Change of ACE/ACE2 expression in mouse kidney after tourniquet shock

AIM: To investigate the change of angiotensin-converting enzyme/angiotensin-converting enzyme 2(ACE/ACE2) expression in mouse kidney after tourniquet shock (TS) and to study the effects of ACE/ACE2 imbalance on the kidney of TS mice. METHODS: The male ICR mice were used in the study. The model of TS was made using bilateral tourniquets placed high in the inguinal region on both hind legs for 2 h to induce ischemia, and reperfusion was initiated by cutting latex rings. The expression of ACE/ACE2 in the kidney at different time points was determined by Western blotting and immunohistochemistry. The content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in the kidney were determined by chemical colorimetric method. The morphological changes of the kidney were observed under microscope with HE staining. RESULTS: Western blotting showed that ACE was increased and ACE2 was decreased in the kidney after TS. MDA was increased and SOD was decreased in TS groups as compared with control group. The kidney of TS groups displayed distinct injuries including inflammatory cell infiltration and degeneration of tubule epithelial cells. The results of immunohistochemistry showed that ACE expressed in endochylema of the renal tubular epithelial cells was increased and ACE2 expressed in epithelium of proximal tubules was decreased in the TS mice. CONCLUSION: Both ACE and ACE2 are expressed in the kidney. The imbalance of ACE/ACE2 expression in the kidney after TS may be related to the kidney injury.     

Role of post-hemorrhagic shock mesenteric lymph in enhancement of vascular permeability

AIM：To investigate the role of post-hemorrhagic shock mesenteric lymph (PHSML) in the enhancement of vascular permeability. METHODS：Eighteen Wistar rats were randomized into sham group, shock group, and shock plus mesenteric lymph drainage (shock + drainage) group. The rats in shock group and shock + drainage group were routinely subjected to hemorrhagic shock and hypotension ［(40±2） mmHg］ was maintained for 90 min, and then the fluid resuscitation was performed. Mesenteric lymph was drained in the rats in shock+drainage group from resuscitation finished to 6 h, for the observation of PHSML drainage on the vascular permeability in multiple tissues of hemorrhagic shock rats. Afterwards, human umbilical vein endothelial cells (HUVECs) were incubated with the PHSML in vitro to observe the effects of PHSML on the morphology and permeability of HUVECs. RESULTS：The degree of blue color and concentrations of Evens blue in the lung, myocardium, kidney, liver, spleen and small intestine were significantly increased in the shocked rats than that in sham group, while the ratios of the dry weight to the wet weight were decreased. The mesenteric lymph drainage reversed these changes. Meanwhile, 4% and 10% of PHSML at 0~3 h and 3~6 h after resuscitation, and lipopolysaccharide (10 mg/L) all caused the damage of HUVECs, decreased the viability and trans-endothelial electrical resistance of HUVECs, and increased the permeability of HUVECs to fluorescein isothiocyanate-labeled albumin. CONCLUSION：PHSML is a vital factor in the enhancement of vascular permeability.     

Dexmedetomidine attenuates acute kidney injury induced by hemorrhagic shock/resuscitation in rats

AIM: To investigate the effects of dexmedetomidine on hemorrhagic shock/resuscitation (HS/R)-induced acute kidney injury (AKI) in rats, and to explore the possible mechanisms. METHODS: Wistar rats (n=32) were randomly divided into 4 groups (n=8):normal saline control group (NS group), dexmedetomidine group (D group), HS/R group and HS/R+D group. The animals were sacrificed at 6 h after resuscitation. The levels of serum creatinine (Cr) and blood urine nitrogen (BUN) were examined. The kidneys of all rats were removed for evaluation of histological characteristics, and the levels of malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and superoxide dismutase (SOD) were measured. The expression of nuclear factor-κB (NF-κB) and hemeoxygenase-1 (HO-1) was determined by Western blot. RESULTS: Compared with NS group, the levels of Cr, BUN, MDA, TNF-α and IL-1β were obviously increased in HS/R group, which were obviously decreased in HS/R+D group (P<0.05). Compared with NS group, the SOD activity was obviously decreased in HS/R group, which was obviously increased in HS/R+D group (P<0.05). Compared with NS group, the protein expression of NF-κB was obviously increased in HS/R group, which was obviously decreased in HS/R+D group (P<0.05). Compared with NS group, the protein expression of HO-1 was increased in HS/R group. Compared with HS/R group, the protein expression of HO-1 was obviously increased in HS/R+D group. Compared with NS group, HS/R induced marked kidney histological injury, which was less pronounced in HS/R+D group.CONCLUSION: Dexmedetomidine effectively protects rats against AKI caused by HS/R, and its mechanism may be associated with the increase in HO-1 expression and the inhibition of NF-κB expression.     

