脂质体对人角膜基质细胞影响的实验研究

目的:观察脂质体LipofectamineTM2000对人角膜基质细胞的影响,探索其应用于人角膜基质细胞的可行性及安全范围。方法:体外培养人角膜基质细胞,取其第3-5代细胞鉴定后用于实验。采用MTT法检测不同浓度和时间脂质体对人角膜基质细胞增殖率的影响;采用台盼蓝染色法检测对存活率的影响。结果:脂质体对人角膜基质细胞的影响与浓度和作用时间有关。浓度高于一定水平时可引起细胞增殖率和存活率的下降,浓度相同时作用时间越长下降越明显。浓度低于40mg/L作用24h不会对细胞增殖率和存活率产生明显影响。结论:LipofectamineTM2000在一定范围内不引起细胞毒性,有望在角膜基质细胞的基因治疗中发挥重要作用。     

原生质体法获取致病性烟曲霉菌干扰时间窗的实验研究

目的:制备致病性烟曲霉菌原生质体,并观察原生质体从细胞壁剥离到恢复为完整形态这一时间窗内的生物学性状。方法:1mol/L山梨醇为渗透压稳定剂配制浓度为1g/dL蜗牛酶、1g/dL纤维素酶及0.1g/dL溶壁酶复合裂解酶液,与浓度为5×109个/L的烟曲霉菌分生孢子液按体积比1∶1配比,30℃下以80r/min酶解2h,使用3-氨基-7-甲氨基-2-甲基吩嗪盐酸盐溶液检测原生质体活力。结果:烟曲霉菌分生孢子原生质体的平均生成量为2.84×109个/L,完成酶解后0,6,12,18,24h活力分别为86.6%,77.4%,73.9%,70.6%,66.2%,原生质体最早在完成酶解18h后出现再生现象,36～48h内有活性的原生质体基本完成再生。结论:采用复合酶法可以获得生成率达56.8%的烟曲霉菌原生质体,恢复为完整形态前的可干扰时间窗至少为18h,原生质体可以在24h内保持较高活力。     

角膜基质细胞Toll样受体4对茄病镰刀菌炎性反应的实验研究

目的 检测茄病镰刀菌刺激小鼠角膜基质细胞后Toll样受体4(Toll like receptor 4,TLR4)的表达分布状况,探讨TLR4与炎性因子分泌的关系.方法 对小鼠角膜基质细胞进行原代培养和鉴定;制备茄病镰刀菌液;MTT法观察菌液刺激对角膜基质细胞生长作用的影响;免疫组化、RT-PCR测定刺激后不同时间点角膜基质细胞TLR4的表达;ELISA检测封闭TLR4对菌液诱导的角膜基质细胞分泌TNF-α、IL-8的影响.结果 采用消化法1～2 d培养出小鼠角膜基质细胞,抗波形蛋白免疫荧光染色阳性;菌液刺激48h后,MTT法显示刺激组较对照组OD值明显下降;正常角膜基质细胞TLR4在蛋白及mRNA水平呈弱表达,刺激6h可达到高峰,12h开始逐渐降低;菌液可上调角膜基质细胞TNF-α、IL-8的释放,刺激3h、6h、12 h的TNF-α、IL-8的浓度与TLR4 mRNA的表达呈明显的正相关(P＜0.05);预先封闭TLR4,可明显降低TNF-αt、IL-8的释放.各时间组间的差异有统计学意义(P＜0.05).结论 角膜可能通过TLR4识别真菌感染,TLR4在角膜对真菌的免疫炎性防御反应中起到重要作用.     

MTT法检测转化生长因子-β对人角膜基质细胞增殖的影响

目的探讨转化生长因子-β(TGF-β)对体外培养的人角膜基质细胞增殖的影响.方法体外培养的传2～3代人角膜基质细胞,分别加入0.01,0.1,1,5ng/ml的TGF-β,采用MTT法研究TGF-β对人角膜基质细胞增殖的影响.结果 TGF-β以剂量依赖方式促进人角膜基质细胞增殖,其作用在第2天达到高峰.结论 TGF-β能明显促进人角膜基质细胞增殖,因而可能成为促进角膜溃疡愈合的新方法.     

