游泳训练对脑梗死大鼠大脑皮质中神经生长因子及神经营养因子-3表达的影响

目的观察游泳训练对脑梗死大鼠神经生长因子（NGF）及神经营养因子-3（NT-3）表达的影响,并初步探讨运动训练对脑梗死大鼠的神经保护机制。 方法共选取健康雄性SD大鼠45只,采用随机数字表法将其分为假手术组、对照组及训练组。采用线栓法将对照组及训练组大鼠制成左侧大脑中动脉阻塞（MCAO）2h再灌注模型,假手术组大鼠制模期间不阻塞大脑中动脉血流。训练组大鼠制模后给予游泳训练,每日1次,每次持续10min,对照组及假手术组大鼠制模后不给予任何特殊处理。于制模后3d、7d及14d时采用Bederson评分法评定各组大鼠神经功能缺损情况;采用RT-PCR法检测各组大鼠缺血侧脑皮质NGF及NT-3 mRNA表达量。 结果假手术组大鼠术后无神经行为缺陷,制模后3d、7d及14d时训练组大鼠Bederson评分均显著低于同时相点对照组水平（P<0.05）,高于同时相点假手术组水平（P<0.05）,并且制模后14d时训练组Bederson评分［（1.20±0.45）分］亦显著低于制模后3d及7d时水平（P<0.05）。训练组各时相点缺血侧脑皮质NGF及NT-3 mRNA表达量均较对照组、假手术明显增强（P<0.05）;随着时间进展,制模后14d时训练组NGF及NT-3 mRNA含量［分别为（0.66±0.07）,（0.79±0.06）］均较制模后3d及7d时明显提高（P<0.05）。 结论游泳训练能上调脑梗死大鼠缺血脑皮质NGF及NT-3 mRNA表达,这可能是运动训练促进脑梗死大鼠受损神经功能恢复的重要机制之一。     

Vascular-Resident CD169-Positive Monocytes and Macrophages Control Neutrophil Accumulation in the Kidney with Ischemia-Reperfusion Injury

Monocytes and kidney-resident macrophages are considered to be involved in the pathogenesis of renal ischemia-reperfusion injury (IRI). Several subsets of monocytes and macrophages are localized in the injured tissue, but the pathologic roles of these cells are not fully understood. Here, we show that CD169⁺ monocytes and macrophages have a critical role in preventing excessive inflammation in IRI by downregulating intercellular adhesion molecule-1 (ICAM-1) expression on vascular endothelial cells. Mice depleted of CD169⁺ cells showed enhanced endothelial ICAM-1 expression and developed irreversible renal damage associated with infiltration of a large number of neutrophils. The perivascular localization of CD169⁺ monocytes and macrophages indicated direct interaction with blood vessels, and coculture experiments showed that the direct interaction of CD169⁺ cell-depleted peripheral blood leukocytes augments the expression levels of ICAM-1 on endothelial cells. Notably, the transfer of Ly6C^lo monocytes into CD169⁺ cell-depleted mice rescued the mice from lethal renal injury and normalized renal ICAM-1 expression levels, indicating that the Ly6C^lo subset of CD169⁺ monocytes has a major role in the regulation of inflammation. Our findings highlight the previously unknown role of CD169⁺ monocytes and macrophages in the maintenance of vascular homeostasis and provide new approaches to the treatment of renal IRI.     

MicroRNA-687 Induced by Hypoxia-Inducible Factor-1 Targets Phosphatase and Tensin Homolog in Renal Ischemia-Reperfusion Injury

Ischemia-reperfusion injury contributes to tissue damage and organ failure in clinical settings, but the underlying mechanism remains elusive and effective therapies are still lacking. Here, we identified microRNA 687 (miR-687) as a key regulator and therapeutic target in renal ischemia-reperfusion injury. We show that miR-687 is markedly upregulated in the kidney during renal ischemia-reperfusion in mice and in cultured kidney cells during hypoxia. MiR-687 induction under these conditions was mediated by hypoxia-inducible factor-1 (HIF-1). Upon induction in vitro, miR-687 repressed the expression of phosphatase and tensin homolog (PTEN) and facilitated cell cycle progression and apoptosis. Blockade of miR-687 preserved PTEN expression and attenuated cell cycle activation and renal apoptosis, resulting in protection against kidney injury in mice. Collectively, these results unveil a novel HIF-1/miR-687/PTEN signaling pathway in ischemia-reperfusion injury that may be targeted for therapy.     