Isolation of exosomes and effect of stellate ganglion block on the number of exosomes in post-hemorrhagic shock mesenteric lymph of rats

AIM To isolate the exosomes in mesenteric lymph, verify the source of exosomes, and observe the effect of stellate ganglion block （SGB） on the number of exosomes in post-hemorrhagic shock mesenteric lymph （PHSML） of rats. METHODS Twenty-four male rats were randomly divided into sham, sham+SGB, shock, and shock+SGB groups. SGB was performed before the establishment of hemorrhagic shock model using the routine methods in our lab. The PHSML was drained for exosomes isolation. The exosomes were identified through particle size analysis and CD63 protein expression. The expression of epithelial cell adhesion molecule （EpCAM） was detected to identify whether the exosomes were derived from epithelial cell. The number of exosomes in various mesenteric lymphs was measured using the flow cytometry. RESULTS The diameter of granular material extracted from mesenteric lymph was about 100 nm. The positive expression of exosomes pecific protein CD63 indicated the successful isolation of exosomes, and the EpCAM expression verified the exosomes were derived from intestinal epithelial cells. The number of exosomes in mesenteric lymph isolated from the rats of Shock group was obviously increased compared to that from the Sham group （P<0.05）, while the exosomes from the Shock+SGB group was markedly decreased when compared to Shock group （P<0.05）. CONCLUSION The current study establishes the isolation technique of exosomes in mesenteric lymph, and proved the exosomes were derived from the intestinal epithelial cells. SGB treatment reduces the number of exosomes in PHSML.     

Role of hydrogen sulfide in alleviation of liver injury by mesenteric lymph drainage in hemorrhagic shock rats

AIM：To investigate the role of hydrogen sulfide (H2S) in alleviation of liver injury by mesenteric lymph drainage in hemorrhagic shock rats. METHODS：A hemorrhagic shock model was established in male Wistar rats. DL-propargylglycine (PPG), an inhibitor of cystathionine γ-lyase (CSE) which is a synthase of H2S, or sodium hydrosulfide (NaHS), a donor of H2S, was administered to the hemorrhagic shock rats with mesenteric lymph drainage. The rats were randomly divided into sham, shock, shock+drainage, shock+drainage+PPG (45 mg/kg, ip, 0.5 h before hemorrhage) and shock+drainage+NaHS (28 μmol/kg, ip, 0.5 h before hemorrhage) groups. Fluid resuscitation was performed 1 h after hypotension, and then mesenteric lymph was drained in the rats of shock+drainage, shock+drainage+PPG and shock+drainage+NaHS groups for 3 h. The hepatic histomorphology was observed. The biochemical indexes of hepatic function in plasma, and H2S, CSE, Toll-like receptor 4 (TLR4), interleukin (IL)-10, IL-12 and tumor necrosis factor α (TNF-α) in hepatic homogenate were also examined. RESULTS：The levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and total bile acid (TBA) in plasma, and H2S, CSE, TLR4, IL-10, IL-12 and TNF-α in hepatic homogenate in shock group were significantly higher than those in sham group. Mesenteric lymph drainage obviously reduced these indexes in shock rats, except for TLR4. PPG further decreased these indexes except for CSE, while NaHS increased these indexes except for TBA and CSE. Morphological observation showed that liver injury appeared in the rats from shock and shock+drainage+NaHS groups, and there was nearly normal hepatic structure in the rats from sham, shock+drainage and shock+drainage+PPG groups. CONCLUSION：The mechanism of mesenteric lymph drainage alleviating liver injury in hemorrhagic shock rats is related to reducing the production of H2S and alleviating the H2S-mediated inflammation.     

