OBJECTIVE: To observe the neuroprotective effect of 6-shogaol (6-SH) in global cerebral ischemia/reperfusion injury (CIRI) following cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) in rats. METHODS: Computer-aided molecular docking was used to determine whether 6-SH could spontaneously bind to death-associated protein kinase 1 (DAPK1). SPF-grade male SD rats were randomly divided into a sham group (n = 5), a CPR group (n = 7), and a CPR+6-SH group (n = 7). The CPR group and CPR+6-SH group were further divided into 12-, 24-, and 48-hour subgroups based on observation time points. A rat model of global CIRI after CA-CPR was established by asphyxiation. In the sham group, only tracheal and vascular intubation was performed without asphyxia and CPR induction. The CPR group was intraperitoneally injected with 1 mL of normal saline immediately after successful modeling. The CPR+6-SH group received an intraperitoneal injection of 20 mg/kg 6-SH (1 mL) immediately after successful modeling, followed by administration every 12 hours until the endpoint. Neurological Deficit Score (NDS) was recorded at each time point after modeling. After completion of observation at each time point, rats were anesthetized and sacrificed, and brain tissue specimens were collected. Histopathological changes of neurons were observed under light microscopy after hematoxylin-eosin (HE) staining. Ultrastructural changes of hippocampal neurons and autophagy were observed by transmission electron microscopy (TEM). Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect mRNA expression levels of DAPK1, vacuolar protein sorting 34 (VPS34), Beclin1, and microtubule-associated protein 1 light chain 3 (LC3) in brain tissues. Western blotting was used to detect protein expression levels of DAPK1, phosphorylated DAPK1 at serine 308 (p-DAPK1 ser308), VPS34, Beclin1, and LC3. Immunofluorescence was used to observe Beclin1 and LC3 expression in brain tissues under a fluorescence microscope. RESULTS: Molecular docking results indicated that 6-SH could spontaneously bind to DAPK1. Compared with the sham group, the NDS scores of the CPR group rats were significantly increased at all modeling time points; under light microscopy, disordered cell arrangement, widened intercellular spaces, and edema were observed in brain tissues, with pyknotic and necrotic nuclei in some areas; under TEM, mitochondria were markedly swollen with intact membranes, dissolved matrix, reduced or disappeared cristae, vacuolization, and increased autophagosomes. Compared with the CPR group, the NDS scores of the CPR+6-SH group rats were significantly decreased at all modeling time points; under light microscopy, local neuronal edema and widened perinuclear space were observed; under TEM, mitochondria were mostly mildly swollen with intact membranes, fewer autophagosomes, and alleviated injury. RT-qPCR results showed that compared with the sham group, mRNA expression levels of DAPK1, VPS34, Beclin1, and LC3 in brain tissues were significantly upregulated in all CPR subgroups, with the most pronounced changes at 24 hours. Compared with the CPR group, the CPR+6-SH group showed significantly lower mRNA expression of the above indicators at each time point [24 hours post-modeling (relative expression): DAPK1 mRNA: 3.41±0.68 vs. 4.48±0.62; VPS34 mRNA: 3.63±0.49 vs. 4.66±1.18; Beclin1 mRNA: 3.08±0.49 vs. 4.04±0.22; LC3 mRNA: 2.60±0.36 vs. 3.67±0.62; all P < 0.05]. Western blotting results showed that compared with the sham group, the protein expression levels of DAPK1, VPS34, Beclin1, and LC3 in all CPR subgroups were significantly increased, while the expression of p-DAPK1 ser308 was significantly decreased, with the most pronounced changes observed in the CPR 24-hour subgroup. Compared with the CPR group, the CPR+6-SH subgroups exhibited significantly reduced protein expression of DAPK1, VPS34, Beclin1, and LC3 [24-hour post-modeling: DAPK1/β-actin: 1.88±0.22 vs. 2.47±0.22; VPS34/β-actin: 2.55±0.06 vs. 3.46±0.05; Beclin1/β-actin: 2.12±0.03 vs. 2.87±0.03; LC3/β-actin: 2.03±0.24 vs. 3.17±0.23; all P < 0.05]. Conversely, the expression of p-DAPK1 ser308 was significantly upregulated in the CPR+6-SH group compared to the CPR group [24-hour post-modeling: p-DAPK1 ser308/β-actin: 0.40±0.02 vs. 0.20±0.07, P < 0.05]. Under the fluorescence microscope, fluorescence intensities of Beclin1 and LC3 in the CPR 24-hour group were significantly higher than those in the sham 24-hour group; compared with the CPR 24-hour group, the CPR+6-SH 24-hour group showed significantly reduced fluorescence intensities of Beclin1 and LC3. CONCLUSION 6-SH inhibited the expression of DAPK1, alleviated excessive autophagy after global CIRI following CA-CPR in rats, and exerted neuroprotective effects. The mechanism may be related to phosphorylation at the DAPK1 ser308 site.
