blank control. The LPS group involved stimulating primary hepatocytes with LPS. The BRL+LPS group involved pretreating primary hepatocytes with BRL-44408 maleate followed by LPS stimulation. The OE-NC+LPS group involved transfecting primary hepatocytes with an empty vector followed by LPS stimulation. The OE-Adra2a+LPS group involved transfecting primary hepatocytes with a lentivirus overexpressing Adra2a, followed by LPS stimulation. The in vivo experimental groups were divided into Control', LPS', BRL+LPS', OE-NC+LPS', and OE-Adra2a+LPS' groups. The Control' group served as the blank control. The LPS' group received intraperitoneal injection of LPS. The BRL+LPS' group received intraperitoneal injection of BRL-44408 maleate for pretreatment, followed by LPS injection. The OE-NC+LPS' group received intraperitoneal injection of empty vector for pretreatment, followed by LPS injection. The OE-Adra2a+LPS' group received intraperitoneal injection of a lentivirus overexpressing Adra2a for pretreatment, followed by LPS injection. Cell viability after Adra2a inhibition and overexpression was assessed via the Cell Counting Kit-8 (CCK-8) assay. RT-qPCR measured changes in gene expression levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) after Adra2a inhibition and overexpression. Western blotting was performed to detect Adra2a protein expression and phosphorylation levels of extracellular signal-regulated kinase 1/2 (ERK1/2), p38 mitogen-activated protein kinase, and c-Jun N-terminal kinase (JNK) following LPS stimulation. ResultsIn vitro experiments revealed that LPS stimulation significantly decreased Adra2a protein expression in primary hepatocytes from C57BL/6J mice compared to the Control group (P<0.05), whereas it increased in primary hepatocytes from Lbp^-/- mice (P<0.001). Compared to the LPS group, the BRL+LPS group exhibited significantly increased cell viability (P<0.01), reduced TNF-α, IL-6, and IL-1β gene transcription levels (P<0.01, P<0.001, P<0.001), and decreased phosphorylation levels of MAPK signaling pathway-related proteins ERK1/2, p38, and JNK (P<0.01, P<0.001, P<0.001). Compared with the OE-NC+LPS group, the OE-Adra2a+LPS group showed significantly decreased cell viability (P<0.001), increased gene transcription levels of TNF-α, IL-6, and IL-1β genes (P<0.001, P<0.01, P<0.001), and elevated phosphorylation levels of MAPK signaling pathway-related proteins ERK1/2, p38, and JNK (P<0.001, P<0.01, P<0.001). In vivo experiments showed that, compared with the LPS' group, the BRL+LPS' group exhibited significantly reduced phosphorylation levels of MAPK signaling pathway-related proteins ERK1/2, p38, and JNK (P<0.001, P<0.01, P<0.01). In the OE-Adra2a+LPS' group, the phosphorylation levels of ERK1/2, p38, and JNK were significantly elevated compared to the OE-NC+LPS' group (P<0.01, P<0.001, P<0.01). ConclusionLPS stimulation can cause a significant increase in Adra2a protein expression in primary hepatocytes of Lbp^-/- mice. Adra2a protein can regulate the level of LPS-induced inflammation in primary hepatocytes of Lbp^-/- mice through the MAPK signaling pathway.

Objective To identify potential drug target genes associated with idiopathic pulmonary fibrosis(IPF)and predict therapeutic candidates using a two-sample Mendelian randomization(MR)approach across the druggable genome.Methods Druggable genome data from the DGIdb database and Finan were integrated to identify overlapping genes.A two-sample MR analysis was performed to infer causal relationships between genes and IPF.Functional enrichment analyses,including Gene Ontology(GO)and Kyoto encyclopedia of genes and genomes(KEGG),were conducted to explore biological pathways.Drug-target interactions were predicted via DSigDB database screening,followed by molecular docking simulations to evaluate binding affinities.Results Among the 2588 overlapping druggable genes,thirty exhibited significant causal associations with IPF(P＜0.05).Four hub genes(NOD2,LATS2,LTA,and TCF7L2)were enriched in IPF-related pathways,notably Hippo and TNF signaling.Six potential therapeutics were identified:oxyphenbutazone,moexipril,α-galactosylceramide,GSK429286A,CGP74514A,and JW-7-24-1.Molecular docking confirmed strong binding affinities between these drugs and their targets.Conclusion This study has identified thirty druggable gene targets and six candidate drugs for IPF.The enrichment of hub genes in key pathways and validated drug-target interactions provide insights into IPF therapies.

