1.Studies on glycosides from the n-butanol fraction of Aconitum tanguticum
Mengyuan ZHAO ; Siyang FANG ; anting LI ; Qien LI ; Ke PAN ; Zhiqi YIN
Journal of China Pharmaceutical University 2026;57(2):189-195
In order to investigate the chemical constituents of glycosides in Aconitum tanguticum (Maxim.) Stapf, column chromatographic techniques such as silica gel, ODS, Sephadex LH-20, and semi-preparative high performance liquid chromatography were used to afford eight glycosides from the n-butanol fraction of the 85% ethanol extract of Aconitum tanguticum. Based on the physicochemical properties and spectral data, these compounds were identified as N-4-O-(β-D-glucopyranosyl)-phenethylbenzamide (1), N-(2'-β-D-glucopyranosyl-5'-methoxysalicyl)-4-hydroxy-3-methoxyanthranilic acid methyl ester (2), N-(2'-β-D-glucopyranosyl-5'-hydroxysalicyl)-4-hydroxy-3-methoxyanthranilic acid methyl ester (3), salidroside (4), benzyl primeveroside (5), phenethanol-β-D-xylose-(1''→6')-β-D-glucopyranoside (6), 4-dihydroxyphenethoxy-8-O-β-D-[6-O-(4-O-β-D-glucopyranosyl)-feruloyl]-glucopyranoside (7), phenethanol-α-L-arabinopyranosyl-(1''→6')-β-D-glucopyranoside (8). Among them, compounds 1 and 2 were new compounds, and compounds 5,6,8 were isolated from Aconitum tanguticum for the first time.
2.Exploring on Processing Mechanism of Enhanced "Invigorating Spleen and Stopping Diarrhea" Effect of Soil-fried Atractylodis Macrocephalae Rhizoma Based on "Microscopic Characterization, Chemical Analysis and Pharmacodynamic Evaluation" Trinity
Guoshun SHAN ; Yuyan XIAO ; Chu YUAN ; Xiuai CHEN ; Qimiao ZHAO ; Xiang LIU ; Hao WU ; Ke ZHANG ; Siqi LIU ; Yongduo YU
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(8):182-193
ObjectiveTo analyze the processing mechanism underlying the enhanced effect of invigorating spleen and stopping diarrhea of soil-fried Atractylodis Macrocephalae Rhizoma(AMR) by analyzing the changes of microstructure, chemical composition and anti-ulcerative colitis(UC) activity before and after soil stir-frying. MethodsThe microstructure and elemental composition of AMR before and after soil stir-frying were analyzed by scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS), to investigate the differences in microstructure and the underlying causes. Ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UPLC-Q-TOF-MS) coupled with UNIFI 1.9.2 natural product analysis platform were used to analyze and identify the chemical constituents in raw and soil-fried products, and multivariate statistical methods including principal component analysis(PCA) and orthogonal partial least squares-discriminant analysis(OPLS-DA) were used to explore the differences and sources of chemical constituents between them. A dextran sulfate sodium(DSS)-induced UC mouse model was established. The method of disease activity index(DAI) was used to evaluate the severity of intestinal inflammation. Hematoxylin-eosin(HE) staining was used to observe the pathological changes of colon tissue, enzyme-linked immunosorbent assay(ELISA) was used to detect the levels of inflammatory factors, Real-time quantitative polymerase chain reaction(Real-time PCR) and Western blot were used to analyze the expressions of key genes and proteins involved in the intestinal mucosal barrier. The 16S rRNA sequencing was used to evaluate the diversity of intestinal flora, headspace gas chromatography-mass spectrometry(HS-GC-MS) was used to explore the levels of short-chain fatty acids(SCFAs) in feces. Base on the above findings, this paper investigated the effects of raw and soil-fried AMR on the biological, chemical, mechanical and immune barriers of model animals, and the differences in pharmacological effects and underlying mechanisms from the perspective of regulating the intestinal mucosal barrier in UC mice. ResultsSEM observation revealed numerous hearth soil particles on the surface of soil-fried AMR, accompanied by bubble-like bulges. At the same time, there were many cracks and folds on the surface of the hearth soil. EDS analysis revealed that the contents of Si, Al, Mg and Ca in soil-fried AMR were significantly higher than those of raw products, and these elements constituted the primary components of hearth soil. UPLC-Q-TOF-MS combined with database comparison was used to identify the chemical constituents of raw and soil-fried AMR. In positive ion mode, a total of 132 components were identified, primarily comprising three categories of terpenoids, polyphenols and amino acids. In negative ion mode, a total of 40 components were identified, primarily polyphenolic