Changes of ACE and ACE2 expression in kidney of AGT-REN double transgenic hypertensive mice

AIM: To investigate the role of imbalance between angiotensin-converting enzyme (ACE) and ACE2 in hypertensive renal damage by observing the changes of ACE and ACE2 expression in angiotensinogen (AGT)-renin(REN) double transgenic hypertensive mice carrying both human AGT and REN genes. METHODS: Twenty-four male mice of 4 genotypes including wild-type (WT) mice, AGT transgenic mice, REN transgenic mice and AGT-REN double transgenic mice were used in this study. All animals were 10 months old. The carotid artery was catheterized for observation of mean arterial pressure (MAP). After an hour, the mice were killed. The left kidney was prepared for the paraffin fixation, sectioning and HE staining to observe the pathological changes. ACE/ACE2 expression in the kidney was detected by the method of immunohistochemistry. The right kidney was used for Western blotting. RESULTS: No significant difference between AGT transgenic mice and WT mice in MAP was observed(P>0.05). MAP was approximately 15 mmHg lower in REN transgenic mice than that in WT mice (P<0.05). However, MAP was approximately 30 mmHg higher in AGT-REN double transgenic mice than that in WT mice (P<0.05). Compared with WT mice, AGT and REN transgenic mice did not show obvious pathological change, and AGT-REN double transgenic mice showed significant pathological changes, including thickened arteriolar wall, narrow lumen, fibrinoid necrosis and hyalinization. The results of both immunohistochemisty and Western blotting showed that the expression of renal ACE in AGT-REN double transgenic mice was markedly increased, and the expression of ACE2 was significantly decreased, suggesting that the expression of ACE and ACE2 was significantly imbalanced in AGT-REN double transgenic mice. CONCLUSION: Double transgenic mice carrying both human AGT and REN genes show malignant hypertension, renal damage, and imbalance of ACE and ACE2 expression. The imbalance of ACE and ACE2 in the kidney may play an important role in the pathogenesis of hypertension.     

Roles of SARS-CoV-2 receptor ACE2 in various diseases

It is well know that severe acute respiratory syndrome coronavirus 2 （SARS-CoV-2） can enter host cells through angiotensin-converting enzyme 2 （ACE2）, which is a key step in the development of coronavirus disease 2019 （COVID-19）. At the same time, ACE2 is expressed in a variety of tissues and regulates many biological functions, including inflammation, cell proliferation and oxidative stress, as a key negative regulator of the renin-angiotensin system. It plays an important role in the changes of physiological functions and pathological diseases of multiple systems and organs. Therefore, in addition to COVID-2019, ACE2 is also a potential therapeutic target for the diseases such as acute lung injury, cardiovascular diseases, cancer, and kidney diseases. This article reviews the mechanism of ACE2 in the above diseases and new strategies for therapeutic application.     

Role of PI3K/Nrf2 signaling pathway in endotoxin-induced acute kidney injury in rabbits

AIM: To evaluate the role of phosphatidylinositol 3-kinase/nuclear factor E2-related factor 2 (PI3K/Nrf2) signaling pathway in endotoxin-induced acute kidney injury in rabbits. METHODS: Healthy male New Zealand white rabbits were randomly divided into 5 groups: control group (group C), LPS group (group L), wortmannin+LPS group (group WL), wortmannin group (group W) and dimthyl sulfoxide (DMSO) group (group D). Wortmannin at dose of 0.6 mg/kg was injected via the auricular vein in groups W and WL, DMSO at concentration of 0.08 mL/kg was injected in group D, while normal saline (0.08 mL/kg) was injected in groups C and L. LPS at dose of 5 mg/kg was injected via the auricular vein in groups L and WL 30 min later, and equal volume of normal saline was injected in group C, D and W for control. The rabbits were sacrificed 6 h after LPS or normal saline administration. The kidneys were removed for microscopic examination and the determination of histological scores of kidney (HSK). The concentrations of blood urea nitrogen (BUN) and creatinine (Cr), urinary α1-microglobulin (α1-MG), MDA content, SOD activity, the mRNA expression of Nrf2 and HO-1, and the protein levels of total Akt, p-Akt, total Nrf2, p-Nrf2, nuclear Nrf2 and HO-1 in the renal tissues were also detected. RESULTS: Compared with groups C, D and W, the concentrations of BUN and Cr, urinary α1-MG concentration, MDA content and HSK were significantly increased, while SOD activity was significantly decreased (P<0.05). The mRNA expression of Nrf2 and HO-1, and the protein levels of p-Akt, total Nrf2, p-Nrf2, nuclear Nrf2 and HO-1 in the renal tissues were significantly increased in groups L and WL. No significant change among groups C, D and W was observed. Compared with group L, the concentrations of BUN and Cr, urinary α1-MG concentration, MDA content and HSK were significantly increased, while SOD activity, the mRNA expression of Nrf2 and HO-1, and the protein levels of p-Akt, total Nrf2, p-Nrf2, nuclear Nrf2 and HO-1 in the renal tissues were significantly decreased in group WL. CONCLUSION: Activation of PI3K/Nrf2 signaling pathway may be one of the regulatory mechanisms of the body adapting to the endotoxin-induced acute kidney injury in rabbits.     

