川芎嗪联合氨胍治疗对糖尿病大鼠视网膜血管内皮生长因子表达的影响

目的 观察川芎嗪联合氨胍治疗对糖尿病大鼠视网膜血管内皮生长因子（VEGF）表达的影响。探讨川芎嗪联合氨胍治疗糖尿病视网膜病变（DR）的机制。方法 应用链尿佐菌素（STZ）制作糖尿病大鼠模型。分为正常对照组,糖尿病未治疗组,川芎嗪治疗组,氨胍治疗组和川芎嗪联合氨胍治疗组,分别于第4周,第12周和第20周应用免疫组化方法观察各组大鼠视网膜组织VEGF表达的变化。结果 正常大鼠视网膜组织VEF表达仅见于内核层,糖尿病大鼠视网膜组织VEGF阳性表达随周龄的延长而增强,且在毛细血管内和节细胞层可见VEGF表达,治疗12周和20周后,川芎嗪治疗组和氨胍治疗组大鼠视网膜组织VEGF阳性表达比未治疗组明显减弱,但仍高于正常对照组,而川芎嗪联合氨胍治疗组视网膜组织VEGF表达接近正常。结论 川芎嗪联合氨胍治疗可抑制糖尿病大鼠视网膜VEGF的过度表达。是川芎嗪联合氨胍治疗糖尿病视网膜病变（DR）的机制之一。     

西洛他唑对糖尿病视网膜病变中血小板反应素表达影响的研究

探讨西洛他唑对糖尿病视网膜病变病理生理中的影响及可能的作用机制.用链脲佐菌素(STZ)腹腔注射建立糖尿病模型,用免疫组织化学法、实时荧光定量PCR法观察西洛他唑治疗组、糖尿病对照组和正常对照组视网膜中血小板反应素(TSP-1)的变化.每隔1周测量血糖一次,4周后糖尿病治疗组、糖尿病组与正常组大鼠的体重、血糖有显著性差异(P＜0.01);糖尿病治疗组、糖尿病对照组和正常对照组间TSP-1表达有显著性差异(P＜0.01).在早期糖尿病大鼠的视网膜神经节细胞层、内核层中均有明显的TSP-1表达,糖尿病西洛他唑治疗组视网膜中TSP-1的表达要低于糖尿病对照组.实验显示西洛他唑可能通过阻止TSP-1的过度表达,在一定程度上延缓其糖尿病视网膜病变的发生.     

秦岭滑蜥视网膜年龄相关的显微结构特征和胶质纤维酸性蛋白免疫组织化学定位

光学显微镜下观察了秦岭滑蜥Scincella tsinlingensis视网膜年龄相关的显微结构特征,并对胶质纤维酸性蛋白(GFAP)免疫组织化学定位及表达强度进行了统计分析。结果显示:秦岭滑蜥视网膜由内至外共分为10层,与昼行性蜥蜴类视网膜结构特征一致。亚成体和成体视网膜总厚度较幼体明显增加,但三者神经节细胞层、外界膜以及视杆视锥层厚度之间无明显差异。不同年龄组视网膜细胞核层数无差异:外核层1~2层,神经节细胞层3~4层,内核层6~8层。视网膜GFAP免疫阳性主要定位于内界膜和神经纤维层,且神经纤维层阳性最强。GFAP阳性表达呈现成体最强、幼体较强、亚成体最弱的年龄相关性,这可能与视网膜胚后发育中的生理功能调节相关。     

吡格列酮治疗STZ诱导糖尿病大鼠视网膜中TSP-1的变化

观察吡格列酮在治疗STZ诱导糖尿病大鼠视网膜中血小板反应素Ⅰ(thmmbospondin-1,TSP-1)的变化,探讨噻唑烷二酮类药物在糖尿病视网膜病变中的影响和可能作用机制。用链脲佐菌素(STZ)腹腔注射建立大鼠糖尿病模型,随机分正常对照组(C组),糖尿病安慰剂组(D组)和糖尿病吡格列酮治疗组(DP组),8周后取视网膜组织行免疫组织化学、RT-PCR半定量检测TSP- 1mRNA水平的变化,结果显示在糖尿病早期视网膜神经节细胞层、内核层中均有明显的TSP1表达,对比于糖尿病对照组,糖尿病治疗组视网膜单位面积表达TSP1的细胞数量要较二组对照组高;糖尿病治疗组、糖尿病对照组和正常对照组间TSP-1的荧光灰度值分别为528.2±47.78、493.4±39.36和417.7±28.74:内参照GAPDH的荧光灰度值分别为796.4±21.18、811.2±36.80和832.4±43.18,各组间TSP-1 mRNA表达有显著性差异,提示吡格列酮对糖尿病早期视网膜中TSP-1的表达变化有影响,吡格列酮可能在延缓糖尿病视网膜病变的发生发展中起一定的作用。     

