1.Efficacy of N-acetylcysteine plus beta-blocker versus beta-blocker alone in preventing postoperative atrial fibrillation after cardiac surgery: A meta-analysis of randomized controlled trials
Giovanni Vista ; Von Jerick B. Tenorio ; Marivic V. Vestal
Philippine Journal of Cardiology 2025;53(1):73-86
BACKGROUND
Postoperative atrial fibrillation (POAF) is the most common arrythmia to occur after cardiovascular surgery. Inflammation being pivotal in POAF perpetuation has been utilized as a therapeutic target. Owing to their anti-inflammatory and anti-oxidant effects, beta-blockers (BB) and N-acetylcysteine (NAC) became research interests in the pursuit for an effective POAF prevention strategy.
OBJECTIVETo determine the efficacy of NAC plus BB versus BB alone in preventing POAF in cardiac surgery patients.
METHODOLOGYA literature search using the following search engines: PubMed/Medline, Cochrane Review Central, Clinical Trials Registry, ResearchGate, Mendeley and Google Scholar for relevant randomized trials were conducted. Published and unpublished studies indexed from inception until 2023 were included. Three independent reviewers evaluated the randomized clinical trials (RCTs) for eligibility. The pooled estimates for POAF prevention as primary outcome and MACE, mortality, myocardial infarction, stroke, ICU LOS and hospital LOS as secondary outcomes were measured using the RStudio statistical software.
RESULTSSeven eligible RCTs allocated 1069 cardiac surgery patients to NAC + BB (n=539) and BB alone (N = 530) treatment arms. The effect estimate using random effect model disclosed significantly reduced POAF events (RR 0.62, 95% CI [0.44, 0.86], p = 0.005) in those on NAC + BB. While no statistical difference between the study arms were demonstrated in reducing mortality (RR 0.63, 95% CI [0.23, 1.73], p = 0.37); myocardial infarction (RR 1.02, 95% CI [0.49, 2.13], p = 0.96); stroke (RR 0.95, 95% CI [0.24, 3.68], p = 0.94); ICU LOS (std. mean difference 0.14, 95% CI [-0.43, 0.70], p = 0.41), and hospital LOS (std. mean difference 0.08, 95% CI [-0.06, 0.21], p = 0.19).
CONCLUSIONAmong cardiac surgery patients, the use of NAC in combination with BB compared with BB alone significantly reduced POAF.
Acetylcysteine ; Arrhythmias, Cardiac ; Atrial Fibrillation ; Myocardial Infarction ; Omega-chloroacetophenone
2.Clinical features of dyskinesis and related risk factors in female patients with Parkinson disease
Journal of Apoplexy and Nervous Diseases 2025;42(2):109-114
Objective To investigate the clinical features of dyskinesia and related risk factors in female patients with Parkinson disease (PD). Methods A cross-sectional study was conducted among the female patients who met the diagnostic criteria for PD at the outpatient service of PD in Aerospace Center Hospital, and demographic data and clinical data were collected and compared between groups, including levodopa equivalent daily dose (LEDD), Unified Parkinson’s Disease Rating Scale-Ⅲ(UPDRS-Ⅲ), UPDRS-Ⅳ, scores of non-motor symptoms (cognition and depression), presence or absence of dyskinesia, and single levodopa dose (LD) during the onset of dyskinesia. A binary logistic regression analysis was used to investigate the influencing factors for dyskinesia in female patients with PD. Results A total of 146 female PD patients were enrolled, among whom 30 patients had dyskinesia, with an incidence rate of 20.5%. Compared with the non-dyskinesia group in terms of clinical features, the dyskinesia group had a significantly younger age of onset [(54.3±12.5) years vs (62.7±10.0) years, P<0.001], a significantly longer disease duration [(9.9±3.7) years vs (4.5±3.7) years, P<0.001], a significantly higher severity of disease [H-Y stage: (2.65±0.58) vs (2.35±0.83), P=0.03], a significantly longer duration of LD administration [(7.5±3.2) years vs (3.2±2.6) years, P<0.001], a significantly higher LEDD [(703.2±203.9) mg vs (442.1±226.3) mg, P<0.001], and significantly lower body weight [(54.1±8.2) kg vs (60.0±8.7) kg, P=0.001] and BMI [(20.9±3.1) kg/m2 vs (23.4±3.1) kg/m2, P<0.001]. The multivariate logistic regression analysis showed that high BMI (OR=0.770, P=0.005) was a protective factor against dyskinesia in female PD patients, while long disease duration (OR=1.304, P=0.001) and high LEDD (OR=1.003, P=0.012) were risk factors for dyskinesia. Conclusion There is a relatively high incidence rate of dyskinesia in female PD patients, which should be taken seriously in clinical practice, and high BMI is a protective factor, while long disease duration and high LEDD are risk factors for dyskinesia in female PD patients.
