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 drainage in restoring balance of ACE/ACE2 in kidney of mice

AIM: To study the role of post-hemorrhagic shock mesenteric lymph (PHSML) drainage on the balance of angiotensin-converting enzyme (ACE) and ACE2 in the kidney. METHODS: A hemorrhagic shock model was established and then fluid resuscitation was performed to the animals in shock and shock+drainage groups, and the PHMSL was drained in shock+drainage group after fluid resuscitation. After 6 h of resuscitation, the mRNA expression of ACE, ACE2, angiotensin Ⅱ (Ang Ⅱ) type 1 receptor (AT1R) and Mas-related G-protein-coupled receptor (MasR), and the levels of Ang Ⅱ and Ang (1-7) in the renal tissues were observed. RESULTS: Hemorrhagic shock increased the levels of ACE mRNA, AT1R mRNA and Ang Ⅱ, and decreased the levels of ACE2 mRNA, MasR mRNA and Ang(1-7) in the kidney. PHSML drainage abolished the effect of hemorrhagic shock on ACE2 and AT1R mRNA expression. Meanwhile, PHSML drainage reduced the hemorrhagic shock-induced increases in the ratios of ACE/ACE2, Ang Ⅱ/Ang(1-7) and AT1R/MasR. CONCLUSION: The PHSML drainage restores the balance of ACE/ACE2, which is beneficial to alleviate acute kidney injury following hemorrhagic shock in the mice.     

Roles of mitochondrial dysfunction in cardiovascular diseases

Mitochondria are important organelles of energy generation in eukaryocytes and play a pivotal role in cell calcium homeostasis, signal transduction and apoptotic regulation. The possible causes leading to mitochondrial dysfunction include oxidative stress, Ca2+ disorder, reduction of mitochondrial biosynthesis and mitochondrial DNA mutations, all of which are also closely related to the development of cardiovascular diseases. Understanding the mitochondrial dysfunction and its important role in cardiovascular diseases are very significant for elucidating the mechanisms of cardiovascular diseases.     

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.     

CB2 receptor agonist JWH133 exerts protective effects on rat model of paraquat-induced acute lung injury

AIM: To study the protective effects of cannabinoid CB2 receptor agonist JWH133 on rat acute lung injury induced by paraquat (PQ).METHODS: Male Sprague-Dawley rats (n=72) were randomly divided into 4 groups. PQ group: PQ was administered intraperitoneally at the dose of 20 mg/kg; Low-dose JWH133 pretreatment group (L-JWH133 group): JWH133 (5 mg/kg, ip) was administered 1 h before PQ exposure; high-dose JWH133 pretreatment group (H-JWH133 group): JWH133 (20 mg/kg, ip) was administered 1 h before PQ exposure; control group: 1 mL saline was administered intraperitoneally. Arterial blood, bronchoalveolar lavage fluid (BALF) and lung tissue samples were collected at 8 h, 1 d and 3 d after PQ exposure. PaO2 and the levels of TNF-α and IL-1β in BALF were measured via blood gas analyzer and ELISA, respectively. The pathological changes and lung injury scores were assessed at 3 d after PQ exposure. NF-κB and AP-1 protein levels were also determined by Western blotting.RESULTS: The decrease in PaO2, structural injury of the lung tissues, interstitial pulmonary edema, and the increase in IL-1β and TNF-α in BALF were observed in PQ-treated rats compared with control group. JWH133 pretreatment reduced the degree of lung tissue injury, decreased the levels of IL-1β and TNF-α in BALF and the NF-κB and AP-1 protein expression in the lung tissue compared with PQ group, especially in H-JWH133 group. CONCLUSION: CB2 receptor agonist JWH133 inhibits NF-κB and AP-1 protein expression in the lung tissues, and reduces the secretion of IL-1β and TNF-α in BALF after paraquat exposure, thus attenuating paraquat-induced acute lung injury.     

Progress on role of CCN1 in pulmonary diseases

Cysteine-rich angiogenic inducer 61 (Cyr61/CCN1) is an extracellular matrix-associated signaling protein consisting of 381 amino-acid residues, which has the regulatory function for a multitude of cellular responses. The pleiotropic effects of CCN1 on the initiation and resolution of inflammation as well as oncogenesis and development of tumor were reported. According to the numerous data from experimental and clinical studies, this article provides an overview on CCN1 and summarizes the latest understanding of the role of CCN1 in pulmonary diseases.     