三维球体间充质干细胞移植对大鼠缺血再灌注损伤脑组织Nogo-A及NgR表达的影响

目的 探讨胎盘来源间充质干细胞移植对脑缺血再灌注后大鼠脑组织Nogo—A及其受体NgR的mRNA及蛋白表达的影响及意义。方法 实验动物随机分为假手术组(Sham组)及模型组,模型组再分为治疗组(MSCs组)以及溶剂对照组(Vehicle组),应用线栓法制备大鼠大脑中动脉缺血模型,缺血2h后拔除鱼线再灌注,1d后MSCs组注射间充质干细胞,Vehicle组注射等量培养基溶液,移植后1d,3d,7d应用RT-PCR法检测mRNA表达水平;Western blot法检测蛋白表达水平。结果 与Vehicle组相比,MSCs组大鼠7d神经运动功能有明显改善(P<0.05);MSCs组1,3,7dmRNA及蛋白水平均较Vehicle组降低(P<0.05)。结论 胎盘间充质干细胞移植可以改善脑缺血再灌注后神经运动功能,其机制可能与下调脑组织Nogo—A及其受体NgR水平有关。     

运动预处理对脑缺血再灌注大鼠血清炎症因子水平的影响

目的探讨运动预处理对脑缺血再灌注大鼠血清白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)及肿瘤坏死因子α(TNF-α)含量的影响。方法雄性Sprague-Dawley大鼠24只分为运动预处理组(n=8)、模型组(n=8)、假手术组(n=8)。线栓法制备大鼠大脑中动脉阻塞(MCAO)缺血再灌注模型。再灌注后2 h、24 h分别行神经功能缺损评分。随后取材,HE染色观察大鼠缺血侧脑组织病理形态变化,酶联免疫吸附法检测血清TNF-α、IL-1β及IL-6的含量。结果脑缺血再灌注后24 h,运动预处理组神经功能评分较模型组改善(P0.05),血清TNF-α、IL-1β及IL-6含量明显降低(P0.01);脑缺血区皮质病理损伤减轻,间质水肿程度减轻,细胞排列较整齐,缺血区变性和坏死的神经元数量明显减少。结论运动预处理可以降低急性脑缺血再灌注大鼠炎症反应,降低神经功能缺损。     

Acute myocardial infarction and myocardial ischemia-reperfusion injury: a comparison

Myocardial infarction (MI) denotes the death of cardiac myocytes due to extended ischemia. Myocardial reperfusion is the restoration of coronary blood flow after a period of coronary occlusion. Reperfusion has the potential to salvage ischemic myocardium but paradoxically can cause injury, a phenomenon called as ‘reperfusion injury’ (IR). Standard histologic, immunohistochemical and Elisa techniques were used to study the histopathologic, oxidative, apoptotic and inflammatory changes in MI and IR. The IL-6 levels in the LV of the MI group were significantly raised as compared to the IR group (P=0.0008). Plasma IL-6 was also significantly increased in the MI group as compared to the IR group (P=0.031). MI model was also associated with increase in the neutrophil polymorphs number in the infarction related myocardium as compared to the re-perfused myocardium. A significant increase in troponin I level in the MI group as compared to the IR group is also seen (P=0.0001). Our IR model showed enhanced pro-apoptotic mediators like cleaved caspase-3 (P=0.005) and cytochrome c in the myocardium as compared to the MI model. In conclusion, myocardial damage in MI is mainly due to ischemic necrosis and inflammatory mechanisms while apoptosis is the main mechanism of cell death in IR in addition to limited ischemic necrosis.     

Effects of curcumin on interleukin-23 and interleukin-17 expression in rat retina after retinal ischemia-reperfusion injury

Objective: This study aimed to investigate the effect of curcumin on the retinal structure and the expressions of interleukin-23 (IL-23) and IL-17 in the rat retina after retinal ischemia-reperfusion injury (RIRI). Methods: 150 Sprague-Dawley rats were randomly divided into RIRI group (MG), low-dose curcumin group (LDCG) and high-dose curcumin group (HDCG), (n = 50 per group). RIRI was generated by anterior chamber perfusion of normal saline to the right eye. The left eye served as a normal control group (NCG). Rats in LDCG and HDCG received an intraperitoneal injection of 20 mg/kg/d and 100 mg/kg/d curcumin respectively, at 30 min before RIRI and once daily after RIRI. Results: The morphological changes in HDCG group were improved as compared to MG and LDCG groups. Immunohistochemistry showed that IL-23 and IL-17 were mainly expressed in the ganglion cell layer and the inner nuclear layer of the retina. Low IL-23 and IL-17 expressions were observed in NCG, but increased significantly in MG and LDCG groups. Western blot assay and ELISA also showed that IL-23 and IL-17 expressions increased significantly after RIRI (vs. NCG, P<0.01). Moreover, the IL-23 expression reached a peak at 24 h, whereas IL-17 expression peaked at 72 h after RIRI. Curcumin reduced IL-23 and IL-17 expressions significantly in a dose-dependent manner (vs. MG, P<0.01). Conclusion: The IL-23 and IL-17 expressions increase after RIRI and curcumin significantly reduces retinal IL-23 and IL-17 expressions in a dose-dependent manner and is able to prevent the RIRI induced damage to the retina.     