Parkinson Disease
;
Dyskinesias
;
Levodopa
3.Effect of Huayu Tongluo moxibustion on learning-memory ability in rats with vascular dementia based on hippocampal Mst1/NF-κB p65 pathway.
Ping WANG ; Jun YANG ; Yu KONG ; Yating ZHANG ; Yinqiu FAN ; Haiping SHI ; Lanying LIU
Chinese Acupuncture & Moxibustion 2025;45(1):53-60
OBJECTIVE:
To observe the effects of Huayu Tongluo (transforming stasis and unblocking collaterals) moxibustion on learning-memory ability and hippocampal mammalian sterile 20-like kinase 1 (Mst1)/nuclear factor κB (NF-κB) p65 pathway related to inflammatory response in rats with vascular dementia (VD).
METHODS:
A total of 60 male Wistar rats of SPF grade were randomly divided into a sham operation group (12 rats) and a modeling group (48 rats). VD model was established by the method of modified bilateral common carotid artery permanent ligation in the modeling group. Thirty-six rats with successful modeling were randomly divided into a model group, a moxibustion group and a western medication group, with 12 rats in each group. Huayu Tongluo moxibustion was applied at "Dazhui" (GV14), "Baihui" (GV20) and "Shenting" (GV24) in the moxibustion group, 20 min each time, once a day, 7 day-intervention was as one course, and 1 day-interval was taken between two courses, for a total of 3 courses. In the western medication group, piracetam was given 0.72 mg/kg by intragastric administration, twice a day, the course of intervention was same as that of the moxibustion group. The learning-memory ability was detected by Morris water maze test; the morphology of hippocampal CA1 region was observed by HE staining; the mRNA expression of Mst1, M1 microglia markers CD86, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) was detected by real-time PCR; the levels of IL-6 and TNF-α in hippocampus were detected by ELISA; and the protein expression of Mst1 and NF-κB p65 in hippocampus was detected by Western blot in rats of each group.
RESULTS:
Compared with the sham operation group, the escape latency was prolonged in the model group (P<0.05); compared with the model group, the escape latency was shortened in the moxibustion group and the western medication group (P<0.05). The cells in the CA1 region of hippocampus were disordered, cell collapse and irregular nuclei could be observed in the model group; compared with the model group, the cell arrangement in the CA1 region of hippocampus was more regular, and the damage was improved in the moxibustion group and the western medication group. Compared with the sham operation group, the mRNA expression of Mst1, CD86, IL-6 and TNF-α, as well as the protein expression of Mst1, NF-κB p65 in hippocampus were increased in the model group (P<0.05). Compared with the model group, the mRNA expression of Mst1, CD86, IL-6 and TNF-α, as well as the protein expression of Mst1, NF-κB p65 in hippocampus were decreased in the moxibustion group and the western medication group (P<0.05). Compared with the sham operation group, the levels of IL-6 and TNF-α in hippocampus were increased in the model group (P<0.05). Compared with the model group, the levels of IL-6 and TNF-α in hippocampus were decreased in the moxibustion group and the western medication group (P<0.05).