Liquid resuscitation combined with hydrogen inhalation reduce acute kidney injury during septic shock in rats

AIM: To investigate the therapeutic effects of a novel fluid resuscitation protocol (early fluid resuscitation plus 2% hydrogen inhalation) on acute kidney injury during septic shock induced by lipopolysaccharide (LPS) in rats.METHODS: Male Wistar rats were randomly divided into 4 groups (15 rats per group):control group, septic shock group, septic shock with early fluid resuscitation group (fluid group) and septic shock with early fluid resuscitation plus 2% hydrogen inhalation group (fluid+H₂ group). The rats were ventilated, and a 2% hydrogen mixture was used in fluid+H₂ group. LPS (10 mg/kg) was administered to establish the septic shock model in rats and fluid resuscitation was performed in fluid group and fluid+H₂ group.RESULTS: Fluid resuscitation with 2% hydrogen inhalation decreased the le-vels of serum creatinine, blood urea nitrogen and neutrophil gelatinase-associated lipocalin. It also reduced oxidative stress injury and decreased renal tumor necrosis factor-α and interleukin-6 levels compared with fluid resuscitation alone.CONCLUSION: Early fluid resuscitation plus 2% hydrogen inhalation provided more protection against acute kidney injury du-ring septic shock.     

Effect of normal mesenteric lymph on multiple organ injury in mice with endotoxic shock

AIM: To observe the effects of normal mesenteric lymph (NML) on the lung, heart and liver injuries and the phosphorylation levels of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK) in the mice with endotoxic shock (ES). METHODS: The NML was drained form health male BALB/c mice for the intervention of ES after the removal of cellular constituent. Lipopolysaccharide (LPS, 35 mg/kg) was intraperitoneally injected into the mice for the establishment of ES model. After 60 min of LPS injection, the administration of NML (1/15 of whole blood volume) was performed through the femoral artery in NML+ES group. Meanwhile, the mean arterial pressure (MAP) was monitored during the experiment. At 6 h after intraperitoneal injection of LPS or the corresponding time point, blood samples were harvested from the heart through apical centesis for determination of the biochemical indexes to reflect myocardial and hepatocyte injuries. Simultaneously, the lung, heart and liver tissue specimens from a fixed location were harvested for the observation of histomorphology and the measurement of phosphorylation levels of p38 MAPK, ERK1/2 and JNK. RESULTS: Compared with sham shock (SS) group, MAP in ES group and NML+ES group remarkably decreased at multiple time points after intraperitoneal injection of LPS. However, MAP in NML+ES group at 80 min, 90 min, 190 min, 210 min, 240 min, 250 min, 340 min, 350 min, and 360 min were significantly increased compared with ES group. There were normal structures in the lung, liver and myocardium of the mice in SS group, while the morphological damages of these tissues appeared in ES group. Meanwhile, the damages were attenuated in the mice of NML+ES group. The activities of AST, ALT and CK-MB in the plasma in ES group were remarkably higher than those in SS group. The CK-MB activity in NML+ES group was also increased compared with SS group, and the activities of AST and LDH-1 were lower than those in ES group. At 6 h after LPS injection, the phosphorylation levels of p38 MAPK, ERK1/2 and JNK in the lung tissues were remarkably increased. Meanwhile, no statistical difference of these indexes between the myocardial and hepatic tissues was observed. NML intervention decreased the phosphorylation levels of p38 MAPK in the lung tissues, and p38 MAPK, ERK1/2 and JNK in the myocardial tissues. CONCLUSION: The NML administration alleviates multi-organ injuries and reduces the phosphorylation level of p38 MAPK in the lung tissues in the mice subjected to ES.     

