共查询到20条相似文献,搜索用时 46 毫秒
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AIM: To study the expression of MDM2 and mutant-type P53 proteins in primary hepatocellular carcinoma(HCC). METHODS: Using immunohistochemical staining method(SP),the expression of mutant-type P53 and MDM2 proteins was examined in 55 cases of HCC,23 cases of corresponding paracancerous tissues and 10 cases of normal hepatic tissues. RESULTS: The frequencies of MDM2 and P53 positive expression in HCC were 17/55(30.9%) and 23/55 (41.8%), respectively. There was both positive expression of MDM2 and mutant-type P53 in 11 cases (20%) with HCC. Expression of MDM2 showed a significantly positive correlation with expression of mutant-type P53 (r=0.310,P<0.05). The frequencies of MDM2 and P53 positive expression in corresponding paracancerous tissues cells were 1/23 (4.3%) and 2/23(8.6%), respectively. Otherwise, there was a significant statistical difference in MDM2 and mutant-type P53 protein expression between HCC and paracancerous tissues(P<0.05). There was not positive expression of MDM2 and mutant-type P53 in normal hepatic tissue. CONCLUSION: There is MDM2 and mutant-type P53 protein overexpression in HCC. The p53 gene inactivation resulting from MDM2 protein overexpression and/or p53 gene mutation may play an important role in hepatocarcinogenesis. 相似文献
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The potential cardioprotection can be involved during ischemic preconditioning in heart which mechanisms remain unknown yet. It is reported that sarcolemmal and mitochondrial KATP channels mediate cardioprotection, and they play distinct myoprotective roles during ischemic preconditioning. This paper reviews the present progress in myocardial sarcolemmal and mitochondrial KATP Channels in ischemic preconditioning. 相似文献
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WANG Hai-hua QI Ren-bin YU Lei WANG Zhi-gang MA Ying-zhong ZHOU Zhi-yong ZUO Bao-hua 《园艺学报》2002,18(5):535-539
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. 相似文献
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AIM and METHODS:To investigate the cardioprotective effect of adenosine infusion before ischemic preconditioning on immature myocardial reperfusion injury in rabbit heart. Isolated perfused working heart model were performed, all hearts were subjected to 2-hour global hypothermic ischemia and received intermittent cold cardioplegia perfusion.RESULTS:During reperfusion, the recovery of left ventricular systolic pressure, left ventricular end-diastolic pressure, +dp/dtmax, and -dp/dtmax of hearts received adenosine infusion before ischemic preconditioning were significantly improved, myocardial adenosine triphosphate and adenosine diphosphate content and superoxide dismutase activity were higher, the leakage of myocardial creatine kinase and the malondialdehyde content were lower, and myocardial water content was obviously less.CONCLUSION:These results suggest adenosine infusion before ischemic preconditioning enhances cardioprotection of ischemic preconditioning against immature myocardial reperfusion injury in the rabbit heart. 相似文献
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AIM: To study the protective effect of ischemia preconditioning (IPC) on ischemia/reperfusion (IR)-damaged myocardium in young and old rats. METHODS: Male Wistar rats aged at 3 months (young) and 20 months (old) were used to establish myocardial IPC model and IR model with the method of Langendorff heart perfusion. The rats were divided into young ischemia/reperfusion (YIR) group, young ischemic preconditioning (YPC) group, old ischemia/reperfusion (OIR) group and old ischemic preconditioning (OPC) group. Transmission electron microscopy was used to observe the ultrastructural changes of myocardial tissue and myocardial mitochondria. The myocardial infarction area was determined by TTC staining. The lactate dehydrogenase (LDH) content in coronary effluent fluid and the levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in myocardial tissues were detected by the method of colorimetry. The levels of nitrated and carbonylated proteins in myocardial tissue were measured by ELISA. The myocardial cell apoptosis was analyzed by TUNEL assay. The mitochondrial respiratory function and mitochondrial permeability transition pore opening induced by calcium load were evaluated by oxygen electrode method. RESULTS: Compared with YIR group, the myocardial infarction area in YPC group was obviously smaller, SOD activity in myocardial tissues increased, LDH activity in coronary effluent fluid and the content of MDA decreased, and the levels of nitrated and carbonylated proteins in the cardiac tissues reduced. In YPC group, the mitochondrial membrane structure appeared intact, cristae of the mitochondria showed close arrangement, and the matrix was compressed under the electron microscope. Myocardial mitochondrial respiratory control rate, state Ⅲ oxygen consumption and the P/O ratio in YIR group all significantly increased, proton leak decreased, mitochondrial swelling induced by calcium distinctly reduced, and myocardial apoptosis rate declined. No significant difference of the above indexes between OIR group and OPC group was observed. Compared with YPC group, myocardial ultrastructural damage increased clearly, cardiac oxidative stress increased, mitochondrial respiratory function declined, and cell apoptosis and necrosis increased in OPC group. CONCLUSION: Ischemic preconditioning has protective effect against myocardial IR injury in young rat hearts, while old rat hearts were less sensitive to ischemic preconditioning, leading to bluntness of cardioprotection with IPC in aging hearts. This may be related to mitochondrial injury and severe cellular apoptosis caused by increase of cardiac oxidative stress levels in the aging ischemic preconditioning heart. 相似文献
