Therapeutic potential of cannabidiol against ischemia/reperfusion liver injury in rats

The therapeutic potential of cannabidiol, the major non-psychotropic Cannabis constituent, was investigated in rats exposed to ischemia/reperfusion liver injury. Ischemia was induced by clamping the pedicle of the left hepatic lobe for 30 min, and cannabidiol (5 mg/kg, i.v.) was given 1 h following the procedure and every 24 h thereafter for 2 days. Ischemia/reperfusion caused significant elevations of serum alanine aminotransferase and hepatic malondialdehyde, tumor necrosis factor-α and nitric oxide levels, associated with significant decrease in hepatic reduced glutathione. Cannabidiol significantly attenuated the deterioration in the measured biochemical parameters mediated by ischemia/reperfusion. Histopathological examination showed that cannabidiol ameliorated ischemia/reperfusion-induced liver damage. Immunohistochemical analysis revealed that cannabidiol significantly reduced the expression of inducible nitric oxide synthase, cyclooxygenase-2, nuclear factor-κB, Fas ligand and caspase-3, and increased the expression of survivin protein in ischemic/reperfused liver tissue. These results emphasize that cannabidiol represents a potential therapeutic option to protect the liver against hypoxia–reoxygenation injury.     

Involvement of cortical damage in the ischemia/reperfusion-induced memory impairment of wistar rats

The effect of ischemia/reperfusion-induced neuronal damage on the memory impairment were investigated using active avoidance and Morris water maze tasks in Wistar rats. Focal ischemia was induced by 1 h occlusion of the right middle cerebral artery (MCA) of Wistar male rats. Reperfusion was induced by releasing the occlusion and restoring the blood circulation for 24 h. The acquisition and preservation memory tested by active avoidance showed a significant difference between the sham and ischemia/reperfusion group. The water maze acquisition performance was also significant difference between sham and ischemia/reperfusion groups in both latency and moving distance. The infarction volume was increased by the ischemia/reperfusion. Furthermore, the cresyl violet staining of the ischemia/reperfusion brain showed severe neuronal damage (pyramidal cell loss) in the cortex in addition to the striatum lesion of brain. This study shows that pyramidal cell damage in the cortex lesion may be partially related to memorial disturbance in the ischemia/reperfusion brain injury.     

Angiotensin AT1 receptor blockers suppress ischemia/reperfusion-induced gastric injury in rats

Ischemia/reperfusion (I/R) damages gastric mucosa via reactive oxygen species (ROS) activity. ROS was reportedly produced through angiotensin II stimulation in tissues such as kidney, heart and brain. To determine whether AT1 receptor plays a role in gastric mucosal damage, we examined the effect of AT1 receptor blocker (ARB; losartan, candesartan, valsartan) on I/R-induced gastric injury in rats. I/R produced microscopic gastric hemorrhagic injury, and increased gastric microvascular permeability and H₂O₂ production in rats. The mucosal lesions induced by I/R were attenuated by pretreatment of each ARB. The increase in microvascular permeability was suppressed by losartan pretreatment. Additionally, I/R-caused H₂O₂ activation was not observed by pretreatment of losartan, candesartan and valsartan. These results suggest that angiotensin II stimulation via AT1 receptor and following ROS production in the stomach contribute to the pathogenesis of the gastric I/R injury. Received 31 July 2006; revised 29 August 2006; accepted 21 August 2006     

肝移植大鼠胃肠动力改变及机制

目的 探讨大鼠肝移植后早期胃肠动力改变及机制.方法 40只SD大鼠随机分为肝移植组10对、全肝血流阻断组及对照组各10只.移植组采用改良的两袖套法行原位肝移植;全肝血流阻断组参照移植组受体的手术步骤,控制无肝期时间与移植组相同;对照组仅开腹.术后1h测小肠推进率、血浆内毒素含量,肠组织匀浆测Ca2 -ATPase、丙二醛(MDA).结果 与全肝血流阻断组和对照组相比,移植组术后小肠推进率低,血内毒素水平升高、肠组织内Ca2 -ATPase活性降低、MDA升高.结论 大鼠肝移植早期,胃肠动力显著降低,与肠道能量代谢障碍、缺血再灌注损伤、内毒素移位及其它因素有关.     