Role of estrogen in alleviating hemorrhagic shock-induced organ injury

Estrogen has many biological activities and extensive clinical applications. Hemorrhagic shock-induced major organ dysfunction and injury, which are related to sex differences, play a triggering role in irreversible shock. The present article reviews the role of estrogen in alleviating hemorrhagic shock-induced organ injury by analyzing and summarizing the recent studies, thus expanding the clinical application of estrogen and providing a novel approach for treatment of severe hemorrhagic shock.     

Role of Rho kinase in blocking the return of mesenteric lymph to improve vascular calcium sensitivity in hemorrhagic shock rats

AIM: To observe the role of Rho kinase in mesenteric lymph duct ligation or mesenteric lymph drainage to improve vascular calcium sensitivity in the rats subjected to hemorrhagic shock. METHODS: Male Wistar rats were randomly divided into sham group, shock group, shock+ligation (shock plus mesenteric lymph duct ligation) group and shock+drainage (shock plus mesenteric lymph drainage) group. After induction of shock (hypotension at 40 mmHg) for 3 h, the vascular rings of superior mesenteric artery (SMA) were prepared and used to measure the response to gradient calcium ions for determining the calcium sensitivity with a wire myograph system. In shock+ligation group and shock+drainage group, the vascular rings were incubated with Rho kinase agonist angiotensinⅡ or antagonist fasudil before the measurement of the response to gradient calcium ions. RESULTS: The calcium sensitivity of vascular rings in shock group was significantly lower than that in sham group, and that in shock+ligation group and shock+drainage group was significantly higher than that in shock group, but still lower than that in sham group. AngⅡ elevated the contractile activity of the vascular rings in response to gradient calcium ions and the pD₂, and fasudil significantly decreased the response to gradient calcium ions and E_max in shock+ligation group and shock+drainage group. At the same time, fasudil decreased the pD₂ in shock+ligation group. CONCLUSION: Rho kinase plays an important role in blocking shock mesenteric lymph return that improves calcium sensitivity.     

Apoptosis of hepatocytes induced by acute kidney injury in rats

AIM: To observe the cytological changes of hepatocytes undergoing apoptosis induced by acute kidney injury (AKI) in rats. METHODS: The rat models of AKI, including ischemic and non-ischemic AKI, were established. Western blotting, immunohistochemical staining, light and electron microscopy were used in this study. RESULTS: Cellular necrosis in renal tubules, as the basic morphological changes of ischemic AKI, and renal tubular cells undergoing apoptosis were evident in ischemic AKI. Meanwhile, tumor necrosis facotor receptor α (TNFRα) and caspase-3 was strongly expressed in the livers from AKI rats. Caspase-3-positive cells were evident in the livers from AKI rats. Microscopic examinations revealed that hepatocytes undergoing apoptosis and para-apoptosis were observed in damaged livers of both ischemic and non-ischemic AKI animals. No significant difference of hepatic apoptosis between ischemic and non-ischemic AKI animals was observed. CONCLUSION: Either apoptosis, caspase-dependent cell death or para-apoptosis are involved in hepatic injury induced by AKI. TNFRα initiation and cleaved caspase family are the pathways of hepatocytes undergoing apoptosis induced by AKI.     

IL-33-modified BMSCs attenuate acute kidney injury induced by sepsis in rats through MyD88

AIM To investigate the effect of interleukin-33 (IL-33)-modified bone marrow mesenchymal stem cells (BMSCs) on sepsis-induced acute kidney injury (AKI) in rats and the expression of myeloid differentiation factor 88(MyD88). METHODS A septic rat model was established by cecal ligation and puncture. The SD rats (n=80) were randomly divided into control group, model group, negative transfection group (transplanting untransfected BMSCs) and IL-33 transfection group (transplanting BMSCs transfected with IL-33), with 20 in each group. Survival rates of the rats within 72 h in the 4 groups were compared. Serum creatinine (SCr) and blood urea nitrogen (BUN) levels were measured before, and 24, 48 and 72 h after transplantation. The kidney pathological damage was observed by HE staining, and the apoptosis of renal cells was detected by TUNEL method 72 h after transplantation. Western blot was used to detect the protein expression levels of interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), Toll-like receptor 4 (TLR4) and MyD88. RESULTS The survival rate of the rats in model group was significantly lower than that in control group (P<0.05). The survival rate of the rats in IL-33 transfection group was higher than that in model group and negative transfection group (P<0.05). The levels of SCr and BUN in model group were higher than those in control group (P<0.05). The levels of SCr and BUN in IL-33 transfection group were significantly reduced after transplantation, and were lower than those in model group and negative transfection group (P<0.05). The renal tissue pathological injury score in model group was significantly higher than that in control group (P<0.05). Compared with model group and negative transfection group, the renal tissue pathological injury score in IL-33 transfection group was significantly reduced (P<0.05). The proportion of apoptotic cells in the kidney tissues in model group were higher than that in control group (P<0.05). Compared with model group and negative transfection group, the proportion of apoptotic cells in the kidney tissues in IL-33 transfection group was significantly reduced (P<0.05). The protein expression levels of IL-1β, IL-6, TNF-α, TLR4 and MyD88 in model group were significantly higher than those in control group (P<0.05). Compared with model group and negative transfection group, the protein expression levels of IL-1β, IL-6, TNF-α, TLR4 and MyD88 in IL-33 transfection group were significantly decreased (P<0.05). CONCLUSION IL-33 gene-modified BMSCs significantly improve the renal function of AKI rats with sepsis. The mechanism may be related to IL-33 regulating TLR4/MyD88 signaling pathway and inhibiting renal inflammatory response.     

