缺血-再灌注损伤后视网膜形态学改变和Bcl-2/Bax表达

目的观察视网膜缺血-再灌注损伤后的形态学变化;探讨Bcl-2/Bax表达与视网膜神经节细胞数量的关系。方法建立Wistar大鼠视网膜缺血-再灌注模型,计数其再灌注后1、6、12、24、48、72 h的视网膜神经节细胞(RGC);免疫组化SP法检测同时段凋亡相关蛋白Bcl-2、Bax的表达。结果大鼠缺血-再灌注后RGC计数在6 h时开始大量减少,6~12 h快速减少,24 h后呈慢速减少。再灌注6、12、24、48、72h的Bcl-2、Bax蛋白阳性表达结果与正常组比较,有显著差异(P<0.05)。再灌注后6、12 h Bcl-2/Bax比率上升,24、48、72 h下降。结论视网膜缺血再灌注后RGC凋亡与Bcl-2/Bax表达有关。     

GM-1对大鼠视网膜缺血再灌注损伤后NF-кB表达的影响

目的：观察神经节苷脂(monosialoganglioside，GM-1)对大鼠视网膜缺血再灌注损伤后视网膜结构的保护作用及对核因子-κB(nuclear factor-kappaB, NF-κB )表达的影响，探讨其可能的保护机制。方法：健康成年Wistar大鼠75只，随机分为3组：正常组5只、NS组35只、GM-1组35只。正常组不加任何处理因素，NS组和GM-1组通过升高眼压造成视网膜缺血60min，分别于缺血前12、1h及缺血结束时3次腹腔注射NS 3ml·kg-1或GM-1 3ml·kg-1，并于再灌注0(单纯缺血后)、1、6、12、24、72和168h共7个时点取双眼眼球，每时间点5只。HE染色观察视网膜组织结构并测量视网膜内层平均厚度(mean thickness of the inner retinal layers, MTIRL)，免疫组化SP法检测NF-κB的表达并计算阳性细胞率。方差分析法进行统计处理。结果：大鼠视网膜缺血再灌注后，内层视网膜相继出现水肿和萎缩。再灌注后大鼠视网膜内层NF-κB迅速激活，随后其表达逐渐下降。GM-1可明显减轻视网膜缺血再灌注后的组织损伤，并显著抑制NF-κB的活化。结论：NF-κB活化可能是视网膜缺血再灌注损伤的早期始动因素。GM-1对视网膜缺血再灌注损伤具有明确的保护作用，对NF-κB的抑制可能是其保护机制之一。     

缺血再灌注损伤后大鼠视网膜细胞凋亡与低氧诱导因子1α表达的关系

目的研究缺血再灌注损伤后大鼠视网膜细胞凋亡与低氧诱导因子1α（HIF-1α）的表达变化并探讨两者的相关性。方法雄性SD大鼠随机分为正常对照组和缺血再灌注损伤1 d、3 d和5 d组（n=6）。眼前房灌注生理盐水调节大鼠眼压至110 mmHg并持续50 min,制作实验性视网膜缺血再灌注损伤模型。制备视网膜切片,测量内网层（IPL）、内核层（INL）厚度及节细胞层（GCL）细胞数;采用DNA原位末端标记（TUNEL）法检测视网膜凋亡细胞;免疫组织化学染色观察损伤后不同时间HIF-1α在视网膜细胞中的表达;采用RT-PCR检测HIF-1αmRNA的表达。结果缺血再灌注损伤1 d、3 d和5 d组大鼠的IPL和INL厚度显著小于正常对照组（P〈0.01）,GCL细胞少于正常对照组（P〈0.05）。视网膜细胞凋亡位于GCL;缺血再灌注损伤1 d、3 d和5d组的细胞凋亡率均明显高于正常对照组,差异有统计学意义（P〈0.01）。缺血再灌注损伤1 d、3 d、5 d组视网膜GCL的HIF-1α蛋白表达阳性细胞比例分别为（47.88±14.71）%、（50.28±13.11）%、（43.09±10.04）%,与视网膜细胞凋亡率呈正相关（r=0.953）。缺血再灌注损伤3 d组视网膜细胞HIF-1αmRNA表达明显高于正常对照组（P〈0.05）。结论缺血再灌注后大鼠视网膜细胞凋亡与HIF-1α的表达均增加,两者呈正相关;HIF-1α的表达可能参与视网膜细胞凋亡。     

