Effect of whole body hyperthermia on ischemia and reperfusion injury of rat intestine: real-time ATP change studied using (31)P-MRS

We studied the effect of hyperthermia pretreatment on subsequent small intestinal ischemia and reperfusion (I/R) injury in the rat. Systemic hyperthermia has been reported to induce heat shock proteins (HSPs) in several organs [1-6]. We examined the expression of HSP72 in the small intestinal mucosa using Western blotting and immunohistochemistry. We monitored energy metabolism using magnetic resonance spectroscopy continuously during a 60-min ischemia and the following 120 min of reperfusion. Expression of HSP72 in the small intestine was significantly increased at 6-8 h after hyperthermia. Intestinal ischemia was induced by clamping the superior mesenteric artery. Heating of the rat conferred substantial resistance to the I/R injury. In the untreated rats, beta-ATP decreased during ischemia (37.1 +/- 15.5% of the pre-ischemic value) and recovered on reperfusion, but reached only approximately 50% of the pre-ischemic value after 120 min of reperfusion. However, beta-ATP in the pretreated rats was maintained during ischemia at significantly higher levels and on reperfusion reached approximately 80% of the pre-ischemic value. These results indicate that hyperthermia protects the rat intestine from the I/R injury by unknown mechanisms which may include the induction of HSPs.     

Effect of trapidil in ischemia/reperfusion injury on rat small intestine.

To investigate the effect of trapidil on the intestinal ischemia-reperfusion injury, we determined malondialdehyde levels as a indicator of lipid peroxidation, nitrite and nitrate levels as reflections of nitric oxide metabolism, and histopathological findings in rats subjected to 40 min of ischemia and 2 h of reperfusion. Histopathological evaluation demonstrated that trapidil treatment has a protective effect on intestinal mucosa and reduces inflammatory cell infiltration in lamina propria, which is consistently noted in the untreated ischemic and reperfused intestines. Possible mechanism of this effect may be explained by the reduced lipid peroxidation (mean malondialdehyde level 3.72 +/- 0.27 vs. 6.13 +/- 0.44, p <.0001) and improved nitric oxide metabolism (mean nitrite plus nitrate 38.21 +/- 2.33 vs. 30.14 +/- 1.47, p =.022).     

Hypothermic perfusion preservation of liver: the role of phosphate in stimulating ATP synthesis studied by 31P NMR

Hypothermic perfusion of rat livers was investigated by ³¹phosphorus nuclear magnetic resonance (³¹P NMR) spectroscopy using a temperature-controlled module that allowed data acquisition at various time points during a 48-h period. The livers were perfused with an oxygenated lactobionate/raffinose-based solution containing adenosine and inorganic phosphate, and changes in tissue oedema were monitored by direct on-line measurements of liver weight changes. Liver tissue ATP concentrations, determined by fluorimetric assay, were low immediately after organ removal, probably reflecting metabolic stress during the removal period, and these increased slightly during the next 3 h. This was reflected by changes in the ³¹P NMR spectra. However, by 24 h ATP levels had increased significantly, and these were maintained for up to 48 h, suggesting a shift in the balance between energy production and consumption. When inorganic phosphate was replaced by another anion (citrate), ATP was maintained at a constant lower level during perfusion for 48 h. Tissue weight changes were similar in both groups, suggesting that volume control was not affected by the different ATP contents of the livers. By combining the temperature-controlled module with a separate perfusion circuit, NMR spectroscopy can provide a sensitive method for following energy metabolism in the same organ over long periods during hypothermic perfusion.     

Protective effect of tadalafil on ischemia/reperfusion injury of rat ovary

Background/Purpose

The aim of the study was to evaluate the effects of tadalafil (TDF) on ischemia/reperfusion (I/R) injury in rat ovaries.

Methods

Thirty-five female Sprague-Dawley rats were randomly divided into 5 groups (n = 7): sham (S), I/R1, I/R2, TDF1, and TDF2. In the I/R1 and TDF1 groups, 3-hour ischemia was followed by 12-hour reperfusion; and in the I/R2 and TDF2 groups, 3-hour ischemia was followed by 24-hour reperfusion. In the TDF groups, 30 minutes before reperfusion, a single dose of 5 mg/kg TDF was administered intraperitoneally. The ovarian tissue levels of malondialdehyde and nitric oxide (NO), and the activities of superoxide dismutase and catalase were measured biochemically. Tissue damage to ovarian tissue was scored by histopathologic examination.