OBJECTIVE To investigate the biodistribution of lipid nanoparticles(LNPs)with different surface charges and different particle sizes in mice.METHODS LNPs were prepared using microfluidic technology by incorporating positively charged phospholipids,negatively charged phospholipids,ioniz-able phospholipids,and neutral phospholipids into the formulation to create LNPs with corresponding surface charges.The particle size of the LNPs was controlled by polyethylene glycol(PEG)modifica-tion and measured using dynamic light scattering(DLS)and transmission electron microscopy(TEM),while the surface charge was analyzed using a zeta potential analyzer.The LNPs were labeled with a fluorescent dye,and the mice were intravenously injected with 0.625 μmol·kg-1 of LNPs.At 1,4,12 and 24 h post-injection,the brain,heart,livers,spleen,lungs and kidneys were collected.The fluorescence distribution in different organs was detected using an in vivo imaging system to reflect the distribution of LNPs in various organs.RESULTS Particle size analysis showed that,except the ionizable lipid nanoparticles without PEG modification(LNP-MC3),which had a particle size>200 nm,the particle sizes of positively charged LNPs without PEG modification(LNP-Pos),PEG-modified positively charged LNPs(LNP-Pos-P),PEG-modified neutral LNPs(LNP-Neu-P),PEG-modified ionizable LNPs(LNP-MC3-P),and PEG-modified negatively charged LNPs(LNP-Neg-P)were all<200 nm.Zeta potential analysis revealed that the surface charges of the LNPs were the highest in LNP-Pos,followed by LNP-Pos-P,LNP-MC3-P,LNP-Neu-P,LNP-MC3 and LNP-Neg-P.In vivo imaging results indicated that LNP-Pos-P,LNP-Pos and LNP-MC3-P were primarily distributed in the livers,lungs and kidneys,respectively,while LNP-Neu-P and LNP-Neg-P in the livers,kidneys,and lungs,respectively.The distribution of LNP-MC3-P in the brain,heart,spleen and kidneys peaked at 12 h post-injection,but at 24 h in the livers.The distribution of LNP-Pos-P in the lungs peaked at 1 h post-injection.CONCLUSION LNPs are primarily distributed in the livers.Surface charges influence the second most highly-distributed organs.LNP-Pos-P and LNP-MC3-P are the second most highly-distributed in the lungs,and LNP-Neu-P and LNP-Neg-P in the kidneys.

Objective:To investigate the risk factors of skin adverse events associated with immune checkpoint inhibitor (ICI) therapy in patients with urologic neoplasms, and establish a predictive model.Methods:A single-center retrospective case-control study enrolled 91 advanced urologic neoplasms patients who received ICI therapy at the Department of Urology, Beijing Friendship Hospital, Capital Medical University from January 2020 to June 2025. Patients were divided into the skin lesion group ( n=44) and the control group ( n=47). Patients in the skin lesion group experienced related skin adverse events during ICI treatment, while patients in the control group did not experience such events during ICI treatment. The general data and laboratory indicators were compared between the two groups. The normally distributed measurement data were expressed as mean±standard deviation ( ± s), and the independent sample t-test was used for comparison between groups; the non-normally distributed measurement data were expressed as the median (interquartile range) [ M ( Q1, Q3)], and the Kruskal-Wallis test was used for comparison between groups. The count data were expressed as the number of cases and percentages, and the Chi-test was used for comparison between groups. First, a univariate analysis was conducted on the influencing factors of skin adverse events in patients with urologic neoplasms after ICI treatment. Then, the indicators with statistically significant differences in the univariate analysis were further included in the multivariate Logistic regression model to screen the independent risk factors for predicting skin adverse events. The R software was used to incorporate the factors with significant differences from multivariate analysis into the prediction model and construct a Nomogram. The calibration curve was utilized to evaluate the consistency between predicted values and actual observed results. Meanwhile, the discrimination of the model was verified by the receiver operating characteristic (ROC) curve and the area under the curve (AUC), so as to comprehensively verify the reliability and clinical application value of the prediction model. Results:The results of univariate analysis showed that there were statistically significant differences between the skin lesion group and the control group in terms of the proportion of other immune responses, serum albumin level, absolute eosinophil count, and C-reactive protein (CRP) levels ( P<0.05). These factors were included in multivariate Logistic regression, which identified elevated absolute eosinophil count and elevated CRP as the independent risk factors for related skin adverse events in patients with urologic neoplasms after ICI treatment. A predictive nomogram was built based on these factors. The calibration curve showed high consistency between predicted and actual probabilities, and ROC analysis confirmed the combined model had high predictive value (AUC=0.883, P<0.001). Conclusions:Elevated absolute eosinophil count and elevated CRP level are independent predictors of immune-related skin adverse events in urologic neoplasms patients after ICI treatment. The prediction model constructed based on these two factors facilitates early clinical screening and identification of high-risk patients.

