1.Data analysis of resolution discrepancies in minipool nucleic acid testing: A 2024 national study of Chinese blood stations
Ying YAN ; Qing HE ; Wei ZHENG ; Jie MA ; Le CHANG ; Huimin JI ; Huizhen SUN ; Lunan WANG
Chinese Journal of Blood Transfusion 2026;39(4):423-429
Objective: To investigate the incidence, characteristics, and influencing factors of resolution discrepancies within the minipool (MP) testing model across Chinese blood station laboratories in 2024. Methods: A nationwide, multicenter, cross-sectional study was conducted, including 334 blood station laboratories that reported nucleic acid reactive data among enzyme immunoassay non-reactive samples. Of these, 296 laboratories adopted the pool resolution model, with a total of 12 536 273 samples tested. Systematic analysis was performed on resolution data, focusing on the MP-NAT reactivity rate, the pool resolution concordance rate, and the resolution discrepancy rate. Subgroup analyses were conducted based on reagent types, viral targets, and Ct values. Potential causes were further explored through laboratory surveys and re-examination of raw amplification curves. Results: In 2024, the national average MP-NAT reactivity rate was 0.15%. The overall pool resolution concordance rate was 57.86%, which showed a gradual decline as Ct values increased across all reagents. The national average resolution discrepancy rate was 0.081‱(102/12 536 273), with 17.91%(53/296) of laboratories reporting at least one discrepancy. Nine reagent types were associated with these events, exhibiting reagent-specific patterns. For Reagent A2, the predominant discrepancy was HBV reactive pools resolving as HIV (36.36%); for Reagent D1, HBV pools frequently resolved as HCV (38.89%); and for Reagent E, the most common pattern was HIV pools resolving as HBV (48.00%). These resolution discrepancies were strongly associated with high Ct values: the median pool Ct for HBV exceeded 38, while those for HCV and HIV both exceeded 40. Investigations across 16 laboratories revealed that most discrepant samples exhibited “tailing” amplification curves, with some cases linked to cross-contamination or reagent batch-specific issues. Conclusion: While the incidence of resolution discrepancies in the MP-NAT model remains low in China, variations exist across different reagents and laboratories. These discrepancies are closely associated with low viral load, reagent performance, and laboratory operational practices.
2.Randomized, double-blind, parallel-controlled, multicenter, equivalence clinical trial of Jiuwei Xifeng Granules(Os Draconis replaced by Ostreae Concha) for treating tic disorder in children.
Qiu-Han CAI ; Cheng-Liang ZHONG ; Si-Yuan HU ; Xin-Min LI ; Zhi-Chun XU ; Hui CHEN ; Ying HUA ; Jun-Hong WANG ; Ji-Hong TANG ; Bing-Xiang MA ; Xiu-Xia WANG ; Ai-Zhen WANG ; Meng-Qing WANG ; Wei ZHANG ; Chun WANG ; Yi-Qun TENG ; Yi-Hui SHAN ; Sheng-Xuan GUO
China Journal of Chinese Materia Medica 2025;50(6):1699-1705
Jiuwei Xifeng Granules have become a Chinese patent medicine in the market. Because the formula contains Os Draconis, a top-level protected fossil of ancient organisms, the formula was to be improved by replacing Os Draconis with Ostreae Concha. To evaluate whether the improved formula has the same effectiveness and safety as the original formula, a randomized, double-blind, parallel-controlled, equivalence clinical trial was conducted. This study enrolled 288 tic disorder(TD) of children and assigned them into two groups in 1∶1. The treatment group and control group took the modified formula and original formula, respectively. The treatment lasted for 6 weeks, and follow-up visits were conducted at weeks 2, 4, and 6. The primary efficacy endpoint was the difference in Yale global tic severity scale(YGTSS)-total tic severity(TTS) score from baseline after 6 weeks of treatment. The results showed that after 6 weeks of treatment, the declines in YGTSS-TSS score showed no statistically significant difference between the two groups. The difference in YGTSS-TSS score(treatment group-control group) and the 95%CI of the full analysis set(FAS) were-0.17[-1.42, 1.08] and those of per-protocol set(PPS) were 0.29[-0.97, 1.56], which were within the equivalence boundary [-3, 3]. The equivalence test was therefore concluded. The two groups showed no significant differences in the secondary efficacy endpoints of effective rate for TD, total score and factor scores of YGTSS, clinical global impressions-severity(CGI-S) score, traditional Chinese medicine(TCM) response rate, or symptom disappearance rate, and thus a complete evidence chain with the primary outcome was formed. A total of 6 adverse reactions were reported, including 4(2.82%) cases in the treatment group and 2(1.41%) cases in the control group, which showed no statistically significant difference between the two groups. No serious suspected unexpected adverse reactions were reported, and no laboratory test results indicated serious clinically significant abnormalities. The results support the replacement of Os Draconis by Ostreae Concha in the original formula, and the efficacy and safety of the modified formula are consistent with those of the original formula.
