Effect of bilateral in vivo ischemia/reperfusion on the activities of superoxide dismutase and catalase: Response to a standardized grape suspension

Purpose: Ischemia/reperfusion (I/R) is a major etiological factor in the bladder dysfunctions observed in men with lower tract obstruction, women with postmenopausal incontinence and with aging. A standardized grape suspension protects the rabbit urinary bladder from both the contractile dysfunctions and the morphologic changes mediated by I/R. Using a model of in vivo bilateral ischemia/reperfusion, the current study investigated the effect of this grape suspension on the endogenous antioxidant defense systems. Materials and methods: 24 NZW rabbits were separated into 6 groups of 4. Groups 1–3 were treated by gavage with aqueous grape suspensions; groups 4–6 received sugar-water vehicle. Groups 3 and 6 were controls. Groups 1 and 4 were subjected to bilateral ischemia for 2 h (I). Groups 2 and 5 underwent bilateral ischemia for 2 h and reperfusion for 1 week (I/R). For all rabbit bladders, the muscle and mucosa were separated by blunt dissection and analyzed separately. The effects of the various treatments on bladder antioxidant systems of cytoplasmic superoxide dismutase (Cu-Zn superoxide dismutase; SOD), and catalase (CAT) were evaluated. Results: The standardized grape suspension up-regulated both SOD and CAT activity of bladder muscle and mucosa in control animals. There were few differences in the grape suspension treated animals after ischemia, and in general the activities decreased following I/R. Conclusions: Increases of SOD and CAT activity in control animals as a result of grape suspension suggest a greater antioxidant capacity. This increase in the antioxidant defense system may explain the increased protection of grape suspension in the face of ischemia and I/R. However, the activities of both enzyme systems decreased in the smooth muscle subjected to I/R showing that reperfusion damages these systems probably via oxidation damage to the enzymes themselves.     

Low-dose Tadenan protects the rabbit bladder from bilateral ischemia/reperfusion-induced contractile dysfunction

Recent studies indicate that focal ischemia/reperfusion (I/R) can cause the contractile dysfunctions induced in animal models of partial bladder outlet obstruction. Tadenan (Pygeum africanum) pretreatment can prevent the rabbit bladder from developing the contractile and biochemical dysfunctions induced by partial outlet obstruction, possibly by protecting the bladder from ischemic injury. The current study was designed to determine whether pre-treating rabbits with a clinically relevant dose of Tadenan could prevent the bladder from developing the contractile dysfunctions that are induced by bilateral ischemia followed by reperfusion. New Zealand White rabbits were separated into two groups. One group was pre-treated by oral gavage for 3 weeks with Tadenan (3.0 mg/kg body wt./day). The second group was treated with vehicle (peanut oil). Five rabbits from each group were subjected to either bilateral ischemia for 1 or 3 h and than reperfused for either 1 h or 1 week. Five rabbits from each group were subjected to sham surgery and run with each of the experimental groups. The results of the current study show that Tadenan pre-treatment at the clinically relevant dose of 3.0 mg/kg body wt./day protected the bladder from the contractile dysfunctions induced by bilateral ischemia followed by reperfusion. These data are consistent with the assertion that Tadenan therapy in both rabbits and humans acts by protecting the bladder smooth muscle against cellular damage caused by ischemia and reperfusion.     

Protective effects of salusin-α and salusin-β on renal ischemia/reperfusion damage and their levels in ischemic acute renal failure