and glycoside compounds. Among them, the contents of sesquiterpenes and polyphenolic acids were changed significantly before and after processing. Soil-fried AMR could reduce the DAI score of UC mice, alleviate the shortening of colon length, reduce the levels of pro-inflammatory factors such as interleukin(IL)-17, IL-18, γ-interferon(IFN-γ) and tumor necrosis factor(TNF)-α in serum, increase the levels of anti-inflammatory factors such as secretory immunoglobulin A(sIgA), IL-10, IL-4 and transforming growth factor-β(TGF-β) in serum, increase the expressions of key genes and proteins of intestinal mucosal barrier such as tight junction protein-1(ZO-1), Occludin, Claudin-1 and mucin 2(MUC2) in colonic mucosa, and improve the disorders of intestinal flora diversity and the levels of SCFAs(P<0.05, P<0.01). The raw and stir-fried products of AMR also exhibited the aforementioned effects, but they were weaker than the soil-fried products. Additionally, the auxiliary material hearth soil also had a certain pharmacodynamic effect. ConclusionSoil-fried AMR can enhance the protective effect on intestinal mucosal barrier in UC mice. These changes or heating-induced alterations in the microscopic structure and chemical composition of AMR may be attributed to the dual effects of adsorption of hearth soil.
3.Exploring on Processing Mechanism of Enhanced "Invigorating Spleen and Stopping Diarrhea" Effect of Soil-fried Atractylodis Macrocephalae Rhizoma Based on "Microscopic Characterization, Chemical Analysis and Pharmacodynamic Evaluation" Trinity
Guoshun SHAN ; Yuyan XIAO ; Chu YUAN ; Xiuai CHEN ; Qimiao ZHAO ; Xiang LIU ; Hao WU ; Ke ZHANG ; Siqi LIU ; Yongduo YU
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(8):182-193
ObjectiveTo analyze the processing mechanism underlying the enhanced effect of invigorating spleen and stopping diarrhea of soil-fried Atractylodis Macrocephalae Rhizoma(AMR) by analyzing the changes of microstructure, chemical composition and anti-ulcerative colitis(UC) activity before and after soil stir-frying. MethodsThe microstructure and elemental composition of AMR before and after soil stir-frying were analyzed by scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS), to investigate the differences in microstructure and the underlying causes. Ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UPLC-Q-TOF-MS) coupled with UNIFI 1.9.2 natural product analysis platform were used to analyze and identify the chemical constituents in raw and soil-fried products, and multivariate statistical methods including principal component analysis(PCA) and orthogonal partial least squares-discriminant analysis(OPLS-DA) were used to explore the differences and sources of chemical constituents between them. A dextran sulfate sodium(DSS)-induced UC mouse model was established. The method of disease activity index(DAI) was used to evaluate the severity of intestinal inflammation. Hematoxylin-eosin(HE) staining was used to observe the pathological changes of colon tissue, enzyme-linked immunosorbent assay(ELISA) was used to detect the levels of inflammatory factors, Real-time quantitative polymerase chain reaction(Real-time PCR) and Western blot were used to analyze the expressions of key genes and proteins involved in the intestinal mucosal barrier. The 16S rRNA sequencing was used to evaluate the diversity of intestinal flora, headspace gas chromatography-mass spectrometry(HS-GC-MS) was used to explore the levels of short-chain fatty acids(SCFAs) in feces. Base on the above findings, this paper investigated the effects of raw and soil-fried AMR on the biological, chemical, mechanical and immune barriers of model animals, and the differences in pharmacological effects and underlying mechanisms from the perspective of regulating the intestinal mucosal barrier in UC mice. ResultsSEM observation revealed numerous hearth soil particles on the surface of soil-fried AMR, accompanied by bubble-like bulges. At the same time, there were many cracks and folds on the surface of the hearth soil. EDS analysis revealed that the contents of Si, Al, Mg and Ca in soil-fried AMR were significantly higher than those of raw products, and these elements constituted the primary components of hearth soil. UPLC-Q-TOF-MS combined with database comparison was used to identify the chemical constituents of raw and soil-fried AMR. In positive ion mode, a total of 132 components were identified, primarily comprising three categories of terpenoids, polyphenols and amino acids. In negative ion mode, a total of 40 components were identified, primarily