牛角膜基质细胞的两步酶消化法高效分离及体外培养观察

背景高效、低成本分离出生物学功能活性高的角膜基质细胞是开展角膜基础研究的需要。目前的分离方法成本高、分离效率低，而通过培养达到扩增细胞数会导致细胞表型快速改变。应用成本较低的Ⅰ型胶原酶，通过改良的两步酶消化法可能达到高效、快速、低成本分离牛角膜原代基质细胞的目的。目的评价设计的Ⅰ型胶原酶两步酶消化法分离原代牛角膜基质细胞的效果，并观察体外培养原代牛角膜基质细胞的形态学变化。方法分别用基础培养液配制的0．5g／L及1．0g／L Ⅰ型胶原酶以两步酶消化法顺序消化牛角膜组织，分离角膜基质细胞，以细胞计数板进行计数，检测基质细胞收获效率；锥虫蓝染色法检测收获细胞的存活率；分离的细胞进行原代培养，倒置显微镜下观察细胞形态和生长的变化；应用Alexa488标记的鬼笔环肽检测原代培养的牛角膜基质细胞中F—actin的分布。结果牛角膜经两步酶消化法基质逐步解离和降解，绝大多数细胞得以释放和分离，分离的牛角膜基质细胞呈圆形，透亮且大小均匀。每个角膜收获（2．109±0．142）×10。个基质细胞，细胞存活率（91．693±3．551）％，贴壁率（81．195±1．214）％。原代培养的牛角膜基质细胞贴壁呈树突样，铺伸至星状，融合时树突连接呈网状，其F—aetin局限性分布于细胞皮质。结论两步酶消化法可使牛角膜基质完全消化降解，具有高细胞收获率、高细胞存活率和操作简便等特点。原代培养的牛角膜基质细胞呈树突状，F—actin分布于细胞皮质。     

蛋白激酶Cα在人角膜基质细胞中的表达

目的 观察蛋白激酶Ca（PKCα）在原位及体外培养的人角膜基质细胞中的表达。方法标本来源于北京大学第一医院眼库。人角膜基质细胞体外原代及传代培养，应用免疫组织化学法检测PKCα在培养的人角膜基质细胞中的表达；制作人正常角膜组织冰冻切片，观察PKCα在角膜基质细胞中的表达。结果免疫组织化学法检测显示：正常人原位角膜基质细胞对PKCα无明显表达，而体外培养的人角膜基质细胞有明显阳性表达。结论特殊的角膜创伤模型——体外培养人角膜基质细胞中PKCα有明显阳性表达，提示PKC在角膜基质细胞增生过程中扮演了重要角色，抑制PKC的活性有可能成为治疗角膜瘢痕愈合的一个新途径。     

8型重组腺相关病毒介导绿色荧光蛋白基因在角膜基质细胞中的表达及影响

目的:评价8型重组腺相关病毒(rAAV8)介导增强型绿色荧光蛋白基因(EGFP)转染角膜基质细胞后的表达及对细胞增殖的影响。方法:以不同MOI的rAAV8-EGFP转染大鼠角膜基质细胞,转染后以倒置荧光显微镜观察角膜基质细胞中GFP的表达,流式细胞仪分析角膜基质细胞中rAAV8-EGFP表达的阳性率。MTT法分别检测rAAV8和rAAV8-EGFP转染对角膜基质细胞增殖的影响。结果:倒置荧光显微镜观察rAAV8-EGFP转染角膜基质细胞后GFP的阳性表达7d达到高峰,此时流式细胞仪检测rAAV8-EGFP对角膜基质细胞的转染效率分别为31.5%(MOI=5×103),42.5%(MOI=5×104),54.8%(MOI=5×105);MTT检测结果显示rAAV8及rAAV8-EGFP转染对角膜基质细胞增殖均无明显影响。结论:rAAV8-EGFP能有效地转染角膜基质细胞,并且对细胞增殖无明显影响。     