Animals ; Rats, Sprague-Dawley ; Male ; Rats ; Cardiopulmonary Resuscitation ; Autophagy/drug effects* ; Heart Arrest/therapy* ; Death-Associated Protein Kinases/metabolism* ; Reperfusion Injury/metabolism* ; Disease Models, Animal ; Neuroprotective Agents/pharmacology* ; Brain Ischemia/metabolism*

Objective:To investigate whether 6-shogaol (6-SH) alleviates oxygen-glucose deprivation/reoxygenation (OGD/R)-induced neuronal autophagy and calcium overload by promoting the expression of microRNA-26a-5p (miR-26a-5p) and inhibiting death-associated protein kinase 1 (DAPK1), and to explore its potential mechanisms.Methods:Primary cultured logarithmic growth phase mouse hippocampal neurons HT22 cells were taken and cell counting kit-8 (CCK-8) was used to detect cell viability, searching for the optimal concentration of Na 2S 2O 4. HT22 cells were divided into blank control group (NC group), OGD/R group (sugar-free culture medium + 10 mmol/L Na 2S 2O 4 treatment for 1.5 hours followed by normal culture medium for 4 hours), 6-SH intervention group (cultured with 10 μmol/L 6-SH for 4 hours after OGD), negative control inhibitor pretreatment group (transfected with negative control inhibitor for 48 hours followed by OGD, then cultured with 6-SH for 4 hours), and miR-26a-5p inhibitor pretreatment group (transfected with miR-26a-5p inhibitor for 48 hours followed by OGD, then cultured with 6-SH for 4 hours). Cell viability of each group was detected by CCK-8 method; cell ultrastructure was observed under transmission electron microscopy; real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the gene expressions of DAPK1 and miR-26a-5p; molecular docking were used to verify the interaction between 6-SH and miR-26a-5p; dual-luciferase assay was used to verify the targeting relationship between DAPK1 and miR-26a-5p; flow cytometry was used to determine the levels of intracellular Ca 2+; Western blotting was used to detect the protein expressions of phosphorylated-glutamate receptor 2B (p-NMDAR2B) Ser1303, DAPK1, autophagy related protein Beclin1, light chain 3 (LC3), and p-DAPK1 Ser308; immunofluorescence was used to detect the expression of LC3 and Beclin1. Results:The results of the CCK-8 assay showed that the cell viability of the 6-SH intervention group was significantly increased compared to the OGD/R group, while the cell viability of the miR-26a-5p inhibitor pretreatment group was significantly decreased compared to the 6-SH intervention group. Transmission electron microscopy revealed that the number of autophagosomes in the 6-SH intervention group was significantly reduced compared to the OGD/R group, while the number of autophagosomes in the miR-26a-5p inhibitor pretreatment group was significantly increased compared to the 6-SH intervention group. RT-qPCR results showed that compared with the OGD/R group, the expression of miR-26a-5p was significantly upregulated and the expression of DAPK1 mRNA was significantly downregulated in the 6-SH intervention group; compared with the 6-SH intervention group, the expression of miR-26a-5p was significantly downregulated and the expression of DAPK1 mRNA was significantly upregulated in the miR-26a-5p inhibitor pretreatment group. Molecular docking verified the interaction between 6-SH and miR-26a-5p. Dual-luciferase reporter gene assay showed that compared with the negative control group, mmu-miR-26a-5p significantly downregulated the luciferase expression of m-DAPK1-3UTR-WT, indicating a binding interaction between them. Flow cytometry results showed that compared with the OGD/R group, the level of intracellular Ca 2+ was significantly decreased in the 6-SH intervention group; compared with the 6-SH intervention group, the level of Ca 2+ was significantly increased in the miR-26a-5p inhibitor pretreatment group. Western blotting results showed that compared with the OGD/R group, the protein expressions of p-NMDAR2B Ser1303, DAPK1, Beclin1, and LC3 were significantly decreased in the 6-SH intervention group (p-NMDAR2B Ser1303/β-actin: 2.34±0.27 vs. 4.78±0.39, DAPK1/β-actin: 1.40±0.13 vs. 2.37±0.21, Beclin1/β-actin: 2.61±0.32 vs. 4.32±0.29, LC3/β-actin: 2.52±0.45 vs. 5.09±0.18, all P < 0.05), while the protein expression of p-DAPK1 Ser308 was significantly increased (p-DAPK1 Ser308/β-actin: 0.66±0.09 vs. 0.40±0.02, P < 0.05); compared with the 6-SH intervention group, the protein expressions of p-NMDAR2B Ser1303, DAPK1, Beclin1, and LC3 were significantly increased in the miR-26a-5p inhibitor pretreatment group (p-NMDAR2B Ser1303/β-actin: 4.08±0.14 vs. 2.34±0.27, DAPK1/β-actin: 1.96±0.15 vs. 1.40±0.13, Beclin1/β-actin: 3.92±0.31 vs. 2.61±0.32, LC3/β-actin: 4.33±0.33 vs. 2.52±0.45, all P < 0.05), while the expression of p-DAPK1 Ser308 protein was significantly decreased (p-DAPK1 Ser308/β-actin: 0.33±0.12 vs. 0.66±0.09, P < 0.05); immunofluorescence staining showed that compared with the OGD/R group, the fluorescence intensity of LC3 and Beclin1 was significantly decreased in the 6-SH intervention group; compared with the 6-SH intervention group, the fluorescence intensity of LC3 and Beclin1 was significantly increased in the miR-26a-5p inhibitor pretreatment group. Conclusion:6-SH can alleviate neuronal damage by regulating miR-26a-5p/DAPK1 to reduce autophagy and calcium overload in cells.

Continuous renal replacement therapy (CRRT) has become an effective multiple organ support therapy instead of single renal replacement as initially expected, and it is widely used in intensive care unit (ICU). After the outbreak of coronavirus disease 2019 (COVID-19), a series of expert recommendation or consensus have been developed to diagnose and treat the disease, including CRRT in acute kidney injury (AKI) and hyper inflammatory response. However, CRRT in COVID-19 is extraordinarily different from regular one due to different pathophysiology and infectious clinical scenarios. Accordingly, the paper aims to elaborate the similarities and differences between CRRT in COVID-19 and routine treatment in terms of safety and accessibility, indications and timing, clinical operation, anticoagulation, fluid management, prevention and control of infectious diseases, etc.