Transforming growth factor-β1 promotes homing of bone marrow mesenchymal stem cells in renal ischemia-reperfusion injury

Backgrounds: Acute ischemia reperfusion-induced kidney injury is a common cause of acute renal failure, and it is also an important cause of delayed recovery of transplanted kidney functions and even loss of function. However, there is no effective treatment method in clinical applications presently. Objective: The objective was to investigate effects of transforming growth factor-β1 on homing of bone marrow mesenchymal stem cells in renal ischemia-reperfusion injury. Methods: Effects of TGF-β1 over-expression in MSCs on expression of CXCR4 and chemotactic effect to SDF-1 were investigated by in vitro transmembrane chemotaxis. Anti-TGF-β1 antibody was incubated with ischemia reperfusion injury renal tissue homogenate and effects of anti-TGF-β1 antibody were observed. In addition, effects of TGF-β1 gene transfection and anti-CXCR4 antibody treatment in MSCs on expression of SDF-1/CXCR4 axis of renal tissues and damage repair were further explored. Results: Expression of TGF-β1 mRNA in the IRI group increased significantly, and MSCs transplantation could enhance expression of CXCR4 mRNA in rats of the IRI group, the expression of CXCR4 can be decreased by the anti-TGF-β1 antibody and the anti-CXCR4 antibody. TGF-β1 induced homing of MSCs in repair of renal ischemic reperfusion injury by regulating expression of CXCR4 on cell membranes. Blue fluorescence of DAPI-positive MSCs cells of renal parenchyma in the IRI+MSC group was enhanced significantly, which was significantly inhibited by anti-TGF-β1 and anti-CXCR4 antibody, and the inhibitory effect of anti-CXCR4 antibody was more obvious than that of anti-TGF-β1 antibody. Conclusion: Transforming growth factor-β1 promotes homing of bone marrow mesenchymal stem cells in renal ischemia-reperfusion injury, which will provide useful data on role of TGF-β1 in regulating SDF-1/CXCR4 axis-induced MSCs homing.     

肝硬化大鼠肝缺血-再灌注损伤后Bsep、Mrp2表达在胆汁淤积中的作用研究

目的 研究肝硬化大鼠肝缺血-再灌注损伤（HIRI）后胆汁淤积的部分分子机制。方法 将健康SD大鼠随机分成A、B、C3组,每组15只,建立肝硬化、HIRI模型。A组为正常大鼠HIRI组,B组为肝硬化大鼠假手术组,C组为肝硬化大鼠HIRI组。每组大鼠肝门阻断时间为30min。分别检测各组大鼠术后第1、3、5天的胆汁DBil、TBil含量,血清AST、ALT、TBil、DBil含量;Westernblot分析各组大鼠术后第1、3、5天胆盐输出泵（Bsep）、多耐药相关蛋白2（Mrp2）表达变化;免疫组织化学法分析Bsep蛋白的细胞亚定位。结果术后第1天,C组大鼠胆汁TBil、DBil含量均低于A组（均P＜0.05）;术后第3天,C组大鼠胆汁TBil、DBil含量均低于A组和B组（均P＜0.05）;术后第5天,3组大鼠胆汁TBil、DBil含量比较差异均无统计学意义（均P＞0.05）。C组大鼠术后第1、3天血清AST、ALT水平均高于A组,术后第1、3、5天血清TBil、DBil含量均高于A、B组（均P＜0.05）。术后第1、3、5天,C组大鼠Bsep蛋白表达量均低于A组,术后第3、5天均低于B组（均P＜0.05）;C组Mrp2表达均低于A、B组（均P＜0.05）。肝细胞Bsep蛋白明显向细胞质移位。结论与正常肝脏相比,硬化肝对缺血耐受能力差,HIRI后硬化肝的胆汁淤积情况更加严重。Bsep、Mrp2表达降低以及Bsep蛋白由细胞膜向细胞质移位的改变在硬化肝HIRI后胆汁淤积中起了重要作用。     

缺血后处理对大鼠睾丸缺血再灌注损伤的影响

目的观察缺血后处理对大鼠睾丸缺血再灌注损伤的影响。方法 60只成年雄性SD大鼠随机分为对照组、缺血再灌注组和缺血后处理组,每组20只。对照组行左侧睾丸假手术。缺血再灌注组予左侧睾丸扭转720度,2h后复位。缺血后处理组予左侧睾丸扭转720度,2h后行缺血后处理,即先将睾丸复位,血流再灌注10s,然后将睾丸再次扭转720度,使睾丸缺血10s,反复6个循环,最后睾丸复位,血流持续灌注。复位后4h,每组处死大鼠10只,行左侧睾丸切除术,测定睾丸组织丙二醛水平。复位后3个月,各组处死剩余的大鼠,行左侧睾丸切除术,分析睾丸生精功能。结果睾丸组织丙二醛含量缺血后灌注组缺血后处理组处理组[(2.73±0.34)、(1.86±0.29)、(1.45±0.20)mmol/mg](P0.05),睾丸生精功能对照组缺血后处理组缺血后灌注组[(22.03±1.97)、(15.13±1.81)、(2.14±0.42)×106](P0.05)。结论缺血后处理对睾丸缺血再灌注损伤有保护作用,其作用机制可能与降低活性氧水平有关。