OBJECTIVE To investigate the acute lung injury effects of pulmonary phospholipids and their phospholipase A2(PLA2)decomposition products-lysophospholipids and fatty acids-on mice.METHODS Mice were randomly assigned to the following groups:① solvent control(PBS)and PLA2;② solvent control and glycerol phospholipid groups:1,2-dioleoyl-sn-glycero-3-phosphoserine(DOPS),1,2-dipalmitoyl-sn-glycero-3-phosphoserine(DPPS),1,2-dioleoyl-sn-glycero-3-phosphoethanol-amine(DOPE),1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine(DPPE),1,2-dipalmitoyl-sn-glycero-3-phosphocholine(DPPC),and 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine(SOPC);③ solvent con-trol and fatty acid groups:palmitic acid(PA),oleic acid;④ solvent control and lysophospholipid groups:1-oleoyl-2-hydroxy-sn-glycero-3-phosphoserine(18∶1 LysoPS),1-stearoyl-sn-glycero-3-phosphoserine(18∶0 LysoPS),1-palmitoyl-sn-glycero-3-phosphoserine(16∶0 LysoPS),1-palmitoyl-sn-glycero-3-phos-phoethanolamine(16∶0 LysoPE),1-palmitoyl-sn-glycero-3-phosphocholine(16∶0 LysoPC);⑤ solvent control,PLA2,DPPC,PA,16∶0 LysoPC,16∶0 LysoPS,and 18∶1 LysoPS.Following anesthesia,mice were administered nebulized PBS in the solvent control group,2.1 ug·kg-1 PLA2 in PBS in the PLA2 group and 2.5 mg·kg-1 of the corresponding substance in PBS in other experimental groups.For group①,survival times were recorded and survival curves were plotted.At 1 h post-treatment,lung tissues from groups ①②③④ were collected,photographed to obtain white light images,and subjected to HE staining to assess histopathological changes and pathological scoring.At 2 h post-treatment,pulmonary blood flow in group ⑤ was assessed using laser speckle contrast imaging,arterial blood gas was analyzed with a blood gas analyzer,and lung function was evaluated using whole-body pleth-ysmography.At 6 hours post-treatment,blood cells from group ⑤ were analyzed using an automated hematology analyzer.RESULTS Compared with the solvent control group,severe pathological changes were observed in lung tissues of the PLA2 group,accompanied by extensive inflammatory infiltration and interstitial thickening,with all mice succumbing within 240 min.In mice treated with glyc-erol phospholipids,alveolar structures remained clear,alveolar walls were intact and continuous,and alveolar spaces were translucent,with only occasional minor inflammatory cell infiltration in the septa.No significant pathological alterations were detected in the fatty acid groups.Minor inflammatory cell infiltration was seen in the 16∶0 LysoPE and 16∶0 LysoPC groups.However,such pathological changes as patchy hemorrhage,alveolar interstitial edema,increased alveolar wall thickness,and elevated neutrophil counts were observed in the 18∶1 LysoPS,18∶0 LysoPS,and 16∶0 LysoPS groups.Pathological scores based on HE staining were significantly increased in the 16∶0 LysoPS and 18∶1 LysoPS groups com-pared with the solvent control.The percentage of the lung tissue injury area was also markedly higher in the 16∶0 LysoPS group.A significant decrease in the mean fluorescence intensity of blood flow was observed in the 16∶0 LysoPS group.Arterial partial pressure of oxygen(pO2)was significantly reduced in the PLA2 group,while arterial partial pressure of carbon dioxide(pCO2)was markedly elevated in the 16∶0 LysoPS and 18∶1 LysoPS groups.Lung function tests revealed that the 16∶0 LysoPS group exhibited significant increases in expiratory time,end-expiratory pressure,and enhanced pause,in contrast to significant decreases in tidal volume,expired volume,and minute volume.The 18∶1 LysoPS group also exhibited a significant decline in minute volume.No significant changes in inflammatory cell concentrations were detected in blood,with the exception of neutrophils in the 16∶0 LysoPS group,which showed a significant but physiologically normal increase.CONCLUSION Pulmonary phospholipids and their PLA2-derived fatty acid metabolites do not induce severe lung injury in mice while the lyso-phospholipid metabolites,particularly lysophosphatidylserine,are found to cause significant lung injury.

