Effect of L-arginine on expression of bcl-2 and bax mRNA in pulmonary injury induced by ischemia-reperfusion in rabbits

AIM:To investigate the effect of L-arginine (L-Arg) on expression of bcl-2, bax mRNA during pulmonary ischemia and reperfusion injury (PIRI) in rabbits.METHODS:Single lung ischemia and reperfusion animal model was used in vivo. The rabbits were randomly divided into three groups: sham operated group (sham, n=12), ischemia-reperfusion group (I/R, n=12) and I/R+ L-arginine group (L-Arg, n=12). Changes of several parameters, which included apoptotic index (AI), wet to dry ratio of lung tissue weight (W/D) and index of quantitative assessment of histologic lung injury (IQA), were measured at 300 min after reperfusion in lung tissue. Meanwhile the location and expression of bcl-2, bax mRNA as well as the ratio of bcl-2 mRNA/bax mRNA were observed. The lung tissue was prepared for light microscopic and electron microscopic observation at 60, 180 and 300 min after reperfusion. RESULTS:As compared with I/R group, in intima and extima of small pulmonary artery, alveoli, and bronchiole epithelia, the expression of bcl-2 mRNA and the ratio of bcl-2 mRNA/bax mRNA were increased, and the expression of bax mRNA was decreased in L-Arg treatment group. The values of AI, W/D and IQA showed significantly lower than that in I/R group at 180 minutes after reperfusion in lung tissue (P<0.01 and P<0.05). Meanwhile, abnormal changes of the lung tissue in morphologically were markedly lessened in L-Arg treatment group.CONCLUSION:L-arginine produces a notable protective effect on PIRI in rabbits by up-regulating bcl-2 mRNA expression, down-regulating bax mRNA expression in lung tissue and regulating the balance of bcl-2 mRNA and bax mRNA to decrease apoptosis.     

Protective effect of rapid ischemic preconditioning against spinal cord ischemic injury in rabbits

AIM: To evaluate the protective effect of rapid phase of ischemic preconditioning against spinal cord ischemic injury in rabbits. METHODS: Thirty six male New Zealands white rabbits were randomly assigned to 3 groups (12 in each group): ischemia and reperfusion injury group (IR group), ischemic preconditioning + IR group (IPC+IR group) and sham operation group (sham). In IR group, spinal cord ischemia was induced by an infrarenal aorta clamping for 20 min; The rabbits in IPC+IR group underwent a 6 min ischemic preconditioning followed by 30 min of reperfusion before the 20 min clamping; The rabbits in sham group underwent the same procedures as the IR group except for infrarental aortic unclamping. Neurologic status was scored at 8, 12, 24 and 48 h after reperfusion. All animals were sacrificed at 48 h after reperfusion and the spinal cords (L_5-7) were removed for histopathologic study and determination of the activity of Na⁺, K⁺-ATPase. RESULTS: The neurologic function scores in sham group and IPC+IR group at each observation interval were higher than those in IR group (P＜0.01). Compared to IR group, there were more normal neurons in anterior horn of spinal cord in sham group and IPC+IR group (P＜0.01); the activity of Na⁺, K⁺-ATPase in sham group and IPC+IR group were higher than those in IR group (P＜0.01). CONCLUSION: The rapid phase of ischemic preconditioning has a protective effect against spinal cord ischemic injury in rabbits, and this neuroprotection may be related to the maintenance of Na⁺, K⁺-ATPase activity.     

Effects of Radix Angelicae Sinensis on changes of IL-6, TNF-α and bFGF in renal ischemia/reperfusion injury in rabbits

AIM: To determine the effect of Radix Angelicae Sinensis(RAS) on renal ischemia/reperfusion injury in rabbits and to explore its mechanism. METHODS: Twenty-five rabbits were divided randomly into the sham operated group(Control group), renal ischemia/reperfusion injury group(IR group) and RAS+IR group. At the time point of reperfusion 48 h after renal ischemia 1 h, the renal tissue were observed by electron-microscope and the contents of creatinine(Cr) in serum, tumor necrosis factor-α(TNF-α), interleukin-6(IL-6)and basic fibroblast growth factor(bFGF) in the renal tissue were measured. RESULTS: A remarkably degenerative changes in renal tissue were showed under electronmicroscope in IR group, but the changes in RAS+IR group were slight. The contents of Cr, TNF-α and IL-6 in IR group were higher than those in Control group, these parameters in RAS+IR group were lower than those in IR group, the difference between these groups was significant(P< 0.05 or P< 0.01). At the same time, the content of bFGF in IR group was lower than that in Control group(P< 0.01), while the content of bFGF in RAS+IR group was higher than that in IR group(P< 0.01) and Control group(P< 0.05). CONCLUSION: RAS has an effect of alleviating the renal ischemia/reperfusion injury by modulating the production or release of TNF-α, IL-6 and bFGF.     