胰高血糖素样肽-1与胃肠动力研究进展

胰高血糖素样肽-1(GLP-1)为一种重要的肠促胰岛素,可通过多种机制发挥重要的降血糖作用,因而在2型糖尿病(T2DM)的治疗中备受重视。另外,GLP-1亦发挥重要的心血管保护、肾脏保护、调节脂代谢,及改善胰岛素敏感性等功能。值得注意的是,GLP-1对胃排空及胃肠动力亦具有一定的抑制作用。因此,本文就GLP-1与胃肠动力关系的研究进展做一综述,旨在为GLP-1在胃肠动力障碍性疾病的发病机制及治疗中的潜在价值开辟新的视角。     

Protective effects of ibuprofen on testicular torsion/detorsion-induced ischemia/reperfusion injury in rats

The aim of this study was to investigate the protective effect of ibuprofen on testicular torsion/detorsion-induced ischemia/reperfusion (I/R) injury. A total of 48 prepubertal male Wistar albino rats were divided into two models: early and late orchiectomy. Testicular torsion was created by rotating the right testis 720° in a clockwise direction. The ischemia period was 5 h and orchiectomy was performed after 5 h of detorsion in the early orchiectomy model (EOM). In the late orchiectomy model (LOM), the ischemia period was 5 h and orchiectomy was performed after 7 days of detorsion. In the EOM, ibuprofen (70 mg/kg, po) was administrated only once, 40 min prior to detorsion. In the LOM, ibuprofen (70 mg/kg, po) was administered 40 min before detorsion, once daily for 7 days. Bilateral orchiectomy was performed in all groups to measure the tissue levels of malondialdehyde (MDA) and to microscopically investigate light and electrons. The presence of endothelial nitric oxide synthase (eNOS) activity was shown with immunohistochemical studies. Spermatogenesis and mean seminiferous tubule diameter (MSTD) were significantly decreased in ipsilateral and contralateral testis when both early and late I/R groups were compared to the sham groups. Furthermore, ibuprofen-treated animals showed an improved histological appearance in both models of testicular torsion. Ibuprofen treatment prevented lipid peroxidation resulting in decreased MDA accumulation in the testes of both models. After I/R, eNOS immunoreactivity was increased in the testicular tissues. Ibuprofen treatment decreased eNOS immunoreactivity in the germ cells of the tubules in the contralateral testes, but intense eNOS immunoreactivity was shown in the ipsilateral testes of the LOM. Electron microscopy of the testes of rats demonstrated that ibuprofen pretreatment was particularly effective in preventing the mitochondrial degeneration in both Sertoli and spermatid cells in the LOM. Because of its anti-inflammatory and antioxidant effects, ibuprofen pretreatment may have protective effects in the experimental testicular torsion/detorsion model in rats.     

Inhibition of autophagy by geniposide protects against myocardial ischemia/reperfusion injury

Geniposide (GP), extracted from a traditional Chinese herb Gardenia jasminoides, has extensive pharmacological effects. But the effects and the potential mechanisms of GP on myocardial ischemia/reperfusion (I/R) injury are poorly understood. In present study, we investigated the effect of GP on myocardial I/R injury in vivo and hypoxia/reoxygenation (H/R) in vitro respectively, and its mechanism. The results showed that GP reduced myocardial infarct size, alleviated acute myocardial injury, improved cardiac function, regulated apoptosis-related proteins and inhibited apoptosis. In vitro experiments revealed that GP enhanced the cell viability, regulated apoptosis-related proteins and prevented cell apoptosis during H/R in H9c2 cells. GP inhibited the expression of autophagy-related proteins and autophagosome accumulation both in vivo and in vitro. The effects of GP were blocked by rapamycin (RAPA) administration. In summary, our results showed that GP protected against myocardial I/R injury and involved inhibition of autophagy, which might be through activating AKT/mTOR signaling pathways.     