大鼠视网膜缺血再灌注后多聚二磷酸腺苷核糖聚合酶的表达变化

目的观察大鼠视网膜缺血再灌注损伤后不同时相视网膜结构变化及多聚二磷酸腺苷核糖聚合酶(PARP)的表达情况。方法升高眼压到110mmHg持续1h，建立大鼠视网膜缺血再灌注模型。HE染色观察视网膜组织病理学改变；免疫组化Ehvision^TM法检测视网膜细胞PARP表达。结果正常对照组大鼠视网膜仅见微量PARP表达；缺血1h再灌0h组视网膜结构未见明显变化；再灌注6h，视网膜开始有中性粒细胞浸润，神经节细胞层(ganglion cell layer，GCL)PARP表达显著增加；12、24h组视网膜中有较多中性粒细胞浸润，神经节细胞层PARP表达24h达高峰后下降，但仍维持较高水平；24h后内核层(inner nuclear layer，INL)细胞PARP表达明显增高，168h达高峰，伴之神经节细胞层和内核层细胞明显变薄。另外，也见自身对照眼视网膜神经节细胞层PARP表达增加。结论大鼠视网膜缺血再灌注早期PARP即表达上调，24h组在GCL达高峰，168h组在INL达高峰，这一过程可能与视网膜神经节细胞层和内核层细胞凋亡有关。     

环磷酰胺对脑缺血再灌注海马GFAP表达的影响

目的观察环磷酰胺对脑缺血再灌注后大鼠大脑海马区胶原纤维酸性蛋白（GFAP）表达的影响。方法设正常组、假手术组、缺血再灌注组（I／R）和环磷酰胺处理组（T）,以改良Longa线栓法建立sD大鼠局灶性脑缺血模型。处理组缺血后1h给予环磷酰胺腹腔注射,处理组和I／R组均于缺血后2h形成再灌注,每组均分为三个时间段（24h、72h和5d）分别观察。应用免疫组织化学技术检测各组脑组织不同时段以及正常脑组织中海马GFAP的表达情况。结果脑缺血再灌注5d内,随着缺血时间的延长,GFAP在海马区星形胶质细胞中的阳性表达逐渐增多,缺血24h后即有表达,缺血再灌注72h后增多,5d后表达最高;经过环磷酰胺处理后,海马区GFAP表达减少（P〈0．05）。正常组及假手术组未见GFAP表达。结论大鼠脑缺血再灌注后5d内GFAP在海马中的表达与缺血时间呈明显的相关性,随着缺血时间延长而增加。用环磷酰胺处理后GFAP表达明显减少,提示环磷酰胺对缺血诱导的星形胶质细胞活化具有抑制作用,可能对脑缺血再灌注损伤的恢复起重要作用。     

视网膜缺血再灌注后c-fos、c-jun蛋白表达

目的:观察大鼠视网膜缺血再灌注(RIR)后,凋亡即刻基因cfos、cjun在视网膜各层细胞中的表达变化,进一步明确凋亡即刻基因和RIR损伤发生机制的关系。方法:采用视网膜中央动脉结扎方法诱导大鼠视网膜缺血60min,解除结扎,建立RIR模型。缺血60min,再灌注0,1,3,6,12,24h作视网膜石蜡切片,cfos,cjun免疫组化观察。结果:正常对照组和缺血组未见cfos、cjun表达,RIR后,视网膜神经节细层(ganglioncelllayer,GCL)和内核层(innernuclearlayer,INL)1h开始少量表达(P<0.05),3h达到高峰(P<0.05),6h开始下降(P<0.05),24h几乎趋于正常组表达(P>0.05)。而外核层(outernuclearlayer,ONL)几乎无阳性表达。结论:cfos、cjun参与RIR损伤发生,RIR中视网膜节细胞层和内核层细胞存在凋亡征象,尤以3h组最为显著。     