牛磺酸抑制糖尿病大鼠视网膜Muller细胞VEGF表达的研究

目的:进一步了解糖尿病引起视网膜受损的分子机制、探讨牛磺酸保护糖尿病大鼠视网膜损伤的可能机制.方法用链脲佐茵素诱导SD大鼠患糖尿病,分为正常对照组、糖尿病组、1%牛磺酸干预糖尿病组、5%%牛磺酸干预糖尿病组、胰岛素治疗糖尿病组.正常对照组、糖尿病组、胰岛素治疗组饲以基础饲料,牛磺酸干预组饲以基础饲料分别添加1%、5% 牛磺酸的饲料喂养,胰岛素治疗组每天皮下注射20U/kg胰岛素.在第2周、1月、2月、3月取视网膜,用RT-PCR、免疫组织荧光化学、Western-blotting检测视网膜Muller细胞VEGFmRNA和蛋白表达情况.结果:经链脲佐菌素诱导惠糖尿病2周后,SD大鼠视网膜Muller细胞VEGFmRNA和蛋白表达增加,且随病程的延长表达量有持续增加趋势(P＜0.05).患糖尿病3月后,整个视网膜中VEGF免疫染色明显增强,尤以外网状层(OPL)、内网状层(IPL)和视网膜外段变化最明显.牛磺酸干预糖尿病1月后.大鼠视网膜Muller细胞VEGFmRNA和蛋白的表达下调(P＜0.05).结论:牛磺酸抑制糖尿病患者视网膜Muller细胞VEGF的表达,减轻糖尿病引起的视网膜损害.     

血小板反应素1在STZ诱导大鼠糖尿病性视网膜病变的表达研究

探讨TSP1表达在糖尿病视网膜病变中的作用和机制,为治疗和预防糖尿病视网膜病变提供新的实验和理论依据。用链脲佐菌素(STZ)腹腔注射建立糖尿病模型8周后,采用免疫组织化学、RT-PCR及实时荧光定量PCR法,分析TSP1在早期链尿佐菌素诱导的糖尿病SD大鼠视网膜中的表达。结果显示在早期糖尿病大鼠的视网膜表面血管、神经节细胞层、内外核层中均有明显的TSP1表达,糖尿病视网膜组TSP1 mRNA表达要高于对照组,其中实时荧光定量PCR CT值的结果显示糖尿病组TSP1 mRNA表达量较对照组要高约3．48倍,二组间差别有显著性意义(P<0．01),提示TSP1在视网膜组织中的表达与糖尿病视网膜病变的发生密不可分,TSP1表达的增加可能在糖尿病视网膜病变的发生和发展中起重要作用。     

肾上腺髓质素在糖尿病视网膜细胞高表达的研究

探讨肾上腺髓质素(Adrenomedullin,AM)在糖尿病视网膜病变(Diabeticretinopathy,DR)发病中的作用。Sprague-Dawley雄性大鼠尾静脉注射链脲佐菌素造模,以血糖测定和尿糖水平测定进行筛选,正常对照组尾静脉注射等量枸橼酸钠缓冲液。成模后继续饲养4周,取出眼球视网膜组织,连续冰冻切片,用免疫组织化学SABC法染色观察各组大鼠视网膜RPE细胞AM的表达情况。糖尿病大鼠成模前,两组动物的体重、血糖和尿糖检测结果间无显著性差异(P>0.05)。成模后4周,糖尿病组与正常组大鼠体重、血糖和尿糖数值差异有显著性意义(P<0.01)。AM在正常组大鼠视网膜节细胞层及内核层均有表达,正常组大鼠视网膜AM的光密度值为76.3±5.3,单位面积AM阳性细胞数为(4.5±1.1)×103/mm2。糖尿病大鼠视网膜内RPE细胞肾上腺髓质素表达显著增强,糖尿病大鼠视网膜RPE细胞AM的光密度值为105.7±11.9,单位面积AM阳性细胞数为(17.9±2.3)×103/mm2。两组相比,差异具有显著性(P<0.01)。AM在糖尿病大鼠视网膜RPE细胞表达量增加很可能是DR发生、发展的重要因素。     

