Objective To establish a rat model of Alzheimer's disease (AD) expressing human triple mutant amyloid precursor protein (APP) in the hippocampus, and to provide a model for the study of disease mechanisms and drug development. Methods Twenty-four 12-week-old SPF-grade female SD rats were randomly divided into a blank control group, a virus control group and an experimental group, with eight rats in each group; among them, the experimental group received a stereotaxic injection of adeno-associated virus (AAV) carrying the human triple mutant APP and NanoLuc luciferase genes into the hippocampus. In vivo imaging was used to observe viral expression in the brains of rats in each group, the novel object recognition test was used to assess the recognition memory of the rats in each group, real-time fluorescent quantitative PCR was used to detect the expression level of the APP gene, HE staining was used to examine the brain histopathology, Nissl staining was used to assess the hippocampal lesions, and immunohistochemistry was used to detect the deposition of amyloid β-protein (Aβ). Results In vivo imaging showed that reporter fluorescence was detected in the brains of rats in both experimental and virus control groups. Fluorescence quantitative PCR showed that the expression level of the APP gene was significantly increased in the brains of rats in the experimental group (P<0.01). Novel object recognition test revealed that the recognition memory of rats in the experimental group was significantly reduced compared with that of the blank control group (P<0.01). Six months after recombinant AAV virus infection, HE staining and Nissl staining of brain tissues showed that the number of neurons and Nissl bodies in the CA1 region of the hippocampus in the experimental group was reduced and disorganized; immuno-histochemistry testing of the CA1 region of the hippocampus and the pyramidal cell layer of the experimental group revealed prominent brown deposits, indicating Aβ protein deposition. Conclusion The rat model successfully established by stereotaxic injection and AAV-mediated delivery of human triple mutant APP gene exhibits typical AD features, providing a valuable animal model for studying AD pathology and developing drug therapies targeting Aβ protein deposition.

Objective To establish a rat model of Alzheimer's disease (AD) expressing human triple mutant amyloid precursor protein (APP) in the hippocampus, and to provide a model for the study of disease mechanisms and drug development. Methods Twenty-four 12-week-old SPF-grade female SD rats were randomly divided into a blank control group, a virus control group and an experimental group, with eight rats in each group; among them, the experimental group received a stereotaxic injection of adeno-associated virus (AAV) carrying the human triple mutant APP and NanoLuc luciferase genes into the hippocampus. In vivo imaging was used to observe viral expression in the brains of rats in each group, the novel object recognition test was used to assess the recognition memory of the rats in each group, real-time fluorescent quantitative PCR was used to detect the expression level of the APP gene, HE staining was used to examine the brain histopathology, Nissl staining was used to assess the hippocampal lesions, and immunohistochemistry was used to detect the deposition of amyloid β-protein (Aβ). Results In vivo imaging showed that reporter fluorescence was detected in the brains of rats in both experimental and virus control groups. Fluorescence quantitative PCR showed that the expression level of the APP gene was significantly increased in the brains of rats in the experimental group (P<0.01). Novel object recognition test revealed that the recognition memory of rats in the experimental group was significantly reduced compared with that of the blank control group (P<0.01). Six months after recombinant AAV virus infection, HE staining and Nissl staining of brain tissues showed that the number of neurons and Nissl bodies in the CA1 region of the hippocampus in the experimental group was reduced and disorganized; immuno-histochemistry testing of the CA1 region of the hippocampus and the pyramidal cell layer of the experimental group revealed prominent brown deposits, indicating Aβ protein deposition. Conclusion The rat model successfully established by stereotaxic injection and AAV-mediated delivery of human triple mutant APP gene exhibits typical AD features, providing a valuable animal model for studying AD pathology and developing drug therapies targeting Aβ protein deposition.