Adolescent
;
Child
;
Child, Preschool
;
Female
;
Humans
;
Male
;
Double-Blind Method
;
Drugs, Chinese Herbal/therapeutic use*
;
Tic Disorders/drug therapy*
;
Treatment Outcome
3.Multifaceted mechanisms of Danggui Shaoyao San in ameliorating Alzheimer's disease based on transcriptomics and metabolomics.
Min-Hao YAN ; Han CAI ; Hai-Xia DING ; Shi-Jie SU ; Xu-Nuo LI ; Zi-Qiao XU ; Wei-Cheng FENG ; Qi-Qing WU ; Jia-Xin CHEN ; Hong WANG ; Qi WANG
China Journal of Chinese Materia Medica 2025;50(8):2229-2236
This study explored the potential therapeutic targets and mechanisms of Danggui Shaoyao San(DSS) in the prevention and treatment of Alzheimer's disease(AD) through transcriptomics and metabolomics, combined with animal experiments. Fifty male C57BL/6J mice, aged seven weeks, were randomly divided into the following five groups: control, model, positive drug, low-dose DSS, and high-dose DSS groups. After the intervention, the Morris water maze was used to assess learning and memory abilities of mice, and Nissl staining and hematoxylin-eosin(HE) staining were performed to observe pathological changes in the hippocampal tissue. Transcriptomics and metabolomics were employed to sequence brain tissue and identify differential metabolites, analyzing key genes and metabolites related to disease progression. Reverse transcription-quantitative polymerase chain reaction(RT-qPCR) was employed to validate the expression of key genes. The Morris water maze results indicated that DSS significantly improved learning and cognitive function in scopolamine(SCOP)-induced model mice, with the high-dose DSS group showing the best results. Pathological staining showed that DSS effectively reduced hippocampal neuronal damage, increased Nissl body numbers, and reduced nuclear pyknosis and neuronal loss. Transcriptomics identified seven key genes, including neurexin 1(Nrxn1) and sodium voltage-gated channel α subunit 1(Scn1a), and metabolomics revealed 113 differential metabolites, all of which were closely associated with synaptic function, oxidative stress, and metabolic regulation. RT-qPCR experiments confirmed that the expression of these seven key genes was consistent with the transcriptomics results. This study suggests that DSS significantly improves learning and memory in SCOP model mice and alleviates hippocampal neuronal pathological damage. The mechanisms likely involve the modulation of synaptic function, reduction of oxidative stress, and metabolic balance, with these seven key genes serving as important targets for DSS in the treatment of AD.
Animals
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Alzheimer Disease/genetics*
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Male
;
Drugs, Chinese Herbal/administration & dosage*
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Mice
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Mice, Inbred C57BL
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Metabolomics
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Transcriptome/drug effects*
;
Maze Learning/drug effects*
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Hippocampus/metabolism*
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Humans
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Disease Models, Animal
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Memory/drug effects*
4.Mechanism of Qingrun Decoction in alleviating hepatic insulin resistance in type 2 diabetic rats based on amino acid metabolism reprogramming pathways.