Progress of P-selectin glycoprotein ligand-1 in kidney diseases

P-selectin glycoprotein ligand-1 (PSGL-1) is an adhesion molecule mainly expressed on the surface of leukocytes and platelets, which plays a vital part in immune recognition, inflammatory response and thrombosis. The prevalence of chronic kidney disease (CKD) is increased gradually and it has been one of major diseases that threaten the world's public health. In addition, its etiology is complicated, and most of the pathogenesis is incompletely understood. Researches show that PSGL-1 participates in the development of kidney diseases in a variety of ways, and its mechanism may involve signaling pathways such as TGF-β1/Smad and PI3K/AKT/GSK-3β, as well as key renal regulators such as connective tissue growth factor and chemokine (C-C motif) ligand 2. This review summarizes the research progress of PSGL-1 in renal fibrosis, lupus nephritis, obesity-related kidney disease and acute kidney injury.     

Expression of NGAL in serum and renal tissues of patients with primary nephrotic syndrome and acute kidney injury

AIM: To observe the changes of neutrophil gelatinase-associated lipocalin (NGAL) level in serum and renal tissues of the patients with primary nephrotic syndrome (PNS) and acute kidney injury (AKI). METHODS: Seventy-two PNS patients were selected in the study and divided into 2 groups according to the pathological results of renal biopsy.The patients in PNS+AKI group included 15 cases of PNS with acute tubular necrosis (ATN), in which there were 10 cases of minimal change disease (MCD) with ATN and 5 cases of mesangial proliferative glomerulonephritis (MsPGN) with ATN. The patients in PNS alone group included 57 cases of PNS without ATN. According to the pathological types, they were divided into MCD group (24 cases), membranous nephropathy (MN) group (23 cases) and MsPGN group (10 cases). Serum samples from 15 healthy persons and 5 cases of normal renal tissues were used as controls. The serum levels of NGAL were detected by ELISA. The distribution and expression of NGAL in the renal tissues were observed by immunohistochemical method. RESULTS: (1) The serum level of NGAL in PNS alone group (including MCD group, MN group and MsPGN group) was significantly higher than that in normal control group. Compared with MCD group and MsPGN group, the serum level of NGAL in MN group increased significantly. The renal tissue positive expression index of NGAL in MCD group, MN group and MsPGN group was significantly higher than that in normal control group. (2) The serum level of NGAL and the renal tissue positive expression index of NGAL in MCD+ATN group and MsPGN+ATN group were significantly increased compared with PNS alone group. (3) The serum level of NGAL was positively correlated with 24 h urine protein, blood urea nitrogen and serum creatinine. No relation with serum albumin and β2 microglobulin was observed. The serum level of NGAL was positively correlated with the NGAL level in the renal tissue. CONCLUSION: The serum level of NGAL can be used as one of the sensitive indexes for early and non-invasive detection of PNS with AKI.     

