The pathogenesis of Parkinson's disease is closely related to genetic factors. This article has systematically reviewed the research progress of molecular genetic mechanism on Parkinson's disease by focusing on the role of six high-penetrance pathogenic genes (SNCA, LRRK2, PRKN, PINK1, PARK7, and VPS35) and some risk genes (such as GBA1). These genetic variants eventually converge in three core pathogenic biological pathways, including lysosomal-autophagy pathway disorder, mitochondrial quality control disorder and α-synuclein metabolic abnormality. In-depth understanding of these molecular mechanisms is of great significance for the development of targeted therapy and realization of precision medicine for this disease.
Humans ; Parkinson Disease/metabolism* ; alpha-Synuclein/genetics* ; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/genetics* ; Genetic Predisposition to Disease ; Protein Kinases/genetics* ; Animals ; Glucosylceramidase/genetics* ; Ubiquitin-Protein Ligases/genetics*

OBJECTIVE: To analyze the clinical characteristics of patients with 11q23 rearrangement acute lymphoblastic leukemia (ALL) with non-KMT2A::AFF1 fusion genes. METHODS: The clinical data of 10 patients with KMT2A fusion gene positive and partner gene non-AFF1 ALL admitted to Henan Cancer Hospital from December 2016 to December 2024 were retrospectively summarized. The immunophenotype, molecular genetic characteristics, clinical manifestations and disease prognosis of these patients were analyzed. This research has been approved by the Medical Ethics Committee of Henan Cancer Hospital (Ethics No.: 2019342). RESULTS: Among the 10 patients, the fusion genes were KMT2A::MLLT1 in 7 cases, KMT2A::MLLT4, KMT2A::MLLT3 and KMT2A::MLLT10 in 1 case each. The European Group for the Immunological Classification of Leukemias (EGIL) classification included 6 cases of T-ALL, 2 cases of pro-B-ALL, 1 case of Common-B-ALL and 1 case of pre-B-ALL. 4 cases of B-ALL all expressed CD19, cCD79a, CD38 and HLA-DR, and some expressed CD34 and CD22, without expression or weak expression of CD10, without expression of CD20. One case was accompanied by myeloid marker CD15 expression. 6 cases of T-ALL all expressed CD34, CD7, most expressed CD38, and some expressed CD3, CD5, CD2, CD4 and CD8, and 1 case expressed CD4 and CD8 together. Chromosomal abnormalities were detected in 3 cases, 5 cases were positive for WT1 fusion gene, and 6 cases had gene alterations. 9 patients achieved the first complete remission (CR1) during chemotherapy, and 1 patient relapsed within 6 months after CR1. At the last follow up, 1 patient (the fusion gene was KMT2A::MLLT4) remained unrelieved. There were 2 cases of KMT2A rearrangement (KMT2A-r) persistent positive (+/+) and 8 cases of KMT2A-r negative (+/-). The overall survival (OS) rate and leukemia-free survival (LFS) rate of patients with KMT2A-r persistent positive were significantly lower than those of patients with negative change, and the differences were statistically significant (P values were all < 0.05). Among the 3 patients who received chemotherapy+allogeneic hematopoietic stem cell transplantation (allo-HSCT), no relapse was observed until the follow up day. The OS rate and LFS rate of patients with KMT2A::MLLT1 and chemotherapy+allo-HSCT were higher than those of non-KMT2A::MLLT1 and single chemotherapy patients, and the differences were not statistically significant (P values were all ≥ 0.05). There was no significant difference in OS rate and LFS rate between T-ALL and B-ALL patients (P values were all ≥ 0.05). The median LFS time of the 10 patients was 32 (0 ~ 100) months, and the median OS time was 36 (1 ~ 101) months. CONCLUSION The 11q23 rearrangement ALL with non-KMT2A::AFF1 transcript is mainly KMT2A::MLLT1, T-ALL is more common, and the rate of chromosomal karyotype detection is relatively low. Persistent positive KMT2A-r is unfavorable for patient survival, and allo-HSCT during the CR1 period may improve patient survival.
Humans ; Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics* ; Female ; Male ; Myeloid-Lymphoid Leukemia Protein/genetics* ; Histone-Lysine N-Methyltransferase/genetics* ; Adult ; Adolescent ; Chromosomes, Human, Pair 11/genetics* ; Child ; Transcriptional Elongation Factors/genetics* ; Gene Rearrangement ; Oncogene Proteins, Fusion/genetics* ; Retrospective Studies ; Young Adult ; Middle Aged ; Prognosis ; Child, Preschool ; DNA-Binding Proteins/genetics*

