1.Construction of Perimenopausal Depression Animal Models and Mechanism of Action of Traditional Chinese Medicine: A Review
Xiaoting LI ; Shouzhu XU ; Jun KE ; Zhan ZHANG ; Bao XIN
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(4):258-267
Perimenopausal depression (PMD) is an affective disorder that occurs in women during the transition from sexual maturity to old age. It can induce various complications, such as insomnia and cognitive decline. The etiology of PMD is complex. Although multiple hypotheses have been proposed, there is still no unified theory that fully explains its pathogenesis. Research into its mechanisms relies heavily on animal experiments, and establishing reliable animal models is crucial for experimental studies. Appropriate animal models can better simulate human pathophysiological states, rapidly evaluate the efficacy and safety of drugs and intervention methods, grasp the essence of the disease, and uncover its intrinsic connections, thereby exploring more advanced intervention strategies. However, there is a lack of systematic review and summarization of literature related to model construction. Additionally, traditional Chinese medicine (TCM), adhering to the principles of ''syndrome differentiation and treatment'' and ''holistic concept'', has shown significant efficacy in treating PMD. In recent years, research exploring and analyzing its therapeutic mechanisms has been increasing. Therefore, to gain a clearer and more comprehensive understanding of PMD animal modeling methods and the mechanisms of TCM, this paper reviewed Chinese and English literature on PMD animal models and mechanisms of TCM in PMD treatment. It summarized the construction methods of single-factor and multi-factor PMD models, and discussed the advantages and disadvantages of each modeling approach. Furthermore, it delved into the mechanisms of TCM intervention in PMD, revealing that TCM formulas primarily exert their effects by regulating the hypothalamic-pituitary-adrenal axis, hypothalamic-pituitary-ovarian axis, gut-brain axis, cell signaling pathways, neural circuits, hormone levels, and neurotransmitter levels. This review aims to provide a reference for future research in this field. In summary, by summarizing the progress in the methods for PMD animal model construction and the mechanisms of TCM, the paper seeks to offer new insights into the mechanistic research of TCM intervention in PMD.
2.The effect of body mass index and inferior pulmonary ligament division on the residual lung expansion after right upper lobectomy: A retrospective cohort study in a single center
Guang MU ; Wenhao ZHANG ; Hongchang WANG ; Yan GU ; Chenghao FU ; Wentao XUE ; Shiyuan XIE ; Tong WANG ; Ke WEI ; Yang XIA ; Liang CHEN ; Jun WANG
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2026;33(02):261-266
Objective To analyze the effect of releasing the lower pulmonary ligament on right residual lung expansion after right upper lobe resection under different body mass index (BMI) levels. Methods The clinical data of patients who underwent thoracoscopic right upper lobe resection in the First Affiliated Hospital with Nanjing Medical University from 2021 to 2022 were retrospectively analyzed. Patients were divided into a group A (17 kg/m2<BMI≤23 kg/m2), a group B (23 kg/m2<BMI≤29 kg/m2) and a group C (BMI>29 kg/m2) according to BMI. The presence of residual cavity was judged by chest X-ray at 7-10 days after operation, the degree of compensation change of the right main bronchus angle was measured, and the changes in lung volume were determined by CT three-dimensional reconstruction. Results A total of 157 patients who underwent thoracoscopic right upper lobe resection were included, including 71 males and 86 females, with an average age of (59.7±11.2) years. There were 50 patients in the group A, 75 patients in the group B, and 32 patients in the group C. In the group A, compared with those without releasing the lower pulmonary ligament, patients with releasing had a lower incidence of postoperative residual cavity (P=0.016), greater changes in bronchus angle (P<0.001), and smaller changes in lung volume (P<0.001). In the group B and C, there was no significant effect of releasing the lower pulmonary ligament on postoperative residual cavity, bronchus angle, and lung volume changes (P>0.05). Conclusion For patients with thin and long body shape and low BMI, releasing the lower pulmonary ligament is helpful to promote the expansion of the residual lung after right upper lobe resection and reduce the occurrence of postoperative residual cavity in patients.
