Naringenin attenuates myocardial injury by regulating AMPK/Nrf2/HO-1 signaling pathways in diabetic mice

AIM: To investigate the effects of naringenin (NAR) on the myocardium as well as its effects on adenosine monophosphate-activated protein kinase (AMPK)/nuclear factor (NF)-E2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) signaling pathways in diabetic mice. METHODS: C57BL/6 mice (n=50) were randomly divided into normal group (N group) and model group. The mouse model of type 1 diabetes mellitus was established by intraperitoneal injection of streptozotocin (STZ), then the mice were divided into diabetes group (D group), diabetes+low dose of NAR intervention group (D+L-NAR group), diabetes+middle dose of NAR intervention group (D+M-NAR group) and diabetes+high dose of NAR intervention group (D+H-NAR group). The mice in intervention groups were received NAR at low, middle and high doses respectively by gavage, and the mice in N group and D group were received equal volume of normal saline. After 6 weeks, the mice were sacrificed to observe the effects of NAR at different doses on the body weight and blood glucose. The histopathological changes of the cardiac tissues were observed with HE staining. The myocardial collagen volume fraction (CVF) was calculated by Masson staining. Immumohistochemical staining was used to test the protein levels of interleukin-6 (IL-6) and IL-10, and the TUNEL was used to observe the apoptosis of myocardial tissues. The production of reactive oxygen species (ROS) in the myocardial cells was analyzed by fluorescence probe of DHE, and superoxide dismutase (SOD) activity and malondiodehyde (MDA) content in the myocardial cells were measured by SOD and MDA kits. Western blot was applied to determine the protein levels of p-AMPKα, AMPKα, Nrf2, HO-1, NAD(P)H:quinone oxidoreductase 1 (NQO1) and cleaved caspase-3 in the myocardial tissues. RESULTS: Compared with N group, the blood glucose of the mice in D groups was increased and the body weight was decreased significantly. Compared with D group, the blood glucose of the mice in NAR intervention groups was decreased and the body weight was increased. Compared with N group, the CVF, apoptotic rate and the protein levels of IL-6, cleaved caspase-3 were increased, while the protein levels of IL-10, p-AMPKα, Nrf2, HO-1, NQO1 and SOD activity were decreased, the ROS production rate and MDA content was increased significantly in D group (P < 0.05). Compared with D group, the CVF, apoptotic rate and the protein levels of IL-6, cleaved caspase-3 were relatively decreased, conversely the protein levels of IL-10, p-AMPKα, Nrf2, HO-1, NQO1 were increased in NAR intervention groups(P < 0.05). No significantly difference of the ROS production rate, SOD activity and MDA content between D group and D+L-NAR group was observed. However, the ROS production rate and MDA content was decreased,SOD activity were increased in D+M-NAR group and D+H-NAR group as compared with D group. CONCLUSIONS: NAR attenuates myocardial injury in diabetic mice, and its mechanism may be related to regulation of AMPK/Nrf2/HO-1 signaling pathway, enhancement of the antioxidant reaction, reduction of myocardial fibrosis, apoptosis and inflammation.     

Protective effects of taurine on LPS-induced myocardial damage in rats

AIM: To investigate the effects of taurine on lipopolysaccharide (LPS)-induced myocardial damage in rats. METHODS: Healthy male SD rats (n=30) were randomly divided into control group (CON), LPS model group (LPS) and taurine treatment group (TAU). The rats in CON group and LPS group were intravenously injected with normal saline, and the rats in TAU group were injected with taurine (100 mg/kg). After 2 h, the rats in LPS group and TAU group were intraperitoneally injected with LPS at 10 mg/kg, and the rats in CON group were injected with normal saline. Six hours after injection of LPS, the blood samples were collected for determination of superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) levels. The myocardial tissues were processed for histological examination and the analysis of Western blot. RESULTS: Compared with CON group, LPS significantly reduced SOD activity in the serum and heme oxygenase 1 (HO-1) protein expression in the myocardial tissues, increased the serum content of MDA and levels of TNF-α and IL-6. LPS also significantly elevated the levels of TNF-α and IL-6, and up-regulated the cyclooxygenase-2 (COX-2) expression and phosphorylation of nuclear factor kappa B (NF-κB) in the myocardial tissues. Taurine pretreatment significantly elevated SOD activity and HO-1 protein expression level, decreased the levels of COX-2, TNF-α, IL-6 and phosphorylated NF-κB. Histological observation showed that taurine reduced inflammatory response in the myocardial tissue. CONCLUSION: Taurine attenuates LPS-induced myocardial damage in rats. The beneficial effects of taurine may be associated with its reduction of p-NF-κB/COX-2 signaling by activation of HO-1/CO.     