Salusin-α and salusin-β are expressed in many tissues including the central nervous system, vessels and kidneys; they have been shown to decrease endoplasmic reticulum stress during heart ischemia/reperfusion (I/R) and to decrease apoptosis. We investigated the relation of salusin-α and salusin-β levels to acute ischemic renal failure. We also investigated whether these peptides are protective against renal I/R damage. Fifty-three rats were divided into six groups: control, I/R, I/R + salusin-α1, I/R + salusin-α10, I/R + salusin-β1 and I/R + salusin-β10. After removing the right kidney, the left kidney was subjected to ischemia for 1 h and reperfusion for 23 h. The treatment groups were injected subcutaneously at the beginning of ischemia with 1 or 10 μg/kg salusin-α, and 1 or 10 μg/kg salusin-β. Histopathology was assessed at the end of the experiment. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX) activity and malondialdehyde (MDA) levels were measured in the kidney tissue. Serum levels of blood urea nitrogen (BUN), creatinine (Cre), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-1 beta (IL-1β) also were measured. Levels of salusin-α and salusin-β were measured in the serum and kidney tissues of the control and I/R groups. SOD, CAT and GSH-PX activities were decreased and the levels of MDA, TNF-α, IL-6, IL-1β, BUN and Cre were increased in the I/R group compared to controls. Severe glomerular and tubular damage was apparent in the I/R group compared to controls. The level of salusin-β was decreased in the serum and kidney tissue of the I/R group compared to controls, whereas the level of salusin-α was decreased in the serum and increased in the kidney tissue. Salusin-α and salusin-β administration increased SOD and GSH-PX enzyme activation and decreased the levels of MDA, TNF-α, IL-6 and IL-1β compared to the I/R group. BUN and Cre levels were decreased in the I/R + salusin-α1 group and the level of Cre was decreased in I/R + salusin-β10 group compared to the I/R group. We demonstrated a protective effect of salusin-α and salusin-β against renal I/R damage. Changes in the levels of salusin-α and salusin-β in the I/R group suggest that these peptides may be associated with acute renal failure.     

Effect of duration of ischemia on myocardial proteome in ischemia/reperfusion injury

Ischemia/reperfusion (I/R) injury is a serious problem resulting from clinical setting of coronary revascularization. Despite extensive studies on I/R injury, the molecular bases of cardiac dysfunction caused by I/R are still unknown, but are likely to result from alterations in protein expression. Isolated rat hearts were subjected to 15-30 min of no-flow ischemia without (Ischemia protocol) or with 30 min of reperfusion (I/R protocol). 2-DE analysis of heart proteins from both experimental protocols showed wide-ranging changes in protein levels. In the Ischemia protocol, 39 protein spots were changed in ischemic groups and those changes correlated with duration of ischemia. Ninety percent of the affected proteins were increased. In contrast to increased protein levels, the total messenger RNA (mRNA) level decreased approximately two fold. Compared to the Ischemia protocol, changes in protein levels in the I/R protocol did not correlate with the duration of ischemia and the degree of recovery of mechanical function. The decrease of affected protein from I/R protocol was associated with the increase in total protein level in reperfusate. Our studies show that the protein increase is correlated with the mechanical function of the I/R hearts and the increase is not likely associated with an increase in protein synthesis.     

A comparative study on the antioxidant effects of hesperidin and ellagic acid against skeletal muscle ischemia/reperfusion injury

Abstract

The antioxidant effects of ellagic acid (EA) and hesperidin (HES) against skeletal muscle ischemia/reperfusion injury (I/R) were performed. Hindlimb ischemia has been induced by tourniquet occlusion for 2?h on left hindlimb. At the end of ischemia, the tourniquate has been removed and initiated reperfusion for 2?h. EA (100?mg/kg) has been applied orally before ischemia/reperfusion in the EA?+?I/R group. HES (100?mg/kg) has been given orally in the HES?+?I/R group. The left gastrocnemius muscle has been harvested and stored immediately at??80?°C until assessed for the levels of MDA and antioxidant enzymes activities. MDA level has statistically increased in I/R group (p?<?0.05) compared to other groups. The muscle tissue antioxidant enzymes activities were lower than the other groups in the I/R group (p?<?0.05). EA and HES treatments significantly reversed the damage level in I/R, also activity of tissue SOD increased in the EA?+?I/R and HES?+?I/R groups.     