Sphingosine-1-phosphate receptor-2 attenuates lipopolysaccharide-induced acute lung injury

AIM: To investigate the effects and mechanisms of sphingosine-1-phosphate receptor-2 (S1P2R)on lipopolysaccharide (LPS)-induced acute lung injury (ALI). METHODS: ALI model was induced by intratracheal administration of LPS in both wild-type mice and S1P2R -deficient mice. The pathological changes in the lung tissues were observed, and the protein concentration, total cell number, neutrophil ratio, TNF-α level and IL-6 level were determined in the bronchoalveolar lavage fluid (BALF) 24 h after LPS injection. In order to investigate the mechanisms of S1P2R in LPS-induced ALI, 10 min before LPS injection, both wild-type mice and S1P2R -deficient mice were injected with nitric oxide synthase inhibitor by tail vein injection, the pathological changes of the lung tissues were observed, and the protein concentration and total cell number in BALF were determined 12 h after LPS injection. RESULTS: Compared with wild-type mice, S1P2R -deficient mice showed more severe LPS-induced ALI, and the protein concentration, neutrophils and inflammatory cytokines in BALF were significantly increased in S1P2R -deficient mice. Administration of nitric oxide synthase inhibitor N^ω-L-nitro-arginine methyl ester protected S1P2R -deficient mice from aggravation of ALI. CONCLUSION: S1P2R mediates the protection from LPS-induced ALI possibly through inhibiting nitric oxide synthase.     

Antioxidant effect of carnosine on H9N2 swine influenza virus-induced acute lung injury in mice

AIM:To investigate the antioxidant effect of carnosine on H9N2 swine influenza virus (H9N2-SIV)-induced acute lung injury (ALI). METHODS:One hundred and fifty SPF female BALB/c mice (6 to 8 weeks old) were randomly divided into control group, ALI group and carnosine intervention group with 50 each. The mice in control group were inoculated intranasally with normal allantoic fluid of chick embryos. The mice in ALI group were inoculated intranasally with allantoic fluid containing H9N2-SIV. The mice in carnosine group were treated with H9N2-SIV plus carnosine. On the 2nd, 4th, 6th, 8th and 14th days after treatment, 8 mice in each group were killed to observe the pathological changes of the lung. Meanwhile, the activity of superoxide dismutase (SOD) and myeloperoxidase (MPO), the content of malondialdehyde (MDA) and the wet weight/dry weight ratio (W/D) of the lung tissues were determined. RESULTS:Carnosine alleviated the symptom of the mice induced by H9N2-SIV infection, and increased the viability of the mice. In carnosine intervention group, edema degree of the lung (W/D) was apparently reduced (P<0.05). The pathological changes were alleviated on the 6th and 8th days of the experiment. On the same days, the content of MDA was lower obviously (P<0.05) and the activity of SOD was improved remarkably (P<0.05). On the 4th day of the experiment, the activity of MPO was reduced apparently (P<0.05) and continuously decreased on the 6th and 8th days (P<0.05). CONCLUSION: Carnosine protects the mice from acute lung injury induced by H9N2-SIV infection and increases the viability by reducing the content of MDA, lowering the activity of MPO, increasing the activity of SOD and inhibiting the production of free radicals and lipid peroxidation.     

Progress in role of lncRNA in cardiovascular diseases

Cardiovascular diseases are closely related to proliferation, injury and apoptosis of the cells in the cardiovascular system. For instance, endothelial cells play an important role in the pathogenic process of hypertension and atherosclerosis, and smooth muscle cells and monocytes/macrophages involve in the formation of atherosclerotic plaque. Recently, it has been confirmed that long noncoding RNA (lncRNA) regulates proliferation, apoptosis, injury, autophagy and differentiation of the cells by a series of regulatory mechanisms, thus participating in the development and progression of cardiovascular diseases. This article is to review the recent research progress on the function of lncRNAs and their regulatory roles in the cardiovascular diseases at cellular and molecular levels.     

Roles of PI3K/Akt and JAK2/STAT3 signaling pathways in protection of SO2 against limb ischemia/reperfusion-induced acute lung injury in rats