3.Dendrobium officinale polysaccharide on high glucose-induced apoptosis in retinal capillary pericytes
Chunyan FENG ; Sheng CHEN ; Lin LIN ; Junchang CAO ; Zhaoda YE ; Fajie KE ; Jun HU
International Eye Science 2026;26(5):753-759
AIM:To investigate the protective effects of Dendrobium officinale polysaccharide(DOP)on high glucose-induced apoptosis in retinal capillary pericytes and its potential mechanism involving mitochondrial function.METHODS:Retinal capillary pericytes were allocated into five groups: normal control(NC), high glucose(HG), and three DOP treatment groups(low, DOP-L; medium, DOP-M; high, DOP-H). Pericyte ultrastructure was analyzed using transmission electron microscopy(TEM). Apoptotic rate was quantified via Annexin V-FITC staining. Mitochondrial transmembrane potential was assessed using the JC-1 probe. Quantitative real-time polymerase chain reaction(qRT-PCR)and Western blot were employed to measure expression levels of cytochrome C(Cyt C), B-cell lymphoma 2(Bcl-2), Bcl-2-associated X protein(Bax), Caspase-9, and Caspase-3, respectively.RESULTS:Compared to the NC group, pericytes exposed to HG exhibited significant mitochondrial damage, elevated apoptotic rate, increased mRNA and protein expression of Cyt C, Bax, Caspase-9, and Caspase-3(all P<0.01), alongside a marked reduction in mitochondrial transmembrane potential and expression of Bcl-2 mRNA and protein(all P<0.01). In contrast, DOP treatment groups(DOP-M,DOP-H)dose-dependently ameliorated mitochondrial damage, reduced apoptotic rate, downregulated Cyt C, Bax, Caspase-9, and Caspase-3 expression, enhanced mitochondrial transmembrane potential, and upregulated Bcl-2 expression relative to the HG group(all P<0.05).CONCLUSION:DOP attenuates high glucose-induced apoptosis and mitochondrial injury in retinal capillary pericytes. The underlying mechanism may involve the restoration of mitochondrial transmembrane potential.
4.The Diversity of Filamentous Morphologies and Magnetic Sensitivity Modulated by Diverse MagR Expression in Bacteria
Ya-Fei CHANG ; Jing ZHANG ; Peng ZHANG ; Xiu-Juan ZHOU ; Meng-Ke WEI ; Tian-Tian CAI ; Pei-Qi HE ; Jun-Feng WANG ; Can XIE
Progress in Biochemistry and Biophysics 2026;53(5):1439-1456
Objective Magnetoreception, the remarkable ability of diverse animals to sense and utilize the geomagnetic field for orientation and navigation, remains a molecularly unresolved mystery in sensory biology. The putative magnetoreceptor (MagR, previously known as IscA1) is a highly conserved iron-sulfur protein implicated in both magnetoreception and iron metabolism; however, the functional diversity among its cross-species homologs remains poorly understood. Cellular morphology is a key genetically determined trait that can be altered through genetic or environmental modifications—a process known as cell morphology engineering. Constructing engineered cells with specific morphological features and magnetic sensitivity to achieve remote, non-invasive magnetic modulation represents a crucial goal in this field with significant application potential. Therefore, this study aims to systematically investigate the effects of MagR heterologous expression on bacterial morphology and magnetic sensing capabilities, screen for MagR-based magnetically sensitive morphology engineering pathways, and reveal the underlying molecular mechanisms. Methods We systematically screened 28 MagR homologous genes from diverse prokaryotic and animal taxa to evaluate their expression and corresponding phenotypic effects in Escherichia coli (E. coli). To compare the differential magnetic responses among bacteria expressing various recombinant MagR proteins, we utilized high-throughput automated bright-field microscopic imaging and scanning electron microscopy (SEM). Furthermore, comprehensive biochemical and biophysical characterizations of iron and iron-sulfur cluster binding were performed using Ferrozine colorimetric assays, electron paramagnetic resonance (EPR) spectroscopy, ultraviolet-visible (UV-Vis) absorption, and circular dichroism (CD) spectroscopy. Additionally, 100 mT static magnetic field (SMF) exposure experiments were conducted to assess magnetically tunable phenotypes, while