polyphenolic and glycoside compounds. Among them, the contents of sesquiterpenes and polyphenolic acids were changed significantly before and after processing. Soil-fried AMR could reduce the DAI score of UC mice, alleviate the shortening of colon length, reduce the levels of pro-inflammatory factors such as interleukin(IL)-17, IL-18, γ-interferon(IFN-γ) and tumor necrosis factor(TNF)-α in serum, increase the levels of anti-inflammatory factors such as secretory immunoglobulin A(sIgA), IL-10, IL-4 and transforming growth factor-β(TGF-β) in serum, increase the expressions of key genes and proteins of intestinal mucosal barrier such as tight junction protein-1(ZO-1), Occludin, Claudin-1 and mucin 2(MUC2) in colonic mucosa, and improve the disorders of intestinal flora diversity and the levels of SCFAs(P<0.05, P<0.01). The raw and stir-fried products of AMR also exhibited the aforementioned effects, but they were weaker than the soil-fried products. Additionally, the auxiliary material hearth soil also had a certain pharmacodynamic effect. ConclusionSoil-fried AMR can enhance the protective effect on intestinal mucosal barrier in UC mice. These changes or heating-induced alterations in the microscopic structure and chemical composition of AMR may be attributed to the dual effects of adsorption of hearth soil.
4.Analysis of the disease burden of hypertensive heart disease among individuals aged≥60 years globally and in China from 1990 to 2021
Jiali LI ; Chunzhen REN ; Fan LIU ; Keyan WANG ; Zhijiang BI ; Xiaoxiao ZHAO ; Lixin KE ; Haibo WANG ; Wenxi PENG ; Zhifei WANG ; Qiang ZHANG ; Peng XU ; Yingdong LI ; Xiuxiu DENG ; Xinke ZHAO ; Cuncun LU
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2026;33(02):281-290
Objective To systematically analyze the characteristics of the disease burden of hypertensive heart disease (HHD) in the elderly (≥60 years) globally and in China from 1990 to 2021, and to predict its future trends from 2022 to 2040, with the aim of providing data support for optimizing comprehensive prevention and control strategies for HHD. Methods Based on the Global Burden of Disease (GBD) 2021 database, the number of prevalent cases and disability-adjusted life years (DALYs) of HHD in the elderly were extracted for the world, China, and five regions categorized by sociodemographic index (SDI). Joinpoint regression was used to analyze the temporal trends of age-standardized prevalence rate and age-standardized DALYs rate of HHD in the elderly. A three-factor decomposition method was applied to evaluate the relative contributions of aging, population growth, and epidemiological changes to the variations in the elderly HHD burden. Additionally, a Bayesian age-period-cohort model was used to predict the elderly HHD burden from 2022 to 2040. Results In 2021, the number of prevalent elderly HHD cases reached 10 283 000 globally and 3 412 400 in China, representing increases of 179.20% and 159.20% respectively, compared with 1990. The DALYs of elderly HHD were 18 812 700 person-years globally and 4 731 400 person-years in China, rising by 76.08% and 29.45% respectively from 1990. Meanwhile, the growth rates of the number of prevalent cases and DALYs of elderly HHD varied across different SDI regions. From 1990 to 2021, the age-standardized prevalence rate of elderly HHD in China, as well as the age-standardized DALYs rate of elderly HHD both globally and in China, showed significant downward trends (all average annual percentage changes<0, all P<0.001). In 2021, the 70-74 years age group accounted for the highest proportion of prevalent cases and DALYs of elderly HHD, both globally and in China. Decomposition analysis revealed that population growth was the dominant factor driving the increase in the elderly HHD burden across all regions. The prediction model results indicated that the number of prevalent cases and DALYs of elderly HHD would continue to rise globally and in China from 2022 to 2040, with the growth rate of the elderly HHD burden in China between 2021 and 2040 expected to exceed the global average. Conclusion Over the past 32 years, although the age-standardized disease rates of elderly HHD have mainly shown a downward trend globally and in China, the absolute number of the disease burden has increased substantially. The projection model indicates a continued upward trajectory, with the growth rate in China higher than the global average. Therefore, there is an urgent need to implement precise prevention and control strategies to effectively mitigate the disease burden of elderly HHD.