AIM: To investigate the role of PI3K/Akt and JAK2/STAT3 pathways in the protection of sulfur dioxide (SO₂) against limb ischemia/reperfusion (I/R)-induced acute lung injury (ALI) in rats. METHODS: ALI was induced by limb I/R in the SD rats. Na₂SO₃(0.54 mmol/kg, ip)/NaHSO₃ (0.18 mmol/kg, ip) as SO₂ donor was injected at 20 min before reperfusion. The inhibitors of JAK2/STAT3 and PI3K/Akt pathways, Stattic (3 mg/kg, iv) and LY294002(40 mg/kg, iv), respectively, were injected at 1 h before reperfusion. Peripheral blood and lung tissues were collected for determining the contents of the cytokines, the protein levels of the molecules related to the signaling pathways, apoptosis and histopathologic changes by ELISA, TUNEL and Western blot. RESULTS: Compared with control group, the content of MDA, the activity of MPO, lung coefficient, apoptotic index, cytokine expression, and the protein levels of p-Akt and p-STAT3 in I/R group all increased significantly, and administration of Na₂SO₃/NaHSO₃ attenuated the damage in the lung. Besides, the results of Western blot showed that the rat lung tissues expressed p-STAT3 protein and p-Akt protein. After I/R, the protein levels of p-STAT3 and p-Akt were increased. After using Na₂SO₃/NaHSO₃, p-Akt was increased, but p-STAT3 was decreased (P<0.05). CONCLUSION: Both JAK2/STAT3 and PI3K/Akt pathways are likely involved in the protective effect of SO₂ against limb I/R-induced ALI in rats. The activation of JAK2/STAT3 signaling pathway increases I/R injury. Reversely, the activation of PI3K/Akt signaling pathway reduces I/R injury. Besides, JAK2/STAT3 and PI3K/Akt signaling pathways may have crosstalk during I/R-induced ALI and JAK2/STAT3 pathway may have an impact on the P13K/Akt pathway.     

Protective effect of N-acetylcysteine on mice with acute lung injury induced by H9N2 swine influenza virus

AIM: To investigate the effects of N-acetylcysteine (NAC) on acute lung injury induced by H9N2 swine influenza virus (SIV) in mice. METHODS: BALB/c mice were used to establish the animal model of acute lung injury by nasal inoculation of H9N2 SIV. The mice were divided into control group (without SIV infection), H9N2 SIV group (inoculation of H9N2 SIV) and NAC group (inoculation of H9N2 SIV plus pretreatment with NAC). The pulmonary edema was evaluated by determining the lung wet weight/dry weight (W/D) ratio. The pathological changes of the lung tissues were observed. The concontrations of TNF-α, IL-1β and IL-6 in bronchoalveolar lavage fluid (BALF) were measured.The virus titer, T-SOD activity, MPO activity and MDA content in the homogenate of the lung tissues were detected. RESULTS: Treatment with NAC decreased the morality of infected mice, and significantly prolonged the survival time of infected mice. The pathological changes of the lung tissues, the lung W/D ratio and the lung index were relieved when SIV infected the mice treated with NAC. Treatment with NAC significantly decreased the infiltration of inflammatory cells including macrophages, lymphocytes and neutrophils in the BALF. The levels of TNF-α, IL-6, IL-1β and MDA and the activity of MPO were also decreased. Treatment with NAC also significantly increased the T-SOD activity. CONCLUSION: The protective effect of NAC on the acute lung injury mouse model is related to suppression of the oxidative stress and inflammatory responses.     

Role of sulfur dioxide in acute lung injury induced by ischemia-reperfusion of hind limbs in rats

AIM：To explore the role of endogenous and exogenous sulfur dioxide(SO2) in acute lung injury(ALI) induced by ischemia-reperfusion(IR) of limbs in rats. METHODS：The rat model of ALI was induced by ischemia and reperfusion of the hind limbs using a tourniquet. The rats(n=96) were randomly divided into 6 groups: sham, IR, sham+SO2, sham+hydroxamate(HDX), IR+SO2 and IR+HDX. The morphological changes of the lung tissues were observed under light microscope. Meanwhile, polymorphonuclear neutrophils(PMN) in alveolar septum, lung coefficient, lung levels of malondialdehyde(MDA) and intercellular adhesion molecule(ICAM)-1, serum tumor necrosis factor(TNF)-α and interleukin(IL)-1, the content of SO2 and the activity of aspartate aminotransferase(AST) in the lung tissues, and 24 h survival rate of the rats were measured. RESULTS：IR of the rat limbs resulted in the damage of the lung tissues, and the increases in PMN in alveolar septum, lung coefficient, the lung levels of MDA and ICAM-1 and the serum levels of TNF-α and IL-1 were also observed with the reductions of SO2 content and AST activity. Pretreatment with SO2 donor Na2SO3/NaHSO3 alleviated the changes of the indicators above. HDX, an inhibitor of SO2-producing enzymes, aggravated the changes above. CONCLUSION：Down-regulation of AST/SO2 pathway is involved in the pathogenesis of limb IR-induced ALI. Administration of exogenous SO2 might attenuate lung injury through anti-inflammation and anti-oxidation.     