the intrinsic magnetic properties of purified MagR proteins were directly measured using a superconducting quantum interference device (SQUID) magnetometer. Results Our results demonstrated that the heterologous expression of MagR homologs induced varying degrees of bacterial filamentation. From this comprehensive screen, two distinct morphological patterns were identified: hydra (Hydra vulgaris) MagR (hyMagR) promoted uniform cell elongation and filamentation, exhibiting robust magnetic sensitivity manifested as significantly enhanced filamentation under the 100 mT SMF. In contrast, pigeon (Columba livia) MagR (clMagR) induced only low-frequency, extreme filamentation (sporadically exceeding 80 μm) with a relatively weaker magnetic morphological response. Mechanistically, our data unambiguously proved that these phenotypic differences are primarily driven by distinct iron redox preferences rather than total cellular iron accumulation. Specifically, hyMagR preferentially binds ferrous iron (Fe2+), whereas clMagR favors ferric iron (Fe3+) and forms more stable iron-sulfur clusters. Intriguingly, although SQUID magnetometry showed that purified clMagR exhibited approximately five-fold higher mass magnetic susceptibility than hyMagR, its cellular magnetic response was weaker. We hypothesize that the Fe2+-preferred intracellular environment associated with hyMagR overexpression primes the cell for enhanced generation of reactive oxygen species (ROS) via the Fenton reaction. Exposure to an SMF synergizes with this primed redox state, triggering the bacterial SOS response and upregulating cell division inhibitors to efficiently induce uniform filamentation. Conclusion Our findings identify the Fe2+/Fe3+ redox state as a critical determinant of MagR-mediated morphological remodeling and magnetic responsiveness. This discovery suggests a potential strategy for engineering magnetically responsive cellular systems for synthetic biology applications, and provides a plausible framework, which potentially combines intrinsic protein magnetism with redox-state modulation, for further investigating the evolutionary mechanisms of MagR-mediated magnetoreception.
5.The Diversity of Filamentous Morphologies and Magnetic Sensitivity Modulated by Diverse MagR Expression in Bacteria
Ya-Fei CHANG ; Jing ZHANG ; Peng ZHANG ; Xiu-Juan ZHOU ; Meng-Ke WEI ; Tian-Tian CAI ; Pei-Qi HE ; Jun-Feng WANG ; Can XIE
Progress in Biochemistry and Biophysics 2026;53(5):1439-1456
Objective Magnetoreception, the remarkable ability of diverse animals to sense and utilize the geomagnetic field for orientation and navigation, remains a molecularly unresolved mystery in sensory biology. The putative magnetoreceptor (MagR, previously known as IscA1) is a highly conserved iron-sulfur protein implicated in both magnetoreception and iron metabolism; however, the functional diversity among its cross-species homologs remains poorly understood. Cellular morphology is a key genetically determined trait that can be altered through genetic or environmental modifications—a process known as cell morphology engineering. Constructing engineered cells with specific morphological features and magnetic sensitivity to achieve remote, non-invasive magnetic modulation represents a crucial goal in this field with significant application potential. Therefore, this study aims to systematically investigate the effects of MagR heterologous expression on bacterial morphology and magnetic sensing capabilities, screen for MagR-based magnetically sensitive morphology engineering pathways, and reveal the underlying molecular mechanisms. Methods We systematically screened 28 MagR homologous genes from diverse prokaryotic and animal taxa to evaluate their expression and corresponding phenotypic effects in Escherichia coli (E. coli). To compare the differential magnetic responses among bacteria expressing various recombinant MagR proteins, we utilized high-throughput automated bright-field microscopic imaging and scanning electron microscopy (SEM). Furthermore, comprehensive biochemical and biophysical characterizations of iron and iron-sulfur cluster binding were performed using Ferrozine colorimetric assays, electron