血竭素高氯酸盐促进离体兔角膜基质细胞凋亡的作用

目的 观察天然药物血竭素高氯酸盐(Dp)对离体兔角膜基质细胞增生的抑制作用,探讨其对细胞凋亡的影响,为临床上角膜瘢痕的防治提供新思路.方法 新西兰白兔18只,采用组织块培养法,在含10%胎牛血清的DMEM/F12培养液中培养兔角膜基质细胞,通过含有EDTA的胰蛋白酶消化进行传代.采用四甲基偶氮唑盐(MTT)比色法检测不同质量浓度Dp(10～80 μg/mL)对细胞生长的抑制率,电镜观察Dp作用后角膜细胞的凋亡情况,流式细胞术(FCM)检测Dp作用后细胞凋亡率.结果 第3代角膜基质细胞呈现对波形蛋白单克隆抗体阳性反应和对角蛋白12多克隆抗体的阴性反应.角膜上皮细胞对角蛋白12抗体呈现绿色的荧光反应.Dp作用24、48、72 h后,其IC50分别为47.721、41.40、32.01 μg/mL.MTT比色法显示Dp对角膜基质细胞的抑制率呈现明显的质量浓度依赖性;电镜可观察到角膜细胞的凋亡;FCM检测Dp作用24 h的细胞凋亡率呈剂量依赖性升高(P<0.01).在Dp作用后24、48、72 h,Dp质量浓度与抑制率呈正相关(r=0.984,P<0.01;r=0.947,P=0.007;r=0.920,P=0.03).结论 Dp对兔角膜基质细胞的增生具有显著的抑制作用,且呈量效关系促进角膜基质细胞发生凋亡.     

明胶酶在兔真菌性角膜炎病理改变中的作用研究

目的探讨明胶酶包括基质金属蛋白酶（MMP）2与MMP-9在兔真菌性角膜炎病理改变中的作用。方法80只新西兰白兔随机分为4组,每组20只。其中3组为实验组,兔右眼分别注入100μl茄病镰刀菌、烟曲霉菌及白色念珠菌的悬液;另1组为对照组,兔右眼注入等量生理盐水。免疫组织化学方法观察MMP-2与MMP-9的来源,明胶酶谱法检测其活性。组织病理学方法观察炎性细胞的浸润、角膜细胞外基质（ECMs）的降解以及真菌菌丝在角膜内的生长方式与入侵深度。结果MMP-2主要由角膜基质细胞产生,真菌感染后5d检测出活性,8d活性升高。MMP-9主要来源于嗜中性粒细胞,接种后1d即检测到活性,3d活性升高,之后逐渐下降。茄病镰刀菌感染后3d,角膜内散在嗜中性粒细胞,浅层ECMs被降解,菌丝平行于角膜基质纤维生长。烟曲霉菌和白色念珠菌感染后3d,角膜内可见大量嗜中性粒细胞,周围ECMs降解明显,菌丝表现为垂直生长。接种后8d,茄病镰刀菌和白色念珠菌感染的角膜内炎性细胞和菌丝明显减少,而烟曲霉菌感染的角膜变化不明显。结论茄病镰刀菌、烟曲霉菌及白色念珠菌感染兔角膜后,产生的明胶酶活性明显不同;明胶酶对降解角膜ECMs发挥了重要作用;随着ECMs降解程度的不同,菌丝在角膜内的生长方式、入侵深度等病理改变出现差异。     

角膜基质细胞—PGA生物支架复合体外培养研究

目的 研究角膜基质细胞与PGA亲和力,为组织工程技术建构角膜提供重要的理论依据和参数。方法 体外分离获得角膜基质细胞,经培养扩增后接种于PGA,并对细胞－生物材料复合物进行体外培养,观察细胞生长代谢。应用MTT技术测定角膜基质细胞与PGA的黏附率。结果 角膜基质细胞能够在PGA中黏附、伸展和分泌基质,MTT测得细胞黏附率为71．40％。结论 角膜基质细胞与PGA具有较好的亲和力,PGA可以作为构建角膜的生物材料。     

