1.Oxidative Stress-related Signaling Pathways and Antioxidant Therapy in Alzheimer’s Disease
Li TANG ; Yun-Long SHEN ; De-Jian PENG ; Tian-Lu RAN ; Zi-Heng PAN ; Xin-Yi ZENG ; Hui LIU
Progress in Biochemistry and Biophysics 2025;52(10):2486-2498
Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive cognitive decline, functional impairment, and neuropsychiatric symptoms. It represents the most prevalent form of dementia among the elderly population. Accumulating evidence indicates that oxidative stress plays a pivotal role in the pathogenesis of AD. Notably, elevated levels of oxidative stress have been observed in the brains of AD patients, where excessive reactive oxygen species (ROS) can cause extensive damage to lipids, proteins, and DNA, ultimately compromising neuronal structure and function. Amyloid β‑protein (Aβ) has been shown to induce mitochondrial dysfunction and calcium overload, thereby promoting the generation of ROS. This, in turn, exacerbates Aβ aggregation and enhances tau phosphorylation, leading to the formation of two pathological features of AD: extracellular Aβ plaque deposition and intracellular neurofibrillary tangles (NFTs). These events ultimately culminate in neuronal death, forming a vicious cycle. The interplay between oxidative stress and these pathological processes constitutes a core link in the pathogenesis of AD. The signaling pathways mediating oxidative stress in AD include Nrf2, RCAN1, PP2A, CREB, Notch1, NF‑κB, ApoE, and ferroptosis. Nrf2 signaling pathway serves as a key regulator of cellular redox homeostasis, exerts important antioxidant capacity and protective effects in AD. RCAN1 signaling pathway, as a calcineurin inhibitor, and modulates AD progression through multiple mechanisms. PP2A signaling pathway is involved in regulating tau phosphorylation and neuroinflammation processes. CREB signaling pathway contributes to neuroplasticity and memory formation; activation of CREB improves cognitive function and reduce oxidative stress. Notch1 signaling pathway regulates neuronal development and memory, participates in modulation of Aβ production, and interacts with Nrf2 toco-regulate antioxidant activity. NF‑κB signaling pathway governs immune and inflammatory responses; sustained activation of this pathway forms “inflammatory memory”, thereby exacerbating AD pathology. ApoE signaling pathway is associated with lipid metabolism; among its isoforms, ApoE-ε4 significantly increases the risk of AD, leading to elevated oxidative stress, abnormal lipid metabolism, and neuroinflammation. The ferroptosis signaling pathway is driven by iron-dependent lipid peroxidation, and the subsequent release of lipid peroxidation products and ROS exacerbate oxidative stress and neuronal damage. These interconnected pathways form a complex regulatory network that regulates the progression of AD through oxidative stress and related pathological cascades. In terms of therapeutic strategies targeting oxidative stress, among the drugs currently used in clinical practice for AD treatment, memantine and donepezil demonstrate significant therapeutic efficacy and can improve the level of oxidative stress in AD patients. Some compounds with antioxidant effects (such asα-lipoic acid and melatonin) have shown certain potential in AD treatment research and can be used as dietary supplements to ameliorate AD symptoms. In addition, non-drug interventions such as calorie restriction and exercise have been proven to exerted neuroprotective effects and have a positive effect on the treatment of AD. By comprehensively utilizing the therapeutic characteristics of different signaling pathways, it is expected that more comprehensive multi-target combination therapy regimens and combined nanomolecular delivery systems will be developed in the future to bypass the blood-brain barrier, providing more effective therapeutic strategies for AD.
2.Anti-endometritis effect of carbonized Scutellariae Radix in mice induced by LPS via inhibiting cell pyroptosis through IKBKE/NLRP3 signaling axis.