葛根素预处理在大鼠肝脏缺血再灌注损伤中的抗氧化作用

目的观察葛根素预处理对大鼠肝脏缺血再灌注损伤的防护作用。方法雄性SD大鼠,建立肝脏缺血再灌注模型（HIR）。随机分为假手术组、HIR组和HIR-葛根素预处理组。黄嘌呤氧化酶法、硫代巴比妥酸比色法分别测定肝组织中丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性的变化,同时分析NO含量的改变。结果肝脏缺血再灌注损伤后,与假手术组比较,肝组织中MDA活性及NO含量均显著增加,而SOD活性显著降低;经40mg/kg剂量的葛根素预处理7d后,与模型组相比,肝组织中MDA活性及NO含量显著降低,而SOD活性增高。结论葛根素预处理对大鼠缺血再灌注肝脏损伤有一定的保护作用。     

丹参对大鼠肾脏缺血再灌注损伤的保护作用机制的研究

目的：探讨丹参对大鼠肾脏缺血再灌注损伤的保护作用。方法：雄性Wistar大鼠随机分为4组,假手术组,模型组（肾脏缺血再灌注损伤）,治疗1组（肾脏缺血再灌注损伤前24h给予药物）,治疗2组（肾脏缺血再灌注损伤后12h给予药物）。双侧肾动脉夹闭22min,制作动物模型;比色法测定血清肌酐和血清尿素氮;Westernblotting检测肾脏组织中,天冬氨酸特异性半胱氨酸蛋白酶（caspase-3）的蛋白表达;TUNEL法检测肾脏上皮细胞凋亡。结果：模型组与假手术组比较,大鼠肾脏功能明显减退（P〈0.05）;肾脏组织中,caspase-3蛋白质表达显著增加（P〈0.05）,大量肾小管上皮细胞凋亡（P〈0.05）。再灌注前24h给予药物,能够显著改善肾脏功能（P〈0.05）,并且显著下调caspase-3的蛋白表达（P〈0.05）,减轻肾脏上皮细胞凋亡（P〈0.05）,再灌注后12h给药,不能改善肾脏功能,也不能显著下调caspase-3的蛋白表达（P〉0.05）。结论：再灌注前给予丹参,能够抑制肾脏缺血再灌注损伤诱导的肾脏上皮细胞凋亡,对肾脏缺血再灌注损伤具有保护作用。     

天山花楸叶总黄酮对大鼠心肌缺血/再灌注损伤的保护作用

目的观察天山花楸叶总黄酮对大鼠心肌缺血/再灌注(I/R)损伤的保护作用,探讨其作用机制。方法采用改良的Langendorff逆行恒压灌流方法,建立大鼠离体心脏I/R损伤模型,观察天山花楸叶总黄酮(4.0、6.0mg·L-1)对心脏I/R损伤后心功能、心肌组织中超氧岐化酶(SOD)活性和丙二醛(MDA)含量变化的影响。利用DPPH、羟自由基、超氧阴离子、脂质过氧化反应体系,检测了天山花楸叶总黄酮(6.25、12.5、25、50、100mg·L-1)体外抗氧化能力。结果天山花楸叶总黄酮(6.0mg·L-1)可明显改善离体心脏I/R损伤后左心室发展压(LVDP)和左室压力升高或降低最大速率(±dp/dtmax),明显增加冠脉流量;天山花楸叶总黄酮(6.0mg·L-1)处理后I/R损伤心肌组织中SOD活性升高,MDA含量减少。天山花楸叶总黄酮(6.25～100mg.L-1)可浓度依赖性地清除DPPH自由基、羟自由基和超氧阴离子自由基,并抑制脂质过氧化反应。结论天山花楸叶总黄酮对心肌缺血/再灌注损伤具有明显保护作用,与其具有较强的抗氧化活性有关。     