Effect of combination of Penthorum chinense Pursh and Puerariae flos on L-02 liver cell injury induced by alcohol

AIM: To explore the effect of Penthorum chinense Pursh and Puerariae flos-containing serum on L-02 liver cell injury induced by alcohol and its possible mechanism. METHODS: After preparing drug-containing serum, the L-02 cells cultured in vitro were divided into 6 groups:blank control group, model group, 1:1 group, 2:1 group and 1:2 group of combination of Penthorum chinense Pursh and Puerariae flos, and tiopronin group. The viability of the L-02 cells was measured by MTT assay. The activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and superoxide dismutase (SOD), and the content of malondialdehyde (MDA) were detected by enzyme label methods. The expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) at mRNA and protein levels was determined by real-time PCR and Western blot, respectively. RESULTS: Compared with control group, the levels of ALT, AST and MDA were increased significantly, and SOD was decreased in model group (P<0.01). Compared with model group, these indexes in all treatment groups were opposite (P<0.01). Compared with control group, the expression of TNF-α and IL-6 at mRNA and protein levels was significantly increased, the mRNA and protein expression of Nrf2 and HO-1 was decreased (P<0.01). Compared with model group, these indexes in combination groups were opposite (P<0.01). CONCLUSION: The therapeutic effects of Pentehorum chinensa Pursh and Puerariae flos-containing serum may affect the expression levels of TNF-α, IL-6, Nrf2 and HO-1, and reduce the inflammatory reaction and oxidative stress in alcohol-induced L-02 liver cells, which plays a role in attenuating alcoholic liver injury.     

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.     

Protective role of carnosine on cardiac dysfunction in type 1 diabetes mellitus rat model

AIM:To explore the effects of carnosine (CAR) on cardiac dysfunction in type 1 diabetic mellitus rats and the underlying mechanism. METHODS:The SD rats were randomly divided into 4 groups:control (C) group, control+carnosine (C+CAR) group, diabetes mellitus (DM) group and diabetes mellitus+carnosine (DM+CAR) group (n=10). The rats were sacrificed after 12 weeks. The cardiac function was assessed by ventricular cannulation. The activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA) were assessed by ELISA. The mRNA levels of tumor necrosis factor α(TNF-α), interleukin-1β(IL-1β) and IL-6 were measured by real-time PCR. The distribution of connexin 43 (Cx43) was examined by immunofluorescence. The protein levels of Cx43 and protein kinase C (PKC) were determined by Western blot. RESULTS:Compared with the C group, the left ventricular end diastolic pressure (LVEDP) was increased whereas the left ventricular pressure maximum rise/fall velocity (±dp/dt_max) was decreased in the DM group (P<0.01). The activity of SOD decreased while the MDA increased in the left ventricular tissues (P<0.01). The mRNA levels of TNF-α, IL-1β and IL-6 were increased (P<0.01). The Cx43 distribution was irregular. The protein levels of phosphorylated Cx43 and PKCε were elevated (P<0.01). Compared with the DM group, the cardiac function of LVEDP and ±dp/dt_max in DM+CAR group was ameliorated (P<0.01), with increased SOD activity and decreased MDA content (P<0.05). The mRNA levels of TNF-α, IL-1β and IL-6 were reduced (P<0.01). The Cx43 distribution was improved and the protein levels of phosphorylated Cx43 and PKCε were decreased (P<0.01). CONCLUSION:CAR treatment can improve the cardiac function by its anti-oxidative and anti-inflammation effects and suppression of Cx43 abnormalities through PKCε in DM rats.     