C-fos基因在大鼠缺血视网膜内的表达

实验用FOS免疫组化方法（ABC法）研究了缺血诱导的大鼠视网膜内c-fos原癌基因的表达情况。实验动物用升高眼压的方法做成视网膜缺血模型,依缺血后存活时间不同分15′、30′、1h、2h、4h、6h、12h七个组,每只大鼠右眼为缺血眼,左眼做自身对照眼,另设正常对照组。动物腹腔麻醉,4％多聚甲醛灌注固定,取双眼冰冻切片,片厚15μm。实验结果显示缺血后15′组大鼠视网膜内核层最先出现少量卵圆型浅棕色的FOS阳性神经元胞核,30分钟至1h FOS表达逐渐增强,节细胞层也出现FOS阳性胞核。缺血后2h FOS表达达最高峰,缺血后4h FOS阳性胞核逐渐减少,12h达正常组水平、自身对照眼及正常对照眼网膜节细胞层偶见FOS阳性胞核。     

急性冷暴露对大鼠肺组织中水通道蛋白AQP-1和AQP-5表达的影响

目的：探讨急性冷暴露后肺组织超微结构变化以及对水通道蛋白-1（AQP-1）和AQP-5表达的影响。方法：12只健康雄性Wistar大鼠随机分为室温（23℃±2℃）对照组和-25℃ 2 h冷暴露组（n=6）;记录冷暴露后大鼠直肠温度;透射电镜观察肺组织超微结构改变;RT-PCR法和Western blot法测定大鼠肺组织AQP-1和AQP-5基因和蛋白的表达水平。结果：急性冷暴露后大鼠的体心温度与对照组相比,明显降低（P<0.05）;肺组织超微结构亦发生改变,基底膜明显增厚,肺泡I上皮细胞（AT-I）核固缩,肺泡Ⅱ上皮细胞（AT-Ⅱ）胞浆空泡化增多;冷暴露后大鼠肺组织AQP-1的基因和蛋白表达未见明显变化,AQP-5的基因和蛋白表达均显著降低（P<0.05）。结论：急性冷暴露肺组织AQP-5基因和蛋白表达降低与寒冷暴露引发肺组织结构损伤可能存在一定因果关系。     

脑红蛋白在家兔视网膜中的分布

目的探讨脑红蛋白(NGB)在家兔视网膜的分布特征。方法选择健康成年家兔5只,利用免疫组织化学染色SP法,观察NGB在家兔视网膜中的分布情况。结果 NGB在家兔视网膜的视神经纤维层、节细胞层、内网状层、外网状层、光感受器内节段和色素上皮层中有强阳性表达,在视网膜的内核层有弱阳性表达,在视网膜的外核层和光感受器外节段中未见有阳性表达,内界膜、外界膜和视神经中亦发现有NGB阳性表达。家兔视网膜NGB阳性表达的细胞类型主要有节细胞、双极细胞和光感受器细胞,其中节细胞的阳性表达定位于细胞质,胞核中未见表达。结论除外核层和光感受器外节段外,NGB在家兔视网膜其它各层中均有表达,提示NGB在维持视网膜氧代谢平衡中发挥着重要作用。     

Changes in retinal aquaporin-9 (AQP9) expression in glaucoma

The eye contains numerous water channel proteins and the roles of AQPs (aquaporins) in the retina are blurred, especially under disease conditions. The purpose of this study was to investigate the expression of AQP9 gene and proteins affected by elevated IOP (intraocular pressure) in a rat model of glaucoma induced by intravitreous injection of hypertonic saline into the episcleral veins. The gene and protein expressions of AQP9 were investigated by real-time PCR and Western blotting. The immunoreactive expression of AQP9, AQP4 and GFAP (glial fibrillary acidic protein) in the optic nerve of rats exposed to experimentally elevated IOP was detected by immunofluorescence microscopy. The mRNA and protein expression levels of AQP9 were up-regulated in the retina of an animal model of glaucoma. The immunoreactivities of the AQP9, AQP4 and GFAP were also detected and increased in the optic nerve region. The expression of AQP9 was up-regulated in this glaucoma model and the immunoreactivities of the AQP4 and GFAP were also detected as co-localizing with AQP9 in the optic nerve region, indicating retina ganglion cells were surrounded by activated astrocytes. This may indicate that the injured neurons may rely on the astrocytes. The alterations of AQP expression may compensate the glaucomatous damage.     

