The timely and efficient repair of the plasma membrane in skeletal muscle cells following injury is critical for maintaining cellular function and tissue integrity. Extracellular vesicles (EVs) play a pivotal role in this process through multi-level mechanisms. This review systematically summarizes the generation, secretion, and multifunctional roles of EVs in the repair of skeletal muscle plasma membrane damage: (1) removing damaged membrane fragments and cellular debris via endocytosis and exocytosis to maintain plasma membrane stability; (2) fusing with the injured plasma membrane to supply essential components for membrane repair and restore membrane integrity; and (3) serving as a vital mediator of intercellular communication, transmitting repair signals, promoting intercellular interactions, and orchestrating multi-level responses to facilitate tissue regeneration and functional recovery. Additionally, this article explores the potential applications of EVs in the treatment of exercise-induced injuries and muscular diseases, aiming to provide theoretical insights and novel strategies for future research and EV-based therapeutic approaches.
Extracellular Vesicles/physiology* ; Humans ; Muscle, Skeletal/physiology* ; Cell Membrane/physiology* ; Animals ; Regeneration/physiology* ; Exocytosis/physiology* ; Endocytosis/physiology* ; Cell Communication/physiology*

OBJECTIVE: To observe the effects of acupuncture combined with bloodletting on the expression of inflammatory factors in serum, the morphology of sensitized skin tissue and the mast cell degranulation in urticaria rats, and to explore the potential mechanism of this therapy for urticaria. METHODS: Among 42 SD rats of SPF grade, 6 rats were randomly collected for the preparation of sensitized antiserum; and the rest 36 rats were randomized into a blank group, a model group, a positive drug group, an acupuncture group, a bloodletting group and a combined treatment group (acupuncture + bloodletting), 6 rats in each one. The rat model of urticaria was established by passive cutaneous anaphylaxis. In the positive drug group, loratadine (1 mg•kg^-1) by gavage was administered once a day. In the acupuncture group, 1 h after gavage with 0.9% NaCl (1 mL), acupuncture was delivered at "Baihui" (GV 20), "Zhongwan" (CV 12), and bilateral "Quchi" (LI 11) and "Xuehai" (SP 10) for 15 min, once daily . In the bloodletting group, 1 h after gavage with 0.9% NaCl (1 mL), bloodletting was operated at "Dazhui" (GV 14) and bilateral "Geshu" (BL 17), around 0.1 mL of bleeding volume at each point, once daily. In the combined treatment group, 1 h after gavage with 0.9% NaCl (1 mL), the interventions as the acupuncture group and the bloodletting group were adopted, once daily. All the interventions started on day 6 of modeling, lasting 2 weeks. After intervention completion, antigenic stimulation was performed in the rats of each group. Using ELISA, the levels of serum immunoglobulin E (IgE), tryptase (TPS), interleukin-4 (IL-4), interleukin-5 (IL-5), tumor necrosis factor-α (TNF-α) were detected. The diameter of the blue spots of the sensitized skin on the back was measured with ruler in each rat. The morphology of sensitized skin tissue was observed using HE staining, and the degranulation of mast cells was observed using Toluidine blue staining. RESULTS: Compared with the blank group, in the model group, the levels of serum IgE, TPS, IL-4, IL-5 and TNF-α increased (P<0.01), the diameter of blue spot on the sensitized part of the rat back was larger (P<0.01), the degranulation rate of mast cells was elevated (P<0.01), and there were obvious inflammatory cell infiltration and edema in the dermis of sensitized skin tissue on the rat back. Compared with the model group, the serum levels of IgE, TPS, IL-4, IL-5 and TNF-α were reduced in the positive drug group, the acupuncture group, the bloodletting group and the combined treatment group (P<0.01, P<0.05); skin blue spot diameter was smaller in the positive drug group and the combined treatment group (P<0.05); the degranulation rate of mast cells decreased in the positive drug group, the acupuncture group, the bloodletting group and the combined treatment group (P<0.01); and the dermal edema, inflammatory infiltration were attenuated in the positive drug group, the acupuncture group, the bloodletting group and the combined treatment group. Compared with the acupuncture group and the bloodletting group, the serum levels of IgE, TPS, IL-4, IL-5 and TNF-α, as well as the degranulation rate of mast cells in the sensitized tissue were lower in the positive drug group and the combined treatment group (P<0.05). CONCLUSION Acupuncture combined with bloodletting effectively suppress mast cell degranulation in the sensitized skin tissue on the back of urticaria rats, and ameliorate the histopathological morphology. Its effect mechanism may be related to inhibiting the differentiation and proliferation of helper T cells 2 and regulating the humoral immune response.
Animals ; Rats ; Mast Cells/immunology* ; Acupuncture Therapy ; Rats, Sprague-Dawley ; Male ; Cell Degranulation ; Humans ; Bloodletting ; Urticaria/immunology* ; Female ; Acupuncture Points ; Tumor Necrosis Factor-alpha/blood* ; Interleukin-4/blood* ; Interleukin-5/blood* ; Combined Modality Therapy ; Immunoglobulin E/blood* ; Disease Models, Animal