Hong TAO ; Rang-Rang TANG ; Qing SU ; Li HUANG ; Li-Li LI ; De-Ling WU ; Qi HUANG
China Journal of Chinese Materia Medica 2025;50(11):3024-3034
This paper investigated the inhibitory effect of carbonized Scutellariae Radix(Cb-SR) on pyroptosis in endometrial epithelial cells of mice with endometritis and its correlation with the IKBKE/NLRP3 signaling axis. Mice model of endometritis was established by using an intrauterine injection of 10 μL polysaccharides(LPS, 5 mg·mL~(-1)), and the mice were randomly divided into model group(LPS), low-dose group of Cb-SR(L-Cb-SR, 0.55 g·kg~(-1)), medium-dose group of Cb-SR(M-Cb-SR, 1.10 g·kg~(-1)), high-dose group of Cb-SR(H-Cb-SR, 2.20 g·kg~(-1)), crude Scutellariae Radix group(Cr-SR, 1.63 g·kg~(-1)), and Fuke Qianjin Capsule group(FQC, 0.30 g·kg~(-1)), with 10 mice in each group. Ten healthy female mice were selected and injected with PBS of equal volume into the bilateral uterus, and they were set as the sham group. The mice in the drug treatment groups were given the corresponding doses of Cb-SR, Cr-SR, FQC, or physiological saline of equal volume by gavage twice a day for seven days. Thirty minutes after the last administration, each mouse was euthanized by cervical dislocation. Hematoxylin-eosin(HE) staining and transmission electron microscopy were applied to observe the histopathological morphology of the uterine tissue. Immunohistochemistry was used to detect the expression of CD38 and CD138. Myeloperoxidase(MPO) values in neutrophils were measured by the kit; Enzyme-linked immunosorbent assay(ELISA) was used to measure the secretion of interleukin-18(IL-18), interleukin-1β(IL-1β), and tumor necrosis factor-α(TNF-α). Immunofluorescence and Western blot were used to analyze the expression of the proteins related to the IKBKE/NLRP3 signaling axis. Mouse endometrial epithelial cells(MEECs) were separated and purified from the uterine tissue of pregnant female mice through in vitro experiments and injured by LPS for 24 h, and then they were cultured with Cb-SR-containing serum. The anti-endometritis effect of Cb-SR was investigated by CCK-8 assay, scanning electron microscopy, and Western blot. The results showed that Cb-SR significantly reduced MPO values, attenuated uterine tissue damage, inhibited the expression of CD38 and CD138, decreased the levels of IL-1β, IL-18, and TNF-α, and inhibited the expression of proteins associated with IKBKE/NLRP3 signaling axis in mice with endometritis. In addition, Cb-SR-containing serum reduced swelling of MEECs organelles induced by LPS, decreased the expression of inflammatory factors, and suppressed the expression of IKBKE/NLRP3 signaling axis-related proteins. These results suggest that Cb-SR can inhibit endometrial epithelial cell pyroptosis in endometritis by suppressing the IKBKE/NLRP3 signaling axis.
Animals
;
Female
;
Mice
;
Pyroptosis/drug effects*
;
Signal Transduction/drug effects*
;
NLR Family, Pyrin Domain-Containing 3 Protein/genetics*
;
Drugs, Chinese Herbal/chemistry*
;
Endometritis/chemically induced*
;
Lipopolysaccharides/adverse effects*
;
Scutellaria baicalensis/chemistry*
;
Humans
;
Epithelial Cells/drug effects*
3.Buqi-Tongluo Decoction inhibits osteoclastogenesis and alleviates bone loss in ovariectomized rats by attenuating NFATc1, MAPK, NF-κB signaling.