参附注射液对心肌缺血/再灌注损伤血流动力学和心肌酶的影响

目的：探讨参附注射液对家兔心肌缺血/再灌注（I/R）损伤的保护作用及其机制。方法：家兔30只,随机分为3组（n=10）：对照组、心肌缺血/再灌注损伤（MI/RI）组和参附注射液组,统一标准喂养。行药物预处理10 min后,手术结扎家兔冠状动脉左心室支,建立急性心肌缺血再灌注模型,观察急性心肌缺血和再灌注状态下血流动力学及心肌组织中酶的变化。结果：与对照组比较：MI/RI组心脏舒缩功能减退,丙二醛（MDA）含量增高,超氧化物歧化酶（SOD）、谷光甘肽过氧化物酶（GSH-PX）和细胞能源Na＋-K＋-ATP酶及Ca2＋-ATP酶活性降低,乳酸脱氢酶（LDH）、肌酸激酶（CK）大量释放。而与MI/RI组比较：参附注射液组能不同程度的恢复左心室收缩压（LVSP）、心室内压最大变化速率（±dp/dtmax）（P〈0.01）,降低左室舒张末期压（LVEDP）（P〈0.01）,抑制MDA、LDH、CK升高,增强SOD、GSH-PX、Na＋,K＋-ATP及Ca2＋-ATP活力。结论：参附注射液对心肌缺血/再灌注损伤具有明显的保护作用。     

饲料中添加辅酶Q10对吉富罗非鱼幼鱼生长、抗氧化能力和组织结构的影响

以含辅酶Q10(CoQ10)分别为0、40、80和120 mg/kg的4种饲料饲喂平均初始体重为(19.97±0.13) g的吉富罗非鱼(Oreochromis niloticus, GIFT)幼鱼56d,探讨辅酶Q10对吉富罗非鱼幼鱼生长性能、体成分、抗氧化能力、组织结构和基因表达的影响。结果显示,各辅酶Q10组吉富罗非鱼幼鱼的终末体重、摄食率、特定生长率和饲料效率与对照组均无显著差异, 120 mg/kg辅酶Q10组终末体重、特定生长率和饲料效率均为最高;辅酶Q10含量为120 mg/kg时,吉富罗非鱼幼鱼的干物质消化率显著升高;各辅酶Q10组血清过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)活性均显著高于对照组;各辅酶Q10组肝脏CAT和GSH-Px活性均显著高于对照组, 80和120 mg/kg辅酶Q10组肝脏总超氧化物歧化酶(SOD)和谷胱甘肽S转移酶(GST)活性均显著升高,丙二醛(MDA)含量显著降低;各实验组去内脏全鱼的水分、粗蛋白和灰分含量均无显著性差异, 120 mg/kg辅酶Q10组去内脏全鱼粗脂肪显著低于对照组;各实验组内脏团水分、粗蛋白、粗脂肪和灰分...     

Attenuation of mitochondrial injury by L-arginine preconditioning of the liver

The present study was aimed to evaluate the efficacy of L-arginine on mitochondrial function in ischemic and reperfusion (I/R) induced hepatic injury. Adult Wistar rat were subjected to 1 h of partial liver ischemia followed by 3 hour reperfusion. Eighteen wistar rats were divided into three groups viz. sham-operated control group (I) (n = 6), ischemia and reperfusion (I/R) group (II) (n = 6), L-arginine treated group (100 mg/kg body weight/daily by oral route for 7 days before induced ischemia reperfusion maneuver) (III) (n = 6). Mitochondrial injury was assessed in terms of decreased (P < 0.05) activities of mitochondrial antioxidant enzymes (GSH, SOD, CAT), respiratory marker enzymes (NADH dehydrogenase, cytochrome c oxidases) and hepatocytes nitric oxide production. Pre-treatment with L-arginine (10 mg/kg/p.o. for 7 days) significantly counteracted the alternations of hepatic enzymes and mitochondrial respiratory and antioxidant enzymes. In addition, electron microscopy and histopathology study showed the restoration of cellular normalcy and accredits the cytoprotective role of L-arginine against I/R induced hepatocellular injury. On the basis of these findings it may be concluded that L-arginine protects mitochondrial function in hepatic ischemic and reperfused liver.     