Bacteremia induced by periodontal infection is an important factor for periodontitis to threaten general health. P. gingivalis DNA/virulence factors have been found in the brain tissues from patients with Alzheimer's disease (AD). The blood-brain barrier (BBB) is essential for keeping toxic substances from entering brain tissues. However, the effect of P. gingivalis bacteremia on BBB permeability and its underlying mechanism remains unclear. In the present study, rats were injected by tail vein with P. gingivalis three times a week for eight weeks to induce bacteremia. An in vitro BBB model infected with P. gingivalis was also established. We found that the infiltration of Evans blue dye and Albumin protein deposition in the rat brain tissues were increased in the rat brain tissues with P. gingivalis bacteremia and P. gingivalis could pass through the in vitro BBB model. Caveolae were detected after P. gingivalis infection in BMECs both in vivo and in vitro. Caveolin-1 (Cav-1) expression was enhanced after P. gingivalis infection. Downregulation of Cav-1 rescued P. gingivalis-enhanced BMECs permeability. We further found P. gingivalis-gingipain could be colocalized with Cav-1 and the strong hydrogen bonding between Cav-1 and arg-specific-gingipain (RgpA) were detected. Moreover, P. gingivalis significantly inhibited the major facilitator superfamily domain containing 2a (Mfsd2a) expression. Mfsd2a overexpression reversed P. gingivalis-increased BMECs permeability and Cav-1 expression. These results revealed that Mfsd2a/Cav-1 mediated transcytosis is a key pathway governing BBB BMECs permeability induced by P. gingivalis, which may contribute to P. gingivalis/virulence factors entrance and the subsequent neurological impairments.
Animals ; Rats ; Bacteremia/metabolism* ; Blood-Brain Barrier/microbiology* ; Caveolin 1/metabolism* ; Gingipain Cysteine Endopeptidases/metabolism* ; Permeability ; Porphyromonas gingivalis/pathogenicity* ; Transcytosis ; Virulence Factors/metabolism*

Urticaria pigmentosa (UP) is the most common form of cutaneous mastocytosis in children. It can be diagnosed clinically, based on the appearance of numerous brownish macules and papules that are symmetrically distributed, mostly on the trunk and the extremities. Skin biopsy is helpful in establishing the diagnosis. Treatment options generally include antihistamines and/or topical corticosteroids. In most cases, pediatric UP tends to disappear spontaneously before puberty. We present the case of a 9-month-old male with a history of multiple brownish patches and plaques, which started when he was four months old. He was diagnosed with UP based on clinical and histopathologic findings, and was prescribed oral antihistamines and emollients for symptomatic treatment.
cutaneous mastocytosis ; mast cell degranulation

Sodium salicylate is an anti-inflammatory medication with a side-effect of tinnitus. Here, we used mouse cochlear cultures to explore the effects of salicylate treatment on cochlear inner hair cells (IHCs). We found that IHCs showed significant damage after exposure to a high concentration of salicylate. Whole-cell patch clamp recordings showed that 1-5 mmol/L salicylate did not affect the exocytosis of IHCs, indicating that IHCs are not involved in tinnitus generation by enhancing their neuronal input. Instead, salicylate induced a larger peak amplitude, a more negative half-activation voltage, and a steeper slope factor of Ca²⁺ current. Using noise analysis of Ca²⁺ tail currents and qRT-PCR, we further found that salicylate increased the number of Ca²⁺ channels along with Ca_V1.3 expression. All these changes could act synergistically to enhance the Ca²⁺ influx into IHCs. Inhibition of intracellular Ca²⁺ overload significantly attenuated IHC death after 10 mmol/L salicylate treatment. These results implicate a cellular mechanism for tinnitus generation in the peripheral auditory system.
Animals ; Calcium ; Exocytosis ; Hair Cells, Auditory, Inner ; Mice ; Sodium Salicylate/pharmacology* ; Tinnitus/chemically induced*

