Sevoflurane preconditioning inhibits brain injury in hypoxic mice

AIM: To observe the effects of sevoflurane preconditioning on brain injury in hypoxic mice and its possible mechanism. METHODS: Male C57BL/6J mice were randomly divided into control (C) group, hypoxia (H) group, 2% sevoflurane preconditioning for 30 min + hypoxia (S1+H) group, 2% sevoflurane preconditioning for 60 min+hypoxia (S2+H) group and 4% sevoflurane preconditioning for 30 min + hypoxia (S3+H) group. The hypoxia model was established by continuous inhalation of (6.5±0.1)% O₂ for 24 h. The sevoflurane preconditioning treatments, S1, S2 and S3, were conducted by inhalation of 2% sevoflurane for 30 min, 2% sevoflurane for 60 min and 4% sevoflurane for 30 min, respectively, with the carrier of (21.0±0.5)% O₂, followed by washout for 15 min and then hypoxia treatment. The histological changes of the hippocampal CA1 area were observed under light microscope and transmission electron microscope (TEM), and serum lactate dehydrogenase (LDH) activity was measured by colorimetric method. Furthermore, the protein levels of erythropoietin (EPO) and vascular endothelial growth factor (VEGF) in brain tissue homogenate were examined by ELISA, and the content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were measured by microplate reader. RESULTS: After hypoxia for 24 h, cell edema or pyknosis in the hippocampal CA1 area was observed in H group. Sevoflurane preconditioning reduced hypoxic injury, and the cell ultrastructure under TEM was significantly improved in S2+H group. Compared with C group, the serum LDH activity and the levels of EPO, VEGF and MDA in brain tissues were significantly increased in H group, while the activity of SOD and GPx decreased. After sevoflurane pretreatment, the serum LDH activity and the levels of EPO and VEGF in brain tissues were lower than those in H group, and the most significant difference was observed in S2+H group. Moreover, the MDA content and SOD activity decreased, and the GPx activity increased in the sevoflurane preconditioning groups. CONCLUSION: Sevoflurane preconditioning attenuates brain injury in hypoxic mice by regulating antihypoxic protein synthesis and reducing oxidative stress.     

Study on protective mechanism of non-wounded ischemic preconditioning on rat ischemia/reperfusion myocardium

AIM:To investigate probable protective mechanism of non-wounded legs ischemic preconditioning on ischemia/reperfusion(I/R) myocardium. METHODS: 36 male SD rats, weighting (250±30) g,were divided into 4 groups.They are normal control(NC);I/R; classical ischemic preconditioning(C-IPC)and non-wounded legs ischemic preconditioning(N-WIPC). NO in plasm,expression of myocardial HSP 70 mRNA, the activities of 5’-NT and CAT of myocardium were observed in all groups. RESULTS:The level of NO in plasm significantly enhanced in groups C-IPC and N-WIPC compared with that in groups I/R and NC ( P <0.01),expression of myocardial HSP 70 mRNA was greatly increased in both C-IPC and N-WIPC groups, the activities of 5’-NT, CAT of myocardium were also raised in groups C-IPC and N-WIPC ( P< 0.05 vs I/R),but there was no difference between C-IPC and N-WIPC( P >0.05). CONCLUSION:The possible protective mechanism involved in N-WIPC is similar to that in C-IPC, which is due to increase of endogenous myocardial protective substances.     

