链脲佐菌素诱导的糖尿病大鼠早期视网膜NO的变化

目的利用链脲佐菌素(STZ)诱导的1型糖尿病大鼠模型,研究糖尿病早期视网膜一氧化氮(NO)浓度的变化。方法健康成年雄性SD大鼠腹腔注射STZ60mg/kg,7d后血糖>13.9mmol/L入选为糖尿病组,与正常对照组在无特定病原体(SPF)环境下饲养,每周监测体重与血糖。8周后氯胺酮全身麻醉下摘取眼球,分离视网膜,制成组织匀浆。应用硝酸还原酶法测定组织NO浓度。结果糖尿病组与对照组在8周末时的平均体重差异有极显著统计学意义(t=11,P<0.01)。两组在各观察时段的平均血糖水平差异均有显著统计学意义(P<0.05)。两组视网膜样品的蛋白浓度差异无显著统计学意义(t=0.765,P>0.05)。糖尿病组视网膜平均NO浓度为(0.352±0.256)μmol/gprot,对照组为(0.031±0.017)μmol/gprot,两组间差异有显著统计学意义(t=2.79,P<0.05)。结论STZ诱导的糖尿病大鼠早期视网膜NO浓度增加,是引起糖尿病早期视网膜血管功能性改变的重要因素。     

早期糖尿病大鼠光感受器超微结构变化

目的探讨早期糖尿病视网膜病变光感受器超微结构变化。方法选择健康成年Ｗｉｓｔａｒ大鼠３２只,随机分成正常对照组、糖尿病１,３月和６月组。 ５５ ｍｇ／ｋｇ体重一次性腹腔内注射链脲佐菌素诱导大鼠糖尿病。取大鼠视网膜制备超薄切片,透射电镜观察并计算机图像分析。结果病程１月只见视杆细胞膜盘模糊不清,膜盘间隙略有扩大;病程３月时,膜盘间隙扩大明显,并发生局部断裂溶解。视杆细胞核固缩、异染色质浓集。视杆内节线粒体肿胀、甚至空泡变性。病程６月时,以上改变更加严重。结论糖尿病视网膜病变早期大鼠出现光感受器的形态变化,随病程进展,呈现逐渐加重的趋势。     

链脲佐菌素诱发糖尿病大鼠模型视网膜形态学改变的观察

目的 研究链脲佐菌素(streptozotocin,STZ)诱发SD大鼠糖尿病的视网膜形态学改变,为STZ诱发的糖尿病大鼠作为糖尿病视网膜病变动物模型提供依据.方法 20只成年SD大鼠随机分为2组,A组用STZ腹腔注射法诱发糖尿病,B组作为正常对照.用葡萄糖氧化酶法在建模后1 d、2 d、3 d、1周、2周、3周、4周连续测定大鼠血糖,在建模当天及建模后1周、2周、3周、4周用电子天平连续测量大鼠体质量,判断糖尿病发生的有效性和稳定性.通过临床和实验方法(包括裂隙灯检查,直接、间接眼底镜检查,4周时行组织切片、视网膜血管铺片、透射电镜等方法)检查大鼠眼前后节的病理改变.结果 A组大鼠血糖在注射STZ后1 d达到(33.9±1.7)mm01.L-1,在4周时达到(41.6±4.5)mmol.L-1,而B组始终低于16.7 mmoI.L-1.从建模之后,A组大鼠的体质量与B组相比,增长缓慢,有显著统计学意义.临床检查,A组1只糖尿病大鼠在4周时发生了白内障,B组大鼠眼前后节没有明显改变.发病4周时,组织学检查显示,A组大鼠视网膜厚度要薄于B组,透射电镜显示A组大鼠视网膜各层结构有明显的病理改变包括膜盘间隙扩大、排列紊乱、内外核层细胞疏松等,血管铺片显示4周A组大鼠视网膜毛细血管周细胞数量减少.结论 用STZ方法建立糖尿病模型是有效的,发病4周时糖尿病大鼠已经有较明显的视网膜形态学改变,能够作为糖尿病视网膜病变模型用于临床和科研.     