CONCLUSION
Huayu Tongluo moxibustion can improve the learning-memory ability of VD rats, the mechanism may be related to regulating the activation of microglia through Mst1/NF-κB p65 pathway, reducing the release of pro-inflammatory factors i.e. IL-6 and TNF-α, so as to alleviating the damage of inflammatory factors in the hippocampus of VD rats.
Animals
;
Male
;
Rats
;
Moxibustion
;
Hippocampus/metabolism*
;
Rats, Wistar
;
Dementia, Vascular/genetics*
;
Memory/drug effects*
;
Humans
;
Transcription Factor RelA/genetics*
;
Learning
;
Protein Serine-Threonine Kinases/genetics*
;
Acupuncture Points
;
Interleukin-6/genetics*
;
Signal Transduction/drug effects*
;
Drugs, Chinese Herbal
4.Analgesic effect of "Zhibian" (BL54)-toward-"Shuidao" (ST28) needling technique of acupuncture on primary dysmenorrhea based on NOD1/RIP2/NF-κB signaling pathway in the rats.
Xu JIN ; Yanlin ZHANG ; Boya CHANG ; Jia REN ; Jianheng HAO ; Yuxia CAO ; Haijun WANG ; Laixi JI
Chinese Acupuncture & Moxibustion 2025;45(2):209-216
OBJECTIVE:
To observe the effect of "Zhibian" (BL54)-toward-"Shuidao" (ST28) needling technique on the relative protein expression of the signaling pathway of nucleotide-binding oligomerization domain-containing protein 1 (NOD1)/ receptor-interacting protein 2 (RIP2)/nuclear factor kappa-B (NF-κB) and the expression of proinflammatory cytokines in the rats with primary dysmenorrhea (PD), so as to explore the underlying mechanism of this acupuncture technique for pain alleviation in PD.
METHODS:
Thirty female SD rats of SPF grade with normal estrous cycle were randomized into a blank group, a model group and an acupuncture group, 10 rats in each one. Using the intraperitoneal injection with estradiol benzoate combined with oxytocin, PD model was prepared in the model group and the acupuncture group. In the acupuncture group, during model preparation, the intervention with "Zhibian" (BL54)-toward-"Shuidao" (ST28) needling technique was delivered simultaneously, 20 min each time, once daily for consecutive 10 days. On day 11, within 30 min after the intraperitoneal injection with oxytocin, the writhing reaction (latency, frequency and score) was recorded; the morphology of uterine tissue was observed with HE staining, the contents of prostaglandin E2 (PGE2), prostaglandin F2α (PGF2α), interleukin (IL)-1β, IL-18, cyclooxygenase-2 (COX-2), and tumor necrosis factor-α(TNF-α) in the serum were detected using ELISA method; the relative protein expression of NOD1, RIP2, NF-κB p65, phosphorylation-NF-κB p65 (p-NF-κB p65) was detected in the uterine tissue using Western blot method; and the mRNA expression of NOD1, RIP2 and NF-κB p65 was detected with the quantitative real-time PCR employed.
RESULTS:
Compared with the blank group, in the model group, the writhing latency was prolonged (P<0.01), the writhing frequency and score increased (P<0.01) in the rats; the endometrial epithelial cells showed massive degeneration and necrosis, with severe endometrial edema and widespread shedding, combined with neutrophil infiltration; the serum PGE2 content was dropped (P<0.01), while those of PGF2α, IL-1β, IL-18, COX-2, and TNF-α elevated (P<0.01); the protein expression of NOD1, RIP2, NF-κB p65 and p-NF-κB p65, and the mRNA expression of NOD1, RIP2 and NF-κB p65 in uterine tissue increased (P<0.01). In comparison with the model group, in the acupuncture group, the writhing latency was prolonged (P<0.01), the writhing frequency and score were reduced (P<0.01) in the rats; there was less degeneration and necrosis of endometrial epithelial cells, with mild endometrial edema and very little neutrophil infiltration; the serum PGE2 content increased (P<0.01), while those of PGF2α, IL-1β, IL-18, COX-2, and TNF-α decreased (P<0.01); the protein expression of NOD1, RIP2, NF-κB p65 and p-NF-κB p65 and the mRNA expression of NOD1, RIP2 and NF-κB p65 in uterine tissue were dropped (P<0.05, P<0.01).