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.     

Effect of L-arginine on function and structure of mitochondria in ischemia-reperfusion myocardial cells in rabbits

AIM: To study the effect of L-arginine (L-Arg) on function and structure of mitochondria in ischemia-reperfusion (MRI) myocardial cells. METHODS: Thirty rabbits were randomly divided into three groups (n=10 in each), control group, MIR group and MIR+L-Arg group. The mitochondrial respiratory function, Ca²⁺ concentration ([Ca²⁺]m), malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were determined. Meanwhile, the contents of adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), total adenylic acid number (TAN) and energy charge (EC) in the myocardial tissue were respectively measured. Moreover, the ultrastructure changes in myocardial mitochondria were observed during MIR. RESULTS: The mitochondrial respiratory control rate (RCR), velocity 3 (V₃), SOD, surface density (Sv) and specific surface (δ) in MIR+L-Arg group were higher than those in MIR group, velocity 4 (V₄), [Ca²⁺]m, MDA, volume density (Vv), horizental diameter (Hd) were lower than those in MIR group. ATP, ADP, TAN and EC levels of myocardial tissue were higher than those in MIR group. There was no significant difference between MIR+L-Arg and control group in V₃, V₄, SOD, MDA, Vv, Sv, δ, Nv, Vd, AMP and TNA. CONCLUSION: It is suggested that L-Arg improves the function and structure of mitochondria in myocardial cells in the reperfusion injury after myocardial ischemia by decreasing oxygen free radical level and Ca²⁺ overload in the mitochondria.     

Effects of atorvastatin on nitric oxide,endothelin-1 and myocardial function in a rabbit model of acute myocardial infarction and reperfusion

AIM: To evaluate the effects of atorvastatin on nitric oxide(NO), endothelin-1(ET-1)and myocardial no-reflow in a rabbit model of acute myocardial infarction and reperfusion(AMI/R). METHODS: Twenty-four rabbits were randomized into 3 groups: 8 in AMI/R group, 8 in atorvastatin-treated group(5 mg·kg-1·d-1)and 8 in sham-operated group. Animals in the former two groups were subjected to 60 min of coronary occlusion followed by 120 min of reperfusion. Data on haemodynamics were collected. NO in blood sample, and in normal, and in infarcted reflow and no-reflow myocardium were evaluated respectively by nitrate reductase method. The levels of ET-1 in blood sample, and in normal, infarcted reflow and no-reflow myocardium were determined by radioimmunoassay. RESULTS: (1)Compared to the baselines, the heart rate(HR), systolic blood pressure(SBP), diastolic blood pressure(DBP), left ventricular systolic pressure(LVSP), maximal rate of increase and decline in left ventricular pressure(±dp/dtmax)and cardiac output(CO)in AMI/R and atorvastatin-treated groups were significantly declined, whereas left ventricular end-diastolic pressure(LVEDP)was increased after 60 min of coronary occlusion and 120 min of reperfusion(P<0.05 or P<0.01). However, in atorvastatin-treated group, LVSP, LVEDP, ±dp/dtmax and CO at the time point of 120 min of reperfusion recovered more significantly than those at the time point of 60 min of coronary occlusion(P<0.01), which was more significant than those in AMI/R group(P<0.05 or P<0.01). Compared to AMI/R group, the SBP and DBP were significantly heigher in atorvastatin-treated group(P<0.01).(2)In atorvastatin-treated group, the levels of ET-1 in blood sample were significantly lower than those in AMI/R group(P<0.01), and the levels of NO were significantly higher(P<0.01). Moreover, the levels of NO or ET-1 in infarcted reflow myocardium were significantly lower than that in AMI/R group(P<0.05 or P<0.01).(3)Atorvastatin could ameliorate myocardial function. CONCLUSION: Atorvastatin is effective in increasing NO and reducing ET-1 in blood plasma and local myocardium, and in protection of endothelial cells. Atorvastatin also has a beneficial effect on improving left ventricular function during acute myocardial infarction and reperfusion in rabbits.     