Effect of insulin on early myocardial oxidative stress in severely burnt rats

AIM：To investigate the effect of insulin on early myocardial oxidative stress in severely burnt rats. METHODS：Twenty-four Sprague-Dawley rats were randomly divided into three groups (8 rats in each group): control group (sham scald group), scald injury group and scald injury + insulin group. The rats in the latter two groups were subject to third-degree burn with 30% total burn surface area (TBSA) on the back, and then received intraperitoneal injection of normal saline (40 mL/kg) immediately. The rats in scald injury + insulin group were subcutaneously injected with insulin (1 U/kg), while those in scald injury group received subcutaneous injection of the same volume of normal saline. All rats were sacrificed 24 h after scald, and blood samples from abdominal aorta and myocardial tissues were taken. Blood glucose (BG) content, blood lactate dehydrogenase (LDH) and creatine kinase (CK) activity, and myocardial oxidative and antioxidative indexes, including malondialdehyde (MDA), xanthine oxidase (XO), myeloperoxidase (MPO), superoxide dismutase (SOD), catalase (CAT) and glutathion peroxidase (GPx), were detected by spectrophotometry. RESULTS：(1) Compared with control group, BG levels in scald injury group and scald injury + insulin group were significantly elevated (P<0.05). But BG in scald injury + insulin group was significantly lower than that in scald injury group (P<0.05). (2) Compared with control group, the activity of LDH and CK in scald injury group was significantly increased (P<0.05), while that in scald injury + insulin group was significantly lower than that in scald injury group (P<0.05). (3) Compared with control group, the MDA content and the XOD and MPO activity in scald injury group were significantly increased (P<0.05), while the activity of SO, CAT and GPx was significantly decreased (P<0.05). Compared with scald injury group, the MDA content and the XO and MPO activity in scald injury + insulin group were significantly reduced (P<0.05), while the activity of SOD, CAT and GPx was significantly elevated (P<0.05). CONCLUSION：Insulin intervention attenuates early myocardial oxidative stress in burnt rats and decreases the rise in myocardial enzyme activity, thus exerting a cardioprotective effect.     

Effects of heptanol preconditioning on structure,function and Cx43 content of mitochondria in rabbit model of myocardial ischemia/reperfusion injury

AIM: To investigate the effects of heptanol preconditioning on the changes of structure, function and connexin 43 (Cx43) content in mitochondria in a rabbit model of myocardial isehemia-reperfusion (IR) injury. METHODS: In anesthetized open-chest rabbits, the left anterior descending artery (LAD) was occluded for 30 min and reperfused for 4 h. Sixty-four rabbits were randomly divided into 4 groups (n=16 in each group): sham operation group (sham group), ischemia-reperfusion group (IR group), ischemic preconditioning group (IP group) and heptanol preconditioning group (HT group). All rabbits in the 4 groups were killed 4 h after reperfusion. Myocardial infarct size was determined at the end of the experiment. Mitochondria was isolated by centrifugations. The ultrastructural changes of the mitochondria were observed under electronic microscope. The mitochondrial membrane potential, Ca2+ concentration, MDA content and SOD activity of myocardial mitochondria were also examined. The content of mitochondria Cx43 was detected by Western blotting. RESULTS: Compared to IR group, the myocardial infarct size was significantly reduced in IP (18.97%±2.80%) and HT (19.97%±3.80%) groups, the damage of mitoehondrial ultrastructure was milder (P<0.05), mitochondrial membrane potential was significantly higher and Ca2+ concentration was much lower (P<0.01) in IP group and HT group. No significant difference of MDA content and SOD activity in myocardial mitochondria between IR group and HT group was found. However, MDA content were much lower and SOD activity was significantly higher in IP group as compared to IR group (P<0.01). Compared to sham group, the mitochondria Cx43 expression was distinctly decreased compared to IR group (P<0.05) and no significant difference was found between IP group and HT group (P>0.05). CONCLUSION: Heptanol preconditioning protects myocardium from ischemia-reperfusion injury. The mechanism may be related to increasing in mitochondrial membrane potential, alleviating Ca2+ overload in myocardial mitochondria and attenuating the decrease in mitochondria Cx43 expression induced by isehemia-reperfusion.     

Change of neurobiochemistry induced by renal ischemia-reperfusion injury

AIM:To explore the effects of renal ischemia-reperfusion injury on the changes of biochemistry in blood serum and cerebrospinal fluid. METHODS:Twenty healthy New Zealand rabbits were randomly divided into control group and renal ischemia-reperfusion injury group (IR group). The contents of creatinine (Cr), urea nitrogen (UN), Na+, Ca2+, metabolite of nitric oxide (NO) in blood serum and cerebrospinal fluid were detected and analyzed. The total activity of nitric oxide synthase (NOS) in brain tissues was also measured. RESULTS:Compared with control group, the contents of UN, Cr and NO were obviously higher (P<0.05), and the content of Na+ was obviously lower both in blood serum and cerebrospinal fluid in IR group than those in control at 24 h after renal ischemia-reperfusion injury. The content of Ca2+ was lower in blood serum but higher in cerebrospinal fluid in IR group compared with control group (P<0.05). Both the contents of NO2-/NO3- and the total activity of NOS in brain tissues were higher in IR group than those in control group (P<0.05). CONCLUSION:Not only elements of blood serum but also the biochemistry of cerebrospinal fluid were changed by renal ischemia-reperfusion injury. NO may involve in the influence of the renal ischemia-reperfusion injury on the cerebral function.     