5.A Case of Multidisciplinary Treatment for Inflammatory Myofibroblastic Tumor Complicated by ANCA-Associated Vasculitis
Shaoying WANG ; Linyi PENG ; Ke ZHENG ; Zhiwei WANG ; Dachun ZHAO ; Xia ZHANG ; Lin ZHAO ; Wenhui WANG ; Weiqing WANG ; Zhenzhen ZHU ; Jin XU ; Min SHEN
JOURNAL OF RARE DISEASES 2026;5(1):43-51
A 51-year-old male presented with nasal obstruction, followed by progressive hearing loss and blurred vision. Imaging identified space-occupying lesions in the paranasal sinuses, orbits, and paraspinal regions, while laboratory tests confirmed positive anti-proteinase 3 anti-neutrophil cytoplasmic antibody(PR3- ANCA) immunoglobulin G (IgG)and markedly elevated serum IgG4. Despite treatment with corticosteroids, immunosuppressants, and radiotherapy, the patient exhibited steroid dependency with relentless disease progression. Following multidisciplinary consultation, a diagnosis of inflammatory myofibroblastic tumor (IMT) coexisting with ANCA- associated vasculitis (AAV) was favored, though IgG4-related disease remained a critical differential. Ultimately, profound immunosuppression precipitated a severe herpesvirus infection, leading to disseminated intravascular coagulation and multiple organ dysfunction syndrome. This case underscores the rarity and diagnostic complexity of concurrent IMT and AAV, highlights the therapeutic dilemma of balancing primary disease control against fatal opportunistic infections, and emphasizes the critical role of multidisciplinary collaboration in the diagnosis and treatment of complex diseases.
6.The Role of Mitochondrial Unfolded Protein Response in Neurodegenerative Diseases
Progress in Biochemistry and Biophysics 2026;53(4):875-886
As the core hub of energy metabolism in eukaryotes, mitochondria participate in a variety of cellular activities, including metabolic regulation of the cell matrix, apoptosis, and the activation of signal transduction pathways. Their functional status is closely linked to the initiation and progression of various diseases. Neurodegenerative diseases are primarily characterized by the progressive loss and dysfunction of neurons, and mitochondrial dysfunction is considered one of the key triggers in this process. The specific mechanisms by which mitochondrial dysfunction contributes to neurodegenerative diseases have attracted widespread attention. When misfolded or unfolded proteins are detected, a process known as the mitochondrial unfolded protein response (mtUPR) is activated to promote proper protein folding or degradation, thereby restoring mitochondrial function. As a mitochondrial stress defense mechanism, mtUPR primarily regulates the expression of nuclear-encoded genes, such as chaperones and proteases, to alleviate mitochondrial stress. Studies have shown that, in addition to misfolded and unfolded proteins, other mitochondrial stresses—such as mitochondrial DNA abnormalities and reactive oxygen species (ROS)—can also induce mtUPR. The biological functions of mtUPR extend beyond mitochondria and are crucial for the health of the entire cell and even the whole organism. The mtUPR process involves communication between mitochondria and the nucleus, a phenomenon that is highly conserved and has been observed across different species. Abnormal activation or inhibition of mtUPR is closely associated with the development of various neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease. An in-depth exploration of the dynamic regulatory role and molecular mechanisms of mtUPR is therefore of great significance for understanding the pathogenesis of these disorders. In addition to neuron loss, neurodegenerative diseases are characterized by the accumulation of misfolded proteins in the brain, including insoluble fibrils of amyloid beta, phosphorylated tau, or α-synuclein. While the molecular pathways of mtUPR are largely conserved across different diseases, the possibility of differential regulatory factors cannot be excluded. Although mtUPR activation is predominantly recognized for its cytoprotective role, it may exert deleterious effects when