Results

The tissue malondialdehyde levels were significantly higher and the catalase and superoxide dismutase activities were significantly lower in the I/R groups compared with the S and TDF groups (P < .05). The NO levels were significantly higher in the TDF1 group than the S and I/R1 groups (P < .05). Although the NO levels were increased in the TDF2 group compared with the I/R2 group, the difference was not significant. Ovarian tissue damage scores of the I/R groups were significantly higher than those of the S group (P < .05). Treatment with TDF significantly decreased the ovarian tissue damage scores in the TDF groups compared with the I/R groups (P < .05).

Conclusions

Tadalafil is effective in preventing tissue damage induced by I/R in rat ovaries.     

Intermedin预处理对大鼠肾缺血离体再灌注损伤的保护作用

目的:探讨IMD预处理对大鼠肾缺血再灌注(ischemia/reperfusion,I/R) 伤的保护作用.方法:用动脉夹夹闭大鼠左侧肾蒂1 h再灌注1 h的手术方法制成急性肾缺血再灌注损伤动物模型,将动物分为对照组、肾I/R组、IMD高、低剂量预防组、ADM预防组,检测离体肾脏流出液量及其中乳酸脱氢酶(LDH)含量、肾脏组织过氧化氢酶(CAT)、总超氧化物歧化酶(T-SOD)活性和丙二醛(MDA)含量,肾组织光镜下形态学观察.结果:与单纯肾I/R组相比,IMD高、低剂量组和ADM组均显著增加了离体肾脏流出液量(P<0.01),均显著降低了乳酸脱氢酶活性(P<0.01),均显著增加了离体肾脏的T-SOD和CAT活性(P<0.001);且IMD低剂量组的作用更加显著(P<0.05),均明显抑制了MDA的生成(P%0.001),形态学显示肾I/R组肾小球结构异常,细胞坏死、混浊肿胀或凋亡,基底膜剥脱,IMD高、低剂量组和ADM组肾小球结构基本正常,仅有中、重度空泡形成(P<0.01).结论:IMD、ADM预处理对肾I/R损伤有保护作用,其机制可能与清除自由基、减轻脂质过氧化有关.     

依达拉奉对大鼠肝I/R损伤的保护作用

目的探讨依达拉奉对大鼠肝缺血再灌注(I/R)损伤中的保护作用。方法将60只大鼠随机分为实验组和对照组,建立常温下部分肝脏I/R动物模型。在肝脏I/R开始时和1 h后对实验组大鼠给予依达拉奉注射液,对照组给予同等容量的生理盐水。再灌注0,2,4 h测定肝脏脂质过氧化反应物(LPO)浓度和肝脏酶学指标及TNF-α和E-selectin的mRNA,并行两组肝脏的病理学检查。结果再灌注2,4 h实验组大鼠肝脏LPO反应程度和肝脏酶指标检测值明显低于对照组(P0.05)。再灌注2 h肝TNF-αmRNA和E-selectinmRNA表达明显低于对照组(P0.05)。再灌注2 h实验组大鼠肝脏切片的E-selectin免疫反应性明显低于对照组。结论依达拉奉能抑制氧化应激反应,从而降低肝I/R损伤;并显著减少炎性细胞和黏附分子的产生,抑制炎性反应的发生。     

参附注射液对大鼠移植肝脏缺血再灌注损伤的影响

目的探讨参附注射液(Shenfuinjection,SF)对大鼠移植肝脏缺血再灌注损伤的保护作用及机制。方法采用雄性SpragueDawley(SD)大鼠同种异体原位肝移植模型,60只SD大鼠随机平均分成对照组和SF处理组,移植肝脏再灌注3、6、24h取血及肝脏组织检测。结果SF组血清超氧化物歧化酶(SOD)和一氧化氮(NO)水平明显高于对照组(P<0·05),丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、乳酸脱氢酶(LDH)、透明质酸(HA)、丙二醛(MDA)、肿瘤坏死因子α(TNF-α)、白介素1(IL-1)、内皮素1(ET-1)水平和肝脏细胞凋亡指数明显低于对照组(P<0·05),肝脏组织形态学改变也轻于对照组。结论参附注射液对移植肝脏缺血再灌注损伤具有防治作用,可能的机制包括抑制枯否细胞激活和氧自由基产生,改善微循环,减少细胞凋亡。     