Ozone alleviates ischemia/reperfusion injury by inhibiting mitochondrion‐mediated apoptosis pathway in SH‐SY5Y cells

Cerebral ischemia/reperfusion (I/R) injuries are common and often cause severe complications. Ozone has been applied for protecting I/R injury in animal models of several organs including cerebra, but the detailed mechanism remains unclear. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay and lactate dehydrogenase measurement were used to determine the influence of ozone on cell activity and damage of SH‐SY5Y cells. Some redox items such as catalase (CAT), malondialdehyde (MDA), glutathione peroxidase (GSH‐Px), and superoxide dismutase (SOD) were measured by enzyme‐linked immunosorbent assay. The mitochondrial membrane potential (ΔΨ_m) was determined by JC‐1 assay. Cytochrome‐c (cyt‐c) level in the cytoplasm and mitochondrion was measured by western blotting. Apoptosis was determined by flow cytometry, and some apoptosis‐related molecules were detected by quantitative real‐time polymerase chain reaction and western blotting. Ozone alleviated oxidative damage by increasing GSH‐Px, SOD, CAT, and decreasing MDA. Ozone decreased mitochondrial damage caused by I/R injury and inhibited the release of cyt‐c from mitochondrion to cytoplasm in SH‐SY5Y cells. The cell apoptosis caused by I/R was inhibited by ozone, and ozone could decrease apoptosis by increasing the ratio of Bcl‐2/Bax and inhibiting caspase signaling pathway in SH‐SY5Y cells. Ozone has the ability of maintaining redox homeostasis, decreasing mitochondrion damage, and inhibiting neurocytes apoptosis induced by I/R. Therefore, ozone may be a promising protective strategy against cerebral I/R injury.     

Evodiamine alleviates kidney ischemia reperfusion injury in rats: A biochemical and histopathological study

Renal ischemia/reperfusion (I/R) injury resulting in acute renal failure, is a major clinical problem due to its high mortality rate. Renal I/R increases the reactive oxygen species, secretion of inflammatory cytokines, chemokines and other factors. This suggests that initiating the apoptosis process in the presence of oxidative stress may play a role in life-threatening conditions, such as ischemia. Ischemia reperfusion-induced renal damage can result in renal failure and death. Although many treatment procedures have been carried out to reduce or destroy renal I/R damage in experimental models, so far, a routine method of treatment has not yet been found. For this reason, the current study was planned to investigate the possible protective effects of evodiamine on tissue damage caused by ischemia-reperfusion in kidney tissue in rats and an experimental renal I/R model was used for this purpose. Four groups were formed in the study: the control, sham control, ischemia reperfusion (I/R), and evodiamine (10 mg/kg) + I/R groups. The effects of evodiamine against kidney I/R injury were investigated. TAS (total oxidant status), TOS (total oxidant status), interleukin-1β (IL-1β), IL-6, IL-10 and tumor necrosis factor-α levels were determined by enzyme-linked immunosorbent assay. The oxidative stress index was calculated from TAS and TOS levels. In addition, the renal ischemia reperfusion injury was examined histopathologically. The IL-10 and TAS levels in the I/R group decreased when compared with the control and Sham groups, while these levels increased in the evodiamine group. Histopathologic examination revealed that caspase 3 and nuclear factor-κB levels decreased in the evodiamine group compared with the I/R group. The application of evodiamine significantly reduced ischemia reperfusion-induced kidney damage due to its antioxidant, anti-inflammatory and antiapoptotic properties.     