Introduction: Arginine vasopressin deficiency (AVP-D) is characterized by impaired antidiuretic hormone secretion, leading to polyuria and a significant dehydration risk. The British Islamic Medical Association classifies AVP-D as a “very high risk” condition, advising against Ramadan fasting. However, many patients fast due to religious convictions, creating a gap between clinical guidelines and patient practice. This study evaluates the clinical outcomes and safety of fasting in this population. Methodology: A single-centre retrospective cohort study was conducted at Hospital Putrajaya. We included adults with permanent AVP-D on desmopressin therapy for more than 1 year who fasted during Ramadan 2025. Data were extracted from electronic medical records and patient consultations. Primary outcomes included hospitalization rates, dehydration symptoms, and desmopressin dose adjustments. Results: Of the 43 patients (mean age 42.4 ± 15.28 years; 53.5% female), 27 successfully fasted for a mean of 27.6 ± 6.56 days. Pre-Ramadan counseling was documented in only 55.8% of cases. While 25.9% of participants experienced dehydration symptoms (thirst, dizziness), and 22.2% broke their fast for safety reasons, there were no hospitalizations. None of the patients required additional desmopressin dose adjustments. Most patients (66.7%) maintained twicedaily desmopressin dosing (Sahur and Iftar). Anterior pituitary deficiencies were present in 70.3% of the cohort. Conclusion Despite being classified as very high risk, many AVP-D patients safely complete Ramadan fasting without severe adverse events. However, the high rate of dehydration symptoms and the significant gap in pre-Ramadan counseling (44.2% un-counseled) highlight the need for structured clinical reviews 4–6 weeks prior to Ramadan to optimize hydration and dosing
Humans ; Diabetes Insipidus, Neurogenic ; Retrospective Studies ; Arginine ; Fasting

Introduction: Arginine vasopressin deficiency (AVP‑D), previously termed central diabetes insipidus, is a rare paediatric endocrine disorder that may present as an early manifestation of diverse hypothalamic–pituitary conditions. Identifying the underlying etiology is crucial for guiding management and surveillance; however, in some children, the cause remains unresolved, leading to primarily symptomatic treatment. In Malaysia, published literature on paediatric AVP‑D has been limited to isolated case reports, with no cohort‑level data available. This study aims to describe the clinical features, etiological spectrum, and treatment patterns of paediatric AVP-D in a single-centre Malaysian cohort, emphasizing diagnostic yield, unresolved causes, and the central role of neuroimaging. Methodology: A retrospective review was conducted of children diagnosed with AVP-D. Data collected included age at symptom onset, age at presentation, clinical features, etiological classification, neuroimaging findings, comorbidities, treatment modalities, and follow-up outcomes. Descriptive statistics were used for analysis. Results: Twelve children were included, with a median age of 9.8 years; two-thirds were male. Children were referred at a median age of 3.4 years, with presentation ranging from the neonatal period to 10.4 years. Diagnostic delay was minimal overall, although 25% experienced delays exceeding 1 year. The water deprivation test was performed in 33.3% of patients. Magnetic resonance imaging (MRI) was completed in all children and served as the principal determinant of etiology. Structural abnormalities were identified in 50% of the cohort, including semilobar holoprosencephaly (33.3%), Arnold– Chiari I malformation (8.3%), and pituitary stalk interruption syndrome (8.3%). The posterior pituitary bright spot was absent in most patients, and 50% required repeat MRI to clarify evolving neurohypophyseal features. Tumor-related AVP-D accounted for 8.3%, while one-third had no definitive etiology despite imaging. Initial therapy included desmopressin (58.3%), hydrochlorothiazide (25%), and diluted sublingual desmopressin (8.3%), with most requiring dose escalation. Growth impairment occurred in 66.7% of patients, and delayed puberty in 16.7%. Conclusion MRI played a central role in defining etiology, with half of the cohort demonstrating congenital structural abnormalities. Persistent unresolved cases highlight the diagnostic challenges of AVP-D and underscore the importance of early MRI and longitudinal endocrine follow-up.
Child ; Cohort Studies ; Diabetes Insipidus, Neurogenic ; Arginine

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

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 F_2α (PGF_2α), 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 PGF_2α, 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 PGF_2α, 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

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

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

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*

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