CONCLUSION
"Zhibian" (BL54)-toward-"Shuidao" (ST28) needling technique can alleviate the pain symptom of PD rats, and its action mechanism may be related to inhibiting the active expression of NOD1/RIP2/NF-κB signaling pathway in the uterine tissue, thereby reducing the inflammatory response.
Animals
;
Female
;
Rats, Sprague-Dawley
;
Rats
;
Signal Transduction
;
Dysmenorrhea/metabolism*
;
NF-kappa B/metabolism*
;
Acupuncture Points
;
Humans
;
Acupuncture Analgesia
;
Nod1 Signaling Adaptor Protein/metabolism*
;
Receptor-Interacting Protein Serine-Threonine Kinase 2/metabolism*
;
Acupuncture Therapy
5.Effect of acupuncture on chondrocyte autophagy in rats of knee osteoarthritis based on PI3K/Akt/mTOR signaling pathway.
Dekun LI ; Changfeng YAO ; Ziliang SHAN ; Zheng ZHOU ; Xianji ZHANG ; Kewen WANG ; Shaolin DU
Chinese Acupuncture & Moxibustion 2025;45(10):1459-1467
OBJECTIVE:
To observe the effect of acupuncture on chondrocyte autophagy in rats of knee osteoarthritis (KOA) and explore its underlying mechanisms.
METHODS:
Forty male SPF-grade SD rats were randomized into a blank group, a model group, a suspension group, an acupuncture group, and a combined therapy group, 8 rats in each one. Except the blank group, KOA model was prepared by the injection with papain. The suspension exercise therapy (10 min each time, three times daily), acupuncture (at "Yanglingquan" [GB34], "Zusanli" [ST36], and "Dubi" [ST35] on the right side, 30 min each intervention, once daily) and the combined therapy (the suspension exercise therapy combined with acupuncture) were delivered in the suspension group, the acupuncture group and the combined therapy group, respectively. The intervention of each group was performed continuously for 6 days, and 4 consecutive weeks, at the interval of 1 day. Before and after intervention, Lequesne MG score was assessed in the rats. After intervention, HE staining was adopted to observe the cartilaginous tissue morphology of the right knee joints, and Mankin score was evaluated; the serum levels of interleukin (IL)-1β, IL-6, and tumor neurosis factor-α (TNF-α) were measured using ELISA; the real-time PCR was provided to determine the mRNA expression of collagen protein type Ⅱ(COL2), collagen protein type Ⅹ (COL10), phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), mammalian target of rapamycin (mTOR), and autophagy-regulated protein (Beclin-1) in the cartilaginous tissue of the right knee joint; Western blot was employed to detect the protein expression of PI3K, phosphorylated PI3K (p-PI3K), Akt, phosphorylated Akt (p-Akt), mTOR, phosphorylated mTOR (p-mTOR) and Beclin-1 in the cartilaginous tissue of the right knee joint.