肢体远程预处理通过上调机体抗氧化酶活性诱导兔脊髓缺血耐受

目的:证实抗氧化酶活性上调是肢体远程预处理(remote preconditioning,RPC)诱导兔脊髓缺血耐受效应的主要机制之一。方法:60只雄性新西兰大白兔随机分成对照组、远程预处理组、缺血组及RPC 缺血组(对照组n=6,余组n=18)。RPC组行双下肢短暂缺血2次(每次10min,间隔10min);缺血组仅行脊髓缺血模型;RPC 缺血组在远程预处理后1h行脊髓缺血;对照组为假手术组。对照组于脊髓缺血再灌注后48h行神经功能评分后取脊髓,作为对照。余三组分别于再灌注后6h、24h及48h评分后取材,各时间点各取6只。所有动物于缺血前、缺血20min、再灌注20min及再灌注6h采动脉血测血清抗氧化酶活性和丙二醛(MDA)含量;于取材后测定脊髓匀浆抗氧化酶活性和MDA含量。结果:再灌注后6h、24h及48h时对照组、远程预处理组及远程预处理 缺血组神经功能评分均明显高于缺血组(P<0.05)。血浆超氧化物歧化酶(SOD)活性和过氧化氢酶(CAT)活性在每个时间点RPC组均高于对照组,RPC 缺血组高于缺血组(P<0.05);其中缺血20min时,缺血组血浆SOD、CAT活性低于对照组,RPC 缺血组低于RPC组(P<0.05);而与缺血前相比,缺血20min时缺血组及RPC 缺血组SOD和CAT活性显著下降(P<0.05)再灌注24h和48h时,脊髓匀浆SOD、CAT活性对照组低于RPC组,缺血组低于RPC 缺血组(P<0.01);而MDA含量再灌注24h时对照组高于RPC组,缺血组高于RPC 缺血组(P<0.05)。脊髓匀浆SOD、CAT活性与神经功能评分具有显著相关性。结论:RPC诱导脊髓缺血耐受的机制可能为上调抗氧化酶活性,增强机体在缺血再灌注过程中清除氧自由基的能力,从而减少氧自由基介导的损伤,发挥脊髓保护作用。     

缺血预处理对肢体缺血／再灌注肾损伤保护作用的机制初探

目的：探讨缺血预处理对肢体缺血／再灌注时肾损伤的保护作用。方法：复制家兔肢体缺血／再灌注（I／R）损伤模型,观察肢体缺血4h再灌注4h后以及应用缺血预处理干预对肾损伤的影响。分别从右颈外静脉、肾动脉和肾静脉取血,代表外周血以及入、出肾血,观察外周血超氧化物歧化酶（SOD）、丙二醛（MDA）及尿素氮（BUN）;同时测定入肾血和出肾血NO、SOD、MDA和肾组织SOD、MDA、诱导型一氧化氮合酶（iNOS）以及缺血预处理对上述指标的影响。结果：与对照组比较,缺血再灌组松夹后4h外周血、入、出肾血及肾组织SOD活性明显降低,MDA含量增高（P〈0．01）;外周血BUN以及入、出肾血NO和肾组织iNOS含量升高（P〈0．01）;在缺血前给予缺血预处理组．SOD活性升高,而MDA、BUN、NO、iNOS含量降低（P〈0．01）。相关分析显示MDA与SOD间存在明显负相关（P〈0．01）．而MDA与NO、BUN间呈显著正相关（P〈0．01）。结论：肢体缺血／再灌注时伴有肾脏氧自由基代谢紊乱,缺血预处理可以增强肾组织的抗氧化能力,对肢体缺血再灌注肾损伤具有保护作用。     