Human naïve pluripotent stem cells (PSCs) hold great promise for embryonic development studies. Existing induction and culture strategies for these cells, heavily dependent on MEK inhibitors, lead to widespread DNA hypomethylation, aberrant imprinting loss, and genomic instability during extended culture. Here, employing high-content analysis alongside a bifluorescence reporter system indicative of human naïve pluripotency, we screened over 1,600 chemicals and identified seven promising candidates. From these, we developed four optimized media-LAY, LADY, LUDY, and LKPY-that effectively induce and sustain PSCs in the naïve state. Notably, cells reset or cultured in these media, especially in the LAY system, demonstrate improved genome-wide DNA methylation status closely resembling that of pre-implantation counterparts, with partially restored imprinting and significantly enhanced genomic stability. Overall, our study contributes advancements to naïve pluripotency induction and long-term maintenance, providing insights for further applications of naïve PSCs.
Humans ; DNA Methylation/drug effects* ; Genomic Instability ; Pluripotent Stem Cells/metabolism* ; Cell Culture Techniques/methods* ; Cells, Cultured

Senecavirus A (SVA) is a major viral pathogen causing disease in pigs, and effective monitoring of SVA infection is critical for disease control. In this study, we aimed to develop a reliable ELISA method for rapidly detecting neutralizing antibodies against SVA. We used HEK293F cells to express an SVA-specific porcine Fab antibody and verified the biological activity of the Fab antibody by indirect ELISA, immunofluorescence assay, virus neutralization test, and Western blotting. The Fab antibody was biotinylated and used as a competitive antibody to establish a competitive ELISA (C-ELISA) for detecting neutralizing antibodies against SVA. We then evaluated the C-ELISA in terms of sensitivity, specificity, repeatability, and result agreement rate with the VNT. The results showed that we successfully prepared an SVA-specific porcine Fab antibody, which showed high affinity for SVA. We named this antibody 1M33Fab and designated it as Bio-1M33Fab after biotin labeling. The assay conditions were optimized as follows: the coating concentration of SVA particles being 1 μg/mL, the working concentration of Bio-1M33Fab being 0.5 μg/mL, the optimal serum dilution of 1:10, and the optimal dilution of enzyme-labeled avidin being 1:30 000. At a percent inhibition (PI) of 47%, the assay demonstrated the highest sensitivity (96.88%) and specificity (100%), with no cross-reactivity observed with the positive sera of major porcine viral diseases. The intra-assay coefficient of variation ranged from 1.12% to 7.34%, while the inter-assay coefficient of variation ranged from 1.10% to 8.97%, indicating good repeatability. In the detection of 224 clinical pig serum samples, C-ELISA and VNT showed a result agreement rate of 93.75%. In conclusion, we successfully develop a C-ELISA method for detecting neutralizing antibodies against SVA by using a porcine-derived Fab antibody, which lays a foundation for the development of detection kits.
Animals ; Swine ; Antibodies, Neutralizing/immunology* ; Enzyme-Linked Immunosorbent Assay/methods* ; Immunoglobulin Fab Fragments/immunology* ; Antibodies, Viral/immunology* ; Picornaviridae/immunology* ; Humans ; HEK293 Cells ; Swine Diseases/diagnosis* ; Picornaviridae Infections/diagnosis*