Objective To investigate serum metabolites and metabolic pathways alterations in patients with ischemic stroke(IS)through metabolomic analysis,and to identify reliable serum metabolic biomarkers for IS diagnosis.Methods This prospective study enrolled patients with IS admitted to the Department of Neurology at Xiangcheng People's Hospital of Suzhou from December 1,2022 to December 31,2023.Age-and sex-matched healthy individuals were recruited as controls during the same period.Baseline characteristics were collected,including age,sex,height,body mass index,and blood pressure.Venous blood samples were obtained after an 8 h fast for biochemical analysis of blood glucose,total bilirubin,serum creatinine,urea nitrogen,total cholesterol,triglycerides,high-density lipoprotein cholesterol,and low-density lipoprotein cholesterol.Serum metabolites of both groups were extracted and analyzed using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry.Metabolomic data were processed using Simca-p software for unsupervised principal component analysis(PCA)and orthogonal partial least squares discriminant analysis(OPLS-DA)to evaluate group separation and experimental stability.Differential metabolites were defined by variable importance in projection(VIP)≥1.0,fold change(FC)≥2.0 or ≤0.5,and P＜0.05.Drug-derived exogenous metabolites were excluded by cross-referencing the Human Metabolome Database(HMDB,https://hmdb.ca/)and PubChem(https://pubchem.ncbi.nlm.nih.gov/).MetaboAnalyst 6.0(http://www.metaboanalyst.ca),a comprehensive web-based tool for metabolomic data analysis,was employed to map differential metabolites to the Kyoto encyclopedia of genes and genomes(KEGG)databased and to perform pathway enrichment analysis.Machine learning models were developed using Python.Least absolute shrinkage and selection operator(LASSO)regression and random forest(RF)algorithms were employed to identify diagnostic biomarkers capable of effectively distinguishing IS patients from controls.Metabolites identified by both methods were integrated into an extreme gradient boosting(XGBoost)model.Model performance was evaluated using receiver operating characteristic(ROC)curves with 5-fold cross-validation and internal validation(70％training,30％validation set).Results A total of 51 IS patients and 51 matched controls were included.(1)A total of 1 255 serum metabolites were identified(964 in positive ion mode,291 in negative ion mode).PC A and OPLS-DA demonstrated distinct metabolic separation between IS patients and controls.In IS group,260 metabolites were upregulated and 337 downregulated in positive ion mode;99 were upregulated and 34downregulated in negative ion mode.(2)Among the 1 255 metabolites,259 were identified as differential metabolites based on the criteria of VIP ≥ 1.0,FC≥2.0 or≤0.5 and P＜0.05.After excluding drug-derived metabolite through referencing HMDB and PubChem databases,a total of 220 endogenous differential metabolites were found to coexist in both positive and negative ion modes.Among them,119 metabolites were up-regulated and 101 were down-regulated in the IS group.The expression of these 220 metabolites showed significant differences between the IS and control groups.(3)KEGG pathway analysis highlighted five dysregulated pathways:upregulation of denovo triacylglycerol biosynthesis,glycerophosphate shuttle,and cardiolipin biosynthesis;downregulation of bile acid biosynthesis and methylhistidine metabolism.(4)LASSO and RF algorithms identified 24 and 30 candidate biomarkers,respectively.Four overlapping metabolites were selected:2-((3R)-3-((3R,5S,7S,9S,10S,13R,14S,17R)-3,7-dihydroxy-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-17-yl)butanamido)ethane-1-sulfonic acid(m/z 971.571 29),arginine-conjugated cholic acid(m/z 587.379 21),laccaic acid A(m/z 576.010 93)and NCGC00380235-01_C32H48O9_beta-D-xylopyranoside,3,17-dihydroxyspirosta-5,25(27)-dien-1-yl(m/z 559.326 48).The expression levels of 2-((3R)-3-((3R,5S,7S,9S,10S,13R,14S,17R)-3,7-dihydroxy-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-17-yl)butanamido)ethane-1-sulfonic acid(m/z 971.571 29),arginine-conjugated cholic acid(m/z 587.379 21),and laccaic acid A(m/z 576.010 93)were upregulated,while the expression level of NCGC00380235-01_C32H48O9_beta-D-xylopyranoside,3,17-dihydroxyspirosta-5,25(27)-dien-1-yl(m/z 559.326 48)was downregulated.An IS