Remote preconditioning provides myocardial protection against myocardial ischemia/reperfusion injury through downregulating the expression of calreticulin in rats

AIM: To evaluate the role of calreticulin (CRT) in myocardial protection of remote preconditioning against myocardial ischemia/reperfusion injury. METHODS: Thirty SD rats were randomly divided into 5 groups: ischemia reperfusion group (IR), ischemia preconditioning group (IP), remote preconditioning group Ⅰ (RPI), remote preconditioning group Ⅱ (RPII) and pseudo-operation group (PO). The ischemia/reperfusion model was established in vivo. Hemodynamic changes of heart function were observed. Serum cardiac troponin T (cTnT), superoxide dismutase (SOD), malondialdehyde (MDA) and the expression of calreticulin in myocardium were detected. RESULTS: Hemodynamic data, serum cTnT, DA, SOD and the expression of CRT in RPI and IR group were not statistically different (P>0.05). SOD level in IP and RPII group was higher than that in IR group (P<0.05). Accordingly, cTnT, MDA and the expression of CRT in these two groups were lower than those in IR group (P<0.05). CONCLUSION: Remote preconditioning may mimic the protective effect of ischemic preconditioning. Remote preconditioning attenuates myocardial ischemia/reperfusion injury in vivo possibly through down-regulation of CRT expression in rats.     

Effects of simvastatin on expression of Bcl-2 and Bax in myocardium of rats with renal ischemia-reperfusion injury

AIM: To observe the effect of simvastatin on myocardial tissue after renal ischemia-reperfusion injury and its mechanism. METHODS: A rat model of renal ischemia-reperfusion injury was prepared by clamping the bilateral renal arteries for 45 min. The rats (n=36) were randomly divided into sham operation group, renal ischemia-reperfusion (I/R) group and simvastatin group with 12 rats in each group. The content of serum creatinine (SCr), blood urea nitrogen (BUN) and myocardial tissue malondialdehyde (MDA), the myocardial activity of lactate dehydrogenase (LDH), creatine kinase (CK) and superoxide dismutase (SOD), and the myocardial protein expression of Bcl-2 and Bax were detected. RESULTS: Compared with sham operation group, the content of SCr, BUN and myocardial MDA, and the myocardial activity of LDH and CK in I/R group were significantly increased (P<0.05), and the activity of SOD was significantly decreased (P<0.05). Compared with I/R group, the content of SCr, BUN and myocardial MDA, and the myocardial activity of LDH and CK in simvastatin group were significantly decreased (P<0.05), while SOD activity was enhanced (P<0.05). The protein expression of Bcl-2 and Bax in sham operation group was less than that in I/R group (P<0.05), and the protein level of Bax in simvastatin group was significantly lower than that in I/R group (P<0.05), while the protein level of Bcl-2 was increased (P<0.05). CONCLUSION: Simvastatin has a protective effect on the myocardium of the rats with renal ischemia-reperfusion injury, and the protective mechanism may be related to the elimination of free radicals by simvastatin, increase in the protein expression of Bcl-2 and decrease in the protein expression of Bax.     

Effects of lutein on viability of breast cancer cells

AIM:To investigate the effect of lutein on the viability of breast cancer cells and its possible mechanism. METHODS:The human breast cancer T47D cells were divided into control group and lutein (6.25, 12.5, 25, 50 mg/L) treatment groups. The effect of lutein on the viability of T47D cells was measured by MTT assay. The mRNA expression of nuclear factor erythroid 2-related factor 2 (Nrf2), glutathione peroxidase 1 (GPx1) and superoxide dismutase 2(SOD2) was detected by RT-qPCR. Fluorescent probes DCFH-DA was used to determine the production of reactive oxygen species (ROS). The protein expression of Nrf2 and p65 was determined by Western blot. RESULTS:The MTT results showed that lutein inhibited T47D breast cancer cell viability in a dose-and time-dependent manner. The RT-qPCR results showed that the mRNA levels of Nrf2, GPx1 and SOD2 were higher in lutein treatment groups than those in the control group (P<0.05), and with the increased concentrations and extension of intervention time of lutein, the relative mRNA levels were all increased. The ROS levels were significantly decreased in the lutein-treated groups (P<0.05). The results of Western blot demonstrated that the protein expression of Nrf2 was significantly increased (P<0.05), and p65 protein was decreased (P<0.05) in a dose-dependent manner with lutein treatment for 48 h. CONCLUSION:Lutein significantly inhibits the viability of breast cancer cells, and the inhibition roles may be related to up-regulation of the expression of Nrf2, antioxidant enzymes GPx1 and SOD2 mRNA expression and down-regulation of oxidative stress, thus blocking the NF-κB signaling pathway.     

