ObjectiveTo observe the effects of overexpression of S100A4 protein on retinal capillary cells and retinal ganglion cells (RGC) after retinal ischemia-reperfusion injury (RIRI). MethodsOne hundred healthy adult male C57BL/6 mice were randomly divided into normal control group (group C), RIRI group, adeno-associated virus (AAV2)-S100A4 green fluorescent protein (GFP) intravitreal injection group (group S), RIRI+AAV2-GFP intravitreal injection group (group GIR), and RIRI+AAV2-S100A4-GFP intravitreal injection group (group SIR), with 20 mice in each group. The RIRI model was established using the high intraocular pressure anterior chamber method in the RIRI, GIR and SIR groups of mice. Eyes were enucleated 3 days after modelling by over anaesthesia. The number of retinal capillary endothelial cells and pericytes in the retinal capillaries of mice in each group was observed by retinal trypsinised sections and hematoxylin-eosin and periodic acid-Schiff staining; immunofluorescence staining was used to observe endothelial cell, pericyte coverage and RGC survival; The relative expression of Toll-like receptor 4 (TLR4), p38 MAPK and nuclear factor erythroid 2-related factor 2 (NRF2) in retinal tissues was measured by Western blot. One-way analysis of variance was used to compare data between groups. ResultsThree days after modeling, the endothelial cell to pericyte ratio in group C was compared with group S and SIR, and the difference was not statistically significant (F=106.30, P＞0.05); the SIR group was compared with group RIRI and GIR, and the difference was statistically significant (F=106.30, P＜0.000 1). Comparison of endothelial cell coverage in each group, the difference was not statistically significant (F=3.44, P＞0.05); compared with the pericyte coverage in group C, the RIRI group and the GIR group were significantly lower, and the difference was statistically significant (F=62.69, P＜0.001). Compared with the RGC survival rate in group C, it was significantly lower in RIRI and GIR groups, and the difference was statistically significant (F=171.60, P＜0.000 1); compared with RIRI and GIR groups, the RGC survival rate in SIR group was significantly higher, and the difference was statistically significant (F=171.60, P＜0.000 1). The relative expression levels of TLR4, p38 and NRF2 proteins were statistically significant among all groups (F=42.65, 20.78, 11.55; P＜0.05). ConclusionsPericytes are more sensitive to ischemia than endothelial cells after retinal RIRI in mice, and early vascular cell loss is dominated by pericytes rather than endothelial cells. The overexpression of S100A4 protein protects against loss of pericytes and RGC after RIRI by inhibiting the TLR4/p38/NRF2 signaling pathway.
ObjectiveTo explore performances of functional magnetic resonance imaging (MRI) in evaluation of hepatic warm ischemia-reperfusion injury.MethodThe relative references about the principle of functional MRI and its application in the assessment of hepatic warm ischemia-reperfusion injury were reviewed and summarized.ResultsThe main functional MRI techniques for the assessment of hepatic warm ischemia-reperfusion injury included the diffusion weighted imaging (DWI), intravoxel incoherent motion (IVIM), diffusion tensor imaging (DTI), blood oxygen level dependent (BOLD), dynamic contrast enhancement MRI (DCE-MRI), and T2 mapping, etc.. These techniques mainly used in the animal model with hepatic warm ischemia-reperfusion injury currently.ConclusionsFrom current results of researches of animal models, functional MRI is a non-invasive tool to accurately and quantitatively evaluate microscopic information changes of liver tissue in vivo. It can provide a useful information on further understanding of mechanism and prognosis of hepatic warm ischemia-reperfusion injury. With development of donation after cardiac death, functional MRI will play a more important role in evaluation of hepatic warm ischemia-reperfusion injury.