Heme oxygenase-1 protects renal function in septic rats via influencing expression of thrombomodulin

AIM: To investigate the protective effect of heme oxygenase-1 (HO-1) on the kidney of septic rats and the influence of HO-1 on the expression of thrombomodulin (TM) in the kidney. METHODS: Sepsis in rats was developed with cecal ligation and puncture (CLP). The septic rats were randomly divided into sham group, CLP group, CLP+HO-1 inducer group and CLP+HO-1 inhibitor group (n=18). The plasma levels of creatinine (Cr), cystatin-C (Cys-C), carboxyhemoglobin (COHb), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and TM, and the changes of prothrombin time (PT) and activated partial thromboplastin time (APTT) in each group were measured. Histopathological examination was performed in the kidney. The expression of TM in the kidney tissue was detected by Western blot. RESULTS: Compared with sham group, significantly elevated plasma levels of Cr, Cys-C, TNF-α, IL-1β and TM (P<0.05), shortened PT and APTT (P<0.05), significantly increased microthrombus formation, and lowered TM expression in the kidney (P<0.05) of CLP group were observed. The administration of hemin lowered the plasma levels of Cr, Cys-C, TNF-α, IL-1β and TM (P<0.05), prolonged PT and APTT (P<0.05), attenuated microthrombus formation, and up-regulated the expression of TM in the kidney (P<0.05). In contrast, ZnPP had the opposite effects. CONCLUSION: HO-1 increases the expression of TM in the kidney and exerts anticoagulatory and antiinflammatory effects, thereby improving renal function in the septic rats.     

Effects of exercise training on myocardial polyamine metabolism in aged rats

AIM:To explore the effects of exercise training on myocardial polyamine metabolism in aged rats. METHODS:Wistar rats were divided into 3 groups:old+exercise group(Old+Ex), old group(Old) and young group(Young). High-performance liquid chromatography was used to test the content of myocardial polyamines(putrescine, spermidine and spermine). The activity of polyamine synthesis and catabolism rate-limiting enzyme ornithine decarboxylase(ODC) and spermidine/spermine acetyltransferase(SSAT) was analyzed by [¹⁴C] labeling. The level of malondialdehyde(MDA) and the activity of superoxide dismutase(SOD) in the myocardium were detected by colorimetric method. The levels of TNF-α and IL-1β were determined by enzyme-linked immunosorbent assay. The cardiac functions were measured by echocardiography. The changes of myocardial ultrastructure were observed under transmission electron microscope. RESULTS:(1) Compared with Young group, ODC activity decreased, SSAT activity increased, and the levels of spermidine, spermine and total polyamine were significantly decreased in Old group. SOD activity also decreased significantly, the content of MDA, TNF-α and IL-1β also increased dramatically in Old group. In the old rats, both left ventricular end-systolic diameter(LVESD) and end-diastolic diameter(LVEDD) increased, while left ventricular ejection fraction(LVEF) and fractional shortening(LVFS) decreased.(2) Compared with Old group, ODC activity increased, SSAT activity decreased, the levels of spermidine and total polyamine significantly increased, SOD activity increased significantly, and the content of MDA, TNF-α and IL-1β decreased dramatically in Old+Ex group. The functions of left ventricle also improved significantly in Old+Ex group.(3) Ultrastructural observations indicated that the myofilament and mitochondrial cristae were irregular and mitochondrial matrix density decreased in old rat heart. The cardiac sarcomere structure was clear, the mitochondrial matrix was dense and the mitochondrial cristae arranged in order in Old+Ex group. CONCLUSION:Exercise training promotes polyamine synthesis metabolism and inhibits polyamine catabolism in the heart of aged rats, thus fighting against aging-induced myocardial polyamine decrease. Exercise training also improves the capacity of anti-inflammatory and antioxidant processes of aged heart. Maintaining the appropriate levels of myocardial polyamines may be a new mechanism to delay cardiac aging.     