ObjectiveTo investigate the role of sphingosine-1-phosphate （S1P） in abnormal ossification in ankylosing spondylitis （AS）， clarify the relationship between S1P and “angiogenesis-osteogenesis” coupling， and provide new strategies for AS treatment. MethodsFemoral heads from AS patients and patients undergoing routine hip replacement were collected for immunohistochemical （IHC） staining to evaluate osteogenesis and H-type vessel formation. In vitro， ELISA was used to quantify the synthesis of S1P and analyze the expression changes of S1P signaling pathway-related molecules during the osteogenic differentiation of mesenchymal stem cells derived from patients with ankylosing spondylitis （ASMSCs） and those from healthy donors （HDMSCs）， to evaluate the activation status of S1P pathway during osteogenesis. Sphingosine kinase 1 （SK1） expression was knocked down in MSCs， and the S1P receptor inhibitor FTY720 was applied to block S1P signaling. Alkaline phosphatase （ALP） activity and Alizarin Red S （ARS） quantification were used to assess the effect of S1P on ASMSCs osteogenesis. Conditioned medium from osteogenically induced MSCs was used to treat human umbilical vein endothelial cells （HUVECs） to evaluate the effect of S1P on angiogenesis. An AS mouse model （SKG mice） was treated with FTY720 or the SK1 inhibitor PF-543 citrate. IHC staining and micro-CT scanning were used to assess abnormal ossification and spinal fusion， and immunofluorescence was used to evaluate H-type vessel formation. ResultsCompared with Osteonecrosis of the Femoral Head（ONFH） patients， AS patients exhibited excessive osteogenesis and H-type vessel formation （OCN P＜0.001， CD31 P＜0.001， EMCN P＜0.001）. During osteogenic differentiation， S1P expression and secretion were significantly higher in ASMSCs than in HDMSCs （P=0.0179）. Inhibition of S1P signaling with FTY720 or SK1 knockdown significantly suppressed osteogenic differentiation （compared with ASMSC， ARS： HDMSC P=0.001 8， FTY720 P＜0.001， si-SK1 P＜0.001； ALP： HDMSC P=0.032 8， FTY720 P=0.001 6， si-SK1 P＜0.001） of ASMSCs and the angiogenesis of HUVEC（compared with ASMSC， cell-covered area， total loops， total tube length and total branch points P＜0.001）. Treatment with FTY720 or PF-543 markedly inhibited abnormal ossification and spinal fusion（compared with Curdlan， arthritis index score， P＜0.001； OCN：control P=0.002， PF-543 P=0.010 7， FTY720 P=0.015 9 ） in AS mice and reduced H-type vessel formation （CD31⁺EMCN⁺： compared with curdlan， control P＜0.001， PF-543 P=0.001 7， FTY720 P=0.002 1）. ConclusionIncreased S1P synthesis in ASMSCs promotes osteogenic differentiation via autocrine mechanisms and further enhances ossification by facilitating H-type angiogenesis. Inhibiting S1P secretion in ASMSCs significantly suppresses abnormal ossification in AS.

ObjectiveTo investigate the effects of Anmeidan （AMD） on cognitive function， cytochrome C （Cyt C） signaling pathway protein expression， and apoptosis in a geriatric sleep deprivation model. MethodSixty aged C57 mice were randomly divided into a blank group， a model group， AMD high， medium， and low dose （26.26， 13.13， 6.565 g·kg^-1·d^-1） groups， and a melatonin group （1.3 mg·kg^-1·d^-1）， with 10 mice in each group. Continuous sleep deprivation was performed for 4 weeks using a homemade sleep deprivation box. Cognitive function was assessed using the Morris water maze， and morphological changes in pyramidal cells in the CA1 area of the hippocampus were observed by hematoxylin-eosin （HE） staining and Nissl staining. Transmission electron microscopy was used to observe the mitochondrial morphology and structure of hippocampal neurons. Western blot was used to detect Cyt C， cysteine-aspartate protease-3 （Caspase-3）， cysteine-aspartate protease-9 （Caspase-9）， brain-derived neurotrophic factor （BDNF）， mitochondrial transcription factor A （TFAM）， and voltage-dependent anion channel 1 （VDAC1） protein expression. Immunohistochemistry was used to detect protein expression levels of Cyt C， Caspase-3， and Caspase-9， and immunofluorescence was used to detect the protein expression of B-cell lymphoma 2 （Bcl-2） and Bcl-2-associated X protein （Bax）. ResultCompared with the blank group， the model group showed prolonged platform latency （P<0.01）， reduced number of platform crossings， and reduced time and distance in the target quadrant （P<0.01）. The mitochondrial structure was damaged， with disappearance or breakage of cristae， and increased swelling and deformation. The protein expression levels of Cyt C， Caspase-3， Caspase-9， Bax， and VDAC1 were significantly increased （P<0.01）， while BDNF， TFAM， and Bcl-2 protein expression levels were decreased （P<0.01）. Compared with the model group， the AMD high， medium， and low dose groups improved spatial exploration and navigation abilities in geriatric sleep-deprived mice （P<0.05， P<0.01）， alleviated mitochondrial damage， and increased the number of Nissl bodies. Additionally， the expression levels of Cyt C， Caspase-3， Caspase-9， Bax， and VDAC1 proteins were significantly reduced （P<0.05， P<0.01）， while the expression levels of BDNF， TFAM， and Bcl-2 proteins were significantly increased （P<0.05， P<0.01）. ConclusionAMD improved the cognitive function of geriatric sleep-deprived mice， and its effect may be related to the reduction of apoptosis mediated by the Cyt C signaling pathway.