Effects of molsidomine on retinal ischemia/reperfusion injury in rabbits

We investigated the effect of molsidomine (MOL) on ischemia/reperfusion (I/R) injury. Rabbits were assigned to four groups: group 1, sham; group 2, I/R; group 3, MOL treatment for 4 days after I/R; group 4, MOL treatment for 1 day before I/R and 3 days after I/R. Retinal I/R was produced by elevating the intraocular pressure to 150 mm Hg for 60 min. Seven days after I/R, the eyes were enucleated. Retinal changes were examined using histochemistry. The levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) also were measured. We found a significant increase in the thickness of the outer nuclear layer of group 3 compared to the other groups. In groups 3 and 4, caspase-3 stained cells in the ganglion cell layer were decreased compared to group 2. We found a significant increase in caspase-3 stained cells in the inner nuclear layer (INL) of group 2 compared to the other groups. We found a significant increase in caspase-3 stained cells in group 3 compared to group 4 in the INL. The MDA level in group 2 was significantly higher than group 1 and MOL significantly decreased MDA levels in groups 3 and 4. We found that MOL protected the retina from I/R injury by enhancing antioxidative effects and inhibiting apoptosis of retinal cells.     

Changes of Endogenous Antioxidant Enzymes during Ischemic Tolerance Acquisition

The purpose of this study was to investigate the role of superoxide dismutase (SOD) and catalase (CAT) in brain ischemic tolerance induced by ischemic preconditioning. Forebrain cerebral ischemia was induced in rat by four vessel occlusion. The activities of the antioxidant enzymes CuZn-SOD, Mn-SOD and CAT were measured in the hippocampus, striatum and cortex after 5 min of ischemia used as a preconditioning and subsequent reperfusion, by spectrophotometric methods. In all ischemia-reperfusion groups (5 h, 1 and 2 days of reperfusion), CuZn-SOD activities were found to be increased if compared to the sham operated controls. The increase was significant (P < 0.05) in all reperfusion groups, particularly after 5 h of reperfusion (3 times) in all studied brain regions; the largest increase was detected in the more vulnerable hippocampus and striatum. Very similar changes were found in Mn-SOD activity. The activity of CAT was increased too, but reached the peak of postischemic activity 24 h after ischemia. Our attempt to understand the mechanisms of increased SOD and CAT activities by application of protein synthesis inhibitor cycloheximide showed that this increase was caused by de novo synthesis of enzymes during first hours after ischemia. Our findings indicate that both major endogenous antioxidant enzymes SOD and CAT are synthesized as soon as 5 h after ischemia. In spite of significant upregulation of these enzymes a large number of neurons in selectively vulnerable CA1 region of hippocampus undergoes to neurodegeneration within 7 days after ischemia.     

Prevention of ischemia-reperfusion injury in rat ovarian tissue with the on-off method

Ischemia is defined as cell death caused by insufficient perfusion of the tissue due to reduction in arterial or venous blood flow, depletion of cellular energy storages, and accumulation of toxic metabolites. The positive effects of controlled reperfusion are known and are used clinically. But the positive effects of controlled reperfusion on ovarian tissue have not been seen in the literature yet. The biochemical and histopathological comparative investigation of rat ovaries that were experimentally exposed to ischemia (IG), ischemia-reperfusion (I/R), and ischemia-controlled reperfusion (ICR) was aimed. Forty rats were divided into four groups (10 rats per group). First group: 3 h ischemia by vascular clips on ovarian tissue. Second group: 3 h ischemia + 1 h reperfusion. Third group: 3 h ischemia + 1 h controlled reperfusion (on-off method: controlled reperfusion by opening and closing the clips (on/off) in 10-second intervals, for 5 times for a total of 100 seconds). Fourth group: healthy rats. Biochemical (tGSH, MDA, and DNA damage level and SOD activity) and histopathological analysis were performed. The highest glutathione and superoxide dismutase measurements were found in ischemia/controlled reperfusion group among the ischemia or ischemia/reperfusion groups. Similarly the damage indicators (malondialdehyde, DNA damage level and histopathological damage grade) were the lowest in ischemia/controlled reperfusion group. These results indicate that controlled reperfusion can be helpful in minimizing ischemia-reperfusion injury in ovarian tissue exposed to ischemia for various reasons (ovarian torsion, tumor, etc.).     