Xiang-Wei BU ; Xiao-Hui HAO ; Run-Yun ZHANG ; Mei-Zhen ZHANG ; Ze WANG ; Hao-Shuo WANG ; Jie WANG ; Qing NI ; Lan LIN
China Journal of Chinese Materia Medica 2025;50(12):3377-3388
This study aims to investigate the mechanism of Qingrun Decoction in alleviating hepatic insulin resistance in type 2 diabetes mellitus(T2DM) rats through the reprogramming of amino acid metabolism. A T2DM rat model was established by inducing insulin resistance through a high-fat diet combined with intraperitoneal injection of streptozotocin. The model rats were randomly divided into five groups: model group, high-, medium-, and low-dose Qingrun Decoction groups, and metformin group. A normal control group was also established. The rats in the normal and model groups received 10 mL·kg~(-1) distilled water daily by gavage. The metformin group received 150 mg·kg~(-1) metformin suspension by gavage, and the Qingrun Decoction groups received 11.2, 5.6, and 2.8 g·kg~(-1) Qingrun Decoction by gavage for 8 weeks. Blood lipid levels were measured in different groups of rats. Pathological damage in rat liver tissue was assessed by hematoxylin-eosin(HE) staining and oil red O staining. Transcriptome sequencing and untargeted metabolomics were performed on rat liver and serum samples, integrated with bioinformatics analyses. Key metabolites(branched-chain amino acids, BCAAs), amino acid transporters, amino acid metabolites, critical enzymes for amino acid metabolism, resistin, adiponectin(ADPN), and mammalian target of rapamycin(mTOR) pathway-related molecules were quantified using quantitative real-time polymerase chain reaction(qRT-PCR), Western blot, and enzyme-linked immunosorbent assay(ELISA). The results showed that compared with the normal group, the model group had significantly increased serum levels of total cholesterol(TC), triglycerides(TG), low-density lipoprotein cholesterol(LDL-C), and resistin and significantly decreased ADPN levels. Hepatocytes in the model group exhibited loose arrangement, significant lipid accumulation, fatty degeneration, and pronounced inflammatory cell infiltration. In liver tissue, the mRNA transcriptional levels of solute carrier family 7 member 2(Slc7a2), solute carrier family 38 member 2(Slc38a2), solute carrier family 38 member 4(Slc38a4), and arginase(ARG) were significantly downregulated, while the mRNA transcriptional levels of solute carrier family 1 member 4(Slc1a4), solute carrier family 16 member 1(Slc16a1), and methionine adenosyltransferase(MAT) were upregulated. Furthermore, the mRNA transcription and protein expression levels of branched-chain α-keto acid dehydrogenase E1α(BCKDHA) and DEP domain-containing mTOR-interacting protein(DEPTOR) were downregulated, while mRNA transcription and protein expression levels of mTOR, as well as ribosomal protein S6 kinase 1(S6K1), were upregulated. The levels of BCAAs and S-adenosyl-L-methionine(SAM) were elevated. The serum level of 6-hydroxymelatonin was significantly reduced, while imidazole-4-one-5-propionic acid and N-(5-phospho-D-ribosyl)anthranilic acid levels were significantly increased. Compared with the model group, Qingrun Decoction significantly reduced blood lipid and resistin levels while increasing ADPN levels. Hepatocytes had improved morphology with reduced inflammatory cells, and fatty degeneration and lipid deposition were alleviated. Differentially expressed genes and differential metabolites were mainly enriched in amino acid metabolic pathways. The expression levels of Slc7a2, Slc38a2, Slc38a4, and ARG in the liver tissue were significantly upregulated, while Slc1a4, Slc16a1, and MAT expression levels were significantly downregulated. BCKDHA and DEPTOR expression levels were upregulated, while mTOR and S6K1 expression levels were downregulated. Additionally, the levels of BCAAs and SAM were significantly decreased. The serum level of 6-hydroxymelatonin was increased, while those of imidazole-4-one-5-propionic acid and N-(5-phospho-D-ribosyl)anthranilic acid were decreased. In summary, Qingrun Decoction may improve amino acid metabolism reprogramming, inhibit mTOR pathway activation, alleviate insulin resistance in the liver, and mitigate pathological damage of liver tissue in T2DM rats by downregulating hepatic BCAAs and SAM and regulating key enzymes involved in amino acid metabolism, such as BCKDHA, ARG, and MAT, as well as amino acid metabolites and transporters.