paramagnetic resonance (EPR) spectroscopy, ultraviolet-visible (UV-Vis) absorption, and circular dichroism (CD) spectroscopy. Additionally, 100 mT static magnetic field (SMF) exposure experiments were conducted to assess magnetically tunable phenotypes, while the intrinsic magnetic properties of purified MagR proteins were directly measured using a superconducting quantum interference device (SQUID) magnetometer. Results Our results demonstrated that the heterologous expression of MagR homologs induced varying degrees of bacterial filamentation. From this comprehensive screen, two distinct morphological patterns were identified: hydra (Hydra vulgaris) MagR (hyMagR) promoted uniform cell elongation and filamentation, exhibiting robust magnetic sensitivity manifested as significantly enhanced filamentation under the 100 mT SMF. In contrast, pigeon (Columba livia) MagR (clMagR) induced only low-frequency, extreme filamentation (sporadically exceeding 80 μm) with a relatively weaker magnetic morphological response. Mechanistically, our data unambiguously proved that these phenotypic differences are primarily driven by distinct iron redox preferences rather than total cellular iron accumulation. Specifically, hyMagR preferentially binds ferrous iron (Fe2+), whereas clMagR favors ferric iron (Fe3+) and forms more stable iron-sulfur clusters. Intriguingly, although SQUID magnetometry showed that purified clMagR exhibited approximately five-fold higher mass magnetic susceptibility than hyMagR, its cellular magnetic response was weaker. We hypothesize that the Fe2+-preferred intracellular environment associated with hyMagR overexpression primes the cell for enhanced generation of reactive oxygen species (ROS) via the Fenton reaction. Exposure to an SMF synergizes with this primed redox state, triggering the bacterial SOS response and upregulating cell division inhibitors to efficiently induce uniform filamentation. Conclusion Our findings identify the Fe2+/Fe3+ redox state as a critical determinant of MagR-mediated morphological remodeling and magnetic responsiveness. This discovery suggests a potential strategy for engineering magnetically responsive cellular systems for synthetic biology applications, and provides a plausible framework, which potentially combines intrinsic protein magnetism with redox-state modulation, for further investigating the evolutionary mechanisms of MagR-mediated magnetoreception.
6.Creation and Exploration of the"Organized Fill-in-the-Blank Format"Disci-pline Construction Model for Forensic Medicine in the New Era
Zhi-Wen WEI ; Hong-Xing WANG ; Jun-Hong SUN ; Hao-Liang FAN ; Hong-Liang SU ; Le-Le WANG ; Wen-Ting HE ; Zhe CHEN ; Jie ZHANG ; Xiang-Jie GUO ; Ji LI ; Geng-Qian ZHANG ; Xin-Hua LIANG ; Jiang-Wei YAN ; Qiang-Qiang ZHANG ; Cai-Rong GAO ; Ying-Yuan WANG ; Hong-Wei WANG ; Jun XIE ; Bo-Feng ZHU ; Ke-Ming YUN
Journal of Forensic Medicine 2025;41(1):25-29
Forensic medicine has been designated as a first-level discipline,presenting new opportunities and challenges for the development of forensic medicine.Since the 1980s,the establishment of foren-sic medicine discipline and the cultivation of high-level forensic talents have become hot topics in the development of forensic medicine in China.Since the 13th Five-Year Plan,the forensic team of Shanxi Medical University has been aiming at the forefront,proposing the development goals of"Five First-class"and the discipline development path"Six Major Achievements".It has selected benchmark disci-plines,identified gaps in disciplinary development,unified thoughts,formulated completion timelines,concentrated superior resources,assigned tasks to individuals,and created an"Organized Fill-in-the-Blank Format"forensic medicine discipline construction model with the characteristics of the new era.The construction model of forensic medicine has achieved good results in the goals,discipline frame-work,scientific research,talent cultivation,discipline team and platform construction,forming a rela-tively complete discipline construction and management system,and accumulating valuable experience for the construction of first-level discipline and high-level talent cultivation of forensic medicine.