Changes in gastrointestinal motility influence the absorption of desmopressin

Objective: The antidiuretic effect of desmopressin is widely utilized in the treatment of neurogenic diabetes insipidus and nocturnal enuresis in children. The objective of the present study was to assess how changes in gastrointestinal motility, induced by erythromycin and loperamide, influence the pharmacokinetics of orally administered desmopressin. Methods: This study was conducted using an open randomized, three-period, three-treatment design in 18 healthy subjects. On each study day a single oral dose of 400 μg desmopressin was administered in the morning. The desmopressin dose was either given alone (reference) or after pretreatment with either loperamide tablets (4 mg at −24, −12 h and −1 h) or erythromycin capsules (250 mg q.i.d, with the first dose in the morning 3 days before the study day and the last dose at −1 h). On each study day, blood was sampled up to 8 h after dosing for assessment of desmopressin concentration. Results: Compared with administration of 400 μg of desmopressin alone, pretreatment with loperamide produced significantly (P < 0.05) altered pharmacokinetics of desmopressin as the endpoints; area under the curve up to infinity (AUC), area up to the last determinable plasma concentration (AUC_t) and maximum plasma concentration (C_max) increased 3.1-fold (95% CI 2.3–4.2), 3.2 (2.3–4.4) and 2.3 (1.6–3.2), respectively. Although the estimates were lower, pretreatment with erythromycin did not result in any significant changes in these endpoints. There were no significant changes observed between the three treatments regarding the terminal elimination half-life (t_1/2). However, significant (P < 0.05) changes in the time to reach C_max (t_max) values (median and range) were observed as, compared with administration of desmopressin alone (1.3 h and 0.5–4.0), it was longer after pretreatment with loperamide (2.0 h and 0.5–3.0) and shorter following pretreatment with erythromycin (0.9 h and 0.5–1.3). Conclusion: Presumably due to slower gastrointestinal motility, pretreatment with loperamide significantly increases the gastrointestinal absorption of desmopressin. Except for a shortening of t_max, pretreatment with erythromycin did not significantly influence absorption of the drug. Received: 1 September 1998 / Accepted in revised form: 29 December 1998     

粉防己碱预处理减轻大鼠肝脏缺血再灌注损伤的机制研究

目的研究粉防己碱（tetrandrine,TET）预处理对大鼠肝缺血再灌注损伤的预防作用及其机制。方法大鼠肝脏左中叶缺血50 min,再灌注24 h后处死（I/R组）,TET＋I/R组缺血前30 min腹腔注射TET（50 mg/kg）,余同I/R组。大鼠处死前采血检测丙氨酸氨基转移酶（ALT）,天门冬氨酸氨基转移酶（AST）,乳酸脱氢酶（LDH）,取缺血肝组织进行超氧化物歧化酶（SOD）,一氧化氮（NO）,丙二醛（MDA）,湿重干重（W/D）比检测和组织学检查。结果I/R组血清ALT,AST和LDH升高,组织MDA水平,W/D比值也明显升高,SOD活性和NO含量下降。在TET＋I/R组,血清ALT,AST,LDH,以及组织W/D比值较I/R组降低,SOD活性和NO含量升高。此外,TET＋I/R组大鼠血清ALT,AST,组织MDA和W/D比值较假手术组升高,SOD活性和NO含量降低.组织学检查显示TET＋I/R组肝损害减轻。结论TET能减轻但不能防止肝I/R损伤的发生,减少脂质过氧化物产生是TET抗I/R损伤的原因之一。     

The roles of kupffer cells in hepatic dysfunction induced by ischemia/reperfusion in rats