ObjectiveTo summarize the mechanism of neutrophil extracellular traps (NETs) in hepatic ischemia-reperfusion injury (HIRI) and the research progress in targeting NETs to reduce HIRI, providing valuable reference for reducing HIRI. MethodThe related literatures at home and abroad about the role of NETs in the pathogenesis of HIRI and target NETs to alleviate HIRI were retrieved and reviewed. ResultsHIRI usually appeared in the process of liver surgery and was a common clinical problem, which occured in situations such as liver surgery, organ transplantation, liver ischemia and so on. This kind of injury would lead to tissue necrosis, inflammatory response and oxidative stress, which was a major cause of hepatic dysfunction and multiple organ failure after hepatic surgery, greatly increases the complications and mortality after hepatic surgery. NETs played a crucial role in the aseptic inflammatory response induced by hepatic ischemia/reperfusion. During hepatic ischemia-reperfusion, neutrophils promoted inflammatory cascade reactions and cytokine storms by forming NETs, exacerbating damage caused by hepatic ischemia-reperfusion. At present, some experimental and clinical studies had shown that inhibiting the formation of NETs or eliminating the formed NETs could alleviate the hepatic ischemia-reperfusion injury and improve the prognosis. ConclusionsTargeting NETs may become a new method for treating hepatic ischemia-reperfusion injury. In the future, it is foreseeable that more experiments and clinical trials will be conducted on targeted NETs for the treatment of hepatic ischemia-reperfusion injury. And gradually establish more comprehensive and effective treatment strategies, thereby providing new ways to improve the prognosis of hepatic surgery patients in clinical practice.
ObjectiveTo understand the current research progress on the role of hydrogen sulfide (H2S) in liver diseases. MethodThe relevant literature on the role of H2S in the liver diseases published in recent years was retrieved and reviewed. ResultsCurrent research focused primarily on exploring the mechanisms of H2S in various liver diseases. Studies had shown that H?S played an important role in the occurrence and development of liver diseases through mechanisms such as antioxidative stress, anti-inflammatory effects, regulation of autophagy, endoplasmic reticulum stress, angiogenesis, and cell death. ConclusionsBy supplementing exogenous H2S, adjusting the gut microbiota, or inhibiting key enzymes involved in H?S synthesis, the concentration of H2S in the body can be modulated, providing new strategies for treating liver diseases. However, the related mechanisms are still controversial. Future research should further investigate the specific role of H2S in different liver diseases and how to precisely control its level in the body to achieve targeted drug delivery.
Objective To observe the influence of resveratrol on superoxide dismutase (SOD), malondialdehyde (MDA), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) of intestinal mucosal ischemia-reperfusion injury protection in rats with severe acute pancreatitis (SAP). Methods Fifty-four rats were divided into three groups randomly: sham operation group (SO group), SAP model group (SAP group) and resveratrol-treated group (Res group). SAP model was made by injecting sodium taurocholate 50 mg/kg to pancreatic bile duct and resveratrol was given intravenously at 5 min after inducing SAP model. The rats were sacrificed at 3 h, 6 h and 12 h after inducing SAP model respectively by equal number. The levels of MDA, SOD, ICAM-1 and VCAM-1 and histological changes of small intestine were measured. Results The level of MDA in small intestine tissue in SAP group was significantly higher than that in SO group (P＜0.05), while the activity of SOD was significantly lower in the relevant tissues (P＜0.05). The expressions of ICAM-1 and VCAM-1 in SAP group were higher than those of SO group (P＜0.05). The activity of SOD in small intestine tissue in Res group was significantly higher than that in SAP group (P＜0.05); while the level of MDA was significantly lower in the relevant tissues (P＜0.05). The expressions of ICAM-1 and VCAM-1 in Res group were lower than those of SAP group (P＜0.05). Conclusions Oxygen free radicals are concerned with the process of pathological changes in intestinal mucosal ischemia-reperfusion in rats with SAP. Resveratrol might increase SOD activity and decrease MDA level to attenuate lipid peroxidation in small intestine of SAP, and reduce the expressions of ICAM-1 and VCAM-1 in intestine, thus diminish the damage of the intestine in SAP. And it acts as a protective effect to small intestinal ischemia-reperfusion injury.
Acute kidney injury (AKI) is characterized by a sudden and rapid decline of renal function and associated with high morbidity and mortality. AKI can be caused by various factors, and ischemia-reperfusion injury (IRI) is one of the most common causes of AKI. An increasing number of studies found out that exosomes of mesenchymal stem cells (MSCs) could alleviate IRI-AKI by the adjustment of the immune response, the suppression of oxidative stress, the reduction of cell apoptosis, and the promotion of tissue regeneration. This article summarizes the effect and mechanism of MSC-derived exosomes in the treatment of renal ischemia-reperfusion injury, in order to provide useful information for the researches on this field.