楤木皂苷对大鼠心肌缺血/再灌注损伤的保护作用

目的:观察楤木皂苷(total saponins extracted from Aralia taibaiensis,s AT)对大鼠心肌缺血/再灌注(myocardia1 ischemia/reperfusion,MI/R)损伤的影响。方法:可逆性冠脉左前降支结扎缺血30 min再灌注3 h复制MI/R模型,将SD大鼠随机分为假手术组、模型组、s AT低、中、高剂量组,每组10只。采用伊文思蓝(EB)、2,3,5-氯化三苯基四氮唑蓝(TTC)双染法测定心肌梗死面积,苏木精-伊红(HE)染色法观察心肌病理学形态变化,并检测血清中乳酸脱氢酶(LDH)、肌酸激酶同工酶(CK-MB)、超氧化物歧化酶(SOD)、丙二醛(MDA)、过氧化氢酶(CAT)及谷胱甘肽过氧化物酶(GSH-Px)水平。结果:与模型组比较,s AT中、高剂量组可明显缩小心肌梗死面积(P0.05),并显著降低血清中LDH、CK-MB及MDA的含量,同时使得血清中SOD、CAT和GSH-Px的活性增加。且所有给药组心肌组织的病理损伤也小于模型组。结论:s AT对大鼠MI/R损伤具有保护作用,其机制可能与抗氧化作用相关。     

Anti-apoptotic protection afforded by cardioplegic celsior and histidine buffer solutions to hearts subjected to ischemia and ischemia/reperfusion

Cardiomyocytes undergo apoptosis in response to ischemia and ischemia/reperfusion (I/R). During heart preservation, inhibition of apoptosis is critical to avoid organ failure. We aimed to compare the protection afforded by Celsior (Cs) and Histidine buffer solution (HBS) against apoptotic signaling in hearts subjected to moderate (4 h) versus severe (6 h) ischemia alone or followed by 30 min reperfusion. The impact of gender on cardioplegic protection was also explored. Hearts from male and female Wistar-Han rats were divided by gender in distinct groups: control, perfusion_control, ischemia, and I/R. Ischemia and I/R groups were divided in subgroups Cs or HBS, and subjected to 4 or 6 h ischemia alone or followed by reperfusion. Proteins involved in apoptotic signaling (p53, Bax, Fas, FasL, and Flip) were quantified by Western blot in mitochondria and/or whole tissue. Caspases 3, 8, and 9-like activities were measured and hemodynamic parameters were monitored. Ischemia activated p53/Bax signaling. After I/R, HBS-preserved hearts had lower p53/Bax content in mitochondrial fractions than Cs-preserved hearts. The p53/Bax decrease in tissue samples was mostly observed in females. Caspase 3-like activity was increased in HBS-preserved male hearts. The heart rate was decreased in Cs and HBS-preserved hearts. Fas protein levels remained unaltered in all conditions but soluble FasL increased from 4 to 6 h preservation in Cs and HBS. Hearts from male rats were more prone to apoptosis and myocardial dysfunction. HBS and Cs were not effective in inhibiting apoptotic signaling although HBS presented best overall results. Both solutions should be improved to prevent apoptosis and myocardial dysfunction after I/R.     

维生素E在青年和老年大鼠肾脏缺血/再灌注损伤中的作用

目的:探讨维生素E(VE)在青年和老年大鼠肾缺血/再灌注损伤(RI/RI)中的作用。方法:采用夹闭双侧肾动、静脉45min后恢复血流的方法制作RI/RI模型,测定血清中尿素氮(BUN)、肌酐(Scr)、丙二醛(MDA)、超氧化物歧化酶(SOD)、一氧化氮(NO)、诱生型一氧化氮合酶(iNOS)浓度,免疫组化检测肾皮质热休克蛋白70(HSP70)表达。流式细胞术检测肾皮质细胞凋亡率。结果:缺血/再灌注(I/R)后BUN、Scr含量明显升高,老年I/R组MDA含量高于青年I/R组,SOD含量低于青年IR组,HSP70、NO以及肾皮质细胞凋亡率高于control组;VE可显著降低RI/RI大鼠BUN、Scr、MDA、iNOS水平,升高NO和SOD水平,增加HSP70的表达,降低肾皮质细胞凋亡率。结论:VE可通过促进肾组织HSP70的表达,增加NO和SOD水平,提高大鼠体内清除自由基的能力,从而对青、老年大鼠肾缺血/再灌注损伤(RI/RI)起到一定的保护作用。     