diagnostic model was established based on four metabolic biomarkers using the XGBoost algorithm.The area under the ROC curve was 1.000(95％CI 1.000-1.000)in the training set and 0.988 in the validation set(95％CI 0.963-1.000).Conclusions Patients with IS exhibit significant metabolic disturbance.The four identified biomarkers may serve as potential biomarkers for the effective identification of IS:2-((3 R)-3-((3R,5S,7S,9S,10S,13R,14S,17R)-3,7-dihydroxy-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-17-yl)butanamido)ethane-1-sulfonic acid(m/z971.571 29),arginine-conjugated cholic acid(m/z587.379 21),laccaic acid A(m/z 576.010 93),and NCGC00380235-01_C32H48O9_beta-D-xylopyranoside,3,17-dihydroxyspirosta-5,25(27)-dien-1-yl(m/z 559.326 48).

OBJCTIVE To evaluate the therapeutic efficacy of intranasal administration of pirfeni-done in treating paraquat-induced pulmonary fibrosis in mice across treatment durations.METHODS Eight-week-old male C57BL/6 mice were randomly divided into six groups(n=8 per group):the normal control group(saline),pirfenidone control group,paraquat group,and three treatment groups receiving a combination of paraquat and pirfenidone for 15,10 and 5 d,respectively.Except the normal and pirfeni-done control groups,all the mice received intraperitoneal injection of paraquat(35 mg·kg-1)to induce pulmonary fibrosis.In the treatment groups,pirfenidone(20 mg·kg-1)was delivered intranasally once daily,beginning on days 1,6,and 11 post-paraquat exposure,until day 15.Fifteen days after paraquat exposure,pulmonary function tests,micro-CT imaging,and arterial blood gas analysis were performed.Histopathological changes and collagen fiber deposition in lung tissues were examined using HE and Masson staining respectively.The protein expression levels of fibrosis markers,including fibronectin(FN),collagen typeⅠ(CollⅠ),E-cadherin(E-cad),vimentin(Vim),and α-smooth muscle actin(α-SMA),were detected by Western blotting.Additionally,inflammatory and pro-fibrotic cytokines,such as tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),IL-8,IL-1β,and connective tissue growth factor(CTGF),were quantified using ELISA.RESULTS Compared with the normal control group,mice treated with paraquat exhibited significant respiratory alterations,including prolonged expiratory time(TE),increased enhanced pause(PENH),and reduced tidal volume(TV).CT imaging revealed reticular high-density shadows and ground-glass opacities in paraquat-treated mice.Blood gas analysis showed reduced partial pressure of oxygen(PaO2),oxygen saturation of blood(SaO2),fractional oxygen saturation of hemoglobin(FO2 Hb),and central venous oxygen saturation(ScvO2),along with increased partial pressure of carbon dioxide(PaCO2)and fractional deoxyhemoglobin saturation(FHHb),indicating that mice exposed to para-quat exhibited severe hypoxemia and hypercapnia.Histological evaluation highlighted pronounced lung interstitial thickening,alveolar collapse,inflammatory infiltration,and extensive fibrotic changes marked by collagen accumulation.Furthermore,exposure to paraquat significantly increased the protein levels of FN,CollⅠ,vimentin,and α-SMA,markedly reduced E-cadherin levels and elevated the levels of inflam-matory cytokines(TNF-α,IL-6,IL-8 and IL-1β)as well as the pro-fibrotic cytokine CTGF.Pirfenidone treat-ment demonstrated time-dependent efficacy,with the 15 d group showing the most significant improvements in pulmonary function as evidenced by reduced PENH levels and increased TV,EV and MV.CT imaging revealed a decrease in high-density opacities and improved lung transparency after pirfenidone treatment.In addition,arterial blood gas measurements indicated markedly elevated levels of PaO2,SaO2 and FO2 Hb.Histological analysis showed that pirfenidone alleviated lung interstitial thick-ening,reduced inflammatory cell infiltration,and decreased collagen deposition.At the molecular level,pirfenidone significantly reduced the protein expressions of FN,CollⅠ,Vim and α-SMA,while increasing E-cad levels.Furthermore,inflammatory cytokines,particularly IL-6 and IL-1β,were notably suppressed following pirfenidone intervention.CONCLUSION Intranasal administration of pirfenidone can exhibit potent time-dependent anti-fibrotic efficacy in paraquat-induced pulmonary fibrosis,with early interven-tions delivering the most substantial therapeutic benefits.