Xinshuaikang inhibits myocardial autophagy and MAPK/ERK1/2 signaling pathway in rats with chronic heart failure

AIM:To explore the effect of Xinshuaikang on myocardial autophagy in the rats with chronic heart failure and its relationship with the MAPK/ERK1/2 signaling pathway. METHODS:The rats were divided into sham group, model group (rat model of chronic heart failure was established by ligation of anterior descending branch of left coronary artery), low-, middle-, and high-dose Xinshuaikang treatment (TL, TM and TH) groups and captopril group (treated with captopril as positive control), with 12 in each group. Doppler echocardiography was used to evaluate the cardiac function. The morphological changes of the myocardium were observed by HE staining. TUNEL staining was used to detect cardiomyocyte apoptosis. The expression of microtubule-associated protein 1 light chain 3-Ⅱ (LC3-Ⅱ) in the myocardium was detected by immunofluorescence labeling. The protein levels of p-ERK, p-p38 MAPK, LC3-Ⅱ, beclin-1 and p62 in the myocardium were determined by Western blot. RESULTS:Compared with sham group, left ventricular end-diastolic dia-meter (LVEDD) and left ventricular end-systolic diameter (LVESD) in model group were increased, while left ventricular posterior wall thickness at end-diastole (LVPWTd), left ventricular posterior wall thickness at end-systole (LVPWTs), left ventricular ejection fraction (LVEF), cardiac output (CO), left ventricular diastolic pressure (LVDP), left ventricular systolic pressure (LVSP) and maximum rate of rise/decrease of left ventricular pressure (+dp/dt_max/-dp/dt_max) were decreased (P<0.05). The myocardial cells were deformed and necrotic, and the myocardial fibers were broken, with inflammatory cell infiltration. The apoptotic rate, the positive rate of LC3-Ⅱ, and the protein levels of p-ERK, p-p38 MAPK, LC3-Ⅱ/LC3-I and beclin-1 were increased, and the protein expression of p62 was decreased (P<0.05). Compared with model group, the levels of LVEDD and LVESD were decreased, LVPWTd, LVPWTs, LVEF, CO, LVSP, LVDP, +dp/dt_max and -dp/dt_max were increased in Xinshuaikang groups and captopril group (P<0.05). The morphological changes of myocardial cells were gradually returned to normal, and inflammatory cell infiltration, the apoptotic rate and the positive rate of LC3-Ⅱ were decreased. The protein levels of p-ERK, p-p38 MAPK, LC3-Ⅱ/LC3-I and beclin-1 were decreased, and the protein expression of p62 was increased (P<0.05). CONCLUSION:Xinshuaikang inhibits myocardial auto-phagy to play a role of cardiac protection in the rats with chronic heart failure, and its mechanism may be related to inhibition of MAPK/ERK1/2 signaling pathway.     

Hypoxia-inducible factor-1α attenuates myocardial inflammatory injury induced by ischemia and reperfusion in rats

AIM:To investigate the role of hypoxia-inducible factor-1α (HIF-1α) stable expression in myocardial inflammatory injury induced by ischemia and reperfusion (I/R) in rats. METHODS:Male Wistar rats were randomly divided into 4 groups:sham operation (sham) group, I/R group, HIF-1α stabilizer dimethyloxalyl glycine (DMOG)+I/R group and HIF-1α inhibitor YC-1+I/R group. The protein expression of myocardial Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) was determined by Western blot. The mRNA levels of interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), IL-6, TLR4 and NF-κB were detected by real-time PCR. The myeloperoxidase (MPO) activity in the myocardial tissues was measured. HE staining was used to observe the infiltration of inflammatory cells. RESULTS:HIF-1α decreased the infiltration of inflammatory cells, the MPO activity, and the mRNA levels of inflammatory factors IL-1β, IL-6 and TNF-α in the myocardial tissues. HIF-1α also reduced the expression of TLR4 and NF-κB at mRNA and protein levels (P<0.05). CONCLUSION:The stable expression of HIF-1α has an anti-inflammatory effect on the myocardial tissues after I/R injury in rats. The mechanism may be related to the inhibition of TLR4/NF-κB signaling pathway.     