Objective
To investigate the mechanism of AMP-activated protein kinase (AMPK) in hepatic ischemia-reperfusion injury (HIRI).
Methods
① Grouping. Forty-two mice were randomly divided into Sham group, 4 ischemia reperfusion (IR) group of different times (2, 6, 12, and 24 h), Compound C group, and Compound C+repamycin (Rapa) group, each group enrolled in 6 mice. Compound C group: mice were modeled at 1 h after intraperitoneal injection of Compound C (25 mg/kg). Compound C+Rapa group: mice were modeled at 1 h after intraperitoneal injection of rapamycin (1 mg/kg) and Compound C (25 mg/kg). Mice of 4 IR groups, Compound C group, and Compound C+Rapa group were used to prepare HIRI model. Mice of Sham group were treated only for laparotomy, freeing the first portal hepatis and closing peritoneal. ② To filter the best IR time. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the serum of mice in Sham group and IR groups of 4 different reperfusion time points were measured. The pathological changes of liver tissues were observed by HE staining, and the expressions of related proteins in liver tissue of mice were detected by Western blot. Considering the results of blood biochemical test, HE staining, and Western blot together to determine the best IR point. ③ The exploration of signal pathway for AMPK. The expressions of proliferating cell nuclear antigen (PCNA) were observed by immunohistochemical staining in the liver tissues of IR-12 h group, Compound C group (12 h after IR) and compound C+Rapa group (12 h after IR). The mitochondrial damage was observed by rhodamine 123 staining, and the apoptotic status of liver cells was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay (TUNEL).
Results
① The 12 h after IR was the best observation time point. Compared with IR-12 h group, the levels of ALT and AST in Sham group, IR-2, 6, and 24 h groups were lower (P<0.05). HE staining showed that liver tissue destruction in IR-12 h group was the most severe. Western blot showed that, expressions of AMPKα, phosphorylated adenylate activated protein kinase α (p-AMPKα), Nip3-like protein X (Nix), BCL-2 homologous water-soluble protein (Bax), as well as ratio of autophagy microtubule-associated protein light chain 3 (LC3)Ⅱto LC3Ⅰof Sham group, IR-2, 6, and 24 h group were all lower than those of IR-12 h group (P<0.05), but the expressions of phosphorylated mammalian target of Rapa (p-mTOR) of Sham group, IR-2, 6, and 24 h group were all higher (P<0.05). Therefore, 12 h after IR was the best time to observe. ② Compared with IR-12 h group, the expression level of PCNA protein in liver tissue of Compound C group was lower (P<0.05), the mitochondrial luminescence intensity was weaker and the apoptotic cells were more. Compared with Compound C group, the expression of PCNA protein in the liver tissue of the Compound C+Rapa group was higher (P<0.05), the mitochondrial intensity was stronger and the apoptotic cells were less. ③ Compared with IR-12 h group, the expressions of Nix and p-AMPKα, and ratio of LC3Ⅱ to LC3Ⅰ in liver tissue of Compound C group decreased (P<0.05), while the expressions of p-mTOR, Caspase-3, and Cleaved Caspase-3 increased (P<0.05). Compared with Compound C group, the expressions of p-AMPKα and Nix in the liver tissue of Compound C+Rapa group increased (P<0.05), while the expressions of p-mTOR, Caspase-3, and Cleaved Caspase-3 decreased (P<0.05).
Conclusion
During the HIRI in mouse, AMPK regulates mitophagy and apoptosis through the mTOR/Nix pathway.
ObjectiveTo summarize the research advances of pyroptosis in hepatic ischamia-reperfusion injury (IRI).MethodThe literatures about the studies of mechanism of pyroptosis in hepatic IRI were retrieved and analyzed.ResultsPyroptosis, also known as inflammatory necrocytosis, was proven to play an important role in the hepatic IRI. When hepatic ischemia-reperfusion occurred, the classical pathway of pyroptosis dependenting on caspase-1 and the non-classical pathway of pyroptosis dependenting on caspase-11 were initiated by specific stimulants, and leaded to the activation of gasdermin D, releases of proinflammatory factors such as interleukin-1β, interleukin-18, etc., and the recruitment and activation of neutrophils. Consequently, pyroptosis caused more severe hepatic inflammation and aggravated existing cell injury and dysfunction of liver during hepatic IRI.ConclusionsPyroptosis plays an important role in liver IRI. Further researches about mechanism of pyroptosis will be beneficial to the prevention and treatment of the pyroptosis of related diseases.