Therapeutic effect of bFGF on retina ischemia-reperfusion injury

Background Basic fibroblast growth factor (bFGF) plays important roles in retina degeneration, light injury, mechanical injury, especially in retina ischemia-reperfusion injury (RIRI). This study was to investigate the therapeutical effect of bFGF on RIRI and its mechanisms.Methods Experimental RIRI was induced by increasing intraocular pressure (IOP) in the eyes of 48 rats. These rats were divided into normal control, ischemia-reperfusion and bFGF-treated groups.Histological and ultrastructural changes of in the retina of different groups were observed, and the number of retinal ganglion cells (RGCs) was quantitatively analyzed under microscopy. Apoptotic cells were detected using the TdT-dUTP terminal nick-end labeling (TUNEL) method. The expression of caspase-3 was determined by streptavidin peroxidase (SP) immunohistochemistry. Atomic absorption spectrum method was used to evaluate the intracellular calcium changes.Results At the early stage of retinal ischemia-reperfusion injury, retina edema in the treated group was significantly eliminated compared with the untreated ischemic animals. RGCs in the bFGF-treated group was more than those in the untreated ischemic group during the post-reperfusion stages. In ischemic group, apoptotic cells could be found at 6th hours after reperfusion and reached the peak at 24th hours. At 72th hours no apoptotic cells could be found. The changes in caspase-3 expression had a similar manner. The intracellular calcium of rat retina began to increase at lth hour, reached the peak at 24 hours, and began to decease at 72th hours. The change of the three markers in the treatment group showed a similar pattern, but they were all relatively less obvious.Conclusion Apoptosis may play a vital role in RIRI. bFGF may has therapeutical effects on RIRI by inhibiting the increase of intracellular calciums and caspase-3 expression.     

神经干细胞移植对脑缺血/再灌注损伤大鼠HIF-1α和HIF-3α表达的影响

目的探讨神经干细胞(NSCs)移植对大鼠脑缺血/再灌注损伤海马区低氧诱导因子1α(HIF-1α)和低氧诱导因子3α(HIF-3α)表达的影响。方法线栓法制作大鼠大脑中动脉缺血/再灌注模型,大鼠随机分为假手术组、模型组、NSCs组。再灌注72 h后神经功能损害评分表(NSS)法行神经功能评分,免疫组化法检测海马区HIF-1α和HIF-3α蛋白表达。结果 NSCs移植后可见PKH26标记的NSCs在海马区有表达。与模型组比较,NSCs组NSS评分显著降低(P<0.05),海马区HIF-1α和HIF-3α蛋白表达显著上调(P<0.05)。结论神经干细胞移植可上调脑缺血/再灌注损伤大鼠海马区HIF-1α和HIF-3α表达,促进脑缺血损伤神经功能恢复。     

MCP-1在大鼠视网膜缺血再灌注损伤中的表达及意义研究

目的了解MCP-1在大鼠视网膜缺血再灌注损伤中的表达及意义。方法建立大鼠视网膜缺血再灌注模型，以SABC法检测MCP-1在视网膜中的表达，统计学分析。结果 MCP-1在视网膜缺血再灌注6h开始表达，第24小时达到最高峰，48h开始表达减弱。结论MCP-1在视网膜缺血再灌注损伤中起重要作用。     

HIF-1α反义寡核苷酸脂质体的制备和对视网膜血管内皮细胞HIF-1α表达的影响

目的应用HIF-1αASODN处理牛眼视网膜微血管内皮细胞,观察细胞摄取ASODN的情况和对缺氧时细胞HIF-1α表达的影响.方法对分离的牛视网膜血管内皮细胞进行HIF-1α反义寡核苷酸的转染,CoCl2模拟缺氧培养,采用免疫组化检测不同缺氧时间HIF-1α的表达.结果硫代化修饰的标有FAM的HIF-1α反义寡核苷酸能被Lipofectin转染进BREC细胞.转染6 h后,在荧光显微镜下可观察到细胞内的绿色荧光斑.计算细胞转染率为(93.8±3.4)%.未转染组开始时HIF-1α有极低表达,在缺氧1 h时表达量显著上升,4 h达到高峰,16h后下降.而ASODN转染组HIF-1α的表达始终在极低水平,两组间有显著性差异(P＜0.01).结论以脂质体为载体能高效率地将HIF-1αASODN转染至视网膜血管内皮细胞内,明显抑制HIF-1α蛋白质的表达,这可能为HIF-1αASODN用于视网膜新生血管的治疗提供理论依据.     