Yongxian LI ; Jinbo YUAN ; Wei DENG ; Haishan LI ; Yuewei LIN ; Jiamin YANG ; Kai CHEN ; Heng QIU ; Ziyi WANG ; Vincent KUEK ; Dongping WANG ; Zhen ZHANG ; Bin MAI ; Yang SHAO ; Pan KANG ; Qiuli QIN ; Jinglan LI ; Huizhi GUO ; Yanhuai MA ; Danqing GUO ; Guoye MO ; Yijing FANG ; Renxiang TAN ; Chenguang ZHAN ; Teng LIU ; Guoning GU ; Kai YUAN ; Yongchao TANG ; De LIANG ; Liangliang XU ; Jiake XU ; Shuncong ZHANG
Chinese Journal of Natural Medicines (English Ed.) 2025;23(1):90-101
Osteoporosis is a prevalent skeletal condition characterized by reduced bone mass and strength, leading to increased fragility. Buqi-Tongluo (BQTL) decoction, a traditional Chinese medicine (TCM) prescription, has yet to be fully evaluated for its potential in treating bone diseases such as osteoporosis. To investigate the mechanism by which BQTL decoction inhibits osteoclast differentiation in vitro and validate these findings through in vivo experiments. We employed MTS assays to assess the potential proliferative or toxic effects of BQTL on bone marrow macrophages (BMMs) at various concentrations. TRAcP experiments were conducted to examine BQTL's impact on osteoclast differentiation. RT-PCR and Western blot analyses were utilized to evaluate the relative expression levels of osteoclast-specific genes and proteins under BQTL stimulation. Finally, in vivo experiments were performed using an osteoporosis model to further validate the in vitro findings. This study revealed that BQTL suppressed receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis and osteoclast resorption activity in vitro in a dose-dependent manner without observable cytotoxicity. The inhibitory effects of BQTL on osteoclast formation and function were attributed to the downregulation of NFATc1 and c-fos activity, primarily through attenuation of the MAPK, NF-κB, and Calcineurin signaling pathways. BQTL's inhibitory capacity was further examined in vivo using an ovariectomized (OVX) rat model, demonstrating a strong protective effect against bone loss. BQTL may serve as an effective therapeutic TCM for the treatment of postmenopausal osteoporosis and the alleviation of bone loss induced by estrogen deficiency and related conditions.
Animals
;
NFATC Transcription Factors/genetics*
;
Drugs, Chinese Herbal/pharmacology*
;
Ovariectomy
;
Osteoclasts/metabolism*
;
Female
;
Osteogenesis/drug effects*
;
Rats, Sprague-Dawley
;
Rats
;
NF-kappa B/genetics*
;
Osteoporosis/genetics*
;
Signal Transduction/drug effects*
;
Bone Resorption/genetics*
;
Cell Differentiation/drug effects*
;
Humans
;
RANK Ligand/metabolism*
;
Mitogen-Activated Protein Kinases/genetics*
;
Transcription Factors
4.Highly Sensitive Detection of Water in Organic Solvents Using Pyrene-Phenol-based Fluorescent Probe
Jing LIANG ; Yan-Li WANG ; Cui-Wen JIANG ; Xiao-Chuan HUANG ; Li TANG ; Tao LI ; Yu YA ; De-Jiao NING ; Li-Ping XIE ; Fei-Yan YAN
Chinese Journal of Analytical Chemistry 2025;53(6):894-902,中插1-中插5
A pyrene-phenol-based fluorescent probe PyP which showed typical intramolecular charge transfer(ICT)and monomer-excimer activities was synthesized by using pyrene carboxaldehyde hydrazone and 4-tert-butyl-2,6-diformylphenol as the raw materials.The effects of solvents on PyP were studied,and the results showed that the color of protic polar solvents(Ethanol,N,N-dimethylformamide,methanol and H2O)were successfully identified.Based on the solvent polarity-regulated PyP monomer-excimer switching,the rapid and highly sensitive ratiometric probe,"Turn-off"and"Turn-on"multimodal probes were established for detection of trace water content in organic solvents(Dimethyl sulfoxide,N,N-dimethylformamide,ethanol and methanol),with detection limits(3σ/k)of 0.0021%,0.046%,0.062%and 0.024%.The method was successfully used to detect water content in dimethyl sulfoxide,N,N-dimethy lformamide,ethanol and methanol commercial organic solvents,with recoveries ranging from 97.2%to 108.0%.The developed method showed good accuracy and stability,and had good application prospect.
