Clinical and Experimental Pharmacology and Physiology最新文献

Myocardial ischemia–reperfusion injury (MIRI) causes severe clinical complications in patients. Although gemfibrozil (GEM) has been extensively studied in metabolic diseases, its effects on MIRI remain unknown. In this study, we investigated the pharmacological effects and molecular mechanisms of GEM in alleviating MIRI through adenosine 5′-monophosphate-activated protein kinase (AMPK) modulation. The results showed that pre-administration of GEM (100 mg/kg) provided significant protection against MIRI in mice, as indicated by reduced infarct size, lower cardiac injury markers such as hydrogen peroxide (H₂O₂), lactate dehydrogenase (LDH), and creatine kinase (CK), and improved cardiac function. This cardioprotective effect of GEM was associated with enhanced myocardial antioxidant capacity, as shown by decreased dihydroethidium (DHE) fluorescence density and reduced nitric oxide (NO) and malondialdehyde (MDA) levels in ischemic cardiac tissue. GEM pretreatment also prevented the I/R-induced increase in TUNEL-positive cells and expression of caspase-3, caspase-9, and Bax, as well as the I/R-induced decrease in Bcl-2 expression in ischemic cardiac tissue, indicating an anti-apoptotic effect of GEM in MIRI. In addition, GEM pretreatment prevented the I/R-induced increase in mRNA expression levels of tumour necrosis factor-α (Tnf-α), interleukin-β (Il-1β), and Il-6 in ischemic cardiac tissue. Further analysis showed that GEM administration prevented the I/R-induced decrease in phospho-AMPK levels in ischemic cardiac tissue, and pharmacological inhibition of AMPK with dorsomorphin (DSMF) abolished all cardioprotective effects of GEM. Taken together, these results suggest that GEM mitigates MIRI-induced cardiac injury by inhibiting apoptosis and oxidative stress via modulation of AMPK, supporting its potential for reducing MIRI-related cardiac damage.

A rapid increase in the incidence of insulin resistance (IR) induced by long-term olanzapine treatment has been observed; however, there are no more efficient ways to prevent IR. Our study aimed to demonstrate the mechanism underlying olanzapine-induced insulin resistance. In this study, we first analysed the data of 120 schizophrenia patients who had been taking olanzapine for at least 3 months. Eventually, it was found that an increase in circulating tumour necrosis factor-α (TNF-α, p < 0.05). Subsequently, we verified this finding in a rat model. We detected the expression levels of the target genes fatty acid binding protein 4 (FABP4) and the palmitoyltransferase Dhhc7 in both rats and three T3-L1 adipocytes by using Western blotting and polymerase chain reaction (p < 0.05). Exposure to olanzapine increased the expression of FABP4 while decreasing the expression of Dhhc7. Additionally, we demonstrated that it may affect metabolism by inhibiting glucose transporter 4 (GLUT4) membrane transport. Finally, we improved olanzapine-induced insulin resistance by injecting FABP4 adenovirus and elucidating its underlying mechanism. In summary, our study demonstrated that long-term exposure to olanzapine increases circulating plasma levels of TNF-α, thus leading to increased expression of FABP4 protein in white adipose tissue and subsequently inhibiting Dhhc7expression, which correspondingly leads to reduced membrane translocation of GLUT4 and consequent insulin resistance. In conclusion, this study elucidated the signalling pathway through which olanzapine inhibits GLUT4 membrane transport via the TNF-α/FABP4/Dhhc7 axis, thus ultimately leading to insulin resistance.

Sepsis-induced cardiomyopathy (SICM) is a severe complication of sepsis, in which mitochondrial dysfunction contributes to poor outcomes. DEAD-box helicase 17 (Ddx17), a member of the DEAD-box RNA helicase family, is known to regulate mitochondrial function, but its role in SICM remains unclear. In this study, mice with cardiomyocyte-specific Ddx17 knockdown (Ddx17-cKD) and overexpression (Ddx17-OE) were generated, and sepsis models were established using cecal ligation and puncture. Mechanistic findings were further validated in vitro using immunoprecipitation and dual-luciferase assays. Ddx17 expression was markedly reduced in the cardiac tissues of septic mice and in lipopolysaccharide-treated cardiomyocytes. Knockdown of Ddx17 increased mitochondrial reactive oxygen species accumulation, enhanced cell death and decreased superoxide dismutase activity. In contrast, Ddx17 overexpression attenuated mitochondrial apoptosis and oxidative stress, restored adenosine triphosphate production and mitochondrial membrane potential and improved cardiac function in septic mice. Mechanistically, Ddx17 interacted with signal transducer and activator of transcription 3 (STAT3) to suppress transcription of the mitochondrial fission protein dynamin-related protein 1 while maintaining the level of the fusion protein mitofusin 1, thereby preserving mitochondrial integrity and cardiomyocyte homeostasis. These findings demonstrate that Ddx17 protects against sepsis-induced cardiomyopathy by regulating mitochondrial dynamics, reducing oxidative stress and preventing apoptosis, thereby highlighting Ddx17 as a potential therapeutic target for septic cardiac dysfunction.