Elevated expression of alphaA- and alphaB-crystallins in streptozotocin-induced diabetic rat

alpha-Crystallin, a predominant protein of the ocular lens, is composed of two subunits, alphaA and alphaB. Of these, alphaB-crystallin has been shown to present widely in non-lenticular tissues while alphaA-crystallin is largely lens-specific. Although, expression of alphaB-crystallin is elevated under various stress and pathological conditions, yet its physiological significance remained unknown. Some studies suggest that the expression of alphaB-crystallin gene is related to oxidative stress. Persistent hyperglycemia during uncontrolled diabetes is known to cause oxidative stress, which has been implicated in various secondary complications of diabetes. Hence, expression of alphaA- and alphaB-crystallins in various tissues of streptozotocin (STZ)-induced diabetic Wistar-NIN rats was investigated by RT-PCR and immunoblotting. While expression of alphaB-crystallin was noted in the wide range of tissues examined in the study, alphaA-crystallin expression was detected only in lens and retina. Interestingly, alphaB-crystallin expression was elevated in lens, heart, muscle, and brain, but decreased in adipose tissue of diabetic rats compared to control rats. alphaA-Crystallin expression was increased in retina of diabetic rat. Increased oxidative stress appears to be a major stimulus for the enhanced expression of alphaA- and alphaB-crystallins in the tissues of diabetic rats and elevated expression of alpha-crystallin may have a protective role against metabolic stress. Interestingly, feeding of curcumin, a dietary antioxidant, to diabetic rats attenuated the enhanced expression of alphaB-crystallin. The results indicate that elevated expression of alpha-crystallins in some tissues may have implications in pathophysiology of diabetic complications.     

Renal Response to L-Arginine in Diabetic Rats. A Possible Link between Nitric Oxide System and Aquaporin-2

The aim of this study was to evaluate whether L-Arginine (L-Arg) supplementation modifies nitric oxide (NO) system and consequently aquaporin-2 (AQP2) expression in the renal outer medulla of streptozotocin-diabetic rats at an early time point after induction of diabetes. Male Wistar rats were divided in four groups: Control, Diabetic, Diabetic treated with L-Arginine and Control treated with L-Arginine. Nitric oxide synthase (NOS) activity was estimated by [¹⁴C] L-citrulline production in homogenates of the renal outer medulla and by NADPH-diaphorase staining in renal outer medullary tubules. Western blot was used to detect the expression of AQP2 and NOS types I and III; real time PCR was used to quantify AQP2 mRNA. The expression of both NOS isoforms, NOS I and NOS III, was decreased in the renal outer medulla of diabetic rats and L-Arg failed to prevent these decreases. However, L-Arg improved NO production, NADPH-diaphorase activity in collecting ducts and other tubular structures, and NOS activity in renal homogenates from diabetic rats. AQP2 protein and mRNA were decreased in the renal outer medulla of diabetic rats and L-Arg administration prevented these decreases. These results suggest that the decreased NOS activity in collecting ducts of the renal outer medulla may cause, at least in part, the decreased expression of AQP2 in this model of diabetes and constitute additional evidence supporting a role for NO in contributing to renal water reabsorption through the modulation of AQP2 expression in this pathological condition. However, we cannot discard that another pathway different from NOS also exists that links L-Arg to AQP2 expression.     

Intact and N- or C-terminal end truncated AQP0 function as open water channels and cell-to-cell adhesion proteins: End truncation could be a prelude for adjusting the refractive index of the lens to prevent spherical aberration

Background

Investigate the impact of natural N- or C-terminal post-translational truncations of lens mature fiber cell Aquaporin 0 (AQP0) on water permeability (Pw) and cell-to-cell adhesion (CTCA) functions.

Methods

The following deletions/truncations were created by site-directed mutagenesis (designations in parentheses): Amino acid residues (AA) 2–6 (AQP0-N-del-2-6), AA235–263 (AQP0-1-234), AA239–263 (AQP0-1-238), AA244–263 (AQP0-1-243), AA247–263 (AQP0-1-246), AA250–263 (AQP0-1-249) and AA260–263 (AQP0-1-259). Protein expression was studied using immunostaining, fluorescent tags and organelle-specific markers. Pw was tested by expressing the respective complementary ribonucleic acid (cRNA) in Xenopus oocytes and conducting osmotic swelling assay. CTCA was assessed by transfecting intact or mutant AQP0 into adhesion-deficient L-cells and performing cell aggregation and adhesion assays.