This study examined the role of Kupffer cells in altering the hepatic secretory and microsomal function during ischemia and reperfusion (Is/Rp). Rats were subjected to 60 min of hepatic ischemia, followed by 1 and 5 h of reperfusion. Gadolinium chloride (GdCl3, 7.5 mg/kg body weight, intravenously) was used to inactivate the Kupffer cells 1 day prior to ischemia. Is/Rp markedly increased the serum aminotransferase level and the extent of lipid peroxidation. GdCl3 significantly attenuated these increases. Is/Rp markedly decreased the bile flow and cholate output, and GdCl3 restored their secretion. The cytochrome P450 content was decreased by Is/Rp. However, these decreases were not prevented by GdCl3. The aminopyrine N-demethylase activity was decreased by Is/Rp, while the aniline p-hydroxylase activity was increased. GdCl3 prevented the increase in the aniline p-hydroxylase activity. Overall, Is/Rp diminishes the hepatic secretory and microsomal drug-metabolizing functions, and Kupffer cells are involved in this hepatobiliary dysfunction.     

米力农对大鼠缺血再灌注损伤中的保护作用

目的探讨米力农对在体肺缺血再灌注（I／R）损伤的保护作用。方法夹闭大鼠左肺门1h，再灌注3h，建立在体缺血再灌注模型。将20只SD大鼠随机分成缺血再灌注组（对照组）；米力农组（实验组）。米力农组缺血前30min给予颈静脉推注米力农1mg／kg。再灌注3h后摘取左肺测超氧化物歧化酶（SOD）活力、丙二醛（MDA）含量及髓过氧化物酶（MPO）活力并行病理学检查。结果再灌注3h后，两组间MPO活力无显著性差异。对照组MDA（nmol／mgprot）含量为0．884±0．06，显著高于实验组0．494±0．11（P〈0．05），而SOD（U／mgprot）活力为16．094±10．73，显著低于实验组35．93±13．50。结论米力农对肺缺血再灌注损伤具有保护作用，可能与其抗氧化作用有关。     

缺血后适应减轻急性下肢缺血再灌注损伤的实验研究

目的 观察缺血后适应(IPC)减轻急性下肢缺血(AU)再灌注损伤的疗效并探讨其机制.方法 将45只新西兰大白兔采用高脂饮食与动脉内膜球囊损伤结合的方式建立下肢动脉粥样硬化狭窄动物模型,随机分为对照组、缺血再灌注组(IR组)、缺血后适应组(IPC组),每组各15只.检测三组大白兔阻断股动脉前、持续再灌注2h后血液中肌酸激酶(CK)、丙二醛(MDA)、超氧化物岐化酶(SOD)水平,观察再灌注后下肢骨骼肌组织学改变,并采用原位末端标记法(TUNEL)分析三组大白兔下肢再灌注后骨骼肌细胞凋亡情况.结果 与IR组比较,IPC组兔血浆CK、MDA明显降低[(7.49±0.84) U/L与(8.19±1.06) U/L,P＜0.05],[(3.67±0.36) nmol/L与(4.06±0.55) nmol/L,P＜0.05],而SOD则显著升高[(420.40±30.94)μmol/L与(384.73±44.12) μmol/L,P＜0.05],骨骼肌细胞凋亡指数降低[(12.27±2.11)％与(16.62±1.44)％,P＜0.01],差异有统计学意义,并且组织形态学观察IPC组兔骨骼肌损伤、坏死程度较IR组减轻.结论 急性下肢缺血应用IPC能显著减轻下肢缺血再灌注损伤,其机制与减少自由基生成、增强抗氧化及减轻缺血再灌注诱导的骨骼肌细胞凋亡有关.     

雷米普利对糖尿病大鼠心肌缺血/再灌注损伤的保护作用

目的研究雷米普利(RAM)对糖尿病大鼠心肌缺血/再灌注损伤的保护作用。方法链脲佐菌素致糖尿病大鼠被随机分为缺血/再灌注(I/R)、缺血预适应(IPC)和RAM3组。RAM组每天用RAM(1mg·kg-1)灌胃,IPC和I/R组用等体积生理盐水灌胃。4wk后各组动物均经历心肌缺血/再灌注损伤,IPC组于缺血前行心肌缺血预适应。连续监测心电图,检测心肌梗死范围、心肌细胞凋亡、凋亡蛋白Bcl-2与Bax表达,光镜下观察心肌形态学改变。结果与I/R组比较,RAM及IPC组ST-段抬高幅度降低,室早出现时间推迟,持续时间缩短,室速、室颤发生率降低,心肌梗死范围缩小,心肌细胞凋亡减轻,Bcl-2/Bax比值升高。结论连续4wk应用RAM可减轻糖尿病大鼠心肌缺血/再灌注损伤。     