5.Establishment and preliminary evaluation of droplet digital PCR methods for detecting Schistosoma japonicum DNA in host infection
Xian-shi TANG ; Jing YANG ; Guo-li QU ; Yong-liang XU ; De-sheng TONG
Chinese Journal of Zoonoses 2025;41(5):544-552
This study established a droplet digital PCR(ddPCR)EvaGreen assay and probe methods for Schistosoma japonicum detection,and evaluated their application in detecting early infections in the S.japonicum host oncomelania and mice.Primers and corresponding probes for both ddPCR methods were designed and synthesized,and plasmids containing target sequences were constructed.The sensitivity of the two methods was tested through detection of the corresponding plasmids,and infectious and mixed oncomelania genomic DNA.Their specificity was evaluated by the detection of genomic DNA of negative oncomelania,Schistosoma mansoni,Clonorchis sinensis,Spirometra mansoni,and S.japonicum(as a positive control).The ddPCR probe method was evaluated by detection of early infection of oncomelania exposed tomiracidium with various ratios and incubation times,and the early migration and distribution of cercaria or schistosomula in mouse hosts infected with 200 cercaria via abdominal skin contact.According to standard curves constructed through the detection of plasmid serial dilutions,the regression equation for the EvaGreen assay was y=-0.839 9x+7.050 9,with a correlation coefficient R2=0.988 1,and the regression equation for the probe method was y=-1.047 5x+7.255 1,with a correlation coefficient R2=0.999 8.The lowest limit of plasmid detection with the probe method was between 38.94 cp/μL and 194.74 cp/μL.Both methods successfully detected positive reactions in the genomic DNA samples of infectious oncomelania at concentrations above 0.002 ng/μL and in the genomic DNA of each group of oncomelania mixtures.No significant differences between probe methods were observed in the detection values in the control group and the genomic DNA of negative oncomelania,S.mansoni,C.sinensis,and S.mansoni.However,the detection value of genomic DNA of negative oncomelania(291 ng/μL)with the EvaGreen assay was(20.3±4.39)cp/μL,a value significantly higher than the(1.5±0.1)cp/μL observed in the control group.For detection of early infection in oncomelania,the probe method detected Schistosoma japonicum DNA after 30 s incubation at room temperature with a≥5∶1 ratio of miracidium to oncomelania;the detection value peaked after a short time(5 min),and the peak value showed a fold increase similar to the increase in the miracidium to oncomelania ratio.Detection of early stage infection in mice with the probe method revealed that the schistosomula entered the lungs on day 2 and the liver on day 4,and continually migrated within the organs with abundant blood supply(spleen,kidney,and brain)in the first 9 days;moreover,a tendency toward ectopic parasitism was observed in the heart and pancreas on day 9,and a constantly negative control level was observed in the testes.The ddPCR probe method was more accurate and specific than the EvaGreen assay in the detection of plasmids,and infectious and mixed oncomelania,and the latter showed non-specific reactions in negative oncomelania detection.In a practical application,the probe method was demonstrated to be sensitive,to effectively reflect the early infection of oncomelania,and to reveal schistosomula migration and distribution in multiple organs of infected mice.