Pseudo-allergic reactions (PARs) widely occur upon application of drugs or functional foods. Anti-pseudo-allergic ingredients from natural products have attracted much attention. This study aimed to investigate anti-pseudo-allergic compounds in licorice. The anti-pseudo-allergic effect of licorice extract was evaluated in rat basophilic leukemia 2H3 (RBL-2H3) cells. Anti-pseudo-allergic compounds were screened by using RBL-2H3 cell extraction and the effects of target components were verified further in RBL-2H3 cells, mouse peritoneal mast cells (MPMCs) and mice. Molecular docking and human MRGPRX2-expressing HEK293T cells (MRGPRX2-HEK293T cells) extraction were performed to determine the potential ligands of MAS-related G protein-coupled receptor-X2 (MRGPRX2), a pivotal target for PARs. Glycyrrhizic acid (GA) and licorice chalcone A (LA) were screened and shown to inhibit Compound48/80-induced degranulation and calcium influx in RBL-2H3 cells. GA and LA also inhibited degranulation in MPMCs and increase of histamine and TNF-α in mice. LA could bind to MRGPRX2, as determined by molecular docking and MRGPRX2-HEK293T cell extraction. Our study provides a strong rationale for using GA and LA as novel treatment options for PARs. LA is a potential ligand of MRGPRX2.
Animals ; Anti-Allergic Agents/therapeutic use* ; Calcium/metabolism* ; Cell Degranulation ; Glycyrrhiza ; HEK293 Cells ; Humans ; Hypersensitivity/drug therapy* ; Mast Cells/metabolism* ; Mice ; Mice, Inbred C57BL ; Molecular Docking Simulation ; Nerve Tissue Proteins/metabolism* ; Rats ; Receptors, G-Protein-Coupled/metabolism* ; Receptors, Neuropeptide/therapeutic use*

This paper was aimed to establish a new method for evaluating the anaphylactoid reaction of 15 batches of Zushima Injection from different manufacturers in vitro. Basophilic leukemia cell line RBL-2 H3 cells were cultured in vitro and Compound 48/80 was selected as positive drug. Real-time cell analysis(RTCA) system was used to detect the changes of cell index(CI) value after drug intervention. The degranulation of RBL-2 H3 cells was verified with the toluidine blue staining technology by observing the changes of cell morphology and skeleton. Clustering method was used to analyze the CI values of 15 batches of Zushima Injection on RBL-2 H3 cells. The results showed Compound 48/80(20 μg·mL~(-1)) significantly changed the cell morphology and cytoskeleton, with obvious degranulation. After adding Compound 48/80, CI value decreased rapidly within 30 minutes, then decreased slowly, suggesting that RTCA system can be used for rapid and sensitive evaluation of RBL-2 H3 cell degranulation. The results of cluster analysis showed that Zushima Injection from different manufacturers had different effects on RBL-2 H3 cells. S1-S8 and Compound 48/80 groups were grouped into one cluster, which suggesting that the sample might have potential clinical anaphylaxis. S9-S15 and the normal control group were grouped into one cluster, suggesting there was no anaphylactoid reaction in the sample. In this study, a rapid in vitro anaphylaxis evaluation technique based on RTCA system and pattern recognition method was established, which can be used for rapid in vitro evaluation of anaphylaxis for traditional Chinese medicine injection.
Anaphylaxis ; Cell Degranulation ; Humans ; Mast Cells ; Medicine, Chinese Traditional ; p-Methoxy-N-methylphenethylamine