Vitexin protects against myocardial ischemia/reperfusion injury in Langendorff-perfused rat hearts by attenuating inflammatory response and apoptosis

The aim of the present study is to investigate the effects and its possible underlying mechanisms of vitexin on myocardial ischemia/reperfusion (I/R) injury in isolated rat hearts. Isolated rat hearts were perfused with Langendorff apparatus, which subjected to 30 min ischemia and then followed by 60 min reperfusion. In the isolated rat heart subjected to I/R injury, treatment of vitexin (50, 100, 200 μmol/L) significantly enhanced coronary flow, and decreased the pathological scores of myocardium. 50, 100, 200 μmol/L vitexin significantly attenuated I/R-induced increases of myocardial TNF-α and IL-1β, and 25, 50, 100, 200 μmol/L vitexin significantly reduced apoptosis index of cardiac muscle cell of rat isolated heart subjected to I/R injury. Vitexin significantly inhibited I/R-induced increase of myocardial Bax protein expression; however, 100, 200 μmol/L vitexin markedly increased myocardial Bcl-2 protein expression. Furthermore, vitexin at concentrations of 50, 100, 200 μmol/L significantly reduced expression of myocardial NF-κBp65 protein. Therefore, these results demonstrate that vitexin exhibits significant protective effect against myocardial I/R injury in isolated rat heart, which is related to inhibition of the release of inflammatory cytokines and the apoptosis of cardiac muscle cell via up-regulating protein expression of Bcl-2 as well as down-regulating Bax and NF-κBp65.     

通络逐瘀汤对脑缺血/再灌注损伤的临床研究

目的观察通络逐瘀汤对脑缺血/再灌注损伤的保护作用,并对其机制作初步探讨。方法对大鼠大脑中动脉缺血2h/再灌注22h模型采用不同方案治疗,比较其神经病学评分、脑梗死范围及抗脑缺血/再灌注损伤的效果;放射免疫法检测患侧皮质内皮素（ET）、血栓素B2（TXB2）、6-酮-前列腺素F1α（6-keto-PGF1α）含量的变化。结果大鼠脑缺血2h/再灌注22h后,假手术组大鼠神经病学评分均为0分,无脑梗死;尼莫地平组和通络逐瘀汤30、60mg/kg组神经病学评分和脑梗死范围均小于生理盐水组,差异有统计学意义（P〈0.05）。生理盐水组ET及TXB2含量高于假手术组,6-Keto-PGF1α活性低于假手术组,差异均有统计学意义（P〈0.05）;尼莫地平组和通络逐瘀汤30、60mg/kg组ET及TXB2含量低于生理盐水组,6-Keto-PGF1α活性高于生理盐水组,差异均有统计学意义（P〈0.05）。结论通络逐瘀汤对脑缺血/再灌注损伤有保护作用,其作用机制与抑制ET、TXB2含量,提高6-keto-PGF1α活性,维持TXB2/6-keto-PGF1α动态平衡有关。     

p38MAPK在纳洛酮减轻大鼠心肌缺血再灌注损伤中的作用

目的 研究大鼠心肌缺血再灌注损伤后p38 MAPK的变化及纳洛酮对其的影响.方法SD大鼠24只随机均分为假手术组(sham)、缺血再灌注组(IR)、纳洛酮组(Nal).采用结扎左冠状动脉左前降支30 min,再灌注2h制作心肌缺血再灌注模型.观察心电图J点电位的变化;Western Bloting检测p38 MAPK、...