Relationship between apoptosis and change of P53 expression in mouse renal tissues after acute kidney injury

AIM: To investigate the relationship between renal cell apoptosis induced by ischemia/reperfusion injury and the activation of P53. METHODS: Eighteen mice were randomly divided into 3 groups: sham operation group, acute kidney injury (AKI) group and pifithrin-alpha(PFT-α) treatment group. The AKI model was established by clamping bilateral renal arteries for 45 min and then performing reperfusion. The mice in PFT-α group were intraperitoneally injected with PFT-α at dose of 2.2 mg/kg 5 min before AKI model was established. The changes of serum creatinine and urea nitrogen were determined and renal pathological changes were observed 48 h after AKI. The P53 expression in the kidney was evaluated by Western blotting and immunofluorescence methods. Apoptosis of the renal cells was observed by TUNEL assay. The protein expression of tumor necrosis factor receptor (TNFR), caspase-3 and Bcl-2 was detected by immunohistochemical method. RESULTS: The levels of serum creatinine and urea nitrogen in AKI group and PFT-α group were higher than those in sham operation group. Compared with AKI group, the levels of serum creatinine and urea nitrogen were significantlydecreased in PFT-α group. No pathological change of the kidney was observed in sham operation group. In AKI group, the pathological changes such as shedding of brush border, vacuolus and dropwise degeneration in the renal tissues were observed. These pathological changes were attenuated in PFT-α group as compared with AKI group. The protein was expression level of P53 and the apoptotic cells were much higher in AKI group than those in sham operation group, and P53 protein was mainly expressed in the renal cortex, while those were significantly decreased in PFT-α group as compared with AKI group. Compared with sham operation group, the expression levels of TNFR and caspase-3 were increased and the Bcl-2 levels was decreased. Compared with AKI group, the expression level of TNFR and caspase-3 decreased and Bcl-2 expression was increased. CONCLUSION: P53 protein is mainly expressed in the renal cortex and induces apoptosis by increasing the expression of caspase-3 and regulating the expression of TNFR and Bcl-2 in the kidney following ischemia/reperfusion injury.     

Effect of bone marrow-derived mesenchymal stem cells combined with vitamin E on inflammatory reaction in acute kidney injury

AIM:To explore the effect of bone marrow-derived mesenchymal stem cells (BMSCs) combined with vitamin E on the inflammatory reaction in acute kidney injury (AKI) rats. METHODS:Gentamicin was used to induce AKI and the rats were treated with BMSCs combined with vitamin E. After treatment, the rat plasma and kidney tissues were collected, and the expression of inflammatory factors at mRNA and protein levels was detected by real-time quantitative PCR and ELISA. RESULTS:After the treatment with BMSCs combined with vitamin E, the inflammatory proteins were down-regulated in the plasma and the renal tissues. Compared with single treatment group, the decreases in the inflammatory proteins were more obvious in combined treatment group. CONCLUSION: The method of BMSCs combined with vitamin E takes the anti-inflammatory effect on AKI, indicating a new and potential mode in clinical application for AKI therapy.     

Effect of continuous renal replacement therapy on mRNA expression of autophagy-related molecules and prognosis in patients with acute kidney injury

AIM To explore the effect of continuous renal replacement therapy （CRRT） on mRNA expression of autophagy-related molecules and the prognosis in the patients with acute kidney injury （AKI）. METHODS A total of 174 patients from our hospital who were diagnosed to have AKI and underwent CRRT between February 2015 and March 2018 were involved in this study. The plasma levels of interleukin-1β （IL-1β） and interleukin-6 （IL-6）, the serum creatinine （SCr） level, and the mRNA expression levels of autophagy-related molecules, including microtubule-associated protein 1 light chain 3-II （LC3-II）, autophagy-related protein 5 （Atg5） and beclin-1, in the monocytes from peripheral blood were compared before and after CRRT. According to the survival of AKI patients after 4 weeks of CRRT, the enrolled patients were divided into death group （n=43） and survival group （n=131）, and the mRNA expression levels of the above molecules were compared between the 2 groups. RESULTS After CRRT treatment, the plasma levels of IL-1β and IL-6, the level of SCr, and the mRNA expression levels of LC3-II, Atg5 and beclin-1 in the monocytes were significantly lower than those before CRRT treatment （P<0.05）. The mRNA expression levels of LC3-II, Atg5 and beclin-1 in death group were significantly higher than those in survival group （P<0.05）. The positive correlation between SCr and IL-1β, IL-6, LC3-II or beclin-1 was observed （P<0.05）, and no correlation between SCr and Atg5 was found （P>0.05）. CONCLUSION CRRT decreases the mRNA expression levels of autophagy-related molecules in the patients with AKI and reduces the autophagy activity, which is protective for the patients. These autophagy-related molecules may be applied as a potential markers to predict the prognosis of CRRT.