缺血后处理对大鼠移植肝缺血再灌注损伤的保护作用

目的探讨在体条件下缺血后处理对大鼠移植肝缺血再灌注损伤的保护作用及其可能机制。方法采用SD大鼠原位肝移植模型,供肝冷保存时间100min,无肝期控制于18min以内,60只雄性健康SD大鼠随机分为3组,对照组12只,缺血再灌注损伤组和后处理组各24只。对照组开腹后仅游离肝周韧带;缺血再灌注损伤组受体大鼠供肝切除前仅以肝素化生理盐水经门静脉灌注;后处理组供肝植入后完全再灌注前,给予多次短暂复灌复停作为缺血后处理。缺血再灌注损伤组、后处理组受体一半（6只）于再灌注后2h留取血液及肝组织,另一半（6只）于再灌注后6h留取肝组织。对照组于关腹后相应时间留取血液及肝组织。各组分别检测肝功能,采用酶联免疫吸附法测定血清肿瘤坏死因子Or．和中性粒细胞弹性蛋白酶。根据酶促反应原理,利用分光光度仪测定肝脏谷胱甘肽过氧化物酶、丙二醛、髓过氧化物酶、超氧化物歧化酶。肝组织HE染色后光镜下观察组织学变化。结果缺血再灌注损伤组和后处理组血清肝功能指标、炎性细胞因子水平及肝组织过氧化物含量均高于对照组（P〈0．05）,而后处理组较缺血再灌注损伤组则明显低（P〈0．05）;缺血再灌注损伤组和后处理组肝组织抗氧化酶活力显著低于对照组（P〈0．05）,而后处理组较缺血再灌注损伤组则明显高（P〈0．05）。结论缺血后处理对大鼠移植肝的缺血再灌注损伤有明显的保护作用。提高组织的抗氧化能力和降低炎性细胞因子水平可能是缺血后处理保护作用的机制之一。     

Protective effect of fucoidin (a neutrophil rolling inhibitor) on ischemia reperfusion injury: experimental study in rat epigastric island flaps.

The objective of this study was to examine whether a decrease in neutrophil-mediated tissue injury using Fucoidin, a nontoxic neutrophil rolling inhibitor, would improve flap survival in an island flap model after ischemia-reperfusion. Myeloperoxidase activity (an indirect index of tissue neutrophil count) and malondialdehyde (an indicator of lipid peroxidation), the degree of neutrophil infiltration by direct counting, and macroscopic flap survival were assessed in the flap after arterial ischemia-reperfusion. Epigastric island skin flaps were elevated in 56 rats. The first group of 21 rats was subjected to 6 hours of arterial ischemia. The second group of 21 rats was subjected to 10 hours of arterial ischemia, and the rest of the rats were used as nonischemic controls (sham flaps). For inhibiting neutrophil rolling, a nontoxic polysaccharide agent-Fucoidin-was used. Each ischemic group was divided further into three subgroups: Subgroup I (control rats) received saline, subgroup II received 10 mg per kilogram Fucoidin, and subgroup III received 25 mg per kilogram Fucoidin before reperfusion. The results were evaluated as tissue neutrophil counts, tissue malondialdehyde content, tissue myeloperoxidase activity, and flap survival. Neutrophil counts and tissue myeloperoxidase activity were decreased significantly (p <0.001) in subgroup III, but lipid peroxidation by means of tissue malondialdehyde content was not affected by Fucoidin administration. The authors conclude that administration of Fucoidin before reperfusion can limit tissue injury apparently by inhibiting neutrophil rolling in a dose-dependent manner.     