OBJECTIVE To establish skin contamination models with sulfur mustard analogue 1-chloro-2-ethylsulfanyl ethane(CEES),and evaluate the therapeutic efficacy of reactive skin decontamination lotion kit(RSDL).METHODS ①Kunming,BALB/c,BALB/c-nu,and C57BL/6N were contaminted with CEES 75 μL·kg-1 using exposed method and covered method for 10 min on the dorsal skin.Wound healing times and areas were assessed to determine the stock of mice and exposure method.② BALB/c mice were exposed to a gradient of CEES at the doses of 75,150,250,350 and 500 μL·kg-1(10 min)using the covered method.Wound healing times,areas and Kaplan-Meier survival curves were used to determine the optimal dose.③ BALB/c mice were exposed to CEES 150 μL·kg-1 for varying durations(5,10 and 20 min)using the covered method.Wound healing times,areas and Kaplan-Meier survival curves were analyzed to determine the optimal exposure time.④ BALB/c mice were divided into four groups:control(exposed with the covered method at 150 μL·kg-1,10 min),treatment(20 μL RSDL treatment after exposure,as the control group),5 min treatment(20 μL RSDL treatment after 5 min of exposure,followed by 5 min of coverage)and immediate-treatment(exposed with the exposed method at 150 μL·kg-1,immediately treated with 20 μL RSDL,followed by 10 min of coverage).The therapeutic efficacy was evaluated based on the wound area,subcutaneous microvesicle count,epidermal thick-ness,and inflammatory cytokine(IL-6 and TNF-α)expressions.RESULTS ① The covered method caused more severe and prolonged wounds than the exposed method.BALB/c mice exhibited a high sensitivity to CEES with delayed wound healing and were therefore selected as the model animal.② Survival rates in BALB/c mice dropped below 50%at doses of 250,350 and 500 μL·kg-1,whereas an 83.3%survival rate was observed at 150 μL·kg-1.③ The mice exposed to CEES(150 μL·kg-1,20 min)died within 3 days.The wound area was consistently smaller in the 5 min covered group than in the 10 min covered group.④CEES-induced skin injury led to epidermal nuclear pyknosis,follicular disrup-tion,inflammatory infiltration,and microvesicle formation in both treatment and poisoned control groups.As more immediate treatment,the wound area significantly decreased.While the IL-6 expres-sion showed no significant intergroup difference,the TNF-α expression was significantly higher in the treatment group.CONCLUSION A CEES-induced skin contamination model has been established in BALB/c mice using the covered method(150 μL·kg-1,10 min covered).However,RSDL should be ad-ministered in 10 min post-contamination.