Effects of endogenous nitric oxide on potassium channels of bronchial smooth muscle cells from asthmatic rats

AIM: To investigate the effects of in vivo application of L-arginine on potassium channels in bronchial smooth muscle cells (BSMC) isolated from asthmatic model rats. METHODS: Male SD rats were randomly divided into control group, asthmatic group and asthmatic rats treated with L-arginine (L-Arg group). Single BSMCs were obtained by acute enzyme separation method. The resting membrane potential (Em), Ca2+-activated K+ channels (BKCa) currents and voltage-dependent K+ channel (Kv) currents in BSMCs were recorded under whole-cell patch clamp technique. RESULTS: (1) The Em of asthmatic group was significantly lower than that in control group (P<0.05). In vivo application of L-Arg significantly hyperpolarized BSMCs near to control group (P>0.05). (2) The peak current density at +50 mV of KCa: IKca in asthmatic group ［(43.8±16.5) pA/pF］ was significantly lower than that in normal group ［(72.5±19.9) pA/pF］ (P<0.01). Treatment with 300 mg/kg L-Arg significantly increased IKca in asthmatic group to (58.7±12.4) pA/pF (P<0.05). (3) The peak currents density at +50 mV of Kv: IKv in asthmatic group ［(32.4±8.7) pA/pF］ was significantly lower than that in control group ［(57.7±9.8) pA/pF］ (P<0.01). Treatment with L-Arg also significantly increased IKv in asthmatic group to (43.6±7.9) pA/pF, (P<0.05). CONCLUSION: Endogenous NO improves Em in asthmatic BSMCs, increases the activities of BKCa channels and Kv channel. These findings implicate that NO may have a potential therapeutically role in airway hypersensitivity.     

Protective effects of liposomes containing L-arginine,Se and taurine on intestinal ischemia-reperfusion injury in rats

AIM and METHODS:To study the protective effects of liposomes containing L-Arg,Se and taurine on intestinal ischemia-reperfusion injury in rats. Wistar rats were divided randomly into sham operated group,ischemia-reperfusion(I/R) group,pretreatment with liposomes group and treatment with liposomes at reperfusion group. In the experiments, superior mesenteric artery was clipped for 60 min, and then unclipped. 2 hours of reperfusion later, MDA content, T-SOD and Ca²⁺-Mg²⁺-ATPase activities in intestinal tissues were detected respectively, ultrastructure and bcl-2 expression in intestinal mucosa tissue were observed.RESULTS:MDA content in liposomes-treated group was less than I/R group (P＜0.01).The activities of T-SOD and Ca²⁺-Mg²⁺-ATPase in liposomes-treated group were higher than I/R group(P＜0.01). Bcl-2 staining was negative in I/R group, and was positive in liposomes-treated group (P＜0.01).There was no difference in above indexes between pretreatment with liposomes group and treatment with liposomes at reperfusion group(P＞0.05). CONCLUSION:Liposomes containing L-arginine, Se and taurine can protect intestine against ischemia-reperfusion injury in rats,which may be related to inhibiting lipid peroxidation, stabilizing internal circumstances and inducing bcl-2 protein expression.     

Effects of tirofiban on no-reflow and activation of NF-κB after myocardial ischemia/reperfusion in rats