6.Mechanism of action of Qingjie Huagong decoction reducing inflammatory response of acute pancreatitis based on PI3K/AKT/NF-κB signaling pathway
Xiao-dong ZHU ; Min-chao FENG ; Kun-rong LIU ; Ying BAN ; Pan SU ; Chuan-feng XUAN ; Xiao-yi HUANG ; De-wen LI ; Xi-ping TANG ; Guo-zhong CHEN
Chinese Pharmacological Bulletin 2025;41(5):978-984
Aim To explore the therapeutic effect and mechanism of Qingjie Huagong decoction in modulating PI3K/AKT/NF-κB signaling pathway in inflammatory response of acute pancreatitis(AP)mice.Methods Twenty-four mice were randomly divided into Blank group,Model group,Ustekin group,and Qingjie Hua-gong decoction group,with six mice in each group.The AP model was prepared by using rain frogin.Serum α-AMS,PNLP,IL-1β,IL-6,IL-8,IL-18,and TNF-α lev-els were detected by ELISA;the pancreatic pathology was detected by HE staining;the expressions of PI3K,AKT,and NF-κB-related proteins and mRNAs were de-tected by immunohistochemistry,Western blot,and RT-qPCR.Results Compared with the blank group,the model group showed obvious pathological damage to the pancreas,with significantly higher serum α-AMS,PN-LP,IL-1β,IL-6,IL-8,IL-18,and TNF-α levels(P<0.01),and significantly higher levels of PI3K,AKT,and NF-κB-related proteins and mRNA expression(P<0.01).Compared with the model group,both the Qingjie Huagong decoction group and the ustekin group improved the histopathological changes in the pancreas of AP mice,decreased the serum α-AMS,PNLP,IL-1β,IL-6,IL-8,IL-18,and TNF-α levels,and down-reg-ulated the expression levels of pancreatic PI3K,AKT,NF-κB-related proteins and mRNA(P<0.05 or P<0.01).Conclusion Qingjie Huagong decoction may inhibit the inflammatory response and protect pancreat-ic tissues by regulating the expression of PI3K/AKT/NF-κB signaling pathway.
7.Mechanism of action of Qingjie Huagong decoction reducing inflammatory response of acute pancreatitis based on PI3K/AKT/NF-κB signaling pathway
Xiao-dong ZHU ; Min-chao FENG ; Kun-rong LIU ; Ying BAN ; Pan SU ; Chuan-feng XUAN ; Xiao-yi HUANG ; De-wen LI ; Xi-ping TANG ; Guo-zhong CHEN
Chinese Pharmacological Bulletin 2025;41(5):978-984
Aim To explore the therapeutic effect and mechanism of Qingjie Huagong decoction in modulating PI3K/AKT/NF-κB signaling pathway in inflammatory response of acute pancreatitis(AP)mice.Methods Twenty-four mice were randomly divided into Blank group,Model group,Ustekin group,and Qingjie Hua-gong decoction group,with six mice in each group.The AP model was prepared by using rain frogin.Serum α-AMS,PNLP,IL-1β,IL-6,IL-8,IL-18,and TNF-α lev-els were detected by ELISA;the pancreatic pathology was detected by HE staining;the expressions of PI3K,AKT,and NF-κB-related proteins and mRNAs were de-tected by immunohistochemistry,Western blot,and RT-qPCR.Results Compared with the blank group,the model group showed obvious pathological damage to the pancreas,with significantly higher serum α-AMS,PN-LP,IL-1β,IL-6,IL-8,IL-18,and TNF-α levels(P<0.01),and significantly higher levels of PI3K,AKT,and NF-κB-related proteins and mRNA expression(P<0.01).Compared with the model group,both the Qingjie Huagong decoction group and the ustekin group improved the histopathological changes in the pancreas of AP mice,decreased the serum α-AMS,PNLP,IL-1β,IL-6,IL-8,IL-18,and TNF-α levels,and down-reg-ulated the expression levels of pancreatic PI3K,AKT,NF-κB-related proteins and mRNA(P<0.05 or P<0.01).Conclusion Qingjie Huagong decoction may inhibit the inflammatory response and protect pancreat-ic tissues by regulating the expression of PI3K/AKT/NF-κB signaling pathway.