地塞米松对缺血再灌注大鼠视网膜的影响

目的 观察地塞米松对大鼠视网膜缺血再灌注损伤(BIR)视网膜的影响。方法 应用前房灌注液体升高眼内压的方法,建立RIR模型,并随机分为防治组和对照组,防治组大鼠地塞米松用药从缺血前6天开始,剂量为1mg/kg,溶于1ml生理盐水中腹腔注射,给药持续8天,对照组用同体积的生理盐水代替,两组缺血60 min后分别再灌注30 min、24 h、72 h,进行视网膜丙二醛(MDA)的检测,其中24 h后每组还作光镜检测。结果 防治组视网膜MDA含量明显低于对照组(p<0.01),病理损害轻于对照组。结论 地塞米松是一种自由基清除剂,对RIR损伤有防治作用。     

HIF-1α在缺血性脑卒中脑组织中表达的实验研究

目的探讨动脉粥样硬化基础上全脑缺血性脑卒中大鼠脑组织缺氧诱导因子-1（hypoxia inducible factor-1α,HIF-1α）的表达及意义。方法制备动脉粥样硬化基础上全脑缺血性脑卒中大鼠模型,分为对照组和实验组,各组分为假手术、全脑缺血0.5、6、12、24h,运用免疫组织化学法检测HIF-1α蛋白表达及RT-PCR技术检测HIF-1αmRNA表达及变化。结果免疫组化法检测检测：对照组及实验组0.5h缺血脑组织中HIF-1α已出现明显表达,6h达峰值。RT-PCR表明：基因水平变化同蛋白水平变化相同。结论在动脉粥样硬化基础上缺血性脑卒中可诱导HIF-1α表达增强,提示HIF-1α对动脉粥样硬化基础上缺血性脑卒中起保护作用。     

Transient retinal ischemia-reperfusion in rats

Objective To investigate the effect of transient ischemia-reperfusion on the retina in rats. Methods Retinal ischemia-reperfusion was induced in rats by increasing the intraocular pressure.After 1 or 5 minutes of ischemia, retinal neuronal cell death at diffesent periods of reperfusion was studied using the TdT-deoxynucleotide terminal nick-end labeling (TUNEL) method and light microscopy.Retinal IL-1β and TNFα were quantified by an enzyme-linked immunosorbent assay (ELISA). Results A few migrating leukocytes were noticed in the retina after transient retinal ischemia-reperfusion. Rare TUNEL-positive (T+) cells were noticed in the outer granular layer or the rod and cone layer, and not in ganglion cell layer in control eyes, but they were significantly increased in the outer granular layer, the inner granular layer, and ganglion cell layer in the eyes treated with 1 or 5 minutes of retinal ischemia-reperfusion (P&lt;0.05).Retinal IL-1β was significantly increased at 6 hours after reperfusion in the eyes treated with 1 or 5 minutes ischemia over the control eyes (P&lt;0.05), but retinal TNFα was not significantly increased (P&gt;0.05 ). Conclusion Transient retinal ischemia-reperfusion for only 1 or 5 minutes of ischemia can induce the upregulation of retinal IL-1β and apoptosis of retinal neuronal cells.This kind of apoptosis in individual cells, however, was not sufficient to affect the whole retinal function.     

Time course degeneration and expression of glial fibrillary acidic protein in mer-knockout mice