AIM: To investigate the effects of platelet glycoprotein Ⅱb/Ⅲa receptor inhibitor tirofiban on myocardial no-reflow and activation of NF-κB after acute ischemia/reperfusion in rats. METHODS: Male Wistar rats were randomized into sham operation group, control group and tirofiban treatment group. Control group and tirofiban group were subjected ischemia for 90 min by ligation of coronary artery after thoracotomy and subsequently reperfusion for 120 min to establish acute myocardial ischemia/reperfusion no-reflow models. Thioflavine S, Evans blue and triphenyltetra zolium chloride (TTC) staining were performed to evaluate the area of no-reflow (ANR), infracted area (IA) and risk area (RA) of the heart. Immunohistochemistry was used for semi-quantitative analysis of the expression of nuclear factor-κB p65 (NF-κB p65) protein in myocytes and arteriole. Activity of myeloperoxidase (MPO) and content of malondialdehyde (MDA) in risk area of the heart were detected by ultraviolet spectrophotometer. RESULTS: After 120 min for reperfusion, compared to sham group, the statistical differences of higher positive expression of NF-κB p65 in myocytes and arteriole, activity of MPO and content of MDA both in control and tirofiban group were observed. Compared to control group, lower positive expression of NF-κB p65 in myocyte and arteriole, activity of MPO and content of MDA in tirofiban group were found (P<0.05, P<0.01). A markedly reduced ANR and IA were observed in tirofiban group than those in control group (34.36%±6.04% vs 52.09%±6.89%, P<0.01; 80.41%±8.48% vs 90.13%±5.72%, P<0.05). CONCLUSION: After myocardial ischemia/reperfusion for 120 min, no-reflow phenomenon can be observed in rats. Tirofiban reduces the areas of anatomic no-reflow and infarction, inhibits the activation of NF-κB in myocyte and arteriole, and decreases the infiltration of neutrophils and release of oxygen free radicals.     

Effects of prostaglandin I2 on mesenteric microcirculation and property of hemorheology in rabbits with renal ischemia/reperfusion injury

AIM: To explore the effects of prostaglandin I2 (PGI2) on mesenteric microcirculation and hemorheology during renal ischemia/reperfusion (IR) injury. METHODS: 36 rabbits were randomly distributed into the sham operated group (sham group)， renal ischemia/reperfusion injury group (IR group) and PGI2+IR group（PGI2 group）. IR group received clamping for 60 min followed by 120 min of reperfusion. A microcircular microscope image analysis system was used to study the changes of mesenteric microcirculation and hemorheology at 60 min of ischemia and 120 min of reperfusion, respectively， while the blood samples were obtained for the measurement of hemorheological indexes. RESULTS: ① In IR group during the period of renal IR， the number of adhesive leukocytes and microthrombus， hemorrhage and hemorheological indexes such as blood viscosity， plasma viscosity， blood reduction viscosity， hematocrit， erythrocyte aggregation index， erythrocyte sedimentation rate， erythrocyte sedimentation rate K and plasma fibrinogen were significantly higher， while microvascular diameters， blood flow velocity and erythrocyte deformation index were significantly lower compared with sham group (P＜0.01 or P＜0.05). ② PGI2 5-40 ng·kg-1·min-1) affected the indexes of mesenteric microcirculation and hemorheology to different extent. In 10 ng·kg-1·min-1 PGI2 group， the diameters of arteriole and venule， blood flow velocity， the number of adhesive leukocytes， microthrombus， hemorrhage and hemorheological indexes significantly changed， compared with IR group (P＜0.01 or P＜0.05). Except that microvascular diameters increased remarkably （P＜0.01）， others showed no significant difference compared to sham group （P＞0.05）. CONCLUSIONS: PGI2 ameliorates the disturbance of mesenteric microcirculation and hemorheology caused by renal IR injury with the best effect at 10 ng·kg-1·min-1.     

自由基清除剂对几种蔬菜衰老种子活力的影响

用外源自由基清除剂ＳＢＮ（１、２ｍｍｏｌ／Ｌ）和ＧＳＨ（０．００１、０．００５ｋｇ／Ｌ）浸种西瓜、甜瓜和萝卜衰老种子能显著促进其萌发，而ＡｓＡ（５、１０、１５ｍｍｏｌ／Ｌ）浸种效果不明显，上述处理要不同程度地提高衰老种子中ＣＡＴ和ＳＯＤ活性，降低Ｏ２＾－产生速率，减轻膜脂过氧化作用。     

Role of heme oxygenase-1/carbon monoxide system in pulmonary ischemia-reperfusion injury