Animals
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Drugs, Chinese Herbal/administration & dosage*
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Rats
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Insulin Resistance
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Diabetes Mellitus, Type 2/genetics*
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Male
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Liver/drug effects*
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Amino Acids/metabolism*
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Rats, Sprague-Dawley
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Humans
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Metabolic Reprogramming
5.Mechanism of Yishen Jiangtang Decoction in regulating endoplasmic reticulum stress-mediated NLRP3 inflammasome to improve renal damage in diabetic nephropathy db/db mice.
Yun-Jie YANG ; Bin-Hua YE ; Chen QIU ; Han-Qing WU ; Bo-Wei HUANG ; Tong WANG ; Shi-Wei RUAN ; Fang GUO ; Jian-Ting WANG ; Ming-Qian JIANG
China Journal of Chinese Materia Medica 2025;50(10):2740-2749
This study aims to explore the mechanism through which Yishen Jiangtang Decoction(YSJTD) regulates endoplasmic reticulum stress(ERS)-mediated NOD-like receptor thermal protein domain associated protein 3(NLRP3) inflammasome to improve diabetic nephropathy(DN) in db/db mice. Thirty db/db mice were randomly divided into the model group, YSJTD group, ERS inhibitor 4-phenylbutyric acid(4-PBA) group, with 10 mice in each group. Additionally, 10 db/m mice were selected as the control group. The YSJTD group was orally administered YSJTD at a dose of 0.01 mL·g~(-1), the 4-PBA group was orally administered 4-PBA at a dose of 0.5 mg·g~(-1), and the control and model groups were given an equal volume of carboxylmethyl cellulose sodium. The treatments were administered once daily for 8 weeks. Food intake, water consumption, and body weight were recorded every 2 weeks. After the intervention, fasting blood glucose(FBG), glycosylated hemoglobin(HbA1c), urine microalbumin(U-mALB), 24-hour urine volume, serum creatinine(Scr), and blood urea nitrogen(BUN) were measured. Inflammatory markers interleukin-1β(IL-1β) and interleukin-18(IL-18) were detected using the enzyme-linked immunosorbent assay(ELISA). Renal pathology was assessed through hematoxylin-eosin(HE), periodic acid-Schiff(PAS), and Masson staining, and transmission electron microscopy(TEM). Western blot was used to detect the expression levels of glucose-regulated protein 78(GRP78), C/EBP homologous protein(CHOP), NLRP3, apoptosis-associated speck-like protein containing CARD(ASC), cysteinyl aspartate-specific proteinase(caspase-1), and gasdermin D(GSDMD) in kidney tissues. The results showed that compared to the control group, the model group exhibited poor general condition, increased weight and food and water intake, and significantly higher levels of FBG, HbA1c, U-mALB, kidney index, 24-hour urine volume, IL-1β, and IL-18. Compared to the model group, the YSJTD and 4-PBA groups showed improved general condition, increased body weight, decreased food intake, and lower levels of FBG, U-mALB, kidney index, 24-hour urine volume, and IL-1β. Specifically, the YSJTD group showed a significant reduction in IL-18 levels compared to the model group, while the 4-PBA group exhibited decreased water intake and HbA1c levels compared to the model group. Although there was a decreasing trend in water intake and HbA1c in the YSJTD group, the differences were not statistically significant. No significant differences were observed in BUN, Scr, and kidney weight among the groups. Renal pathology revealed that the model group exhibited more severe renal damage compared to the control group. Kidney sections from the model group showed diffuse mesangial proliferation in the glomeruli, tubular edema, tubular dilation, significant inflammatory cell infiltration in the interstitium, and increased glycogen staining and blue collagen deposition in the basement membrane. In contrast, the YSJTD and 4-PBA groups showed varying degrees of improvement in renal damage, glycogen staining, and collagen deposition, with the YSJTD group showing more significant improvements. TEM analysis indicated that the model group had extensive cytoplasmic edema, homogeneous thickening of the basement membrane, fewer foot processes, and widening of fused foot processes. In the YSJTD and 4-PBA groups, cytoplasmic swelling of renal tissues was reduced, the basement membrane remained intact and uniform, and foot process fusion improved.Western blot results indicated that compared to the control group, the model group showed upregulation of GRP78, CHOP, GSDMD, NLRP3, ASC, and caspase-1 expression. In contrast, both the YSJTD and 4-PBA groups showed downregulation of these markers compared to the model group. These findings suggest that YSJTD exerts a protective effect against DN by alleviating NLRP3 inflammasome activation through the inhibition of ERS, thereby improving the inflammatory response in db/db DN mice.
