Inflammation Level after Decompression Surgery for a Rat Model of Chronic Severe Spinal Cord Compression and Effects on Ischemia-Reperfusion Injury

Delayed neurological deterioration in the absence of direct spinal cord insult following surgical decompression is a severe postoperative complication in patients with chronic severe spinal cord compression (SCC). The spinal cord ischemia-reperfusion injury (IRI) has been verified as a potential etiology of the complication. However, the exact pathophysiologic mechanisms of the decompression-related IRI remain to be defined. In this study, we developed a practical rat model of chronic severe SCC. To explore the underlying role of inflammation in decompression-related IRI, immunoreactivity of pro-inflammatory cytokines including tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) before and after decompression were measured. In addition, expression level of TNF-α and IL-1β was examined with Western blot. Immunohistochemical staining showed negative result in gray matters in the sham group and sham-decompression group. In the severe compression group, strong positive staining of TNF-α and IL-1β were found, suggesting a dramatic infiltration of inflammatory cells in gray matters. Furthermore, the severe compression group showed a significant increase in expression level of TNF-α and IL-1β as compared with the sham group (p < 0.05). In the severe compression-decompression group, both immunostaining and Western blot showed significant increase of TNF-α and IL-1β levels in the spinal cord compared with the severe compression group (p < 0.05). The results demonstrated that surgical decompression plays a stimulative role in inflammation through increasing the expression of inflammatory cytokines in the rat model of chronic severe SCC injury. Inflammation may be one of the important pathological mechanisms of decompression-related IRI of chronic ischemia.     

异甘草酸镁联合维拉帕米对大鼠肝切除肝缺血再灌注损伤的作用研究

目的 研究异甘草酸镁(magnesium isoglycyrrhizinate,MgIG)联合维拉帕米(verapam-il,异搏定)对肝切除肝缺血再灌注损伤的作用.方法 雄性SD大鼠随机分为假手术组(A组)、50％肝切除肝缺血再灌注损伤组(B组)、50％肝切除肝缺血再灌注损伤+ MgIG治疗组(C组)、50％肝切除肝缺血再灌注损伤+ verapamil治疗组(D组)、50％肝切除肝缺血再灌注损伤+MgIG联合verapamil治疗组(E组).观察各组大鼠肝脏功能、形态学、超氧化物歧化酶(SOD)活性及FasL的表达情况.结果 与B组比较,E组病理改变明显减轻,各时间点血清丙氨酸转氨酶(ALT)水平显著下调(P＜0.05),肝组织SOD活性明显增强(P＜0.05),FasL蛋白表达明显下调(P＜0.05).结论 异甘草酸镁联合维拉帕米能有效减轻肝切除肝缺血再灌注损伤.其对肝细胞的保护作用可能是通过抑制Fas/FasL系统介导的凋亡反应,减轻肝脏过氧化损伤而实现.     

热激活蛋白70识别蛋白在脊髓缺血再灌注损伤后表达变化及其意义

目的:探讨热激活蛋白70识别蛋白(heat shock cognate protein 70,HSC70)在兔脊髓缺血再灌注损伤(spinal cord ischemia-reperfusion injury,SCIRI)后表达变化及其意义。方法:随机将36只新西兰白兔分成6组(每组6只),采用Zivin法建立兔SCIRI模型。A组只显露腹主动脉而不阻断血流,30min后关闭腹腔,取材(L3~L5段脊髓);B组阻断腹主动脉血流30min后关闭腹腔,取材;缺血再灌注组(C、D、E、F组)阻断腹主动脉血流30min后停止夹闭,再灌注6、12、24、48h时采用改良Tarlov评分分别进行运动功能评价后取材。应用差异蛋白质组学技术荧光差异双向凝胶电泳联合质谱分析筛选出应激相关蛋白HSC70,利用免疫印迹对质谱进行印证,结合免疫组化研究其在脊髓内的时空变化特点。结果:成功建立SCIRI兔模型,SCIRI后实验动物后肢功能逐渐好转,C~F组改良Tarlov评分分别为1.167±0.753、1.667±0.516、2.668±0.516和2.167±0.752分,再灌注24h达SCIRI早期最好水平,再灌注48h略有下降。应激相关蛋白HSC70在A组印迹清晰,B组印迹轻微加强,C组和D组印迹再次加强,E组印迹显著减弱至最低,F组印迹灰度回归至再灌注6~12h水平。A组灰质中部体积较小中间神经元胞浆见轻度免疫反应;B组灰质各部位神经元胞浆免疫反应程度与A组相当;C组胶质细胞核免疫反应加重;D组神经元免疫反应减轻,但胶质细胞及雪旺细胞核免疫反应较强烈;E组神经元免疫反应进一步减弱,低于A组水平;F组神经元胞浆免疫反应加重,胶质细胞及雪旺细胞核免疫反应仍强烈。结论:HSC70参与SCIRI发生和发展过程,可作为SCIRI预防、诊断和治疗的靶点。     

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.