OBJECTIVE To construct novel central nervous system(CNS)-targeted lipid nanoparti-cles for the treatment of organophosphorus-induced brain injury in mice.METHODS(1)Preparation,screening,and characterization of lipid nanoparticles.① Lipid nanoreactivators were prepared using the thin-film hydration method,with asoxime(HI-6)as the therapeutic drug and lipid carriers composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine(POPS),1,2-dipalmitoyl-sn-glycero-3-phospho-choline(DPPC),and cholesterol(CHOL)(PDC)at varying molar ratios(1∶6∶3,3∶4∶3,5∶2∶3 and 7∶0∶3)(HI-6@PDC 1∶6∶3,3∶4∶3,5∶2∶3 and 7∶0∶3).② FLU-labeled lipid nanocarriers(FLU@PDC 1∶6∶3,3∶4∶3,5∶2∶3,and 7∶0∶3)were prepared and physically mixed with phospholipase A2(PLA2)solution(at the final PLA2 concentration of 10 kU·L-1)to obtain FLU@PDC+PLA2.Male KM mice were randomly divided into normal control(PBS),FLU,and FLU@PDC+PLA2(1∶6∶3,3∶4∶3,5∶2∶3,and 7∶0∶3)groups(n=7 per group).After intravenous(iv)administration(FLU dose:1 mg·kg-1,carrier dose:80 mg·kg-1),brain tissues were collected at 1 h,homogenized,centrifuged,and analyzed via fluorescence spectrophotom-etry to screen the optimal CNS-targeted lipid carrier composition.③ The morphology of HI-6@PDC 5∶2∶3 was characterized by transmission electron microscope(TEM).The particle size,polydispersity index(PDI),and zeta potential of HI-6@PDC 5∶2∶3 were measured using a Zeta potential and particle size analyzer.Encapsulation efficiency and loading efficiency of HI-6@PDC 5∶2∶3 were determined using an ultrafiltration centrifugation method combined with high-performance liquid chromatography(HPLC).In vitro release kinetics of HI-6@PDC 5∶2∶3 and HI-6@PDC+PLA2 5∶2∶3 were assessed using a dialysis bag diffusion method combined with fluorescence spectrophotometry.(2)Validation of CNS targeting.① Cyanine7(Cy7)-labeled PDC 5∶2∶3(Cy7@PDC)was prepared and mixed with PLA2 solution(Cy7@PDC+PLA2 5∶2∶3).Mice were divided into normal control,Cy7,Cy7@PDC 5∶2∶3 and Cy7@PDC+PLA2 5∶2∶3 groups(n=3 per group).After iv injection(Cy7 dose:1 mg·kg-1,carrier dose:80 mg·kg-1),brain fluorescence was visualized at 3 h using a small animal in vivo imaging(IVIS)system.② Cyanine 3(Cy3)-labeled PDC 5∶2∶3(Cy3@PDC 5∶2∶3)was prepared and mixed with PLA2 solution(Cy3@PDC+PLA2 5∶2∶3).Mice were divided into Cy3@PDC 5∶2∶3 and Cy3@PDC+PLA2 5∶2∶3 groups(n=3 per group).After iv injection(Cy3 dose:1 mg·kg-1,carrier dose:80 mg·kg-1),brain tissues were collected at 2 h for fluorescent staining and Cy3 fluorescence observation.(3)Therapeutic efficacy eval-uation.① Male KM mice were randomly divided into normal control,brain injury,HI-6 treatment,and HI-6@PDC+PLA2 5∶2∶3 treatment groups(n=6 per group).Except for the normal control,all the mice were subcutaneously(sc)injected with soman(120 μg·kg-1),followed by immediate iv treatment(HI-6 dose:22 mg·kg-1,carrier dose:80 mg·kg-1).At 10 min,orbital blood and brain tissues were collected before brain weight was recorded.Acetylcholinesterase(AChE)reactivation in blood and brain was measured using the Ellman method.② Grouping and treatment were identical to ①(n=3 per group).At 24 h,brain tissues were collected for HE staining to assess histopathological damage.③ Mice were divided into brain injury and HI-6@PDC+PLA2 5∶2∶3 treatment groups(n=10 per group)and treated as in ①(soman dose:220 ug·kg-1).Survival rates,neurotoxic symptoms(tremors,salivation),and seizure latency were recorded,and survival curves were plotted.RESULTS(1)PDC 5∶2∶3 exhibited the highest brain fluorescence,indicating optimal CNS targeting.HI-6@PDC 5∶2∶3 appeared in regular spherical shapes,and were negatively charged,with a size of(219.4±3.1)nm,PDI of 0.4±0.02,entrapment effi-ciency of 72.9％and loading efficiency of 49.7％.HI-6@PDC+PLA2 5∶2∶3 showed a cumulative release of 43.5％at 60 min,which was lower than that of rhodamine B(RB)but sufficient for CNS therapeutic timelines.(2)In vivo fluorescence and pathological fluorescence confirmed PLA2-mediated CNS delivery.(3)HI-6@PDC+PLA2 5∶2∶3 significantly enhanced AChE reactivation in the blood and brain compared to HI-6.Histopathology revealed mitigated brain injury in treated mice.HI-6@PDC+PLA2 5∶2∶3 prolonged survival,reduced convulsions,alleviated neurotoxicity,and extended seizure latency.CONCLUSION HI-6@PDC 5∶2∶3 can effectively cross the blood-brain barrier via PLA2 mediation,demonstrating strong CNS targeting.It can significantly improve AChE reactivation in peripheral and central tissues and offers potent therapeutic efficacy against organophosphate-induced brain injury.