Animals
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Endoplasmic Reticulum Stress/drug effects*
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Diabetic Nephropathies/metabolism*
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NLR Family, Pyrin Domain-Containing 3 Protein/genetics*
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Drugs, Chinese Herbal/administration & dosage*
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Mice
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Inflammasomes/drug effects*
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Male
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Kidney/pathology*
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Endoplasmic Reticulum Chaperone BiP
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Humans
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Interleukin-18/genetics*
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Mice, Inbred C57BL
6.Regulatory effects of Dangua Humai Oral Liquid on gut microbiota and mucosal barrier in mice with glucolipid metabolism disorder.
Zhuang HAN ; Lin-Xi JIN ; Zhi-Ta WANG ; Liu-Qing YANG ; Liang LI ; Yi RUAN ; Qi-Wei CHEN ; Shu-Hong YAO ; Xian-Pei HENG
China Journal of Chinese Materia Medica 2025;50(15):4315-4324
The gut microbiota regulates intestinal nutrient absorption, participates in modulating host glucolipid metabolism, and contributes to ameliorating glucolipid metabolism disorder. Dysbiosis of the gut microbiota can compromise the integrity of the intestinal mucosal barrier, induce inflammatory responses, and exacerbate insulin resistance and abnormal lipid metabolism in the host. Dangua Humai Oral Liquid, a hospital-developed formulation for regulating glucolipid metabolism, has been granted a national invention patent and demonstrates significant clinical efficacy. This study aimed to investigate the effects of Dangua Humai Oral Liquid on gut microbiota and the intestinal mucosal barrier in a mouse model with glucolipid metabolism disorder. A glucolipid metabolism disorder model was established by feeding mice a high-glucose and high-fat diet. The mice were divided into a normal group, a model group, and a treatment group, with eight mice in each group. The treatment group received a daily gavage of Dangua Humai Oral Liquid(20 g·kg~(-1)), while the normal group and model group were given an equivalent volume of sterile water. After 15 weeks of intervention, glucolipid metabolism, intestinal mucosal barrier function, and inflammatory responses were evaluated. Metagenomics and untargeted metabolomics were employed to analyze changes in gut microbiota and associated metabolic pathways. Significant differences were observed between the indicators of the normal group and the model group. Compared with the model group, the treatment group exhibited marked improvements in glucolipid metabolism disorder, alleviated pathological damage in the liver and small intestine tissue, elevated expression of recombinant claudin 1(CLDN1), occluding(OCLN), and zonula occludens 1(ZO-1) in the small intestine tissue, and reduced serum levels of inflammatory factors lipopolysaccharides(LPS), lipopolysaccharide-binding protein(LBP), interleukin-6(IL-6), and tumor necrosis factor-α(TNF-α). At the phylum level, the relative abundance of Bacteroidota decreased, while that of Firmicutes increased. Lipid-related metabolic pathways were significantly altered. In conclusion, based on the successful establishment of the mouse model of glucolipid metabolism disorder, this study confirmed that Dangua Humai Oral Liquid effectively modulates gut microbiota and mucosal barrier function, reduces serum inflammatory factor levels, and regulates lipid-related metabolic pathways, thereby ameliorating glucolipid metabolism disorder.
Animals
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Gastrointestinal Microbiome/drug effects*
;
Mice
;
Intestinal Mucosa/microbiology*
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Male
;
Drugs, Chinese Herbal/administration & dosage*
;
Mice, Inbred C57BL
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Humans
;
Glycolipids/metabolism*
;
Lipid Metabolism/drug effects*
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Administration, Oral
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Disease Models, Animal
7.Effect and mechanism of Liujunzi Pills on gut microbiota of rats with spleen Qi deficiency syndrome.