overstimulated or sustained. Chronic mtUPR activity has been linked to mitochondrial dysfunction and increased neuronal vulnerability, contributing to the pathogenesis of various neurodegenerative diseases. This review summarizes the fundamental concepts, major inducers, and signaling pathways of the mtUPR. We focus on the intrinsic relationship and regulatory patterns between mtUPR and neurodegenerative diseases, providing insights that may aid the development of targeted therapies. Finally, we discuss the challenges and future directions of mtUPR research in this field, aiming to pave the way for new therapeutic breakthroughs. A major limitation arises from the experimental models currently used; most findings rely on model organisms or cultured cells, which cannot fully replicate the complexity of human neurons. Future research should therefore focus on three main directions: (1) defining the molecular switches that determine whether mtUPR acts in a protective or detrimental manner; (2) elucidating differences in mtUPR molecular pathways across various models of neurodegenerative diseases; and (3) establishing robust biomarkers for mtUPR activity.
7.Changes in the epidemiology and clinical characteristics of human metapneumovirus in children with acute lower respiratory tract infection following the withdrawal of non-pharmaceutical interventions
Ke HUANG ; Tingting LAN ; Nuo XU ; Ting ZHAO ; Haiyan LI ; Lin DONG
Chinese Journal of Infectious Diseases 2025;43(3):143-150
Objective:To investigate the changes of the epidemiology and clinical characteristics of human metapneumovirus (hMPV) among children with acute lower respiratory tract infection (ALRTI) before and after the discontinuation of non-pharmaceutical interventions (NPI) during coronavirus disease 2019 epidemic.Methods:This was a retrospective cohort study. Children hospitalized at The Second Affiliated Hospital and Yuying Children′s Hospital of Wenzhou Medical University between January 2021 and December 2023, who were diagnosed with ALRTI by nasopharyngeal secretion testing for respiratory pathogens nucleic acid were enrolled. Clinical and laboratory data were collected. Children admitted between January 1, 2021 and January 7, 2023 were classified as the pre-NPI withdrawal group (abbreviated as pre-withdrawal group), while those admitted from January 8, 2023 afterward were classified as the post-NPI withdrawal group (abbreviated as post-withdrawal group). Nasopharyngeal secretions from the enrolled children were tested for 13 respiratory pathogens using polymerase chain reaction-capillary electrophoresis fragment analysis, and bacterial cultures were also performed. Statistical analyses were performed using the Mann-Whitney U test or chi-square test. Results:A total of 30 855 ALRTI cases were enrolled, with 1 679 of hMPV-positive. In the pre-withdrawal group, there were 861 cases with an age of onset of 2.0(1.0, 3.0) years, and the highest proportion was in the 1 to <3 years age group, accounting for 35.3%(304/861). In the post-withdrawal group, there were 818 cases with an age of onset of 3.0(2.0, 4.0) years, and the highest proportion was in the 3 to <5 years age group, accounting for 39.2%(321/818).The age of onset in the post-withdrawal group was significantly older than that in the pre-withdrawal group ( Z=7.69, P<0.001) .The hMPV detection rate was higher in the pre-withdrawal group than that in post-withdrawal group (5.75%(861/14 984) vs 5.15%(818/15 871); χ2=5.25, P=0.022). In the pre-withdrawal group, the epidemic peaks occurred in winter and spring, with the highest rates in January 2022(25.2%(224/890)) and March 2022 (21.6%(186/860)). In the post-withdrawal group, the epidemic peak shifted to spring and summer, and the detection rate became increased since April 2023(10.8%(136/1 258)). The post-withdrawal group showed lower rates of wheezing, shortness of breath, cyanosis, respiratory support, severe pneumonia, intensive care unit admission, and shorter hospital stays compared to the pre-withdrawal group ( χ2=69.09, 31.63, 12.97, 57.96, 55.73, 