Adipophilin induces expression of inflammatory factors through ERK1/2-AP-1 signaling pathway

AIM: To observe the effects of adipose differentiation-related protein (adipophilin) on the expression of inflammatory factors in RAW264.7 macrophage and to clarify the related mechanism. METHODS: The cell models with high expression and low expression of adipophilin were constructed by transfecting PA317 packaging cells with stable high or low expression adipophilin retroviral vectors into the RAW264.7 cells. The concentrations of IL-6, MCP-1 and TNF-α in the cell culture medium were detected by ELISA. The protein levels of AP-1, p-AP-1, ERK1/2 and p-ERK1/2 were measured by Western blot. The protein levels of adipophilin, p-ERK1/2 and p-AP-1 and the releases of the inflammatory factors in the RAW264.7 cells treated with or without ERK1/2 inhibitor PD98059 or AP-1 inhibitor curcumin were determined. RESULTS: The RAW264.7 cells with high expression of adipophilin had higher levels of IL-6, MCP-1 and TNF-α, and higher protein levels of p-AP-1 and p-ERK1/2 than those in the cells with low expression of adipophilin. ERK1/2 inhibitor had no significant effect on the expression of adipophilin, but the protein expression of ERK1/2 and AP-1 was significantly inhibited (P<0.05). The administration of AP-1 inhibitor curcumin had no significant effect on the protein expression of adipophilin and ERK1/2, but the protein expression of AP-1 was significantly inhibited (P<0.05). At the same time, the releases of inflammatory factors IL-6, MCP-1 and TNF-α were significantly decreased. CONCLUSION: Adipophilin may regulate the expression of inflammatory factors through ERK1/2-AP-1 pathway in RAW264.7 macrophages.     

Qishen-Yiqi dripping pills attenuate atherosclerosis by regulating Ca2+ homeostasis via TRPC1/STIM1 pathway

AIM:To explore the therapeutic effect of Qishen-Yiqi dripping pills (QS) on atherosclerosis (AS) and the mechanism. METHODS:AS rat model was established by high-fat diet, and SD rats were randomly divided into normal control group, AS model group, low-dose, middle-dose and high-dose QS groups, and positive group (n=6 each). After administration for 12 weeks, serum samples were collected to detect the serum lipid and Ca²⁺ levels. HE staining was used evaluated the histopathological changes of arterial tissue. The serum levels of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) were measured by ELISA. The nitric oxide (NO) level was detected by nitrate reductase method. The protein levels of transient receptor potential channel protein 1 (TRPC1), stromal interaction molecule 1 (STIM1) and endothelial NO synthase (eNOS) were determined by Western blot. RESULTS:QS significantly reduced the arterial damage via inhibiting the formation of atherosclerotic plaque and attenuated intimal thickening and vascular stenosis. Compared with AS group, the serum levels of total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) were decreased significantly and the levels of high-density lipoprotein cholesterol (HDL-C) were increased significantly in high-dose QS group (P<0.05). The serum levels of IL-1β, IL-6 and TNF-α in high-dose QS group were lower than those in AS group (P<0.05). Compared with AS group, the serum Ca²⁺ level was lowered and the arterial tissue NO level was elevated in QS groups (P<0.05). Compared with AS rats, the protein levels of TRPC1 and STIM1 were decreased significantly and the protein level of eNOS was increased significantly in the rats treated with QS (P<0.05). CONCLUSION:QS regulate calcium homeostasis via TRPC1/STIM1 pathway, increase the production of NO and inhibit the inflammatory responses, thus exerting anti-AS effect.     