Effect of atrial natriuretic peptide on acute lung injury induced by lipopolysaccharide

AIM: To investigate effect of atrial natriuretic peptide (ANP) on acute lung injury (ALI) induced by lipopolysaccharide (LPS) in rat. METHODS: Mean arterial blood pressure (MAP) was recorded with model 6280 physiology intelligentialize grapher, nitric oxide (NO) and endothelin (ET) concentrations in plasma were measured after lipopolysaccharide (LPS) or following LPS ,ANP was injected into vein in rats. After experiment,lung water as well as pulmonary histopathological changes was measured and observed, respectively. RESULTS: Administration of LPS elicited a persistence decrease in MAP (8.1 kPa±2.6 kPa,at 4 h,P<0.01 vs control); NO and ET concentration in plasma was evident higher than that in control group, respectively (P<0.01); Wet-dry ratio of lung was higher than that in control group (5.15±0.43,at 4 h) (P<0.05); Alveolus detelectasis was observed and pulmonary mesenchyme was thicker than that in control group. No erythrocyte and leukocytes in alveolus,which show an interstitial pulmonary edema, was observed in LPS+ANP group, ANP maintained MAP at higher levels (13.35 kPa±2.93 kPa, at 4 h, P<0.05 vs LPS) after an transient decline when LPS was injected; NO and ET concentration of plasma had all significantly decrease, respectively (P<0.05 vs LPS, at 4 h); Wet-dry ratio of lung was lower than LPS group (4.57±0.35, P<0.05). Compared with control group the ratio was not evident difference (P>0.05); The histopathological of lung displayed markedly improved. CONCLUSION: ANP attenuates ALI induced by LPS in the rat. The effect of ANP may be via decreasing secretion of ET,NO and regulation arterial blood pressure.     

Effects of non-wounded ischemic preconditioning on ischemia-reperfusion injury in isolated rat hearts

AIM:To observe the protective effect of non-wounded ischemic preconditioning on ischemic/reperfusion injury in isolated rat hearts. METHODS: 25 male SD rats, weighting (250±30) g, were randomly divided into three groups: control group (C,n=8), anoxia/reoxygenation group (A,n=8) and non-wounded legs ischemic preconditioning group (N-WIP,n=9).Hearts were isolated from rats and perfused on a Langendorff apparatus with a normal Krebs-Henseleit buffer (saturation 95% O₂+5% CO₂) at a constant pressure (8.33 kPa) and temperature (37 ℃) in C group; Following 15 min equilibration, hearts were subjected to 15 min of global ischemia and 15 min reperfusion (37℃) in A group; Rats were subjected to non-wounded leg repeated-brief ischemic preconditioning, and then treated in procedure similar to A group in N-WIP group.The activities of superoxide dismutase (SOD) and Ca²⁺-Mg²⁺-ATPase, malondialdehyde (MDA) content of efflux from coronary vessel and myocardium, myocardium monophasic action potential and contractile force were measured before ischemia, 15 minutes after ischemia and 5, 15 minutes after reperfusion. RESULTS:Compared with A group, non-wounded legs ischemic preconditioning reduced the incidence of reperfusion arrhythmias (P＜0.05), decreased the content of MDA of myocardium (P＜0.01), enhanced the activities of SOD (P＜0.01) and stabilized myocardial membranous potential,the activity of Ca²⁺-Mg²⁺-ATPase and contractile function. CONCLUSION:These results indicate that non-wounded leg ischemic preconditioning has a protective effect on ischemia-reperfusion injury in isolated rat hearts. The mechanism may be related to the strength of antioxidation, the stability of Ca²⁺-Mg²⁺-ATPase activity and membranous structure in myocardium.     