AIM: To investigate the effect of heme oxygenase-1 (HO-1)/carbon monoxide (CO) system on pulmonary ischemia-reperfusion injury (PIRI) in rabbits. METHODS: Single lung ischemia and reperfusion animal model was used in vivo. The rabbits were randomly divided into three groups (n=10 in each), control group (C), PIR group (I-R), PIR+ hemin group (H) and PIR+zinc protoporphyrin IX (ZnPP) group (Z). Changes of several parameters which included plasma carboxyhemoglobin (COHb) at different time points, wet to dry ratio of lung tissue weight (W/D), the injured alveoli rate (IAR) and the HO-1 enzymatic activity were measured at 180 min after reperfusion in lung tissue. The tissue slides were also stained by immunohistochemistry (IHC) and in situ hybridization (ISH) for HO-1 to detect the expression of HO-1 in lung and to analyze the optical density. The lung tissue was prepared for electron microscopic observation at 180 min after reperfusion. RESULTS: The plasma content of COHb in I-R, H, and Z group increased in a time-dependent manner after I-R. But the increment of H group was higher than that of I-R group, while that of Z group was lower. The HO-1 activity in lung tissue was highest in H group, followed by IR group, Z group, and C group (P<0.05 and P<0.01). Except C group, HO-1 was upregulated in all other groups in the pulmonary endothelial cells, part of pulmonary vascular smooth muscle cells, extima of vessels and epithelial cells of airway. H group had the highest average optical density value, then the IR group, Z group and C group (P<0.05 and P<0.01). The value of W/D and IAR was highest in Z group, the second was in IR group, then the H group and C group (P<0.05 and P<0.01). The abnormal changes of the lung tissue in morphology in I-R group, Hemin treatment mitigated the injury of I-R in H group and ZnPP exacerbated the impairment of ultrastructure in Z group were also observed. CONCLUSION: HO-1/CO system possesses notable protective effects on lung during pulmonary ischemia-reperfusion injury in rabbits.     

Effect of propofol on expression of PKC mRNA in pulmonary injury induced by ischemia-reperfusion in rabbits

AIM: To investigate the effect of propofol on expression of protein kinase C (PKC) mRNA during pulmonary ischemia and reperfusion injury (PIRI) in rabbits. METHODS: Single lung ischemia and reperfusion animal model was used in vivo. The rabbits were randomly divided into three groups (n=9 in each): sham operated group (sham), PIR group (I-R) and PIR+ propofol group (PPF). Changes of several parameters including malondialdehyde (MDA), superoxide dismutase (SOD), wet to dry ratio of lung tissue weight (W/D) and index of quantitative assessment of histologic lung injury (IQA) were measured at 60 minutes after reperfusion in lung tissue. Meanwhile the location and expression of PKC mRNA were observed. Lung tissue was also prepared for light microscopic and electron microscopic observation at 60 minutes after reperfusion. RESULTS: As compared with group I-R, PKC mRNA strongly expressed in intima and extima of small pulmonary artery as well as thin-wall vessels (mostly small pulmonary veins) in PPF group. The average optical density values of PKC-α、δ and θ mRNA in small pulmonary veins PPF in group showed significantly higher than that in I-R group (all P<0.01). SOD increased and MDA, W/D and IQA decreased at 60 minutes after reperfusion in lung tissue (P<0.01 and P<0.05). Abnormal changes of the lung tissue in morphology were lessen markedly in PPF group. CONCLUSIONS: Propofol produces notable protective effects on PIRI in rabbits by activating PKC-α， δ and θ mRNA expression in lung tissue, raising NO level, dropping OFR level and decreasing lipid peroxidation.     

Changes of L-arginine,NOS/NO pathway in adventitia of rats with sepsis

AIM: In this study, we aimed to explore the alteration and pathophysiological significance of the L-arginine (L-Arg)/NOS/NO pathway in the adventitia of rats with sepsis. METHODS: Sepsis was induced by cecal ligation and puncture (CLP). Rat cardiac function was determined. NO generation, NOS activity and L-Arg transport were measured. The iNOS mRNA levels was determined by using RT-PCR. RESULTS: Cecal ligation and puncture induced severe sepsis with severe low glucose, high lacticemia and cardiac function inhibition. The iNOS activity was increased by 2.8-fold compared with controls (P<0.01) and the iNOS mRNA level was elevated-6-fold (P<0.01). The NO level in plasma and incubation media (incubation for 40 min) in the sepsis group was increased by 144% and 273% (both P<0.01), respectively. CONCLUSION: The results demonstrated that the L-Arg,NOS/NO pathway was activated in vascular adventitia of rats with sepsis shock. The aortic adventitia L-Arg/NOS/NO pathway might play an important role in the pathogenesis of sepsis and septic shock.     