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AIM:To investigate the effect of ischemic preconditioning (IP) on leukotriene C4 (LTC4) generation during hepatic ischemia-reperfusion(I/R) injury.METHODS:Adult male Sprague-Dawley rats were randomly divided into sham (control) group, I/R group and IP+I/R group. The rat liver was subject to 60 min of partial hepatic ischemia followed by 5 h of reperfusion. LTC4 content was measured by reversed-phase high-performance liquid chromatography (RP-HPLC). The activity of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) was determined, and the changes of histological structures were observed to assess the tissue injury. The reduced glutathione (GSH) level in the liver tissues was also examined by biochemical methods.RESULTS:IP markedly decreased LTC4 content in rat livers compared with I/R group. The activity of serum ALT and AST in I/R group and IP+I/R group was higher than that in control group. Compared with I/R group, the levels of serum ALT and AST were markedly decreased, and the level of GSH in hepatic tissues was elevated in IP+I/R group. In addition, the structural damage of the rat liver tissues in IP+I/R group displayed slighter than that in I/R group.CONCLUSION:IP treatment reduces LTC4 production accompanied with improving the liver function and histological structure during I/R injury, suggesting that the beneficial effects of IP may be involved in its repressing LTC4 generation during hepatic I/R injury. 相似文献
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CHENG Fang-zhou TANG Guo-hua LI Geng-shan YU Xi-qiu LI Yuan-zhong HE Xin-hua BAO Cui-yu ZHOU Yun 《园艺学报》2002,18(8):949-952
AIM: To study the effects of norepinephrine preconditioning(NE-P) and ischemic preconditioning (IP)on apoptosis and Bcl-2, Bax expression in rat myocardial cells in myocardial ischemic reperfusion (I/R). METHODS: The model of rat ischemic-reperfusion was used to conduct NE-preconditioning. Apoptotic myocytes were detected with TUNEL. Bcl-2, Bax expression were detected with immunohistochemistry. RESULTS: The rate of apoptosis cells in I/R group was higher, the rate of apoptosis cells in NE-P group and IP was lower significantly than that in I/R group(P<0.01). The expression of Bcl-2 in I/R group was lower, but the expression of Bax was higher, the expression of Bcl-2 in NE-P group was higher significantly than that in I/R group(P<0.01), the expression of Bax in NE-P group was lower than that in I/R group(P<0.01). There was no significantly difference between NE-P and IP group in the above parameters (P>0.05). CONCLUSION: NE-P reduced myocyte apoptosis by I/R in rats; The expression of Bcl-2 ,Bax genes played an important role in myocardial apoptosis. 相似文献
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AIM: To investigate the protective role of postconditioning in myocardial ischemia/reperfusion in rats and its mechanisms. METHODS: Cardiac contractility was analyzed by the Langendorff method. Infarct size was determined by dual staining with triphenyltetrazolium chloride and Even's blue dye, and the cardiac arrhythmia was evaluated. postconditioning was conducted by 3 cycles of 30 s ischemia followed by 30 s of reperfusion at the beginning of subsequent persistent reperfusion. RESULTS: Left ventricular systolic pressure (LVSP) and maximal rise rate of ventricular pressure (+dp/dtmax) were higher during reperfusion in postconditioning group compared with control. postconditioning reduced the infarct size in ischemia/reperfusion rat hearts. The cardiac arrhythmia score was decreased in postconditioning group in the first 10 min of reperfusion followed by ischemia compared to control group. postconditioning had similar cardioprotective effect as preconditioning. 5-HD, a selective mitochondrial ATP-sensitive potassium channel (mitoKATP) inhibitor, blocked the amelioration of contract function provided by postconditioning. It also abolished the protective effect of postconditioning on cardiac arrhythmia score and infarct size. CONCLUSION: The results show that postconditioning has cardioprotective effect and attenuates reperfusion injury in ischemic heart. The effect might be partly through the activation of mitoKATP channel. 相似文献
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AIM:To study whether ischemic preconditioning(IPC) has a protective effect against ischemia/reperfusion(I/R) injury in brain, and the possible relationship between IPC and the regulating function of microcirculation.METHODS:The I/R models were established both in I/R and IPC groups of Sprague-Dawley rats. Additional procedure was performed of short term cerebral ischemic preconditioning in IPC group 24 hours before I/R. Skull windows were performed through which microcirculation features were measured before ischemia, during ischemia, and reperfusion. Finally, brains were cut into slices and stained with red tetrazoline(TTC).RESULTS:Most TTC stained brains in I/R group presented irregular palely red areas which were few in IPC group. Compared with I/R group, IPC group presented relatively increase in accumulated length of capillaries, mean cerebral microcirculatory perfusion, and microcirculatory velocity in ischemic and reperfusion phase. There was no-reflow phenomenon in I/R group in reperfusion phase, which was substituted by the course of increasing reperfusion in IPC group.CONCLUSIONS:IPC could relieve the reduction of tissue perfusion during ischemia and the no-reflow phenomenon during reperfusion by improving the regulating function of microcirculation, which relatively promote the opening of capillaries and accelerating of microvascular flow, therefore protect brain from I/R injury. 相似文献