Dexamethasone pretreatment attenuates reperfusion arrhythmia in rats

AIM: To investigate the effect of dexamethasone (DEX) preconditioning on reperfusion arrhythmia. METHODS: 46 Sprague-Dawley rats were divided randomly into DEX and control (CON) group, the rats were pretreated with DEX or sodium chloride before their hearts were separated for Langendorff perfusion and for ischemia/reperfusion. The reperfusion arrhythmias were observed dynamically after 60 min reperfusion following 30 min ischemia. The expression of HSP72 in myocardium was examined by Western blotting and immunohistochemistry at reperfusion 60 min. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and the activities of Na+-K+-ATP ase, Ca2+-Mg2+-ATPase on myocardial plasma membrane were detected. RESULTS: Compared with control group, the accumulated points and persistence time of ventricular arrhythmia were reduced significantly in DEX group (P<0.05), the expression of HSP72 was significant upregulated (P<0.05), the level of MDA was reduced significantly, the activities of SOD, CAT, GSH-Px and Na+-K+-ATPase were significantly higher (P<0.05). CONCLUSION: Dexamethasone pretreatment markedly reduces the reperfusion ventricular arrhythmias in rats, which may be attributed to upregulation of HSP72, SOD, CAT, GSH-Px , Na+-K+-ATPase and inhibition of lipid peroxidation.     

Establishment and evaluation of rat heart ischemia-reperfusion injury model in vivo

AIM: To establish and evaluate a rat model of heart ischemia-reperfusion injury in vivo. METHODS: Seventy-two male Sprague-Dawley rats weighing(250±50)g were randomly divided into sham operation group(sham), ischemia-reperfusion group(I/R) and normal group. The animals were anesthetized and heparinized. Myocardial ischemia-reperfusion was induced by ligating the left anterior descending coronary artery with "U-shape tube" for 35 min followed by 120 min or 240 min reperfusion in vivo. The heart infarct size was measured by triphenyltetrazolium chloride(TTC) staining. The myocardial cell apoptotic index was determined by the method of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling(TUNEL). Immunohistochemical method was used to detect the expression of Bcl-2 and Bax in rat ischemia myocardium. The blood level of MB isoenzyme of creatine kinase(CK-MB),cardiac troponin I(cTnI),nitric oxide(NO),malondialdehyde(MDA), total superoxide dismutase(T-SOD)and glutathione peroxidase(GSH-Px) were detected after reperfusion for 2 h and 4 h. RESULTS: Compared with normal group and sham group, there were obvious changes of ST-T segment and Q wave in the electrocardiogram of I/R group. The blood level of CK-MB, cTnI, NO, MDA and GSH-Px in I/R group increased(P<0.05,P<0.01) after reperfusion for 2 h and 4 h, and the blood level of T-SOD in I/R group after reperfusion for 2 h and 4 h also increased(P<0.05). The heart infarct size in I/R group was the largest as compared to other groups. Among these groups, the apoptotic index of I/R group was the highest and the Bcl-2/Bax ratio in I/R group decreased(P<0.01).CONCLUSION: The rat model of heart ischemia-reperfusion injury in vivo can be successfully established with the "U-shape tube". There are obviously changes of heart infarct size, blood level of CK-MB, cTnI, NO, MDA, T-SOD and GSH-Px, myocardial apoptotic index and Bcl-2/Bax ratio between I/R rats and control animals.     

Changes of NO- and H2O2-dependent soluble guanylate cyclase pathway in the hypoxic hypercapnic pulmonary hypertension rats

AIM: To study the effect of hypoxia and hypercapnia on nitric oxide (NO) in plasma and superoxide dismutase (SOD), catalase (CAT), soluble guanylate cyclase (sGC), cyclic guanosine monophospholate (cGMP) in lung tissue in rats, and to explore the effect of NO- and H2O2-sGC pathway on the development of the pulmonary hypertension. METHODS: The model of hypoxic and hypercapnic 1, 2, 4-week group (HH 1 week, HH 2 weeks, HH 4 weeks) and control group was set up. NO content in plasma, CAT and SOD in rat lung were determined by spectrophotometry. The sGC activity in lung tissue was detected by enzyme kinetic analysis. cGMP content in lung tissue was examined with ［125I］-radioimmunoassay. RESULTS: The mean pulmonary artery pressure (mPAP) showed significantly higher in HH 1 week, HH 2 weeks and HH 4 weeks groups compared with control group (all P<0.05). NO concentration in plasma, CAT, SOD, basal or nitroprusside-or H2O2- stimulated sGC activity and cGMP concentration in lung homogenates were significantly lower (P<0.05, P<0.01, P<0.01, respectively) in HH 1 week, HH 2 weeks and HH 4 weeks groups compared with control group. CONCLUSION: The inhibition of NO- and H2O2-sGC pathway by hypoxia and hypercapnia plays an important role in the development of pulmonary hypertension.     