白细胞对早期糖尿病视网膜病变作用的研究

目的探讨白细胞在早期糖尿病大鼠视网膜毛细血管中粘附、堆积及其与视网膜微血管形态学变化的关系。方法健康成年雄性Wistar大鼠90只，随机分成正常对照组和链脲佐菌素（streptozotocin, STZ）诱导的糖尿病组各45只（3、7、14 d组各5只，30、90、180 d组各10只）。取大鼠右眼制备视网膜消化铺片，进行形态学观察及白细胞共有抗原（leukocyte common antigen, CD45）单克隆抗体免疫组织化学研究。结果正常对照组视网膜毛细血管中有少许CD45阳性细胞；糖尿病发生3 d后，CD45的表达明显增加，病程第14 d达高峰，以后基本稳定。病程90 d时，视网膜毛细血管已出现节段性膨大、囊样扩张及闭锁等形态学改变；病程180 d时，上述病变进一步加重。结论白细胞粘附发生在糖尿病视网膜病变（diabetic retinopathy, DR）的早期阶段，是DR在微血管水平病理变化的开端。白细胞粘附可能作为视网膜微血管形态学改变的基础，在DR的发生发展中起着重要作用。(中华眼底病杂志,2003,19:344-347)     

血管内皮生长因子在糖尿病在鼠视网膜中的表达

目的：观察血管内皮生长因子（VEGF）蛋白在链脲佐菌素（STZ）诱导的糖尿病大鼠视网膜中的表达情况，以探讨其在早期糖尿病视网膜病变（DR）中的作用。方法：选择健康成年Wistar大鼠40只，随机分成正常对照组（CON）、糖尿病1个月组（DM1）、糖尿病3个月组（DM3）及糖尿病6个月（DM6）组，每组10只。大鼠腹腔内注射STZ诱发大鼠糖尿病。制备大鼠视网膜石蜡切片行免疫组化ABC法染色，光镜观察。结果：VEGF于CON和DM1组只表达于内核层及节细胞层部分细胞；病程3个月时，尚可见视网膜血管的阳性反应；6个月时，阳性反应范围又扩大至视杆内节和色素上皮细胞。结论：随病程进展，VEGF在视网膜中的表达呈逐渐增强的趋势，提示它在早期DR的发生、发展中起重要作用。     

糖尿病早期大鼠视网膜功能的多焦视网膜电图研究

目的:建立高血糖动物模型并以多焦视网膜电图(mfERG)评价其早期视网膜功能状态。方法:SD大鼠16只,随机分为正常对照组和预造模组,采用化学药物链尿佐菌素(STZ)分2次ip,建立高血糖动物模型,观察2组大鼠一般性生理指标,并分别于成模后1,2,4,8wk末对其进行多焦视网膜电图检测。结果:STZ分次ip大鼠一次成模率80%,8wk死亡率12.5%,血糖始终保持在稳定的高水平;STZ大鼠1wk时N1波和P1波波峰潜时已有延长,反应密度降低,P1波改变较为明显,4wk时与正常组相比P<0.05,8wk时与正常组相比P<0.01。结论:STZ低剂量分次注射是较为理想的高血糖动物造模方法。糖尿病大鼠在1wk时即出现视网膜功能的损害,并随着高血糖状态的持续而逐渐加重,即在出现明显视网膜病变之前已经出现了视网膜功能损害。     

链脲佐菌素诱导的糖尿病大鼠视网膜VEGF、PEDF的动态表达

目的观察血管内皮生长因子（VEGF）和色素上皮源性因子（PEDF）在糖尿病大鼠视网膜中的表达，探讨其在早期糖尿病视网膜病变中的作用。方法选取84只健康SD大鼠，尾静脉注射链脲佐菌素建立糖尿病大鼠模型。根据饲养时间，随机分为正常对照0．5月组（NO．5）、糖尿病0．5月组（DM0．5）、正常对照1月组（N1）、糖尿病1月组（DMl）、     

链脲佐菌素-糖尿病大鼠视网膜微血管病理改变

目的：观察SIZ-糖尿病大鼠视网膜微血管的早期病理变化。方法：45只SD大鼠被随机分为糖尿病组(DM)和对照组(CON)，用链脲佐菌素(streptozotocin，STZ)诱导SD大鼠建立糖尿病动物模型，分别饲养3个月和6个月。各组大鼠到期后，取眼球，采用视网膜消化铺片PAS染色、细胞图像分析及透射电镜技术进行早期糖尿病视网膜微血管形态学检查，记数微血管细胞数和无细胞血管数目，观察微血管及细胞超微结构。结果：糖尿病视网膜早期微血管周细胞数目逐渐减少，无细胞血管增多。超微结构显示微血管细胞结构异常，基底膜变性、增厚。结论：糖尿病视网膜病变早期存在微血管细胞病变、基底膜变性增厚及无细胞血管形成的改变。临床应重视糖尿病视网膜病变(DR)的早期防治，改善微血管循环。     

糖尿病大鼠眼内VEGF阶段性表达的Meta分析

目的：通过分析确定VEGF在糖尿病大鼠眼病各阶段表现,为临床治疗阶段提供最有效的参考。

方法：通过检索PubMed、EMBASE、Medline、中国知网、万方、维普等数据库,筛选以糖尿病大鼠为模型研究VEGF在糖尿病眼病病程中表达的随机对照实验。对入选文献用Jadad评分表(共5分)进行评分,经异质性检验后采用固定效应模型进行数据综合,按时间段进行亚组分析。