Background Muller cells in the mammalian retina normally express low levels of glial fibrillary acidic protein （GFAP）; however, its expression is upregulated in response to the loss of retinal neurons. The change in expression of GFAP is one of the earliest indicators of retinal damage and is correlated with the time course of disease. The aim of this study was to investigate the time course of degeneration and the expression of GFAP in the retina of mer knockout mice. Methods A total of 30 mer knockout mice, aged from 15-20 days to 1 year and 32 age-matched wild type mice as controls were tested. Immunohistochemistry was used to show the expression of GFAP in the central and peripheral retina of mer knockout and control mice at postnatal age of 15 days （P15d）, 20 days （P20d）, 4 weeks （P4w）, 6 weeks （P6w）, 8 weeks （P8w）, 3 months （P3m）, 6 months （P6m） and 1 years （P1y）.Results The expression of GFAP in the central and peripheral retina of wild type mice was limited to the retinal ganglion cell and nerve fiber layers. In the central retina of mer knockout mice, GFAP expression was upregulated at P4w and GFAP immunolabelling penetrates across the entire thickness of the retina at P8w; whereas in the peripheral retina, the GFAP expression was upregulated at P20d and GFAP immunolabelling penetrates the entire retina after P4w. Conclusions Increased expression of GFAP in Muller cells of mer knockout mice occur at P20d in the peripheral retina and P4w in the central retina. GFAP expression in Muller cells appears to be a secondary response to the loss of retinal neurons. Increased expression of GFAP may occur prior to any detectable morphological changes in the retina. This study suggests that the loss of retinal neurons may begin in the early stages of retinitis pigmentosa, prior to the discovery of any morphological changes in the retina.     

Early activation of caspase-1 after retinal ischemia and reperfusion injury in mice

Background Caspases are important in the signaling pathway of cellular apoptosis. Caspase-3 protein expression has been shown to increase and parallel to neuronal apoptosis in retinal ischemia injury. This study was to determine whether caspase-1 is involved in neuronal cell death or in retinal ischemia and repeffusion injury.Methods In twenty-one adult mice, ischemia was induced by increasing the intraocular pressure.The animals were sacrificed at 1 hour, 3 hours, 6 hours, 1 day, 3 days and 7 days after reperfusion.Frozen sections were used for caspase-1 immunostaining and TUNEL labeling.Results In normal retina, no caspase-1 positive cells were seen. One hour after ischemia,numerous positive cells were noted in the ganglion cell layer (GCL) and inner side of inner nuclear layer (INL). At 3 hours, caspase-1 positive cells continued to increase and peaked at 6 hours, then decreased significantly at 1 day. TUNEL positive cells were detected at 3 hours and peaked at 1 day after ischemia. Double labeling of caspase-1 and TUNEL only showed few cells with co-localization after ischemia.Conclusion Caspase-1 immunoreactivity preceds to the TUNEL labeling in the GCL and INL after retinal ischemia and reperfusion injury and its early activation may play an important role in the initiation of neuronal apoptosis.     

大鼠视网膜缺血／再灌流损伤导致视网膜节细胞坏死的定量研究

用大鼠人工眼高压模型，比较观察眼高压所致缺血视网膜（ＩＲ）与缺血／再灌流视网膜（ＩＲＲ）中坏死视网膜节细胞的数量（密度）差异及坏死节细胞在ＩＲＲ中的分布规律。结果表明：ＩＲＲ中的坏死节细胞远比ＩＲ中的为多（Ｐ＜０．０１）；ＩＲＲ４象限中坏死节细胞密度差异无显著性。     

基质金属蛋白酶在视网膜缺血再灌注损伤中早期的表达及意义

目的 :观察基质金属蛋白酶 - 9(MMP— 9)及其抑制剂 - 1(TMP— 1)在大鼠视网膜缺血再灌注损伤 (RIR)早期的表达 ,探讨MMP - 9是否参与视 -血屏障 (RBR)病理损伤过程。方法 :将 38只无眼疾Wistar大白鼠随即分为两组 :正常组和缺血再灌注对照组 ,采用前房灌注加压法建立视网膜缺血再灌注模型 ,其中缺血再灌注对照组分别按 0、3、2 4h不同时间段处死动物 ,利用免疫组化法检测MMP - 9、TIMP - 1的表达 ;电镜观察BRB硝酸镧示踪。结果 :正常组视网膜未见MMP - 9及TIMP - 1表达 ,对照组再灌注后3hMMP - 9表达增高 ,2 4h呈强阳性表达且全层分布 ,TIMP - 1呈微弱表达 ,再灌注后 3h可发现硝酸镧颗粒 ,2 4h明显增多。结论 :视网膜缺血再灌注后视 -血屏障的损害与MMP - 9活性表达增高呈正相关性 (P<0 0 1) ,提示细胞外基质降解、再塑可能是视网膜缺血再灌注病理损伤的又一个重要组成部分。     