Protective role of ornithine decarboxylase (ODC)/polyamines system in the myocardium induced by ischemic preconditioning in rats

AIM: To explore the protective role of ornithine decarboxylase (ODC)/polyamines system in the myocardium induced by ischemic preconditioning in rats.METHODS: The experiment model of simulating myocardial ischemia-reperfusion was replicated by Langendorff perfused rat heart. The hearts were randomly divided into six groups: control group, ischemic-reperfusion group (IR), weak ischemic preconditioning group (IPCw), strong ischemic preconditioning groups (IPCs) and inhibitor groups (DF-EG-IPCw and DF-EG-IPCs). The expression of ODC was quantified by Western blotting analysis. The contents of polyamines (putrescine, spermidine, spermine) in cardiac tissue were detected with high performance liquid chromatography. The hemodynamics was obtained using the PowerLab 8/SP TM data acquisition system. The infarct size was measured using triphenyltetrazolium chloride (TTC) staining and the apoptosis cardiomyocytes were observed under optic microscope after TUNEL method treatment. RESULTS: In contrast with control group, in IR group the putrescine contents increased, the expression of ODC was down-regulated, the contents of spermine and the total polyamine pool decreased (P<0.05). At the same time, the cardiac function declined, with an increase in myocardium infarct size and the apoptosis rate of cardiomyocytes (P<0.05). When compared with IR group in terms of LVDP, HR and CF, both IPCw and IPCs groups had significant improvements in cardiac functions (P<0.05). These two groups also had smaller myocardium infarct size (P<0.01) and apoptosis rate of cardiomyocytes (P<0.01). When compared with IR group, the expression of ODC, the contents of spermine and the total polyamine pool increased in both IPCw (P<0.05) and IPCs groups (P<0.01), but the putrescine contents declined. In the respective inhibitor groups of the weak and ischemic preconditioning, the expression of ODC and the levels of putrescine, spermidine, spermine and the total polyamine pool decreased remarkably (DF-EG-IPCw vs IPCw, P<0.05; DF-EG-IPCs vs IPCs, P<0.01), while the myocardium infarct size and apoptosis rate of cardiomyocyte were relatively bigger in both inhibitor groups (P<0.05). Also, the heart function decreased significantly in terms of LVDP, HR and CF compared to their matched ischemic preconditioning group (P<0.05).CONCLUSION: Ischemic preconditioning significantly up-regulates the ODC / polyamines system in Langendorff perfused rat hearts and provides protective effects on myocardium with ischemia/reperfusion injury. Inhibition of bio-synthesis of polyamine abolishes the cardiac function improvement and the decreases the infarct size and apoptosis rate induced by ischemic preconditioning. It reveals that the ornithine decarboxylase (ODC) /polyamines system may be involved in the protection of myocardium induced by IPC in rats.     

Effect of selenium compounds on ROS and NO production and NOS activity in human umbilical cord mesenchymal stem cells

AIM: To investigate the effects of selenium (Se) compounds on the generation of nitric oxide (NO) and reactive oxygen species (ROS), and the activity of nitric oxide synthase (NOS) in umbilical cord mesenchymal stem cells (MSCs). METHODS: MSCs were cultured in the medium of DMEM/F12 containing 10% FBS and exposed to the compounds of selenium , selenocysteine (Se-Cys) or nano-selenium (Nano-Se) at concentrations of 0.1 μmol/L to 0.5 μmol/L. The concentration of NO and the activity of NOS in treated MSCs were detected by the method of nitrate reductase assay. The fluorescent intensity of ROS was determined by DCFH-DA probe. RESULTS: The production of NO was (18.13±6.80) μmol/L in the control MSCs,(20.93±5.68) μmol/L in the MSCs treated with Se(Ⅳ) at concentration of 0.1 μmol/L and (16.73±5.03) μmol/L in the MSCs treated with Se(Ⅳ) at concentration of 0.5 μmol/L for 24 h. The production of NO was (17.20±9.11) μmol/L (P<0.05) in the MSCs treated with Se(IV) at concentration of 0.1 μmol/L and (9.98±4.35) μmol/L (P<0.01) in the MSCs treated with Se(IV) at concentration of 0.5 μmol/L for 48 h, which was significantly lower than that in the control MSCs . No inhibitory effect of Nano-Se and Se-Cys on the production of NO in MSCs was observed. Compared with the control MSCs, Se(Ⅳ) at concentrations of 0.1 μmol/L and 0.5 μmol/L significantly inhibited the generation of ROS and the activity of NOS in MSCs at 24 h and 48 h. CONCLUSION: Se(Ⅳ) inhibits NO/ROS production and NOS activity in a dose-dependent manner in MSCs.     