Post-myocardial infarction (MI) patients remain at high risk for developing heart failure (HF). This study investigated the therapeutic effects and mechanistic basis of Shenqi Lixin Formula (SQLXF) on angiogenesis and glucose metabolism in MI-HF. MI-HF rat models were generated, and myocardial pathology, infarct area, cardiac function, platelet endothelial cell adhesion molecule-1 (CD31), vascular endothelial growth factor A (VEGFA), hexokinase 2 (HK2), lactate dehydrogenase A (LDHA), lysine demethylase 5B (KDM5B) and ER degradation enhancing alpha-mannosidase like protein 3 (EDEM3) expressions, glucose consumption, lactate production and extracellular acidification rate (ECAR) were evaluated. Hypoxia-treated human cardiac microvascular endothelial cells (HCMECs) were used as in vitro models to assess angiogenic capacity. SQLXF intervention and subsequent analyses were performed to determine KDM5B and EDEM3 expression levels, as well as the enrichment of KDM5B and trimethylation of lysine 4 on histone H3 protein subunit (H3K4me3) on the EDEM3 promoter. In animal models, infarct area enlargement, impaired cardiac function, increased glucose consumption, lactate production, and upregulation of CD31, VEGFA, HK2, LDHA and KDM5B expressions were observed, accompanied by reduced EDEM3 expression. SQLXF administration improved cardiac function, promoted angiogenesis, normalised glucose metabolism, inhibited KDM5B and restored EDEM3 expression. In HCMECs, hypoxia suppressed EDEM3, angiogenesis and metabolic stability while increasing KDM5B expression; these alterations were reversed by high-dose SQLXF. Mechanistically, KDM5B inhibited EDEM3 transcription by reducing H3K4me3 enrichment, whereas SQLXF enhanced H3K4me3 and relieved KDM5B-mediated repression. KDM5B overexpression or EDEM3 knockdown attenuated the beneficial effects of SQLXF.

The study aimed to investigate the neuroprotective functions and the underlying regulatory mechanisms of Tabersonine in cerebral ischemia/reperfusion (I/R) injury. Oxygen–glucose deprivation/reoxygenation (OGD/R)-treated neural cells were used as a cell model under I/R context. Cell counting kit 8 (CCK8) assay and enzyme-linked immunosorbent assay (ELISA) were used to assess the cell viability and the release levels of inflammatory cytokines (interleukin-1β (IL-1β), IL-6 and tumour necrosis factor α (TNF-α)) of treated neural cells. The apoptotic proportions of treated neural cells were analysed by flow cytometry, and the intracellular levels of reactive oxygen species (ROS) and superoxide dismutase (SOD) were quantified by corresponding kits. In this study, molecular docking analysis identified solute carrier family 6 member 2 (SLC6A2) as a potential target of Tabersonine in cerebral infarction, demonstrating a high binding affinity of −7.4 kcal/mol. Tabersonine treatment increased neural cell viability, repressed apoptosis and reduced the release levels of IL-1β, IL-6 and TNF-α under OGD/R stress. Moreover, Tabersonine treatment reduced ROS levels and increased SOD expression in neural cells under OGD/R treatment. In contrast to the protective effect of SLC6A2 knockdown, its overexpression counteracted the neuroprotection conferred by Tabersonine. Tabersonine also inactivated the NF-κB pathway partially via SLC6A2. Furthermore, Tabersonine pretreatment demonstrated significant neuroprotective effects in MCAO/R rats, as evidenced by reduced brain edema and attenuated neural inflammation and apoptosis. In conclusion, Tabersonine can alleviate neural impairment in cerebral I/R injury partially by inactivating the NF-κB pathway through SLC6A2.

Bupivacaine, a commonly used aminoamide local anaesthetic, exerts cellular effects beyond anaesthesia. However, its effects on calcium (Ca²⁺) signalling and the physiological responses of lung fibroblasts remain insufficiently characterised. This study aimed to determine whether bupivacaine disrupts intracellular Ca²⁺ homeostasis and induces cytotoxicity in IMR-90 human foetal lung fibroblasts via Ca²⁺-dependent mechanisms. Cell viability was assessed using the CCK-8 assay, and intracellular Ca²⁺ levels ([Ca²⁺]ᵢ) were monitored in fura-2-loaded cells. Pharmacological inhibitors were used to dissect the signalling pathways involved. Bupivacaine (20–60 μM) caused a concentration-dependent rise in [Ca²⁺]ᵢ and a corresponding decline in cell viability. These effects were significantly attenuated by pre-treatment with the Ca²⁺ chelator BAPTA-AM, indicating a Ca²⁺-dependent cytotoxic mechanism. Mechanistically, bupivacaine induced Ca²⁺ influx through store-operated Ca²⁺ entry (SOCE), involving protein kinase C (PKC), and triggered Ca²⁺ release from the endoplasmic reticulum (ER) via a phospholipase C (PLC)-dependent pathway. Mn²⁺ quenching assays confirmed SOCE as the primary route of Ca²⁺ entry. Bupivacaine disrupts Ca²⁺ signalling through both extracellular influx and intracellular release, contributing to pulmonary cytotoxicity. These findings underscore the relevance of Ca²⁺ homeostasis in anaesthetic-related lung injury and suggest that Ca²⁺ chelation may be a potential protective strategy.