8.Clinical characteristics and genetic research of a child with Spastic Paraplegia 52 caused by AP4S1 gene variant and a Literature review
Li YANG ; Zihao ZHU ; Ran HUA ; Baotian WANG ; Junhong JIANG ; Jiulai TANG ; De WU
Chinese Journal of Medical Genetics 2025;42(9):1106-1113
Objective:To explore the clinical phenotype and genetic characteristics of a child with hereditary Spastic paraplegia type 52 (SPG52) due to variant of AP4S1 gene. Methods:A child diagnosed with SPG52 at the Department of Pediatrics of the First Affiliated Hospital of Anhui Medical University in May 2010 was selected as the study subject. Whole-exome sequencing (WES) was carried out for the child and his parents. Candidate variants were confirmed by Sanger sequencing. Pathogenicity of the candidate variant was interpreted according to the guidelines from the American College of Medical Genetics and Genomics (ACMG). The study protocol was approved by the Ethics Committee of the Hospital (Ethics No.: PJ2024-04-56).Results:The child had presented with global developmental delay from infancy, and featured progressive lower limb spasticity, contractures, talipes equinovarus, and muscle weakness, but with no significant facial dysmorphism. His first febrile seizure occurred before one year of age, followed by several afebrile seizures. The seizures had remitted after 3 to 4 years of antiepileptic therapy, and electroencephalography was normal. However, he had severe intellectual disability, and MRI revealed reduced white matter. WES identified a homozygous AP4S1 c. 289C>T (p.Arg97*) variant in the child, for which both of his parents were heterozygous carriers. The variant was rated as pathogenic based on the ACMG guidelines. Literature review has identified 8 publications on SPG52, involving 18 patients from 12 pedigrees. Combined with our case, 14 had carried homozygous variants of the AP4S1 gene, 3 had compound heterozygous variants, and 2 had heterozygous variants, involving 12 distinct variant sites. The cohort included 7 males and 12 females. All patients exhibited progressive lower limb spasticity and weakness as the primary feature, with certain loss of independent ambulation. Most patients had intellectual disability, some had distinctive facial features, though febrile seizures or epilepsy were common. Electroencephalography often showed increased slow-wave activity. Brain MRI frequently demonstrated ventriculomegaly, a thin corpus callosum, and reduced white matter. Conclusion:The homozygous c. 289C>T (p.Arg97*) variant of the AP4S1 gene probably underlay the pathogenesis of SPG52 in this child. Above discovery has expanded the mutational spectrum of AP4S1 and provided valuable insights for the genetic diagnosis, counseling, and clinical management of SPG52.
9.Clinical characteristics and genetic research of a child with Spastic Paraplegia 52 caused by AP4S1 gene variant and a Literature review
Li YANG ; Zihao ZHU ; Ran HUA ; Baotian WANG ; Junhong JIANG ; Jiulai TANG ; De WU
Chinese Journal of Medical Genetics 2025;42(9):1106-1113
Objective:To explore the clinical phenotype and genetic characteristics of a child with hereditary Spastic paraplegia type 52 (SPG52) due to variant of AP4S1 gene. Methods:A child diagnosed with SPG52 at the Department of Pediatrics of the First Affiliated Hospital of Anhui Medical University in May 2010 was selected as the study subject. Whole-exome sequencing (WES) was carried out for the child and his parents. Candidate variants were confirmed by Sanger sequencing. Pathogenicity of the candidate variant was interpreted according to the guidelines from the American College of Medical Genetics and Genomics (ACMG). The study protocol was approved by the Ethics Committee of the Hospital (Ethics No.: PJ2024-04-56).Results:The child had presented with global developmental delay from infancy, and featured progressive lower limb spasticity, contractures, talipes equinovarus, and muscle weakness, but with no significant facial dysmorphism. His first febrile seizure occurred before one year of age, followed by several afebrile seizures. The seizures had remitted after 3 to 4 years of antiepileptic therapy, and electroencephalography was normal. However, he had severe intellectual disability, and MRI revealed reduced white matter. WES identified a homozygous AP4S1 c. 289C>T (p.Arg97*) variant in the child, for which both of his parents were heterozygous carriers. The variant was rated as pathogenic based on the ACMG guidelines. Literature review has identified 8 publications on SPG52, involving 18 patients from 12 pedigrees. Combined with our case, 14 had carried homozygous variants of the AP4S1 gene, 3 had compound heterozygous variants, and 2 had heterozygous variants, involving 12 distinct variant sites. The cohort included 7 males and 12 females. All patients exhibited progressive lower limb spasticity and weakness as the primary feature, with certain loss of independent ambulation. Most patients had intellectual disability, some had distinctive facial features, though febrile seizures or epilepsy were common. Electroencephalography often showed increased slow-wave activity. Brain MRI frequently demonstrated ventriculomegaly, a thin corpus callosum, and reduced white matter. Conclusion:The homozygous c. 289C>T (p.Arg97*) variant of the AP4S1 gene probably underlay the pathogenesis of SPG52 in this child. Above discovery has expanded the mutational spectrum of AP4S1 and provided valuable insights for the genetic diagnosis, counseling, and clinical management of SPG52.