Research progress in association between angiopoietin-like protein 2 and inflammation-related diseases

Chronic low-grade inflammatory diseases are a subclinical process caused by innate system disorders. In recent years, with the study of chronic low-grade inflammatory diseases, inflammation has become a hot topic of major human diseases, including obesity, diabetes, cardiovascular diseases, cancer and autoimmune diseases. Angiopoietin-like protein 2 (ANGPTL2) is one of the emerging angiogenesis-related factors. Studies show that ANGPTL2 induces vascular inflammation, insulin resistance and other characteristics. The article reviews the research progress in association between angiopoietin-like protein 2 and inflammation-related diseases.     

Role of IL-33/ST2 signaling pathway in fibrosis diseases

Interleukin (IL)-33 is a member of IL-1 family. It is identified as a functional ligand for ST2 which is an IL-1 receptor-like protein. IL-33/ST2 signaling is involved in T-cell-mediated immune responses. Increasing evidence indicates that IL-33 has different roles in different diseases. Recently, some studies have demonstrated that IL-33 may be related to the genesis and development of fibrosis diseases. We review current knowledge of the biological characteristics of IL-33 and the role of IL-33/ST2 signaling pathway in fibrosis diseases.     

Effect of inhaled nitric oxide on aquaporin expression in newborn rat lung in acute hyperoxic lung injury

AIM:To investigate the effect of inhaled nitric oxide on aquaporin expression and alveolar epithelial fluid transport in newborn rats with acute hyperoxic lung injury. METHODS:32 newborn SD rats were randomized to breathe for 48 h room air (C), >95%O₂ (O), >95%O₂+10^-5 NO (NO only in the first 24 h, ONO), room air + NO (CN). Then, the rats were killed, the lung wet-to-dry weight ratio (Q_W/Q_D), the histology, and AQP1, AQP5, α₁-NKA, α-ENaC mRNA expressions in the lungs were measured. RESULTS:Compared with C group, the Q_W/Q_D in O group significantly increased (P<0.01), and AQP1 mRNA expression decreased significantly (P<0.01). Compared with O group, ONO group had a lower level of Q_W/Q_D (P<0.05), and AQP1 mRNA expression increased (P<0.05). AQP5 mRNA expression in all groups remained unchanged. CONCLUSION:In newborn rats with acute hyperoxic lung injury, inhaled 10-5 nitric oxide for 24 h may attenuate lung edema and increase AQP1 mRNA expression, suggesting that inhaled 10^-5 nitric oxide for 24 h may promote the AQP1 expression in lung in this model of acute lung injury.     

Effects of imidapril on blood gas,oxidative stress and inflammatory factors in rats with acute lung injury induced by ammonium chloride

AIM: In this study, the rat lung injury model was induced by ammonium chloride for studying the effect of imidapril on blood gas, serum TNF-α, IL-6 and MDA concentrations, and AngⅡ and CD54 protein expression in rat lung tissue. METHODS: Male rats were randomly divided into 3 groups: control group, lung injury model group and drug group. The rats in control group were given saline (2 mL/kg), while the rats in lung injury model group were given 6% ammonium chloride (2 mL/kg). In drug group, imidapril (3 mg·kg^-1·d^-1) was given to the rats once daily for 1 week by intragastric gavage after given 6% ammonium chloride. On the 7th day, the rats were anesthetized with 2% so-dium pentobarbital. Abdominal aorta blood, venous blood and lung tissue were collected. The blood gas indexes and serum TNF-α, IL-6 and MDA concentrations were determined. The lung tissues were fixed and sliced, and the expression of AngⅡ and CD54 proteins was detected by immunohistochemistry. RESULTS: The PaCO₂ increased in lung injury model group compared with control group and drug group (P < 0.05).The expression of AngⅡ and CD54, and the concentrations of TNF-α, IL-6 and MDA also increased significantly (P < 0.01) in model group. Pulmonary edema, inflammation, alveolus congestion, hemorrhage and hyperplasia in model group were obvious compared with control group and drug group. CONCLUSION: Imidapril improves blood gas indexes, and reduces lipid peroxidation and inflammatory responses in the rats with lung injury induced by ammonium chloride.     

Role of intestinal microbiota-farnesoid X receptor axis in metabolic diseases

Intestinal microbiota is associated with metabolic diseases such as obesity, nonalcoholic fatty liver disease and insulin resistance. Farnesoid X receptor (FXR), also known as bile acid receptor, is a typical nuclear receptor, which is involved in the regulation of bile acid and glycolipid metabolism. Intestinal microbiota regulates FXR activity by affecting bile acid composition, where bile acid hydrolase plays an important role. Recent studies have found that intestinal microbiota affects the development of metabolic diseases through regulating the FXR, and the intestinal microbiota-FXR axis may be an ideal drug target for metabolic diseases.