Tao ZHANG ; Nian CHEN ; Qin-Yao JIA ; Xiao-Xia LEI ; Jie WANG ; Jia-Qing ZHAO ; Ying WEI ; Jing WEN
China Journal of Chinese Materia Medica 2025;50(15):4333-4341
This article aims to explore the effect and mechanism of Liujunzi Pills on the intestinal microbiota of rats with spleen Qi deficiency syndrome. The raw Rhei Radix et Rhizoma water extract(1 g·mL~(-1)) was used to prepare spleen Qi deficiency rat models. A total of 44 SD male rats were randomly divided into a control group, a model group, Liujunzi Pills groups at high(3.24 g·kg~(-1)), medium(1.62 g·kg~(-1)), low(0.81 g·kg~(-1)) doses, and Shenling Baizhu San(2.50 g·kg~(-1)) group. The drug effect was evaluated by observing the following aspects: spleen index, fecal water content, body weight, and intestinal propulsion index. Gut microbiota analysis and 16S rRNA gene sequencing were conducted on feces. Enzyme-linked immunosorbent assay(ELISA) and UV spectrophotometry were used to detect interleukin-1β(IL-1β) and adenosine triphosphate(ATP) levels in small intestine tissues. Hematoxylin-eosin staining and transmission electron microscopy were employed to observe changes in intestinal pathology and microstructure. The results show that, compared with the control group, fecal moisture content is significantly increased while spleen index, body weight, and intestinal propulsion index are significantly reduced in rats of the model group, indicating the successful establishment of the model. The above symptoms can be improved by both Shenling Baizhu San and Liujunzi Pills. Compared with the control group, in the model group, the gut microbiota abundance is changed with an unbalanced development: the abundance of beneficial bacteria within the Bacteroidetes phylum is reduced, accompanied by a significantly decreased Shannon index, and reduced signal levels of nicotinamide adenine dinucleotide phosphate(NADPH)-related enzymes relevant to mitochondria. However, Liujunzi Pills and Shenling Baizhu San can significantly improve the Bacteroidetes phylum abundance in gut microbiota, microbial diversity, and NADPH activity in the model group. Additionally, compared with the control group, the ATP level is decreased and the IL-1β level is increased in small intestinal tissues of the model group, with shorter small intestinal epithelial villi and decreased mitochondrial number. The above symptoms can be improved by Liujunzi Pills and Shenling Baizhu San. In conclusion, Liujunzi Pills can treat spleen Qi deficiency syndrome by enhancing mitochondrial function to regulate gut microbiota balance and diversity.
Animals
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Gastrointestinal Microbiome/drug effects*
;
Drugs, Chinese Herbal/pharmacology*
;
Male
;
Rats, Sprague-Dawley
;
Rats
;
Qi
;
Spleen/metabolism*
;
Splenic Diseases/metabolism*
;
Humans
;
Interleukin-1beta/genetics*
;
Bacteria/drug effects*
;
Feces/microbiology*
;
Adenosine Triphosphate/metabolism*
8.Domestication progress of endangered Chinese medicinal material Fritillariae Cirrhosae Bulbus.