Changes of liver lipid metabolism-related PPAR-γ/LXR-α/ABCG1 pathways and inflammatory factors in atherosclerotic mice and role of Huayu-Qutan recipe

AIM To observe the changes of liver lipid metabolism-related peroxisome proliferator-activated receptor-γ (PPAR-γ)/liver X receptor-α (LXR-α)/ATP-binding cassette transporter G1 (ABCG1) signaling pathways and inflammatory factors in mice with atherosclerosis (AS), and to investigate the effects of Huayu-Qutan recipe (HYQT) on hepatic lipid metabolism and inflammatory response and the mechanisms. METHODS ApoE^-/- mice (n=24) were randomly divided into model group, HYQT group and simvastatin group, and C57BL/6J mice (n=8) were used as control group. Except for the control group, the mice in other groups were given high-fat diet. After 12 weeks of modeling, the mice in HYQT and simvastatin groups were intragastrically given the corresponding drugs, and the mice in control and model groups were given the same volume of normal saline. After 8 weeks, the serum levels of triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were measured by an automatic biochemical analyzer. HE and oil red O staining was used to observe liver histopathological and lipid changes. The hepatic levels of free fatty acid (FFA), TG, tumor necrosis factor-α (TNF-α), Toll-like receptor 4 (TLR4) and interleukin-1β (IL-1β) were detected by ELISA. The protein expression of PPAR-γ, LXR-α and ABCG1 was determined by Western blot. RESULTS Compared with control group, the serum levels of TC, TG and LDL-C in model group were significantly increased (P<0.01), and the HDL-C content was significantly decreased (P<0.01). Liver steatosis, cell size augmentation and lipid deposition were obvious, and liver FFA and TG levels were significantly increased (P<0.01). The liver levels of TLR4, TNF-α and IL-1β were significantly increased (P<0.01), while the protein expression of PPAR-γ, LXR-α and ABCG1 was significantly decreased (P<0.05 or P<0.01). Compared with model group, the serum levels of TC, TG and LDL-C in simvastatin group and HYQT group were significantly decreased (P<0.05 or P<0.01), and the HDL-C content was significantly increased (P<0.01). Liver steatosis was weakened, and liver lipid deposition and FFA and TG levels were significantly decreased (P<0.05 or P<0.01). The liver levels of TLR4, TNF-α and IL-1β were significantly decreased (P<0.01), while the protein expression of PPAR-γ, LXR-α and ABCG1 was significantly increased (P<0.05 or P<0.01). CONCLUSION Huayu-Qutan recipe may exert anti-AS effect by regulating liver PPAR-γ/LXR-α/ABCG1 pathways and attenuating liver TRL4-mediated inflammatory responses.     

Effects of ginsenoside Rg1 of Panax notoginseng on brain tissue injury and Nrf2/HO-1 signal pathway after cerebral ischemia/reperfusion in mice

AIM:To observe the effects of ginsenoside Rg1 of Panax notoginseng on brain tissue injury after mouse cerebral ischemia/reperfusion(I/R), and to explore the mechanisms involving nuclear factor E2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) signal pathway. METHODS:C57BL/6 mice were randomly divided into sham group, cerebral I/R group, ginsenoside Rg1+cerebral I/R group and edaravone+cerebral I/R group. Ginsenoside Rg1 was successively administered for 3 d. One hour after final administration, bilateral common carotid arteries were ligated to induce brain tissue injury for 20 min, and then reperfusion for 24 h. Edaravone, a drug for anti-oxidative stress injury in the treatment of ischemic cerebro-vascular disease, was used as a positive control. The brain tissues were obtained to determine the neural cellular pathology in hippocampal CA1 region. The mRNA expression of Nrf2 and HO-1 was detected by RT-PCR. The protein levels of Nrf2 in the nucleus and cytoplasm and HO-1 in the whole cells in the brain tissues were measured by Western blotting. RESULTS:After ischemia/reperfusion for 24 h, the pathological injury in the neural cells was obvious, and the cell survival rate decreased. Ginsenoside Rg1 and edaravone attenuated the neural cell injury, and significantly increased the cell survival rate. After ischemia/reperfusion for 24 h, the mRNA expression of Nrf2 and HO-1 significantly increased in the brain tissues. The protein levels of Nrf2 in the nucleus and cytoplasm in the brain tissues were increased, the nuclear translocaition rate and the protein expression of HO-1 also increased. Ginsenoside Rg1 and edaravone both decreased the protein levels of Nrf2 in the cytoplasm of the brain tissues, increased that in the nucleus, and also increased Nrf2 nuclear translocation rate and the protein expression of HO-1. The effect of edaravone was higher than that of ginsenoside Rg1, but they had no significant effect on the mRNA expression of Nrf2 in the brain tissues. CONCLUSION: Ginsenoside Rg1 has the effect of anti-brain tissue injury on cerebral ischemia/reperfusion. The mechanisms may be related to activating the Nrf2/HO-1 signal pathway, promoting Nrf2 synthesis and nuclear translocation, thus promoting the expression of downstream antioxidant protein HO-1.     