Se-containing spirulina phycocyanin attenuated liver injury induced by carbon tetrachloride in mice

AIM:To investigate the effect of Se-containing spirulina phycocyanin (Se-SPC) on liver injury of mice induced by carbon tetrachloride (CCl₄). METHODS:The mouse model was conducted by intragastric feeding with 2% CCl₄ oil for three times, meanwhile Se-SPC, spirulina phycocyanin (SPC) and Na₂SeO₃ were injected (ip) to various groups for 7 days. Then selenium (Se), glutathione peroxidase (GPx), superoxide dismutase (SOD), alanine aminotransferase (ALT), malondiaoldehyde (MDA) and nitric oxide (NO) levels in blood and liver were measured. RESULTS:The level of Se,GPx and SOD activities were obviously higher(P<0.05)but ALT activity,MDA and NO₂^-/NO₃^- levels were remarkably lower(P<0.05)in Se-SPC treated groups than those in CCl₄ groups,and effects of high dose Se-SPC on Se,GPx,MDA and NO₂^-/NO₃^- were even more significant(P<0.01).Under the same dose of Se or protein,effects of all selected targets in Se-SPC groups were more efficient than those in SPC groups and inorganic-Se groups.Furthermore,Se levels had a positive correlation with GPx activity(r=01705),which had negative correlation with levels of MDA,NO₂^-/NO₃^- and ALT(r=-0.629,r=-0.336,r=-0.457,respectively), and positive correlations between ALT activity and MDA or NO₂^-/NO₃^- level were found (r=0.519,r=0.641). CONCLUSION:These results indicated that Se-SPC may attenuate liver injury of mice induced by CCl₄ through its anti-inflammatory action and enhancing selenoenzyme expression.     

Changes of gut mucosa antioxidant system and liver,renal function in rats after intestinal ischemia-reperfusion injury

AIM: To investigate the changes of the gut mucosa antioxidant system and liver, renal functions during rat intestinal ischemia-reperfusion injury. METHODS: 30 male Wistar rats underwent 45 min of intestinal ischemia by clamping the superior mesenteric artery followed by reperfusion. The levels of malondialdehyde (MDA), glutathione (GSH), the activities of antioxidant enzymes in the gut mucosa including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), glutathione S- transferase (GST) activity and serum ALT, AST, BUN, Cr were assayed at 2, 4, 8, 12 and 24 h after reperfusion. RESULTS: The levels of MDA and GSH in the gut mucosa increased and decreased significantly at 2 h of reperfusion, respectively (P<0.05). MDA was still lower than sham at 24 h of reperfusion (P<0.05), while GSH decreased to 40% of sham at 4 h of reperfusion (P<0.01) but returned to the level of control at 12 h. The activities of CAT, SOD and GSH-Px did not show significant changes in rat after intestinal ischemia reperfusion. GST decreased 39% at 2 h of reperfusion compared with the sham group and decreased to 56% of sham at 4 h (P<0.05), but returned to the level of control at 12 h after reperfusion. Serum ALT, AST, BUN and Cr increased significantly at 2 h of reperfusion (P<0.05) and increased 208%, 100%, 103%, 41% compared with control at 4 h of reperfusion (P<0.01). However, at 24 h of reperfusion, they returned to normal. CONCLUSION: Intestinal ischemia/reperfusion diminishes GSH level and GST activity, increases MDA level and causes liver and renal reversible damages.     