下肢骨骼肌缺血后处理对兔缺血/再灌注心肌坏死和凋亡的影响

目的:探讨在体情况下,骨骼肌缺血后处理对兔缺血/再灌注心肌坏死和凋亡的影响。方法:新西兰大白兔36只,随机分成3组(每组随机选取6只进行梗死范围的测定,另外6只进行凋亡测定):①假手术组(Sham组);②缺血/再灌注组(I/R组);③远端后处理组(RPostC组)。在缺血前、后及再灌注60 min、120 min分别抽血测定肌酸激酶(CK),乳酸脱氢酶(LDH)的活性。采用伊文思兰(evans blue)和三苯基氯化四氮唑(TTC)染色方法确定心肌缺血区范围以及心肌坏死区范围。用Tunel法检测兔心肌缺血区细胞凋亡情况,免疫组织化学方法检测心肌缺血区蛋白caspase-3、Bcl-2及Bax的表达。结果:RPostC组心肌坏死程度、再灌注末CK活性较I/R组明显减低。RPostC组缺血区心肌Tunel阳性指数显著低于I/R组(21.79%±1.07%vs35.81%±1.10%,P<0.05)。而RPostC组缺血区心肌细胞caspase-3阳性指数显著低于I/R组(25.03%±1.16%vs39%±2.43%,P<0.05)。与Sham组比较,I/R组及RPostC组Bax蛋白表达指数、Bcl-2蛋白表达指数均升高;但RPostC组的Bax/Bcl-2比值降低,而I/R组的Bax/Bcl-2比值升高。与I/R组相比较,RPostC组Bax蛋白表达指数及Bax/Bcl-2比值显著降低,Bcl-2表达指数显著升高,差异均有统计学意义。结论:远端后处理能够明显的减少缺血/再灌注心肌细胞的坏死和凋亡,其减轻心肌细胞凋亡的机制可能与抑制促凋亡基因caspase-3的活化及Bcl-2表达的上调有关。     

Possible neuroprotective effects of lecithin and alpha-tocopherol alone or in combination against ischemia/reperfusion insult in rat brain

A close correlation exists between ischemia/reperfusion (I/R)-induced insult and the release of free radicals. Lecithin is a polyunsaturated phosphatidylcholine that corresponds to the phosphatidylcholine molecule. Phosphatidylcholines are high-energy functional and structural elements of all biologic membranes. alpha-Tocopherol is the major lipid-soluble chain-breaking antioxidant in the body tissues and effectively protects against neuronal damage. Therefore, we studied the effect of lecithin (300 mg/kg, p.o., 14 days) and alpha-tocopherol (200 mg/kg, p.o., 14 days), alone or in combination, on the brain redox state during I/R. Adult male Wistar rats were subjected to global ischemia by the occlusion of the two carotid arteries 24 h after the last dose of drug administration. Reperfusion was carried out 1 h after induction of ischemia and lasted for another hour. Brain lipid peroxides (MDA) and glutathione (GSH) contents, as well as superoxide dismutase (SOD) and catalase (CAT) activities were assessed. The results showed that I/R elevated brain lipid peroxides content which was accompanied by a reduction in both antioxidant enzyme activities, however, brain GSH level remained unaltered. Lecithin, alpha-tocopherol and their combination restored MDA content, as well as CAT activity with a slight tendency to normalize SOD activity. We conclude that lecithin has a possible neuroprotective effect partly through its antioxidant action which is comparable to that of alpha-tocopherol.