Results

AQP0-1-234 and AQP0-1-238 did not traffic to the plasma membrane. Trafficking of AQP0-N-del-2-6 and AQP0-1-243 was reduced causing decreased membrane Pw and CTCA. AQP0-1-246, AQP0-1-249 and AQP0-1-259 mutants trafficked properly and functioned normally. Pw and CTCA functions of the mutants were directly proportional to the respective amount of AQP0 expressed at the plasma membrane and remained comparable to those of intact AQP0 (AQP0-1-263).

Conclusions

Post-translational truncation of N- or C-terminal end amino acids does not alter the basal water permeability of AQP0 or its adhesive functions. AQP0 may play a role in adjusting the refractive index to prevent spherical aberration in the constantly growing lens.

General significance

Similar studies can be extended to other lens proteins which undergo post-translational truncations to find out how they assist the lens to maintain transparency and homeostasis for proper focusing of objects on to the retina.     

Localization and expression of AQP5 in cornea, serous salivary glands, and pulmonary epithelial cells

Aquaporin (AQP) 5 gene was recently isolated from salivary glandand identified as a member of the AQP family. The mRNAexpression and localization have been examined in several organs. Thepresent study was focused on elucidation of AQP5 expression andlocalization in the eye, salivary gland, and lung in rat. RNaseprotection assay confirmed intense expression of AQP5 mRNA in theseorgans but negligible expression in other organs. To examine the mRNA expression sites in the eye, several portions were microdissected fortotal RNA isolation. AQP5 mRNA was enriched in cornea but not in otherportions (retina, lens, iris/ciliary body, conjunctiva, or sclera).AQP5 was selectively localized on the surface of corneal epithelium inthe eye by immunohistochemistry and immunoelectron microscopy using anaffinity-purified anti-AQP5 antibody. AQP5 was also localized on apicalmembranes of acinar cells in the lacrimal gland and on the microvilliprotruding into intracellular secretory canaliculi of the seroussalivary gland. In the lung, apical membranes of type I pulmonaryepithelial cells were also immunostained with the antibody. Thesefindings suggest a role of AQP5 in water transport to preventdehydration or to secrete watery products in these tissues.

     

胆红素脑病SD乳鼠模型中脑水通道蛋白-4表达发生变化

神经细胞水肿是胆红素脑病（bilirubin encephalopathy,BE）发生发展过程中的重要病理变化。水通道蛋白-4（aquaporin-4,AQP4）的表达及分布异常与多种疾病所致细胞毒性脑水肿的发生发展具有密切联系。但胆红素脑病中AQP4的表达变化规律及其在病理进展中的作用尚不清楚。采用7日龄SD大鼠小脑延髓池注射胆红素溶液的方法,建立新生大鼠胆红素脑病模型。胆红素脑病模型根据胆红素作用时间的不同,分为12 h、24 h、48 h、72 h和7 d组。采用HE及尼氏染色,检测各新生大鼠脑组织的病理改变;应用透射电镜(TEM),检测胆红素作用24 h后,鼠脑组织超微结构的变化;应用免疫荧光及Western 印迹,检测 AQP4在脑组织中的表达变化。通过上述实验,以探讨AQP4的表达变化与胆红素所致脑损伤的关系。HE及尼氏染色结果显示,随着胆红素沉积时间的延长,神经细胞逐渐肿胀,细胞间隙增大,尼氏小体数量逐渐减少;电镜结果显示,胆红素脑病24 h后神经细胞线粒体出现肿胀;免疫荧光染色显示,24 h组AQP4的表达范围明显增加,其后表达范围逐渐减少,表达强度也随之减弱;Western 印迹结果显示,AQP4表达在不同时间点呈现先增高后降低的趋势,在24 h达到峰值（24 h组1.38 ± 0.11 vs 对照组0.87 ± 0.21, P＜0.05）,在之后的各时间点上,AQP4的表达呈现下降趋势,而72 h组与7 d组AQP4表达均低于48 h组（P＜0.05）,基本恢复到对照组的表达水平（P＞0.05）。上述结果提示,胆红素脑病中胆红素的毒性作用将引起AQP4表达量的改变,AQP4的表达变化与胆红素脑病中细胞毒性脑水肿的发生相关,并且可能在胆红素脑病脑损伤的进展中发挥作用。     