Effects of electrolyzed free radicals on endothelium of isolated guinea pig coronary and epithelium of airway tube

AIM and METHODS:To study the damage effects of free radicals from electrolyzed krebs solution(direct current,10 mA,1-2 min) on isolated guinea pig coronary and airway tube. RESULTS:In Langendorff’s perfused guinea pig hearts,the electrolyzed free radicals increased coronary perfusion pressure(4.4±1.2) kPa,inhibited myocyte contractility [(0.8±0.8) g vs (2 9±0 6) g, P< 0.05],increased TBARS level and decreased SOD activity.In isolated perfused lungs of guinia pig,electrolyzed Krebs solution promoted significantly the airway perfusion pressure [(0.03±0.01) kPa vs (2.20±0.29) kPa, P< 0.01] and histamine reactivity [(0.65±0.37) kPa vs (2.05±0.25) kPa, P< 0.01]. Hydroxyl radicals scavenger DMSO and natural medicine gypenosides prevented the effects of oxygen free radicals. CONCLUSION: These results indicated that the free radicals by electrolyzation could induce damages of coronary endothelium and airway epithelium.     

Effects of human urotensin II on ischemia/reperfusion injury in isolated perfused rat hearts

AIM: To investigate the effects of human urotensin II (hUII) on ischemia/reperfusion (I/R) injury in isolated rat hearts. METHODS: In the ischemia/reperfusion (I/R) model of isolated perfused rat hearts, the effects of hUII pretreatment on cardiac function was monitored with cardiac function software of MFL Lab200. ATP, total calcium, and malondialdehyde (MDA) content in myocardium were detected. The coronary perfusion flow (CPF) and lactate dehydrogenase (LDH) activity in coronary effluent were measured during reperfusion. RESULTS: In the hUII pretreated group, the release of LDH from myocardium was lower [(78.3±18.1)U/L] than I/R group [(109.3±23.9) U/L, P< 0.05], with decreased contents of MDA and calcium in myocardium (decreased by 24% and 27%, respectively, P< 0.05) and an increased myocardial ATP content [(3.8±0.4)μmol/g dw vs (2.2±0.4)μmol/g dw, P< 0.05)]. At the same time, hUII pretreatment increased CPF [(5.4±0.7) mL/min vs (3.8±0.8) mL/min in I/R group, P< 0.05], reduced left ventricular end-diastolic pressure (LVEDP) by 20% ( P< 0.05) with increased±d p /d t max [(217±38) kPa/s and (119±18) kPa/s vs (173±29) kPa/s and (82±25) kPa/s in I/R groups, respectively, P< 0.05]. hUII pretreatment also increased natrite/natrate (NO₂^-/NO₃^-) content in coronary effluent [(52.2±12.0)μmol/L vs (32.1±10.2)μmol/L in I/R group, P< 0.05)]. CONCLUSION: hUII pretreatment attenuated I/R injury in isolated perfused rat hearts. The protective mechanism might be associated with NO-mediated coronary vasodilation.     

Role of ROS/PKC/p38 MAPK pathway in protective effects of polysaccharide from Fructus cornion rat cardiomyocytes against hypoxia-reoxygenation injury

AIM: To investigate the effect of polysaccharide from Fructus corni(PFC) on cardiomyocytes against hypoxia/reoxygenation (H/R) injury and its possible relationship with ROS/PKC/p38 MAPK pathway.METHODS: Primary cardiomyocytes were isolated from neonatal SD rats and randomly divided into normal group, H/R group, PFC (20 mg/L, 100 mg/L and 200 mg/L) preconditioning+H/R groups, chelerythrine+PFC (100 mg/L)+H/R group and SB203580+PFC (100 mg/L)+H/R group. The cell viability was measured by inverted microscopic observation. Apoptosis in the cardiomyocytes was detected by Hoechst 33258 staining and fluorescence microscopy. The levels of lactate dehydrogenase (LDH) and superoxide dismutase (SOD) in the cell culture supernatants, and the reactive oxygen species (ROS) in the cells were also measured by microplate reader. The protein levels of PKC, p-p38 MAPK and HSP70 in the cells were detected by Western blotting.RESULTS: Compared with normal group, the cell viability and beating frequency were decreased in H/R group. LDH and ROS contents, apoptotic rate and p-p38 MAPK level increased significantly (P<0.01). Compared with H/R group, PFC preconditioning increased beating frequency, SOD activity and the protein level of PKC and HSP70, and decreased ROS production, the protein level of p-p38 MAPK and cell apoptotic rate. However, the effect of PFC was inhibited by chelerythrine or SB203580.CONCLUSION: PFC may protect cardiomyocytes from hypoxia/reoxygenation injury. Its mechanism is possibly involved in the inhibition of ROS via increasing the activity of SOD and the activation of PKC, and suppression of excessive activation of p38 MAPK.