Background Under the backdrop of the national innovation-driven development strategy, the increasing occupational stress and job burnout among employees are noteworthy for their impact on employees' subjective well-being. Objective To clarify the status, distribution characteristics, and the relationship between subjective well-being, occupational stress, and job burnout of employees in research and development (R&D) enterprises, in order to improve their subjective well-being. Methods A total of 3366 employees from R&D departments at 7 enterprises in Minhang District of Shanghai were selected. The well-being level of the research subjects was investigated by using the World Health Organization Well-Being Index (WHO-5) that yielded total scores from 0 to 25, and a higher total score indicated a higher well-being level; the levels of occupational stress and job burnout were investigated by using the Chinese version of the Job Content Questionnaire, and the Chinese version of the Maslach Burnout Inventory-General Survey (MBI-GS). The scores of WHO-5, JDC, and MBI-GS were incorporated into structural equation modeling (SEM) as numerical variables to analyze their relationship. Results The scores of subjective well-being, occupational stress, and job burnout of employees in the R&D enterprises were 13.30±6.09, 1.12±0.45, and 2.18±1.12, respectively. The positive rates of occupational stress and job burnout were 44.4% and 70.9% respectively, and the positive rate of severe job burnout was 11.7%. There were statistically significant differences in the score of subjective well-being among the participants by gender, age, educational level, marital status, registered residence, working seniority, and jobs (P<0.05); there were statistically significant differences in the positive rate of occupational stress by gender, educational level, marital status, working seniority, and jobs (P<0.05); there were statistically significant differences in the positive rate of job burnout by gender, age, educational level, marital status, registered residence, working seniority, and jobs (P<0.05). There was a negative correlation between subjective well-being and occupational stress (r=−0.1747, P < 0.01), a negative correlation between subjective well-being and job burnout (r=−0.2987, P < 0.01), and a positive correlation between occupational stress and job burnout (r=0.3342, P < 0.01). A structural equation containing partial mediating effect of job burnout on the relationship between occupational stress and subjective well-being was established, and the partial effect accounting for 52.5% of the total effect. Conclusion The job burnout among employees in R&D companies partially mediates the impact of occupational stress on subjective well-being. Reducing the level of job burnout will help alleviate occupational stress and thus improve employees' subjective well-being.

AIM: To observe the changes of corneal densitometry(CD)in patients with keratoconus after corneal cross-linking(CXL).METHODS: Retrospective study. A total of 32 patients(43 eyes)with keratoconus in Ningxia Eye Hospital from April 2020 to April 2022 were selected. Pentacam analysis system divided the cornea into three layers: anterior 120 μm, middle layer and posterior 60 μm, and divides it into five regions with diameters of 0-2, 2-6, 6-10, 10-12 mm and full diameter according to the diameter, and measures the CD in different ranges. The changes of CD were compared before operation and at 1, 3 and 6 mo after operation.RESULTS: There were differences in uncorrected visual acuity, best corrected visual acuity and intraocular pressure before and 6 mo after operation(all P<0.05), and there was no difference in corneal endothelial cells(P=0.477). CD reached its peak at 1 mo after operation, and decreased at 3 mo and 6 mo after operation, but it was still higher than that before operation. There is a significant positive correlation between CD and Kmax in the anterior layer and the whole layer(r=0.164, P=0.016; r=0.152, P=0.023).CONCLUSION: The values of CD peaked at 1 mo after CXL, then it gradually decreased, tending to become stable at 6 mo postoperatively.