5.48 and Z=7.11, respectively, all P< 0.05).In the pre-withdrawal group, 412 cases (47.9%(412/861)) had other pathogens detected, compared to 445 cases (54.4%(445/181)) in the post-withdrawal group, indicating a significantly higher rate of co-infections in the post-withdrawal group ( χ2=7.20, P<0.05). The most commonly detected pathogens in both groups were Mycoplasma pneumoniae (MP), rhinovirus, and Streptococcus pneumoniae. However, the post-withdrawal group showed significantly higher detection rates of MP and influenza virus, but lower bacterial detection rates compared to the pre-withdrawal group ( χ2=39.41, 9.70, 5.63, respectively, all P<0.05). The detection rate of Haemophilus influenzae was 2.1%(17/818) in the post-withdrawal group which lower than that (6.7%(58/861)) in the pre-withdrawal group, and the difference was statistically significant ( χ2=21.32, P<0.001). Conclusions:In 2023, following the withdrawal of NPI, the epidemic peak of hMPV in Wenzhou area is delayed to spring and summer. The age of children with hMPV-associated ALRTI increases, with the majority being 3 to <5 years old. The overall severity of the disease decreases. However, the detection of mixed pathogens increases, with MP being the most common, while bacterial detection decreases.
8.The characteristics and mechanism of dynamic changes of different components in microenvironment in regulating the progression of liver fibrosis
Huilan ZHAO ; Zongxu LIU ; Shumin LI ; Zhifeng WANG ; Minghui LIU ; Qian SHENG ; Kunbin KE ; Xinan SHI
Journal of Clinical Hepatology 2025;41(4):755-760
The liver has diverse functions such as metabolism, detoxification, and immune defense, and the maintenance of hepatic microenvironment homeostasis is crucial for overall bodily health. The hepatic microenvironment consists of the components such as parenchymal cells, non-parenchymal cells, and non-cellular components. Chronic inflammatory responses induced by various etiological factors may promote the formation and progression of liver fibrosis. During the dynamic progression of liver fibrosis, from the early to advanced stages, various components within the hepatic microenvironment undergo a series of changes, which can promote the malignant progression of liver fibrosis. An in-depth exploration of the mechanisms underlying such changes in each component of the liver fibrosis microenvironment is of great significance for understanding the pathogenesis of liver fibrosis and discovering potential treatment strategies.
9.Hearing loss prevalence and burden of disease in China: Findings from provincial-level analysis.
Yu WANG ; Yang XIE ; Minghao WANG ; Mengdan ZHAO ; Rui GONG ; Ying XIN ; Jia KE ; Ke ZHANG ; Shaoxing ZHANG ; Chen DU ; Qingchuan DUAN ; Fang WANG ; Tao PAN ; Furong MA ; Xiangyang HU
Chinese Medical Journal 2025;138(1):41-48
BACKGROUND:
Without timely and effective rehabilitation, hearing loss may profoundly affect human life quality. China has a large population of hearing-impaired individuals, which imposes a heavy health burden on society. Moreover, this population is projected to increase rapidly owing to China's aging society.
METHODS:
We used data from a population-representative epidemiological investigation of hearing loss and ear diseases in four Chinese provinces. We estimated the national prevalence using multiple linear regression of the age-group proportions and prevalence in 31 provinces with clustering analysis. We used years lived with disability (YLDs) to analyze the disease burden and forecasted the prevalence of hearing loss by 2060 in China.
RESULTS:
An estimated 115 million people had moderate-to-complete hearing loss in 2015 across the 31 provinces of China (8.4% of 1.37 billion people). Of these, 85.7% were older than age 50 years (99 million people) and 2.4% were younger than 20 years old (2.8 million people). Of all YLDs attributable to hearing loss, 68.9% were attributable to moderate-to-complete cases. By 2060, a projected 242 million people in China will have moderate-to-complete hearing loss, a 110.0% increase from 2015.