RESULTS:
Compared with the blank group, the rats in the model group showed the higher Lequesne MG score (P<0.01), thinner cartilage of the right knee, reduced chondrocytes and disordered arrangement, and higher Mankin score (P<0.01). Besides, in the model group, the serum levels of IL-1β, IL-6 and TNF-α were elevated (P<0.01), the mRNA expression of COL2 and Beclin-1 and the protein expression of Beclin-1 decreased (P<0.01), the mRNA expression of COL10, PI3K, Akt and mTOR, and the protein expression of p-PI3K, p-Akt and p-mTOR increased (P<0.01) in the cartilaginous tissue of the right knee joint. Compared with the model group, in the suspension group, the acupuncture group and the combined therapy group, the Lequesne MG scores were reduced (P<0.01), the cartilage of the right knee was thickened, the arrangement of chondrocytes was improved, and the Mankin scores were lower (P<0.01). Besides, in these intervention groups, the serum levels of IL-1β, IL-6 and TNF-α were reduced (P<0.01), the mRNA expression of COL2 and Beclin-1 and the protein expression of Beclin-1 increased (P<0.05, P<0.01), the mRNA expression of COL10, PI3K, Akt and mTOR, and the protein expression of p-PI3K, p-Akt and p-mTOR decreased (P<0.05, P<0.01) in the cartilaginous tissue of the right knee joint. When compared with the suspension group and the acupuncture group, in the combined therapy group, the Lequesne MG score was reduced (P<0.01), and the Mankin score was reduced (P<0.05, P<0.01). Besides, the serum levels of IL-1β, IL-6 and TNF-α were reduced (P<0.05), the mRNA expression of COL2 and Beclin-1 and the protein expression of Beclin-1 increased (P<0.05), the mRNA expression of COL10, PI3K, Akt and mTOR, and the protein expression of p-PI3K, p-Akt and p-mTOR decreased (P<0.05, P<0.01) in the cartilaginous tissue of the right knee joint.
CONCLUSION
Acupuncture can promote cartilage regeneration of knee joint and autophagy in KOA rats, alleviate inflammation, so as to retard cartilage degeneration, which may be possibly associated with the PI3K/Akt/mTOR signaling pathway.
Animals
;
Male
;
Acupuncture Therapy
;
Proto-Oncogene Proteins c-akt/genetics*
;
TOR Serine-Threonine Kinases/genetics*
;
Osteoarthritis, Knee/physiopathology*
;
Phosphatidylinositol 3-Kinases/genetics*
;
Rats
;
Signal Transduction
;
Rats, Sprague-Dawley
;
Chondrocytes/metabolism*
;
Humans
;
Autophagy
;
Acupuncture Points
6.Artificial intelligence-enabled discovery of a RIPK3 inhibitor with neuroprotective effects in an acute glaucoma mouse model.
Xing TU ; Zixing ZOU ; Jiahui LI ; Simiao ZENG ; Zhengchao LUO ; Gen LI ; Yuanxu GAO ; Kang ZHANG
Chinese Medical Journal 2025;138(2):172-184
BACKGROUND:
Retinal ganglion cell (RGC) death caused by acute ocular hypertension is an important characteristic of acute glaucoma. Receptor-interacting protein kinase 3 (RIPK3) that mediates necroptosis is a potential therapeutic target for RGC death. However, the current understanding of the targeting agents and mechanisms of RIPK3 in the treatment of glaucoma remains limited. Notably, artificial intelligence (AI) technologies have significantly advanced drug discovery. This study aimed to discover RIPK3 inhibitor with AI assistance.
METHODS:
An acute ocular hypertension model was used to simulate pathological ocular hypertension in vivo . We employed a series of AI methods, including large language and graph neural network models, to identify the target compounds of RIPK3. Subsequently, these target candidates were validated using molecular simulations (molecular docking, absorption, distribution, metabolism, excretion, and toxicity [ADMET] prediction, and molecular dynamics simulations) and biological experiments (Western blotting and fluorescence staining) in vitro and in vivo .