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AIM: To investigate the protective effect of ischemic post-conditioning on isolated rat myocardial mitochondrial function during ischemia/reperfusion, and to study the role of mitochondrial ATP-sensitive potassium channel (mitoKATP) in myocardial protection. METHODS: Sprague-Dawley male rats were randomized into 4 groups (n=8 in each group): control group (C), model group (M), ischemic post-conditioning group (IPO) and 5-hydroxydecanoate plus IPO group (5-HD+IPO). The hearts isolated from the SD rats were mounted on a Langendorff apparatus and started with a 20-minute perfusion for equilibration. In C group, the hearts went on perfusion for another 70 min after equilibration. In M group, 4 ℃ St. Thomas cardioplegic solution was administered prior to ischemia, followed by ischemia for 40-minute, and reperfusion for another 30 min. In IPO group, the hearts underwent 40-minute global ischemia after equilibration, then perfusion for 10 s and ischemia for another 10 s. The procedure was repeated 6 times before 28-minute reperfusion. In 5-HD+IPO group, the hearts were perfused with 5-HD (100 μmol/L in K-H solution) and treated as that in IPO group, then reperfusion for 23 min. The reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and respiratory function of myocardial mitochondria were measured at the ends of equilibration and reperfusion. RESULTS: (1) Compared with the data collected at the end of equilibrium, the MMP was obviously decreased at the end of reperfusion in all groups, The highest in C group. MMP in 5-HD+IPO group was markedly higher than that in IPO group and M group. MMP in IPO group was higher than that in M group. (2) In contrast to that at the end of equilibrium, ROS was obviously increased at the end of reperfusion in all groups. However, ROS was observably higher in M group than that in the other 3 groups, and ROS in 5-HD+IPO group was markedly higher than that in IPO group and C group. ROS in IPO group was higher than that in C group. (3) The respiratory function of mitochondria was obviously injured at the end of reperfusion in all groups. The arrangement of the mitochondrial respiratory function from the best to the worse was C group > IPO group > 5-HD+IPO group > M group. CONCLUSION: Ischemic post-conditioning attenuates myocardial reperfusion injury by maintaining the stability of MMP, decreasing the generation of ROS and preserving the respiratory chain function of mitochondria. The mitoKATP antagonist 5-HD can not completely block the myocardial protective effect of ischemic post-conditioning. Myocardial protective effect of ischemic post-conditioning may achieve by activating mitoKATP, meanwhile the other factors may also take part in the myocardial protective processes. 相似文献
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Ischemic postconditioning reduces myocardial damage in rats suffering from limb ischemia-reperfusion
AIM: To investigate the protective effect of limb ischemic postconditioning on the myocardial damage in the rats suffering from limb ischemia-reperfusion (LIR). METHODS: Wistar rats were randomly divided into control group (C group), ischemia-reperfusion group (IR group) and ischemic post-conditioning group (IR+IPostC group). For conducting ischemic postconditioning, the rats in IR+IPostC group underwent 5 min of ischemia and 5 min of reperfusion on their hind limbs repeatedly after 4 h of ischemia, and then, 4 h of reperfusion was applied. The activity of superoxide dismutase (SOD), xanthine oxidase (XOD) and myeloperoxidase (MPO) was measured. The levels of malonaldehyde (MDA) in plasma and myocardial tissues, the levels of creatine kinase (CK), creatine kinase MB (CK-MB), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), α-hydroxybutyrate dehydrogenase (α-HBDH) and myocardial troponin I (cTnI) were also detected. The changes of ultrastructure in the myocardium were observed under electron microscope. RESULTS: Compared with C group,the levels of CK-MB, AST, LDH,α-HBDH and cTnI were all increased in IR and IR+IPostC groups. The levels of MDA and XOD also increased (P<0.05), but the activity of SOD decreased (P<0.05). However, compared with group IR, the levels of CK-MB, AST, LDH, α-HBDH and cTnI decreased (P<0.05) in IR+IPostC group.The levels of MDA and XOD also decreased (P<0.05), but the activity of SOD increased (P<0.05). Under electron microscope, the cardiac myofibrils arranged neatly, light and dark bands were clear, the mitochondrial cristae arranged closely and neatly, and the mitochondrial matrix densification was observed in C group. However, the cardiac fiber arrangement was disordered or disappeared, stromal edema was obvious, most or all mitochondrial cristae and membrane became fusion or disappeared, mitochondrial vacuolization and decrease in glycogen were obvious in IR group. In IR+IPostC group, the pathological changes mentioned above were attenuated somewhat than those in IR group. CONCLUSION: Ischemic postconditioning protects rat myocardium under limb ischemia-reperfusion. 相似文献