胆红素脑病SD乳鼠模型中脑水通道蛋白-4表达发生变化

神经细胞水肿是胆红素脑病（bilirubin encephalopathy,BE）发生发展过程中的重要病理变化。水通道蛋白-4（aquaporin-4,AQP4）的表达及分布异常与多种疾病所致细胞毒性脑水肿的发生发展具有密切联系。但胆红素脑病中AQP4的表达变化规律及其在病理进展中的作用尚不清楚。采用7日龄SD大鼠小脑延髓池注射胆红素溶液的方法,建立新生大鼠胆红素脑病模型。胆红素脑病模型根据胆红素作用时间的不同,分为12 h、24 h、48 h、72 h和7 d组。采用HE及尼氏染色,检测各新生大鼠脑组织的病理改变;应用透射电镜(TEM),检测胆红素作用24 h后,鼠脑组织超微结构的变化;应用免疫荧光及Western 印迹,检测 AQP4在脑组织中的表达变化。通过上述实验,以探讨AQP4的表达变化与胆红素所致脑损伤的关系。HE及尼氏染色结果显示,随着胆红素沉积时间的延长,神经细胞逐渐肿胀,细胞间隙增大,尼氏小体数量逐渐减少;电镜结果显示,胆红素脑病24 h后神经细胞线粒体出现肿胀;免疫荧光染色显示,24 h组AQP4的表达范围明显增加,其后表达范围逐渐减少,表达强度也随之减弱;Western 印迹结果显示,AQP4表达在不同时间点呈现先增高后降低的趋势,在24 h达到峰值（24 h组1.38 ± 0.11 vs 对照组0.87 ± 0.21, P＜0.05）,在之后的各时间点上,AQP4的表达呈现下降趋势,而72 h组与7 d组AQP4表达均低于48 h组（P＜0.05）,基本恢复到对照组的表达水平（P＞0.05）。上述结果提示,胆红素脑病中胆红素的毒性作用将引起AQP4表达量的改变,AQP4的表达变化与胆红素脑病中细胞毒性脑水肿的发生相关,并且可能在胆红素脑病脑损伤的进展中发挥作用。     

低氧脑水肿大鼠脑组织VEGF和AQPs基因及蛋白表达的变化

目的：探讨低氧脑水肿时血管内皮细胞生长因子（VEGF）、水通道蛋白（AQP1和AQP4）基因和蛋白表达变化,为阐明急性低氧对脑组织的损伤及低氧脑水肿的发病机制提供实验依据。方法：Wistar大鼠随机分为4个组：常氧对照组（Control）、低氧暴露4 000 m组（4 000 m）、低氧暴露6 000 m组（6 000 m）和低氧暴露8 000 m组（8 000 m）,低氧组于低压舱中模拟相应海拔高度持续暴露8 h建立低氧脑水肿模型。用干-湿重法测定脑组织水含量,常规光镜观察脑组织形态学的改变;用RT-PCR法和免疫组化法检测低氧脑水肿时大鼠脑组织VEGF、AQP1和AQP4mRNA和蛋白表达的变化。结果：①干-湿重法测定表明,低氧（≥6 000 m）暴露后,大鼠脑组织水含量明显增加（P〈0.01）。②常规光镜检测结果表明,低氧暴露4 000 m时大鼠脑神经细胞、血管内皮细胞和星形胶质细胞足突轻度肿胀,组织中出现漏出液;低氧暴露6 000 m时脑血管内皮细胞和星形胶质细胞足突肿胀加重,血管与组织间隙扩大,组织中漏出液增多;低氧暴露8 000m时脑血管内皮细胞和星形胶质细胞足突重度肿胀,血管与组织间隙进一步扩大,组织中漏出液明显增多。③低氧脑水肿时,VEGF、AQP1、AQP4mRNA表达水平增高,AQP1在内皮细胞异常表达,内皮细胞VEGF和AQP1、星形胶质细胞足突AQP4蛋白质表达水平增高。结论：低氧脑水肿时,VEGF、AQP1和AQP4表达和分布的变化可能是引起血脑屏障损伤、导致低氧脑水肿的发病机制之一。