吡咯烷二巯基氨甲酸对大鼠肾缺血再灌注的保护作用及机制

目的 探讨吡咯烷二巯基氨甲酸(PDTC)对大鼠肾缺血再灌注的保护作用及可能的机制.方法 选择成年、健康及雄性的Wistar大鼠56只,随机分为缺血再灌注损伤(IRI)组,PDTC组及对照组.IRI组:24只,建立大鼠肾缺血再灌注模型;PDTC组:24只,缺血再灌注前15 min经鼠尾静脉注射PDTC 150 mg/kg,其余步骤同IRI组;对照组:8只,不给予缺血再灌注处理.IRI组和PDTC组分别于再灌注后2、6和24 h检测大鼠血清肌酐(Cr)和尿素氮(BUN)水平;检测肾组织中自细胞介素8(IL-8)和肿瘤坏死因子α(TNF-α)的含量;逆转录聚合酶链反应(RT-PCR)检测肾组织中核因子-κB(NF-κB)和诱导型一氧化氮合酶(iNOS)mRNA表达水平;苏木素-伊红(HE)染色观察大鼠肾组织的病理变化.取对照组的各项数据作为正常对照.结果 IRI组大鼠再灌注后各时间点的血Cr、BUN、IL-8及TNF-α含量、NF-κB和iNOS mRNA表达水平均高于对照组和PDTC组(P<0.05).再灌注后6 h时,PDTC组大鼠肾组织中IL-8和TNF-α含量与对照组比较,差异无统计学意义(P>0.05).再灌注后24 h时,PDTC组大鼠各项生化指标与对照组相比,差异均无统计学意义(P>0.05).PDTC组大鼠肾损伤的病理变化较IRI大鼠明显减轻.结论 PDTC通过抑制NF-κB,有效减少IL-8,TNFα和iNOS的产生,对肾缺血再灌注有良好的保护作用.     

Protective effect of N-acetylcysteine on renal ischemia/reperfusion injury in the rat

BACKGROUND: Oxygen free radicals are important components involved in the pathophysiological tissue alterations observed during ischemia/reperfusion (I/R). METHODS: The protective effect of N-acetylcysteine (NAC) against the damage inflicted by reactive oxygen species during renal I/R was investigated in Wistar Albino rats using biochemical parameters. Animals were unilaterally nephrectomized, and subjected to 45 min of renal pedicle occlusion followed by lh of reperfusion. N-acetylcysteine (150 mg/kg, i.p.) or vehicle was administered twice, 15 min prior to ischemia and immediately before the reperfusion period. At the end of the reperfusion period, rats were killed by decapitation. For biochemical analysis, the lipid peroxidation product malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and protein oxidation (PO) were tested. Serum creatinine and BUN concentrations were measured for the evaluation of renal function. RESULTS: I/R induced nephrotoxicity, as evidenced by increases in BUN and creatinine, was reversed by NAC. The decrease in GSH and increases in MDA, MPO and PO induced by I/R indicated that renal injury involves free radical formation. CONCLUSIONS: Since NAC reversed these oxidant responses, and protected rat renal proximal tubules from in vitro simulated reperfusion injury, it seems that NAC protects kidney tissue against oxidative damage.     

Rutin in rat liver ischemia/reperfusion injury: effect on DDAH/NOS pathway

Nitric oxide (NO) plays a key role in the relationship between microcirculatory disorders and I/R injuries. Our results demonstrated a significant modification in the hepatic function of I/R rats compared with the control group; treatment with rutin reported hepatic damage markers to control value. Levels of plasmatic and hepatic thiol groups decreased in the I/R untreated group, and this decrease was inhibited by rutin treatment. In addition, we observed an increase in the iNOS expression in I/R group compared with control and rutin administration attenuated this increase; in post-ischemic reperfused rutin-treated rats there was a significant increase in eNOS expression compared with the I/R untreated group. In the same experimental conditions an increase in DDAH 1 expression was observed in I/R group only; rutin treatment also counteracted this increased expression. These data suggest that rutin treatment could be useful for preventing oxidative damage associated with hepatic post-ischemic reperfusion injury.     

The effect of perfusion speed on graft reperfusion injury after rat orthotopic liver transplantation

Objective

The objective of this study was to investigate the effects of various perfusion speeds on reperfusion injury of grafts after liver transplantation.

Methods

Liver transplantation was performed from Sprague-Dawley (SD) to SD rats. Recipients were divided into 4 groups according to perfusion speed: 50 mL/h for group A, 100 mL/h for group B, 150 mL/h for group C, and 200 mL/h for group D. Peripheral blood was collected from the caudal vein. All survivors were humanely killed at 24 hours posttransplantation. The morphological changes in grafts were evaluated using light microscopy, serum tumor necrosis factor-α (TNF-α), and endothelial nitric oxide synthase (eNOS) proteins as well as their messenger RNA (mRNA)-intragraft levels.

Results

The pathohistological damage of grafts in the 150 mL/h and 200 mL/h groups were compared with the 50 mL/h and 100 mL/h groups. TNF-α in serum was increased at 6 hours, reaching a peak at 12 hours posttransplantation. The TNF-α levels in the 50 mL/h and 100 mL/h groups were significantly lower than the 150 mL/h and 200 mL/h groups; the 50 mL/h group was greater than the 100 mL/h group as well as the 200 mL/h group was greater than the 150 mL/h group. The expressions of eNOS protein and mRNA intragraft in the 150 mL/h and 200 mL/h groups were significantly reduced compared with the 50 mL/h and 100 mL/h groups, and the 50 mL/h group was decreased when compared with the 100 mL/h group. There was no significant difference between the 150 mL/h group and the 200 mL/h group.