7.Innate immune cell LXR-β deficiency exacerbates hepatic injury and fibrosis in murine models of primary sclerosing cholangitis
Xiaohui FANG ; Yang ZHANG ; Junyao WANG ; Yu ZHANG ; Ziliang KE ; Yiken LIN ; Fangyuan CONG ; Feng ZHANG ; Jianhua ZHOU ; Huiting SU ; Shan CAO ; Yulan LIU ; Jun XU
Liver Research 2025;9(3):239-248
Background and aims:Primary sclerosing cholangitis(PSC)is an autoimmune liver disease characterized by complex pathogenesis and limited available therapeutic options.The mechanisms underlying the development and progression of PSCs remain unclear.Liver X receptor beta(LXR-β)is recognized to modulate lipid metabolism and immune response,but its specific involvement in the PSC has not been elucidated.Here,we explored the role and mechanism of LXR-β in PSC induced by 3,5-diethoxycarbonyl-1,4-dihydro-2,4,6-collidine(DDC).Methods:CRISPR-Cas9 technology was applied to generate Abcb4(coding MDR2,next named as Mdr2),Nr1h2(coding LXR-β,next named as Lxrβ),and Rag2(coding RAG2)knockout mice.DDC was used to induce PSC.Hematoxylin and eosin and Sirius red staining were used to assess the extent of hepatic injury and fibrosis.Flow cytometry was used to observe immune cell subsets.Results:We observed a declining trend in hepatic Lxrβ in the PSC model.Unexpectedly,Lxrβ knockout failed to modulate DDC-induced PSC pathogenesis.Concomitantly,assessment of the influence of Rag2 deficiency on PSC progression revealed the absence of aggravated or alleviated hepatic injury or fibrosis in the Rag2-/-DDC mice.However,Lxrβ depletion intensified DDC-induced PSC in the Rag2-/-mice,with more abundant infiltrative inflammatory cells and more severe liver fibrosis.Compared with Rag2-/-DDC mice,Lxrβ-/-Rag2-/-DDC mice had higher serum ALT and AST levels and mRNA expression of proinflammatory and profibrotic genes.Flow cytometry showed that LXR-β deficiency resulted in a diminished population of hepatic innate immune cells.Conclusion:This study indicated innate immune cell LXR-β deficiency can exacerbate hepatic injury and fibrosis in murine models of PSC suggesting that LXR-β may regulate the function of innate immunity in the fibrotic advancement of PSC.
8.Isorhamnetin Alleviates Inflammation-Induced Crosstalk between Kynurenine Pathway and Gut Microbiota in Depressed Mice
Mengjie XU ; Wei HE ; Ke YAN ; Xinru GAO ; Jun LI ; Dongyue XU ; Jiao XIAO ; Tingxu YAN
Biomolecules & Therapeutics 2025;33(2):297-310
Depression is a widespread psychiatric disorder with complex pathogenesis and unsatisfactory therapeutic effects. As a native flavonoid, Isorhamnetin (ISO) has been deemed to exert neuroprotective effects by antioxidation and regulation of immunity. However, no reports of anti-depressed effect of ISO have yet been found. The present study was conducted to clarify the mechanism basis of anti-depressed effect of ISO utilizing behavioral, biochemical, molecular approaches in vitro and in vivo and bio-informatics analysis. The effects of ISO on depressed mice was investigated through the SPT and FST, and the lesions were examined by H&E staining. Besides, the inflammatory factor and indicator in kynurenine pathway were assessed through detection kits, and the microbiota were checked by 16sRNA. Molecular docking study was performed to investigate the target of ISO. Additionally, Western blot was used to test the activation of PI3K/AKT signaling pathway. The results indicated that ISO could enhance the sugar water preference of mice in SPT and reduce immobility time in FST. Further more, ISO suppressed peripheral and central inflammation, regulated the changes in kynurenine pathway and gut microbiota, inhibited activation of PI3K/AKT pathway, and presented good binding patterns with target proteins on PI3K/AKT signaling pathway. Collectively, these findings demonstrate that ISO alleviated depression-like behaviour by normalizing inflammation-induced dysregulation of the crosstalk between KP and gut microbiota disorder through regulated PI3K/AKT/NF-κB pathway.