结果：纳入高质量文献8篇,异质性检验排除两篇。数据综合显示糖尿病大鼠眼内VEGF的表达上升了1.62%, 95%CI(1.20,2.03),P<0.01。

结论：VEGF在2～6月龄糖尿病大鼠眼内组织各个阶段中表达增强,但强度在逐渐下降。     

血管内皮生长因子在糖尿病大鼠视网膜中的表达

目的 :观察血管内皮生长因子 (VEGF)蛋白在链脲佐菌素 (STZ)诱导的糖尿病大鼠视网膜中的表达情况 ,以探讨其在早期糖尿病视网膜病变 (DR)中的作用。方法 :选择健康成年Wistar大鼠 4 0只 ,随机分成正常对照组 (CON)、糖尿病 1个月组 (DM1)、糖尿病 3个月组 (DM3)及糖尿病 6个月 (DM6 )组 ,每组 10只。大鼠腹腔内注射STZ诱发大鼠糖尿病。制备大鼠视网膜石蜡切片行免疫组化ABC法染色 ,光镜观察。结果 :VEGF于CON和DM1组只表达于内核层及节细胞层部分细胞 ;病程 3个月时 ,尚可见视网膜血管的阳性反应 ;6个月时 ,阳性反应范围又扩大至视杆内节和色素上皮细胞。结论 :随病程进展 ,VEGF在视网膜中的表达呈逐渐增强的趋势 ,提示它在早期DR的发生、发展中起重要作用     

Simvastatin suppresses expression of angiogenic factors in the retinas of rats with streptozotocin-induced diabetes

Background  

Angiogenic factors such as vascular endothelial growth factor (VEGF), erythropoietin, and angiopoietin play important roles in the pathophysiology of diabetic retinopathy. Increased amounts of reactive oxygen species (ROS) are also known to associated with diabetic retinopathy and VEGF expression. This study evaluated the effect of a simvastatin on ROS generation and the changes in various angiogenic factors in the retinas of diabetic rats.     

Reduced expression of the adherens junction protein cadherin-5 in a diabetic retina

PURPOSE: Transvascular leakage occurs in diabetic retinopathy. The tight junction proteins occludin and zonula occludens-1 (ZO-1) and adherens junction protein cadherin-5 are critical to the maintenance of endothelial barrier. We report a comparison of junction protein expression in the normal and diabetic retina. METHOD: Case report. Postmortem retinal cryosections were prepared from the left eye of a 73-year-old woman with diabetic retinopathy. Cryosections were immunostained for cadherin-5, occludin, and ZO-1 and compared with retinal cryosections from the right eye of a 72-year-old man with no progression of retinal disease. RESULTS: Immunofluorescence showed positive retinal vessel staining for occludin and ZO-1 in both eyes and cadherin-5 in the normal eye but reduced cadherin-5 staining in the retinal vessels of the diabetic eye. CONCLUSION: Increases in transvascular leakage observed in diabetic retinal vasculature may be associated with reduction in the expression of the critical adherens junction protein, cadherin-5.     

Arachidonic acid metabolism by retinas of rats with streptozotocin-induced diabetes

Arachidonic acid metabolism via the cyclooxygenase pathway and the effects of aspirin and indomethacin were studied in whole retinas of rats with streptozotocin-induced diabetes. Diabetes was induced by intravenous injection of streptozotocin (60 mg/kg) and the animals were examined 5-6 weeks later. Whole retinas of nondiabetic and diabetic animals were incubated for 1 1/2 hours, and the amounts of prostacyclin and prostaglandin E2 (PGE2) accumulated in the media were measured. The amounts of PGE2 in the media of diabetic retinas was significantly lower than levels in media of nondiabetic group. However, the amounts of prostacyclin accumulated in the media of nondiabetic and diabetic retinas did not differ significantly. Addition of arachidonic acid (A.A.) to the incubation media caused an enhancement in the amounts of PGE2 and prostacyclin in the incubation media of both diabetic and nondiabetic retinas. Addition of indomethacin or aspirin to the incubation media caused a reduction of prostacyclin and PGE2 levels in the media of both groups.     

Increased expression of angiotensin-converting enzyme in retinas of diabetic rats.