Conclusion

The optimal perfusion speed for harvesting rat liver graft is 100 mL/h. High-speed perfusion may impair sinusoid endothelial cells and low-speed perfusion may extend the warm ischemia time and increase microthrombus formation.     

重组人促红细胞生成素对骨骼肌缺血再灌注损伤的保护作用

[目的]观察重组人促红细胞生成素（rHuEPO）对肢体骨骼肌缺血再灌注（IZR）损伤的保护作用。[方法]建立大鼠后肢缺血再灌注模型。40只大鼠随机均分为：假手术组（I组），I/R组（Ⅱ组），I/R＋生理盐水组（Ⅲ组），I/R＋rHuEPO组（Ⅳ组）。取血浆测定丙二醛（MDA）、肌酸磷酸激酶（CPK）和乳酸脱氢酶（LDH）含量。取骨骼肌标本测定髓过氧化酶（MP0）活性、湿重／干重比（Wet／dry）。[结果]Ⅱ组与I组比较，血浆和骨骼肌的各项生化指标显著增高（P〈0．01）；IV组血浆及骨骼肌各项测定指标较Ⅱ组相比明显降低（P〈0．01）。Ⅲ组和Ⅱ组之间比较，差异无显著意义。[结论]rHuEPO对肢体骨骼肌缺血再灌注损伤有保护作用。     

The therapeutic effect of cerium oxide nanoparticle on ischaemia/reperfusion injury in rat testis

Testicular torsion is a dangerous urogenital disorder which is caused by twisting of spermatic cord, and unless immediate treatments happen at a proper time, oxidative stress, occurred during ischaemia reperfusion, finally leads to irreversible disintegration of testicular tissue. One of the first preventive lines is to administrate antioxidant factors. In the present study, we investigate the therapeutic effect of cerium oxide nanoparticle on the injury. We divided 45 rats into nine groups, subjected eight groups to testicular torsion–detorsion, injected different doses of cerium oxide nanoparticle into the peritoneum of six groups and analysed all the groups regarding spermatogenetic indices including sperm count, sperm viability and Johnson mean. Our results showed that cerium oxide nanoparticle can alleviate oxidative stress in testis, and this alleviation promotes the reproductive indices as the concentration of cerium oxide nanoparticles increases. The catalase-mimetic and superoxide dismutase-mimetic activities of cerium oxide nanoparticle are the most probable theories to explain the antioxidant effect of the nanoparticle.     

Biochemical and histological investigation of famotidine effect on postischemic reperfusion injury in the rat ovary

Background/Purpose

In this study, an investigation was performed on the ovarian tissue of rats subjected to ischemia-reperfusion for the effect of famotidine on certain parameters of oxidation-antioxidation, cell DNA damage, and histological appearance.

Methods

The effects of famotidine on certain parameters of oxidation-antioxidation (total glutathione [tGSH], superoxide dismutase [SOD], malondialdehyde) and cellular DNA injury in the ovarian tissue of rats subjected to ischemia-reperfusion were investigated and underwent histological examination.

Results

The results show levels of 5.2 ± 0.6 nmol/g protein for tGSH, 8.3 ± 0.8 U/g for SOD activity, and 7.7 ± 0.9 μmol/g protein for malondialdehyde (P < .0001 when compared with controls) in ovarian tissue subjected to ischemia-reperfusion following famotidine treatment. The tGSH levels in control rats and in a healthy animal group were, respectively, 1.76 ± 0.7 and 5.5 ± 0.3 nmol/g protein (P < .0001). The SOD activity was 3.2 ± 0.9 U/g in control and 9.2 ± 0.6 U/g in healthy animal tissues. The differences between the values in the treatment and the control group, and between the healthy animal group and the control group were both highly significant (P < .0001). It was also observed that famotidine prevented, to a significant extent, an increase in the level of 8-hydroxy-2-deoxyguanine/guanine, a DNA damage product, as compared with the control group.

Conclusion

These biochemical and histological results show that famotidine protects the ovarian tissue from ischemia-reperfusion injury.