10.Establishment and preliminary evaluation of droplet digital PCR methods for detecting Schistosoma japonicum DNA in host infection
Xian-shi TANG ; Jing YANG ; Guo-li QU ; Yong-liang XU ; De-sheng TONG
Chinese Journal of Zoonoses 2025;41(5):544-552
This study established a droplet digital PCR(ddPCR)EvaGreen assay and probe methods for Schistosoma japonicum detection,and evaluated their application in detecting early infections in the S.japonicum host oncomelania and mice.Primers and corresponding probes for both ddPCR methods were designed and synthesized,and plasmids containing target sequences were constructed.The sensitivity of the two methods was tested through detection of the corresponding plasmids,and infectious and mixed oncomelania genomic DNA.Their specificity was evaluated by the detection of genomic DNA of negative oncomelania,Schistosoma mansoni,Clonorchis sinensis,Spirometra mansoni,and S.japonicum(as a positive control).The ddPCR probe method was evaluated by detection of early infection of oncomelania exposed tomiracidium with various ratios and incubation times,and the early migration and distribution of cercaria or schistosomula in mouse hosts infected with 200 cercaria via abdominal skin contact.According to standard curves constructed through the detection of plasmid serial dilutions,the regression equation for the EvaGreen assay was y=-0.839 9x+7.050 9,with a correlation coefficient R2=0.988 1,and the regression equation for the probe method was y=-1.047 5x+7.255 1,with a correlation coefficient R2=0.999 8.The lowest limit of plasmid detection with the probe method was between 38.94 cp/μL and 194.74 cp/μL.Both methods successfully detected positive reactions in the genomic DNA samples of infectious oncomelania at concentrations above 0.002 ng/μL and in the genomic DNA of each group of oncomelania mixtures.No significant differences between probe methods were observed in the detection values in the control group and the genomic DNA of negative oncomelania,S.mansoni,C.sinensis,and S.mansoni.However,the detection value of genomic DNA of negative oncomelania(291 ng/μL)with the EvaGreen assay was(20.3±4.39)cp/μL,a value significantly higher than the(1.5±0.1)cp/μL observed in the control group.For detection of early infection in oncomelania,the probe method detected Schistosoma japonicum DNA after 30 s incubation at room temperature with a≥5∶1 ratio of miracidium to oncomelania;the detection value peaked after a short time(5 min),and the peak value showed a fold increase similar to the increase in the miracidium to oncomelania ratio.Detection of early stage infection in mice with the probe method revealed that the schistosomula entered the lungs on day 2 and the liver on day 4,and continually migrated within the organs with abundant blood supply(spleen,kidney,and brain)in the first 9 days;moreover,a tendency toward ectopic parasitism was observed in the heart and pancreas on day 9,and a constantly negative control level was observed in the testes.The ddPCR probe method was more accurate and specific than the EvaGreen assay in the detection of plasmids,and infectious and mixed oncomelania,and the latter showed non-specific reactions in negative oncomelania detection.In a practical application,the probe method was demonstrated to be sensitive,to effectively reflect the early infection of oncomelania,and to reveal schistosomula migration and distribution in multiple organs of infected mice.

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