RESULTS:
AI-driven drug screening techniques have the potential to greatly accelerate drug development. A compound called HG9-91-01, identified using AI methods, exerted neuroprotective effects in acute glaucoma. Our research indicates that all five candidates recommended by AI were able to protect the morphological integrity of RGC cells when exposed to hypoxia and glucose deficiency, and HG9-91-01 showed a higher cell survival rate compared to the other candidates. Furthermore, HG9-91-01 was found to protect the retinal structure and reduce the loss of retinal layers in an acute glaucoma model. It was also observed that the neuroprotective effects of HG9-91-01 were highly correlated with the inhibition of PANoptosis (apoptosis, pyroptosis, and necroptosis). Finally, we found that HG9-91-01 can regulate key proteins related to PANoptosis, indicating that this compound exerts neuroprotective effects in the retina by inhibiting the expression of proteins related to apoptosis, pyroptosis, and necroptosis.
CONCLUSION
AI-enabled drug discovery revealed that HG9-91-01 could serve as a potential treatment for acute glaucoma.
Animals
;
Glaucoma/metabolism*
;
Neuroprotective Agents/pharmacology*
;
Mice
;
Receptor-Interacting Protein Serine-Threonine Kinases/metabolism*
;
Artificial Intelligence
;
Retinal Ganglion Cells/metabolism*
;
Disease Models, Animal
;
Molecular Docking Simulation
;
Mice, Inbred C57BL
;
Male
7.Hypoxia-inducible factor-prolyl hydroxylase inhibitors in treatment of anemia with chronic disease.
Zuolin LI ; Lan SHEN ; Yan TU ; Shun LU ; Bicheng LIU
Chinese Medical Journal 2025;138(12):1424-1432
Anemia of chronic disease (ACD) is the most frequent clinical issue in patients with chronic disease. ACD is usually secondary to chronic kidney disease (CKD), cancer, and chronic infection, which is associated with poor health outcomes, increased morbidity and mortality, and substantial economic costs. Current treatment options for ACD are very limited. The discovery of the hypoxia-inducible factor-prolyl hydroxylase (HIF-PHD) pathway made it possible to develop novel therapeutic agents (such as hypoxia-inducible factor-prolyl hydroxylase inhibitor, HIF-PHI) to treat ACD by stabilizing HIF and subsequently promoting endogenous erythropoietin (EPO) production and iron absorption and utilization. Thus, HIF-PHIs appear to open a new door for the treatment of ACD patients with a novel mechanism. Here, we comprehensively reviewed the latest advancements in the application of HIF-PHIs in ACD. Specifically, we highlighted the key features of HIF-PHIs on ACD, such as stimulation of endogenous EPO, handling iron metabolism, inflammation-independent, and prolonging lifespan of red blood cells. In conclusion, the success of HIF-PHIs in the treatment of ACD may expand the therapeutic opportunity for other types of anemia beyond renal anemia.
Humans
;
Anemia/metabolism*
;
Chronic Disease
;
Hypoxia-Inducible Factor-Proline Dioxygenases/metabolism*
;
Erythropoietin/metabolism*
;
Prolyl-Hydroxylase Inhibitors/therapeutic use*
;
Animals
;
Renal Insufficiency, Chronic
8.Disulfiram alleviates cardiac hypertrophic injury by inhibiting TAK1-mediated PANoptosis.