PURPOSE: The aim of this study was to examine the localization and the changes in the amount of angiotensin-converting enzyme (ACE) and the relationship between the renin-angiotensin (RA) system and vascular endothelial growth factor (VEGF)/VEGF-receptor system in the retinas of diabetic rats. METHODS: Immunohistochemical localization of ACE, VEGF, and VEGF-receptor fetal liver kinase-1 (Flk-1) was examined in cryosections of the retinas of streptozotocin-injected diabetic rats. A semi-quantitative comparison of diabetic rats with age-matched controls was also performed by counting the ACE- or Flk-1-positive vessels per microscopic field. RESULTS: ACE immunoreactivity was localized in the retinal vessel walls, and the percentages of ACE-positive vessels were significantly increased in the retinas of diabetic rats maintained 3 to 5 months. Both VEGF and Flk-1 signals increased simultaneously with the increment of ACE immunoreactivity. CONCLUSIONS: ACE, expressed in the retinal vessel walls, increases simultaneously with the increment of both VEGF and Flk-1 in the retinas of diabetic rats, suggesting that upregulation of ACE might play some role in the progression of diabetic retinopathy through the VEGF/VEGF receptor system.     

硫酸软骨素蛋白多糖在视网膜变性大鼠中的表达

目的 研究硫酸软骨素蛋白多糖(CSPGs)在碘酸钠(NaIO3)诱导的视网膜色素上皮(RPE)细胞变性大鼠中的表达情况.方法 实验研究.24只Sprauge-Dawley(SD)大鼠随机分为4组,正常对照组、造模7d组、造模14 d组、造模28 d组,每组6只.造模组腹腔注射3％ NaIO3(100 mg/kg);取眼球做病理检查,苏木素-伊红(HE)染色及细胞凋亡检测,验证视网膜变性动物模型的建立;免疫荧光法观察视网膜变性大鼠视网膜上CSPGs表达的时空规律;逆转录-聚合酶链反应(RT-PCR)法检测CSPGs多功能蛋白聚糖(Versican) mRNA的表达情况;免疫组织化学法观察视网膜上小胶质细胞表达的巨噬细胞特异性抗原CD68的分布特点.多组比较采用单因素方差分析,两样本间比较采用独立样本t检验.结果 注射NaIO3后,模型大鼠视网膜出现变性改变,且光感受器发牛渐进性凋亡,造模7、14、28 d组凋亡率分别为(21.0±3.5)％、(32.3±2.3)％、(41.7±2.6)％,各组间差异有统计学意义(F=205.27,P＜0.01).造模7d组,CS-56、CD68在脉络膜、视锥视杆层、内核层、节细胞层表达;造模14 d组,CS-56、CD68进一步出现在外核层;造模28 d组,CSPGs继续迁移到外丛状层.随造模时间延长,各层荧光表达逐渐增强,CD68在视网膜各层的表达也明显增多,强度分别为:1.33±0.52、2.67±0.82、4.00±1.10和7.17±1.33,各组间差异有统计学意义(F=38.45,P＜0.01).造模组Versican mRNA表达(1.02±0.06)显著高于正常对照组(0.23±0.02),差异有统计学意义(t=-26.05,P＜0.01).结论 在碘酸钠诱导的视网膜变性动物模型中,随时间延长CSPGs表达范围扩大,表达量增加,并与小胶质细胞分布在大致相同区域,提示CSPGs可能来源于小胶质细胞.     

促红细胞生成素对慢性高眼压下大鼠视网膜Caspase-9表达的影响

目的 探讨促红细胞生成素(erythropoietin,EPO)在视网膜神经节细胞凋亡途径中的作用机制.方法 选取120只大鼠随机分为12组,每组10只20眼;巩膜烧灼法制作大鼠慢性高眼压模型.用药组每只大鼠腹腔注射EPO.应用RT-PCR法、Western blotting印迹法检测备组视网膜组织甲Caspase-9基因Mrna及蛋白表达情况.检测用药前后ERG-b波波幅和视网膜厚度的变化.结果 EPO用药组视网膜水肿明显减轻,视网膜厚度变薄的趋势明显减弱,与未用药组比较差异有统计学意义.用药组ERG-b波波幅明显恢复,2组差异有统计学意义;Caspase-9 Mrna和蛋白在用药后除高眼压后3 d组外,表达均明显减少,与未用药组比较,差异有统计学意义.结论 EPO对慢性高眼压后的视网膜具有保护作用,其机制之一是通过抑制Caspase-9介导的凋亡信号转导途径来完成的.     

Behavioral recovery in albino rats with glutamate-damaged retinas

Adult, male, albino rats were trained to discriminate between two patterned stimuli in a T-maze. Performance on this task was assessed following intravitreal injection of 1 mumol glutamate. Discrimination performance declined to nearly random levels by 1 day postinjection and remained significantly depressed for 2 weeks. However, by 2 months after injection, there was evidence of behavioral recovery to preinjection levels despite significant loss of inner retinal neurons. Task-related experience immediately following or 2 months after injection proved both necessary and facilitative for recovery.