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.     

Effect of taurine on kidney injury induced by paraquat poisoning in rats

AIM:To study the effects of taurine at different doses on renal oxidative stress and inflammation induced by paraquat in rats.METHODS:Male SD rats (n=48) were randomly divided into 4 groups:negative control group,paraquat group,paraquat+low-dose taurine group,and paraquat+high-dose taurine group.The serum levels of creatinine and urea nitrogen were detected by a biochemical analyzer.The levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were measured by colorimetry.The plasma concentrations of IL-6 and intercellular adhesion molecule (ICAM)-1 were detected by ELISA.Renal reactive oxygen species (ROS) was checked by fluorescence probe dihydroethidium (DHE).The protein levels of renal p-P38 MAPK,p-ERK1/2 and p-JNK were determined by Western blot.The mRNA expression of TNF-α,IL-6 and TGF-β1 was detected by real-time PCR.RESULTS:Serum creatinine and urea nitrogen increased after paraquat poisoning,and decreased after feeding with taurine in poisoned rats,with better result in high-dose taurine group.Taurine reduced the oxidative stress and inflammation in the renal tissue,and also reduced the protein levels of p-JNK,p-ERK1/2 and p-P38 in the kidney of paraquat-poisoned rats.CONCLUSION:Taurine attenuates renal injury induced by paraquat poisoning in rats.The mechanism may be related to reducing renal MAPK activity,oxidative stress and inflammatory response.     

Influence of Tangshenfang on diabetic liver injury and the expression of SIRT1 and PGC-1α in the liver tissue

AIM: To observe the effect of Tangshenfang (TS) on the liver protection and the levels of silent information regulator 1 (SIRT1) and peroxisom proliferator-activated receptor γ coactivator-1α (PGC-1α) in the liver tissue. METHODS: The rat model of diabetes mellitus (DM) was established by intravenous injection of streptozotocin (STZ;30 mg/kg) after having the high fat/high glucose diets for 1 month. The diabetic rats were randomly divided into DM group, DM with high-dose TS (TS^Hi) group, medium-dose TS (TS^Med) group and low-dose TS (TS^Low)group. The normal rats were served as control group. There were 8 rats in each group. After treatment with TS for 12 weeks, the serum biochemical indices including fasting blood glucose (FBG), triglyceride (TG), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were tested. Fasting insulin (FINS) was also detected by radioimmunoassay, and homeostatic model assessment for insulin resistance (HOMA-IR) was calculated. The serum levels of tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1) were measured by ELISA. The activity of SOD and content of MDA in the liver tissues were measured by the methods of hydroxylamine and thiobarbituric acid. The liver pathological changes were observed under light microscope with HE and Masson staining. The protein expression of SIRT1and PGC-1α in the liver tissues was determined by Western blot. RESULTS: In DM group, serum FBG, TG, ALT, AST, FINS, HOMA-IR, TNF-α and IL-1 were obviously increased compared with the control group (P<0.01). The fatty changes, local necrosis, inflammation and fibrosis in the liver tissues were observed. The content of MDA in liver increased, while the activity of SOD decreased markedly. The protein expression of SIRT1 and PGC-1α was decreased (P<0.05). In TS treatment groups, all these changes in DM rats were markedly reversed by TS, and the protein expression of SIRT1 and PGC-1α in the liver tissues was markedly increased. CONCLUSION: TS may protect the rats from diabetic liver injury by increasing the expression of SIRT1 and PGC-1α, and thereby improving insulin resistance and oxidative stress.