9.Guiqi Yiyuan Ointment combined with cisplatin inhibits tumor growth in Lewis lung carcinoma-bearing mice by regulating PERK/eIF2α/ATF4/CHOP signaling pathway.
Nan YANG ; Jian-Qing LIANG ; Ke-Jun MIAO ; Qiang-Ping MA ; Jin-Tian LI ; Juan LI
China Journal of Chinese Materia Medica 2025;50(6):1592-1600
This study aims to investigate the anti-tumor effect and mechanism of Guiqi Yiyuan Ointment combined with cisplatin on Lewis lung carcinoma-bearing mice via the protein kinase RNA-like endoplasmic reticulum kinase(PERK)/eukaryotic translation initiation factor 2α(eIF2α)/activated transcription factor 4(ATF4)/C/EBP homologous protein(CHOP) signaling pathway. Sixty SPF-grade male C57BL/6 mice were selected and assigned into a blank group and a modeling group by the random number table method. After modeling of the Lewis lung carcinoma, the mice in the modeling group were randomized into model, cisplatin(5 mg·kg~(-1), once a week), and low-, medium-, and high-dose(1.7, 3.5, and 7.05 g·kg~(-1), respectively, once a day) Guiqi Yiyuan Ointment+cisplatin(5 mg·kg~(-1)) groups(n=10). After 14 days of continuous intervention, the spleen, thymus, and tumor samples of the mice were collected, weighed, and recorded, and the spleen index, thymus index, and tumor suppression rate were calculated. Hematoxylin-eosin(HE) staining was employed to observe the pathological changes in the tumor tissue. The morphological changes of the endoplasmic reticulum of tumor cells were observed by transmission electron microscopy. The positive expression of phosphorylated eIF2α(p-eIF2α) and ATF4 in the tumor tissue was detected by immunofluorescence. Western blot was employed to determine the protein levels of phosphorylated PERK(p-PERK), p-eIF2α, ATF4, CHOP, B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), cyclin-dependent kinase inhibitor 1A(p21), and cyclinD1 in the tumor tissue. Real-time fluorescent quantitative PCR was employed to determine the mRNA levels of PERK, eIF2α, ATF4, CHOP, Bax, Bcl-2, p21, and cyclinD1 in the tumor tissue. Compared with the blank group, the model group showed decreases in spleen index and thymus index(P<0.05). Compared with the model group, the cisplatin group showed decreases in spleen index and thymus index(P<0.05), and the medium-and high-dose Guiqi Yiyuan Ointment+cisplatin groups presented increases in spleen index and thymus index(P<0.05). In addition, the treatment groups all showed decreased tumor mass(P<0.05), increased tumor cell lysis and nuclear rupture, widened gap between rough endoplasmic reticulum, enhanced average fluorescence intensity of p-eIF2α and ATF4(P<0.05), up-regulated protein levels of p-PERK/PERK, p-eIF2α/eIF2α, ATF4, CHOP, Bax, and p21(P<0.05), down-regulated protein and mRNA levels of Bcl-2 and cyclinD1(P<0.05), and up-regulated mRNA levels of PERK, eIF2α, ATF4, CHOP, Bax, and p21(P<0.05). Compared with the cisplatin group, the combination groups showed increases in spleen index and thymus index(P<0.05) as well as mean optical density(P<0.05), and the high-dose Guiqi Yiyuan Ointment+cisplatin group showed decreased tumor mass(P<0.05). In addition, the medium-and high-dose Guiqi Yiyuan Ointment+cisplatin groups showcased enhanced average fluorescence intensity of p-eIF2α and ATF4(P<0.05), up-regulated protein levels of p-PERK/PERK, p-eIF2α/eIF2α, ATF4, CHOP, Bax, and p21(P<0.05), down-regulated protein and mRNA levels of Bcl-2 and cyclinD1(P<0.05), and up-regulated mRNA levels of PERK, eIF2α, ATF4, CHOP, Bax, and p21(P<0.05). In conclusion, Guiqi Yiyuan Ointment combined with cisplatin can effectively inhibit the growth of Lewis lung carcinoma in mice by regulating the expression of proteins related to the PERK/eIF2α/ATF4/CHOP signaling pathway and promoting cell cycle arrest and apoptosis.