Ting XIAO ; Ming-Hao YANG ; Qiu-Ling WANG ; Qiang LYU ; Yu-Qing ZHENG ; Lian-Cheng XU ; Ma YU ; Jian-He WEI
China Journal of Chinese Materia Medica 2025;50(16):4483-4489
Fritillariae Cirrhosae Bulbus is the dried bulb of perennial herbaceous plants in the Fritillaria genus(Liliaceae family) and is a representative traditional Chinese medicinal material with distinctive regional characteristics. Clinically, it is widely used in the treatment of dry cough, bronchial asthma, and other respiratory diseases, possessing significant medicinal and economic value and being highly esteemed in TCM. Currently, Fritillariae Cirrhosae Bulbus primarily relies on wild harvesting. However, due to excessive collection, its wild resources have drastically declined, and all source species have been classified as category Ⅱ in the List of National Key Protected Wild Plants, exacerbating the supply-demand imbalance in the market. To mitigate this issue, large-scale cultivation through the domestication of wild Fritillariae Cirrhosae Bulbus has become an inevitable trend. However, its strict environmental requirements, low propagation efficiency, high seedling mortality, and immature cultivation techniques have severely hindered industrialization. This study investigates the domestication process of Fritillariae Cirrhosae Bulbus, focusing on seed propagation, seedling cultivation, and medicinal material production. It also reviews the species and distribution of wild resources, their endangered status, market supply-demand dynamics, and the historical and current development of domestication. The findings indicate that enhancing propagation efficiency, optimizing cultivation models, and distinguishing between seed propagation and medicinal material production are key measures to accelerate the industrialization of domesticated Fritillariae Cirrhosae Bulbus. This research aims to promote the industrialization of Fritillariae Cirrhosae Bulbus domestication and provide a reference model for the conservation and sustainable utilization of rare and endangered medicinal plant resources.
Fritillaria/chemistry*
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Endangered Species
;
Plants, Medicinal/growth & development*
;
Drugs, Chinese Herbal/economics*
;
China
9.Junctophilin-2 MORN-Helix Domain: Structural Basis for Membrane Binding and Hypertrophic Cardiomyopathy-associated Mutations
Jing-Xin WANG ; Zhi-Wei LI ; Wei LIU ; Wen-Qing ZHANG ; Jian-Chao LI
Progress in Biochemistry and Biophysics 2025;52(8):2103-2116
ObjectiveJunctophilin-2 (JPH2) is an essential structural protein that maintains junctional membrane complexes (JMCs) in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum, thereby facilitating excitation-contraction (E-C) coupling. Mutations in JPH2 have been associated with hypertrophic cardiomyopathy (HCM), but the molecular mechanisms governing its membrane-binding properties and the functional relevance of its membrane occupation and recognition nexus (MORN) repeat motifs remain incompletely understood. This study aimed to elucidate the structural basis of JPH2 membrane association and its implications for HCM pathogenesis. MethodsA recombinant N-terminal fragment of mouse JPH2 (residues1-440), encompassing the MORN repeats and an adjacent helical region, was purified under near-physiological buffer conditions.X-ray crystallography was employed to determine the structure of the JPH2 MORN-Helix domain. Sequence conservation analysis across species and junctophilin isoforms was performed to assess the evolutionary conservation of key structural features. Functional membrane-binding assays were conducted using liposome co-sedimentation and cell-based localization studies in COS7 and HeLa cells. In addition, site-directed mutagenesis targeting positively charged residues and known HCM-associated mutations, including R347C, was used to evaluate their effects on membrane interaction and subcellular localization. ResultsThe crystal structure of the mouse JPH2 MORN-Helix domain was resolved at 2.6 Å, revealing a compact, elongated architecture consisting of multiple tandem MORN motifs arranged in a curved configuration, forming a continuous hydrophobic core stabilized by alternating aromatic residues. A C-terminal α-helix further reinforced structural integrity. Conservation analysis identified the inner groove of the MORN array as a highly conserved surface, suggesting its role as a protein-binding interface. A flexible linker segment enriched in positively charged residues, located adjacent to the MORN motifs, was found to mediate direct electrostatic interactions with negatively charged phospholipid membranes. Functional assays demonstrated that mutation of these basic residues impaired membrane association, while the HCM-linked R347C mutation completely abolished membrane localization in cellular assays, despite preserving the overall MORN-Helix fold in structural modeling. ConclusionThis study provides structural insight into the membrane-binding mechanism of the cardiomyocyte-specific protein JPH2, highlighting the dual roles of its MORN-Helix domain in membrane anchoring and protein interactions. The findings clarify the structural basis for membrane targeting via a positively charged linker and demonstrate that disruption of this interaction—such as that caused by the R347C mutation—likely contributes to HCM pathogenesis. These results not only enhance current understanding of JPH2 function in cardiac E-C coupling but also offer a structural framework for future investigations into the assembly and regulation of JMCs in both physiological and disease contexts.

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