Wei-Dong LI ; Xuan-Yang SHEN ; Xiao-Lu JIANG ; Hong-Fu WEN ; Yuan SHEN ; Mei-Qi ZHANG ; Wen-Tao TAN
Acta Physiologica Sinica 2025;77(2):222-230
The study aims to examine the effects and potential mechanisms of disulfiram (DSF) on cardiac hypertrophic injury, focusing on the role of transforming growth factor-β-activated kinase 1 (TAK1)-mediated pan-apoptosis (PANoptosis). H9C2 cardiomyocytes were treated with angiotensin II (Ang II, 1 µmol/L) to establish an in vitro model of myocardial hypertrophy. DSF (40 µmol/L) was used to treat cardiomyocyte hypertrophic injury models, either along or in combination with the TAK1 inhibitor, 5z-7-oxozeaenol (5z-7, 0.1 µmol/L). We assessed cell damage using propidium iodide (PI) staining, measured cell viability with CCK8 assay, quantified inflammatory factor levels in cell culture media via ELISA, detected TAK1 and RIPK1 binding rates using immunoprecipitation, and analyzed the protein expression levels of key proteins in the TAK1-mediated PANoptosis pathway using Western blot. In addition, the surface area of cardiomyocytes was measured with Phalloidin staining. The results showed that Ang II significantly reduced the cellular viability of H9C2 cardiomyocytes and the binding rate of TAK1 and RIPK1, significantly increased the surface area of H9C2 cardiomyocytes, PI staining positive rate, levels of inflammatory factors [interleukin-1β (IL-1β), IL-18, and tumor necrosis factor α (TNF-α)] in cell culture media and p-TAK1/TAK1 ratio, and significantly up-regulated key proteins in the PANoptosis pathway [pyroptosis-related proteins NLRP3, Caspase-1 (p20), and GSDMD-N (p30), apoptosis-related proteins Caspase-3 (p17), Caspase-7 (p20), and Caspase-8 (p18), as well as necroptosis-related proteins p-MLKL, RIPK1, and RIPK3]. DSF significantly reversed the above changes induced by Ang II. Both 5z-7 and exogenous IL-1β weakened these cardioprotective effects of DSF. These results suggest that DSF may alleviate cardiac hypertrophic injury by inhibiting TAK1-mediated PANoptosis.
Animals
;
MAP Kinase Kinase Kinases/physiology*
;
Rats
;
Myocytes, Cardiac/pathology*
;
Disulfiram/pharmacology*
;
Cardiomegaly
;
Apoptosis/drug effects*
;
Cell Line
;
Angiotensin II
;
Necroptosis/drug effects*
;
Interleukin-1beta/metabolism*
;
Receptor-Interacting Protein Serine-Threonine Kinases/metabolism*
;
Lactones
;
Resorcinols
;
Zearalenone/administration & dosage*
9.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
;
Rats, Sprague-Dawley
;
Physical Conditioning, Animal/physiology*
;
Rats
;
Muscle, Skeletal/metabolism*
;
TOR Serine-Threonine Kinases/metabolism*
;
Male
;
Hypertrophy
;
Adaptation, Physiological/physiology*
;
Adaptor Proteins, Signal Transducing/metabolism*
;
Ribosomal Protein S6 Kinases, 70-kDa/metabolism*
;
Intracellular Signaling Peptides and Proteins
10.Research progress on molecular mechanism of resistance training-induced skeletal muscle hypertrophy: the crucial role of mTOR signaling.
Acta Physiologica Sinica 2025;77(3):573-586
Resistance training promotes protein synthesis and hypertrophy, enhancing strength of skeletal muscle through the activation of the mammalian target of rapamycin (mTOR) and the subsequent increases of ribosome biogenesis and translation capacity. Recent studies indicate that resistance training has positive effects on physical fitness and illness treatment, yet the mechanisms underlying hypertrophic adaptation remain insufficiently understood. Human studies focused on the correlation between mTOR signals and hypertrophy-related protein production, while animal research demonstrated that mTOR complex 1 (mTORC1) is the main regulator of resistance training induced-hypertrophy. A number of upstream factors of mTORC1 have been identified, while the downstream mechanisms involved in the resistance training induced-hypertrophy are rarely studied. mTORC1 regulates the activation of satellite cells, which fuse with pre-existing fibers and contribute to hypertrophic response to resistance training. This article reviews the research progress on the mechanism of skeletal muscle hypertrophy caused by resistance training, analyzes the role of mTOR-related signals in the adaptation of skeletal muscle hypertrophy, and aims to provide a basis for basic research on muscle improvements through resistance training.
TOR Serine-Threonine Kinases/physiology*
;
Resistance Training
;
Humans
;
Signal Transduction/physiology*
;
Muscle, Skeletal/physiology*
;
Hypertrophy
;
Animals
;
Mechanistic Target of Rapamycin Complex 1


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