CONCLUSIONS
The hearing loss prevalence in China is high. Population aging and socioeconomic factors substantially affect the prevalence and severity of hearing loss and the disease burden. The prevalence and severity of hearing loss are unevenly distributed across different provinces. Future public health policies should take these trends and regional variations into account.
Humans
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China/epidemiology*
;
Hearing Loss/epidemiology*
;
Prevalence
;
Middle Aged
;
Male
;
Female
;
Adult
;
Aged
;
Adolescent
;
Young Adult
;
Child
;
Child, Preschool
;
Infant
;
Aged, 80 and over
;
Cost of Illness
10.Eccentric treadmill exercise promotes adaptive hypertrophy of gastrocnemius in rats.
Zhi-Qiang DAI ; Yu KE ; Yan ZHAO ; Ying YANG ; Hui-Wen WU ; Hua-Yu SHANG ; Zhi XIA
Acta Physiologica Sinica 2025;77(3):449-464
The present study aimed to investigate the effects of eccentric treadmill exercise on adaptive hypertrophy of skeletal muscle in rats. Thirty-two 3-month-old Sprague Dawley (SD) rats were selected and randomly assigned to one of the four groups based on their body weights: 2-week quiet control group (2C), 2-week downhill running exercise group (2E), 4-week quiet control group (4C), and 4-week downhill running exercise group (4E). The downhill running protocol for rats in the exercise groups involved slope of -16°, running speed of 16 m/min, training duration of 90 min, and 5 training sessions per week. Twenty-four hours after the final session of training, all the four groups of rats underwent an exhaustion treadmill exercise. After resting for 48 h, all the rats were euthanized and their gastrocnemius muscles were harvested for analysis. HE staining was used to measure the cross-sectional area (CSA) and diameter of muscle fibers. Transmission electron microscope was used to observe the ultrastructural changes in muscle fibers. Purithromycin surface labeling translation method was used to measure protein synthesis rate. Immunofluorescence double labeling was used to detect the colocalization levels of lysosomal-associated membrane protein 2 (Lamp2)-leucyl-tRNA synthetase (LARS) and Lamp2-mammalian target of rapamycin (mTOR). Western blot was used to measure the protein expression levels of myosin heavy chain (MHC) IIb and LARS, as well as the phosphorylation levels of mTOR, p70 ribosomal protein S6 kinase (p70S6K), and eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1). The results showed that, compared with the 2C group rats, the 2E group rats showed significant increases in wet weight of gastrocnemius muscle, wet weight/body weight ratio, running distance, running time, pre- and post-exercise blood lactate levels, myofibrillar protein content, colocalization levels of Lamp2-LARS and Lamp2-mTOR, and LARS protein expression. Besides these above changes, compared with the 4C group, the 4E group further exhibited significantly increased fiber CSA, fiber diameter, protein synthesis rate, and phosphorylation levels of mTOR, p70S6K, and 4E-BP1. Compared with the quiet control groups, the exercise groups exhibited ultrastructural damage of rat gastrocnemius muscle, which was more pronounced in the 4E group. These findings suggest that eccentric treadmill exercise may promote mTOR translocation to lysosomal membrane, activating mTOR signaling via up-regulating LARS expression. This, in turn, increases protein synthesis rate through the mTOR-p70S6K-4E-BP1 signaling pathway, promoting protein deposition and inducing adaptive skeletal muscle hypertrophy. Although the ultrastructural changes of skeletal muscle are more pronounced, the relatively long training cycles during short-term exercise periods have a more significant effect on promoting gastrocnemius muscle protein synthesis and adaptive hypertrophy.
Animals
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Rats, Sprague-Dawley
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Physical Conditioning, Animal/physiology*
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Rats
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Muscle, Skeletal/metabolism*
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TOR Serine-Threonine Kinases/metabolism*
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Male
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Hypertrophy
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Adaptation, Physiological/physiology*
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Adaptor Proteins, Signal Transducing/metabolism*
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Ribosomal Protein S6 Kinases, 70-kDa/metabolism*
;
Intracellular Signaling Peptides and Proteins

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