诱导型热休克蛋白70在大鼠视网膜的表达及其对视网膜缺血再灌注损伤的保护作用

目的　检测锌离子诱导的HSP70 在大鼠视网膜的表达及HSP70 对视网膜缺血再灌注损伤的保护作用。方法　生理盐水前房加压灌注制作视网膜缺血再灌注 (RIR)损伤模型 ,腹腔注射硫酸锌诱导HSP70 表达 ,作为实验组 ;腹腔注射HSP表达抑制剂 -Quercetin(槲皮素 ) ,为实验对照组 ;另取大鼠不行任何处理作正常对照组。不同时间段作视网膜HSP70 免疫组化染色 ,视网膜病理 (HE)染色、神经节细胞 (RGCs)计数 ,视网膜透射电镜观察 ,比较各组差异。结果　实验组在注射硫酸锌后 10h即见视网膜节细胞层有HSP70 阳性表达 ,16h达高峰 ,7d后仍呈弱阳性表达 ,HSP70 主要在RGCs胞浆表达 ;正常对照组及实验对照组均呈阴性表达。RIR后实验组和实验对照组均有RGCs损失 ,其中RIR后 2 4h ,实验组RGCs计数多于实验对照组且有统计学意义 (P <0 .0 5 ) ,RIR后 3d、7d差异有显著性 (P <0 .0 1) ;透射电镜观察显示实验组损伤轻于实验对照组。结论　腹腔注射锌离子可诱导大鼠视网膜的HSP70 表达 ,腹腔注射槲皮素可抑制此作用 ,HSP70 主要在RGCs胞浆表达 ;HSP70 能提高RGCs对RIR损伤的耐受性     

离体电转染pCAGGS．EGFP对小鼠视网膜神经节细胞的标记

目的：通过离体电转染将GFP对胚胎期小鼠视网膜神经节细胞（RGC）进行标记来观察其形态．方法：剥离胚胎小鼠E14的视网膜连同晶状体,放入定制的电转杯中进行电转染,以8～16V电压将pCAGGS—EGFP质粒导入RGC,体外培养视网膜1～5d,观察绿色荧光蛋白GFP的表达情况。结果：以12V,50ms,950InS的间隔,5个脉冲转染效率最高,为81．25％：20～144h期间GFP依次由胞体向轴突、树突扩散分布。结论：在体外培养基中培养1～5d．pCAGGS—EGFP经过最适电压转染后能够在小鼠视网膜神经节细胞中持续扩散表达.     

姜黄素对视网膜缺血再灌注损伤Bcl-2，Bax 表达的影响

目的：研究姜黄素（Cur）预处理对视网膜缺血再灌注损伤（RIRI）Bcl-2和Bax表达的影响,为姜黄素治疗视网膜缺血再灌注损伤（RIRI）提供实验依据。方法将33只健康成熟无眼疾的SD大鼠随机分为正常组（3组）、模型组（15只）、Cur组（15只）,缺血前1h,正常组不进行任何处理,模型组腹腔注射生理盐水,Cur组腹腔注射姜黄素,前房加压法建立视网膜缺血再灌注损伤（RIRI）模型,模型组和Cur组分别在2h,6h,12h,24h,48h5个时间段,通过腹腔注射10g/L戊巴比妥钠处死大鼠,立即摘取实验眼球,通过免疫组化检测Bcl-2和Bax阳性表达。结果正常组未见Bal-2阳性表达,模型组和Cur组在缺血再灌注后2h可见Bal-2阳性表达,6h,12hBal-2阳性表达逐渐增加,24h阳性表达达高峰,48h阳性表达逐渐减少;Bax在正常组未见阳性表达,模型组和Cur组在缺血再灌注后2h可见Bax阳性表达,6hBax阳性表达逐渐增加,12h阳性表达达高峰,24h阳性表达逐渐减少,48h表达明显下降;在各时间段Cur组Bcl-2阳性表达数均高于模型组;Bax阳性表达数均低于模型组,各时间段差异具有统计学意义（P＜0．01）。结论姜黄素预处理大鼠视网膜缺血再灌注损伤,可增加神经节细胞Bcl-2表达,减少Bax阳性表达,减少神经节细胞损伤,对视网膜缺血再灌注损伤具有保护作用。