ObjectiveTo investigate relationship between liver non-parenchymal cells and hepatic ischemia-reperfusion injury (HIRI).MethodThe relevant literatures on researches of the relationship between HIRI and liver non-parenchymal cells were analyzed and reviewed.ResultsDuring HIRI, hepatocytes could be severely damaged by aseptic inflammatory reaction and apoptosis. The liver non-parenchymal cells included Kupffer cells, sinusoidal endothelial cells, hepatic stellate cells, and dendritic cells, which could release a variety of cytokines and inflammatory mediators to promote the damage, and some liver non-parenchymal cells also had effect on reducing HIRI, for example: Kupffer cells could express heme oxygenase-1 to reduce HIRI, and hepatic stellate cells may participate in the repair process after HIRI. The role of liver non-parenchymal cells in HIRI was complex, but it also had potential therapeutic value.ConclusionLiver non-parenchymal cells can affect HIRI through a variety of mechanisms, which provide new goals and strategies for clinical reduction of HIRI.
ObjectiveTo investigate the potential role of immune cells in retinal ischemia-reperfusion injury (RIRI)-associated diseases, employing Mendelian randomization (MR) and colocalization analysis. MethodsGenome-wide association study (GWAS) datasets of immune cells were obtained for conducting two-sample bidirectional MR analysis and colocalization analysis. A total of 731 immune cell phenotypes from the GWAS datasets were selected as exposure variables, and four RIRI-related diseases, namely diabetic retinopathy (DR), primary angle-closure glaucoma (PACG), retinal artery occlusion (RAO), and retinal vein occlusion (RVO), were chosen as outcome variables. The 731 immune cell phenotypes included seven cell types: B cells, classical dendritic cells, T cell maturation stages, monocytes, myeloid cells, TBNK cell group [T cells, B cells, and natural killer cells], and regulatory T cells. The inverse variance weighted (IVW) method was used to assess the causal relationship between immune cell phenotypes and RIRI-related diseases; colocalization analysis was performed to verify the possibility of shared causal variants between immune cell phenotypes and outcomes. ResultsThe IVW method analysis results showed that 117 were related to RIRI. After adjusting the false discovery rate (FDR) (PFDR＜0.05) and conducting reverse MR analysis, 19, 49, 37, 13, and 9 types of immune cell phenotypes were respectively associated with potential causal relationships with non-proliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR), PACG, RAO, and RVO. Among them, in the monocyte group, CD64 on CD14+ CD16+ monocyte significantly increased the risk of NPDR occurrence [odds ratio (OR)=1.544, 95% confidence interval (CI) 1.184-2.014, P=0.011], and CX3CR1 on monocyte significantly decreased the risk of NPDR occurrence (OR=0.823, 95%CI 0.727-0.933, P=0.012); in the TBNK cell group, CD4+ CD8dim% leukocyte significantly increased the risk of PACG occurrence (OR=1.262, 95%CI 1.075-1.483, P=0.025), and CD8 on EM CD8+br cells was a risk factor for PACG occurrence (OR=1.156, 95%CI 1.049-1.275, P=0.026). The colocalization analysis results showed that 32 types of immune cell phenotypes had significant common causal variant signals with outcome variables (posterior probability H4＞0.8), located at 14 gene loci. Five immune cell phenotypes related to B-cell activating factor receptors and PDR were jointly located at the CENPM and TNFRSF13C gene loci. The specific T cell subsets CD45RA-CD4+ T cells and cytotoxic T cell phenotype CD28+ CD45RA- CD8dim %CD8dim T cells (a type of memory CD8dim T cell) were colocalized with PACG at the PTPRC gene. The CD33 and RVO on myeloid cell phenotype monocyte-like myeloid-derived suppressor cells are jointly located at the CD33 locus (rs3865444) of their encoding gene. ConclusionMR and colocalization analysis results reveal complex genetic causal relationships between multiple immune cell phenotypes and four RIRI-related diseases.