Acute kidney injury (AKI) due to renal ischemia reperfusion (IR) is a major clinical problem without effective therapy and is a significant and frequent cause of morbidity and mortality during the perioperative period. Although the pathophysiology of ischemic AKI is not completely understood, several important mechanisms of renal IR-induced AKI have been studied. Renal ischemia and subsequent reperfusion injury initiates signaling cascades mediating renal cell necrosis, apoptosis, and inflammation, leading to AKI. Better understanding of the molecular and cellular pathophysiological mechanisms underlying ischemic AKI will provide more targeted approach to prevent and treat renal IR injury. In this review, we summarize important mechanisms of ischemic AKI, including renal cell death pathways and the contribution of endothelial cells, epithelial cells, and leukocytes to the inflammatory response during ischemic AKI. Additionally, we provide some updated potential therapeutic targets for the prevention or treatment of ischemic AKI, including Toll-like receptors, adenosine receptors, and peptidylarginine deiminase 4. Finally, we propose mechanisms of ischemic AKI-induced liver, intestine, and kidney dysfunction and systemic inflammation mainly mediated by Paneth cell degranulation as a potential explanation for the high mortality observed with AKI.
Acute Kidney Injury ; Apoptosis ; Cell Death ; Cell Degranulation ; Endothelial Cells ; Epithelial Cells ; Inflammation ; Intestines ; Ischemia ; Kidney ; Leukocytes ; Liver ; Mortality ; Necrosis ; Negotiating ; Perioperative Period ; Receptors, Purinergic P1 ; Reperfusion ; Reperfusion Injury ; Toll-Like Receptors

This paper was aimed to establish screening methods of anaphylactoid reaction caused by safflower yellow for injection based on RBL-2 H3 cell degranulation model and mice model for acute anaphylactoid reaction,and evaluate the hypersensitivity caused by safflower yellow for injection from different batches. An in vitro cell model was used to keep the cells stimulated for an hour with different batches of safflower yellow for injection as the drug group,serum-free MEM medium as negative control group and 30 mg·L-1 C48/80 as positive control group respectively. The supernatant was then absorbed,and neutral red staining technique was used to detect the effect of safflower yellow injection on the degranulation of RBL-2 H3 cells with the positive cell rate of degranulation as the indicator.An in vivo model was established to validate the experimental results,and mice model for acute anaphylactoid reaction and ELISA method were adopted to detect the plasma histamine content,and screen the hypersensitivity caused by safflower yellow for injection at the animal level by using plasma histamine content as a test index. The results of the neutral red staining experiments showed that the positive control C48/80 could cause cell degranulation,and most of the cells were deeply stained. There was significant difference in positive cell rate between different batches of safflower yellow and positive control group. In the mice model for acute anaphylactoid reaction,it was found that the positive control C48/80 significantly increased the histamine content in the plasma of mice,while the safflower yellow in each batch did not cause a significant increase in plasma histamine( P<0. 000 1). The mechanism of anaphylactoid reaction is relatively complicated. This study was mainly based on the release of histamine and other active substances by degranulation of mast cells. No significant degranulation reaction of RBL-2 H3 cells induced by safflower yellow for injection was detected,nor was the plasma histamine level significantly increased in mice from the in vitro and in vivo aspects.
Anaphylaxis ; chemically induced ; Animals ; Cell Degranulation ; drug effects ; Cells, Cultured ; Chalcone ; adverse effects ; analogs & derivatives ; Histamine ; blood ; Mast Cells ; drug effects ; Mice

The exocyst is a highly conserved eight-subunit protein complex (EXOC1–8) involved in the targeting and docking of exocytic vesicles translocating from the trans-Golgi network to various sites in renal cells. EXOC5 is a central exocyst component because it connects EXOC6, bound to the vesicles exiting the trans-Golgi network via the small GTPase RAB8, to the rest of the exocyst complex at the plasma membrane. In the kidney, the exocyst complex is involved in primary ciliognesis, cystogenesis, and tubulogenesis. The exocyst, and its regulators, have also been found in urinary extracellular vesicles, and may be centrally involved in urocrine signaling and repair following acute kidney injury. The exocyst is centrally involved in the development of other organs, including the eye, ear, and heart. The exocyst is regulated by many different small GTPases of the RHO, RAL, RAB, and ARF families. The small GTPases, and their guanine nucleotide exchange factors and GTPase-activating proteins, likely give the exocyst specificity of function. The recent development of a floxed Exoc5 mouse line will aid researchers in studying the role of the exocyst in multiple cells and organ types by allowing for tissue-specific knockout, in conjunction with Cre-driver mouse lines.
Acute Kidney Injury ; Animals ; Cell Membrane ; Ear ; Exocytosis ; Extracellular Vesicles ; GTP Phosphohydrolases ; GTPase-Activating Proteins ; Guanine Nucleotide Exchange Factors ; Heart ; Humans ; Kidney ; Mice ; Monomeric GTP-Binding Proteins ; Sensitivity and Specificity ; trans-Golgi Network