Animals
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Cisplatin/administration & dosage*
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Activating Transcription Factor 4/genetics*
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Eukaryotic Initiation Factor-2/genetics*
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eIF-2 Kinase/genetics*
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Carcinoma, Lewis Lung/pathology*
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Drugs, Chinese Herbal/administration & dosage*
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Male
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Mice
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Signal Transduction/drug effects*
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Mice, Inbred C57BL
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Transcription Factor CHOP/genetics*
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Ointments/administration & dosage*
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Humans
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Cell Proliferation/drug effects*
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Antineoplastic Agents/administration & dosage*
10.Structural identification for in vivo metabolites of proanthocyanidin B_2.
Wen-Hui ZHAO ; Hui-Ting TANG ; Jun LI ; Yue-Lin SONG ; Ke ZHANG ; Yun-Fang ZHAO
China Journal of Chinese Materia Medica 2025;50(10):2841-2852
Proanthocyanidin B_2(PAC-B_2), a polyphenolic dimeric compound comprising two epicatechin molecules linked by a C-C bond, is extensively found in traditional Chinese medicines, with anti-tumor and anti-oxidant activities. Given the limited bioavailability, a thorough investigation and comprehensive understanding of PAC-B_2 metabolism in vivo are essential for elucidating therapeutic forms and mechanisms. In the present study, ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) in the negative ion mode was employed to acquire the MS/MS information of PAC-B_2 and metabolites in urine and feces samples of the rats administrated with PAC-B_2. Online energy-resolved MS(ER-MS) was applied as supplementary to obtain the full collision energy ramp-MS~2 spectra(FCER-MS~2) of isomers-of-interest, which implied comprehensive MS~2 information of targeted compounds. Finally, the possible metabolic pathways of PAC-B_2 in rats were proposed. The primary fragmentation behaviors of PAC-B_2 in the negative ion mode included quinone methide fission between C_4-C_8 bond, retro Diels-Alder cracking of F-ring, heterocyclic ring fission of C-ring, and neutral loss of small molecules such as H_2O. A total of 25 metabolites were tentatively elucidated in urine and feces samples of rats administrated with PAC-B_2 by fragmentation pattern and reported literature. Two groups of isomers, M3/M4/M5 and M9/M11, were confirmatively differentiated based on the relationships between optimal collision energy provided by FCER-MS~2 and bond properties, including bond length and bond dissociation energy. In addition to the ring-opening and methylation, PAC-B_2 could also be metabolized into epicatechin and low molecular weight phenolic acids, which were subsequently subjected to dehydroxylation, ring-opening, methylation, sulfation, and glucuronidation. The structural information provided by online ER-MS and FCER-MS~2 enabled the differentiation of isomers and improved the identification confidence. More importantly, the present study deeply analyzes the in vivo metabolic pathways of PAC-B_2, providing a basis for the research on the pharmacological mechanism of this compound.
Animals
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Proanthocyanidins/urine*
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Rats
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Male
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Drugs, Chinese Herbal/chemistry*
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Rats, Sprague-Dawley
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Tandem Mass Spectrometry
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Chromatography, High Pressure Liquid
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Feces/chemistry*
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Molecular Structure

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