Effect of taurine on L-arginine/NO pathway in erythrocytes of rats of hypertension with insulin resistance induced by fructose

AIM and METHODS:The present study observed the change of L-arginine(L-Arg)/Nitric oxide(NO)pathway in ergthrocytes in hypertension with insulin resistance rat induced by fructose and the effect of taurine on L-Arg/NO pathway.RESULTS:Drinking 4%fructose, while inducing blood pressure, glucose and plasma insulin contents increase, obviously decreased the maximal velocity of L-Arg transport about 31%and 37%(P<0.01), more than that of control group in total and Y⁺ carrier, the NO synthase(NOS)activity, nitrite(NO₂^-)content and cyclic guanylate monophosphate(cGMP)level more than that of control group, but obviously enhanced Michaelis Constant(Km)about 35%and 30%(P<0.01)more than that of control group in total and Y⁺ carrier transport.The taurine treatment significantly counteracted the above changes.CONCLUSION:There exists a functional disturbance in L-Arg/NO system in the erythrocyte of hypertension rats with insulin resistance, but taurine can obviously enhanced the maximal velocity of L-Arg transport and NOS activity.Thus, it appears that taurinemay have vital value in the treatment of hypertension with insulin resistance.     

Effects of Astragalus injection on neuronal apoptosis and expression of JNK3 in rat hippocampus after cerebral ischemia reperfusion

AIM:To investigate the effects of Astragalus injection on neuronal apoptosis and expression of c-Jun N-terminal kinase 3(JNK3) in the rat hippocampus after cerebral ischemia reperfusion. METHODS:The rat model of cerebral ischemia reperfusion was set up by a four-vessel occlusion method. The SD rats were randomly divided into 4 groups:sham operation group, cerebral ischemia reperfusion group(model group), cerebral ischemia reperfusion+Astragalus injection group(Astragalus injection group) and cerebral ischemia reperfusion+vehicle group(vehicle group). The rats in model group, Astragalus injection group and vehicle group after transient global cerebral ischemia(30 min) were then divided into 7 subgroups according to the reperfusion time of 0 h, 0.5 h, 2 h, 6 h, 24 h, 72 h and 120 h. The apoptosis of the neuron in the hippocampus was measured by the method of TUNEL staining. The expression of JNK3 at mRNA and protein levels was determined by real-time PCR and Western blotting,respectively. RESULTS:Compared with sham operation group, the number of apoptotic neurons increased in model group(P<0.05). Compared with model group, the number of apoptotic neurons decreased obviously in Astragalus injection group(P<0.05). Compared with sham operation group, the expression of JNK3 at mRNA and protein levels in the hippocampus increased obviously in model group at all time points except 120 h(P<0.05). Compared with model group, the expression of JNK3 at mRNA and protein levels in the hippocampus decreased obviously in Astragalus injection group at all time points except 120 h(P<0.05). CONCLUSION:Astragalus injection decreases neuronal apoptosis in rat hippocampus after cerebral ischemia reperfusion by inhibiting the expression of JNK3 at mRNA and protein levels.     

Effects of panax notoginseng saponins on pneumocyte apoptosis and Fas/FasL expression in rabbits with lung ischemia/reperfusion injury

AIM: AIM: To explore the relationship between apoptosis in the lung tissues and lung ischemia/reperfusion injury, and observe effects of panax notoginseng saponins (PNS) on apoptosis in lung ischemia/reperfusion injury. METHODS: Single lung in situ ischemia/reperfusion animal model was used. Eighty four Japanese white rabbits were randomly divided into control group (control), ischemia/reperfusion 1 h group (IR1h), IR3h, IR5h, Panax Notoginseng Saponins 1 h group (PNS1h), PNS3h and PNS5h. TUNEL, immunocytochemistry and in situ hybridization techniques were used to observe apoptosis and Fas/FasL expression in various phases of lung ischemia/reperfusion. RESULTS: Cell apoptosis in lung tissues were significantly high, Fas/FasL mRNA and its protein were up-regulated in lung tissues of lung ischemia/reperfusion injury compared with control (all of P<0.01). The PNS suppressed apoptosis as well as expression of Fas/FasL mRNA and its protein (P<0.05 or P<0.01, respectively). There was a significant correlation between expression of Fas/FasL protein, Fas/FasL mRNA and cell apoptosis (r=0.540，0.658，0.668，0.686；all P<0.01). CONCLUSIONS: Activation of Fas/FasL system and its initiating cell apoptosis of lung tissues may contribute to the pathogenesis of lung ischemia/reperfusion injury. The protective effects of PNS include suppressing the activation of Fas/FasL system and blocking apoptosis in lung tissues in lung ischemia/reperfusion injury.     

Protective effect of pentoxifylline against spinal cord ischemia/reperfusion injury in rabbits

AIM: To investigate the protection of pentoxifylline against spinal cord ischemia/reperfusion injury.METHODS: Rabbits sustained spinal cord ischemia with 45 min cross-clamping of the infrarenal aorta. Groups were as follows: sham operation (n=8); ischemic control (n=20), receiving only vehicle; PTX A (n=20), receiving PTX before clamping and PTX B (n=20), receiving PTX at the onset of reperfusion. Rabbits were evaluated for hind-limb motor function with the Tarlov scoring system at 48 h. Serum was assayed with ELISA for TNF-α and spinal cords were harvest for MPO activity, histopathologic analysis and TUNEL staining. Immunohistochemistry was used for PECAM-1 and caspase-3 detection, and the numbers of necrosic and apoptotic neuron were counted at 12 h, 24 h, 48 h and 72 h of reperfusion. The necrotic and apoptotic neurons were also observed with transmission electron microscope.RESULTS: Improved Tarlov scores were observed in PTX-treated rabbits as compared with ischemic control rabbits at 48 h. The significant reductions of TNF-α in serum, activity of MPO, immunoreactivity of the PECAM-1 and caspase-3 were found in PTX-treated rabbits. The numbers of necrosic and apoptotic neuron were higher in PTX-treated rabbits than that in the ischemic control rabbits (P<0.05). No necrosic and apoptotic neuron were found in the sham operation group. CONCLUSION: PTX induces protection against ischemia/reperfusion injury in the spinal cord, thereby preventing both necrosis and apoptosis.     

Role of mitochondrial KATP channels in cardioprotection of hyperpolarized cardioplegia

AIM:To study the protective effect of hyperpolarized cardioplegic arrest on reperfused rat heart performance and to investigate the role of mitochondrial ATP-sensitive K+ channels (mitoKATP) opening in the protection of hyperpolarized cardioplegia against ischemia/reperfusion damage. METHODS:Forty Sprague-Dawley rats were randomized into five groups (n=8 in each group): control group (Con); depolarized arrest group (D); hyperpolarized arrest group (H); depolarized cardioplegia with 5-hydroxydecanoate (5-HD) group (5HD+D); hyperpolarized cardioplegia with 5-HD group (5HD+H). The rat hearts were quickly removed to Langendorff apparatus. The heart perfusion was performed for 20 min with 37 ℃ Krebs-Henseleit buffer balanced with gas mixture (O2∶〖KG-*2〗CO2=95%∶〖KG-*2〗5%) at 5.8 kPa perfusion pressure, then cardial arrest was induced by different cardioplegic solution. Hearts were subjected to ischemia at 37 ℃ for 40 min followed by 30 min reperfusion. (1) The hemodynamics was detected at recovery after 30 min reperfusion. (2) Before ischemia and at the end-reperfusion, tissue was harvested for mitochondrial isolation and ultrastructure was observed by transmission electron microscopy (TEM). (3) Production of reactive oxygen species (ROS) was also determined at different time points. RESULTS:(1) Compared with end-equilibration, 30 min reperfusion caused significant differences in left ventricular developed pressure (LADP), left ventricular end-diastolic pressure (LVEDP), double product (DP), heart rate (HR), coronary flow (CF) (P<0.01). TEM showed that the ultrastructures of myocardial and mitochondrial were damaged remarkably. (2) When H group was compared with D, 5HD+H and Con group, significant differences were found in LVDP, LVEDP, DP, HR and CF (P<0.01). TEM showed that the myocardial and mitochondrial ultrastructures were improved remarkably. (3) The rate of ROS generating was lower in group H than that in other four groups at end-reperfusion (P<0.01). CONCLUSION:(1) Of the four cardioplegias, hyperpolarized cardioplegia is superior to improve myocardial performance, attenuates myocardial and mitochondrial injury, and reduces rate of ROS generating. (2) Mitochondrial preservation is one of mechanisms of myocardial protection in hyperpolarized cardioplegia, opening of mitoKATP enhances cardioprotection through decreasing ROS generating, providing better energe supply for reperfused myocardium.