波动的压力对兔角膜内皮细胞的影响

目的　观察波动的压力对角膜内皮细胞的影响。方法　将体外培养的第一代兔角膜内皮细胞分为两组:Ａ组为压力波动组（压力设置为:１５ｍｍＨｇ～２５ｍｍＨｇ～２０ｍｍＨｇ～１０ｍｍＨｇ,每个压力持续６ｈ;１ｋＰａ＝７．５ｍｍＨｇ）;Ｂ组为３０ｍｍＨｇ压力组;Ｃ组为无压力组。三组细胞分别培养２４ｈ。免疫细胞化学染色法鉴定原代角膜内皮细胞形态;台盼蓝-茜素红联合染色检测细胞活性,ＨＥ染色观察细胞形态;Ｗｅｓｔｅｒｎ-ｂｌｏｔｔｉｎｇ检测细胞中Ｂｃｌ-２和Ｐ５３蛋白的表达水平。结果　获取的所有细胞证实为角膜内皮细胞表型,无角膜上皮细胞及基质细胞污染。三组细胞分别培养２４ｈ后,经台盼蓝-茜素红染色和ＨＥ染色证实:两个压力培养组的细胞活性较无压力培养组明显下降,其中压力波动组的细胞活性低于３０ｍｍＨｇ压力组。同时无压力组、３０ｍｍＨｇ压力组和压力波动组细胞中Ｐ５３蛋白的相对表达量分别为０．１５０±０．００５、０．２５３±０．０１４、０．６７０±０．０１９,差异有统计学意义（Ｐ＜０．０５）。结论　证实了高压力及非生理性波动的压力对角膜内皮细胞均具有损伤作用。     

Effect of latanoprost on cultured porcine corneal stromal cells

PURPOSE: Latanoprost reduces intraocular pressure mainly by enhancing uveoscleral outflow that may be involved in the decreased of extracellular matrixes such as collagens. However, the effect of latanoprost on corneal stromal cells is not well understood. In the current study, we investigated the changes of cultured porcine corneal stromal cells upon exposure to latanoprost. METHODS: Porcine corneal stromal cells were acquired from primary culture and maintained in fetal bovine serum-containing medium. Cells were estimated on 3H-thymidine, 3H-leucine, 3H-uridine, 3H-proline uptakes and migration. Dead and living cells were estimated with MTT assay. The changes of type 1 collagen and fibronectin proteins were detected by means of immunofluorescent staining and Western blot assay. Intracellular free Ca2+ ([Ca2+]i) mobility was studied by spectrofluorophotometer after loading with fura-2-AM. RESULTS: Latanoprost has remarkable effects inhibiting cultured corneal stromal cells on 3H-thymidine, 3H-leucine, 3H-uridine, 3H-proline uptakes and cellular migration. The inhibitory effects are in a dose-dependent manner at concentrations ranging from 10(- 5), 10(- 6), 10(- 7) to 10(- 8) M. The 50% inhibitory dosages (ID50) for latanoprost to corneal stromal cells, as measured by 3H-thymidine uptake, 3H-uridine uptake, 3H-leucine uptake, 3H-proline uptakes and cellular migration were 5.01 x 10(- 6) M, 2.81 x 10(- 6) M, 2.09 x 10(- 6) M, 3.89 x 10(- 7) M and 2.2 x 10(- 6) M, respectively. In the presence of latanoprost, the cellular MTT values were also decreased significantly. Immunofluorescent staining displayed that latanoprost changed type 1 collagen distribution in cultured corneal stromal cells. Western blot assay revealed that latanoprost caused cells to decrease in fibronectin protein. In Ca2+-containing buffer, latanoprost induced a significant rise in [Ca2+]i at 10(- 5) and 10(- 6) M. CONCLUSIONS: These results indicate that latanoprost may induce the morphological and biochemical changes in cultured corneal stromal cells. Long-term use of latanoprost needs to be carefully monitored for change in corneal stroma.     

组织工程角膜三维构建的实验研究

目的以人胚胎干细胞（hESC）诱导细胞为种子细胞,以脱细胞猪角膜基质（APCM）为支架三维构建生物工程角膜,以期用于穿透性角膜移植,解决角膜供体极度匮乏的难题。方法实验研究。无菌条件下将新鲜猪角膜组织置于0.5% SDS溶液中4 ℃脱细胞 24 h,获取APCM。将hESCs与人角膜基质细胞通过Transwell共培养5 d,获取眼周间充质干细胞（POMPs）,再于人晶状体上皮细胞源性条件培养基继续培养14 d获取角膜内皮样细胞并进行鉴定和筛选纯化。将纯化后扩增的角膜内皮样细胞接种于APCM构建角膜内皮植片,并移植入角膜内皮功能失代偿动物模型进行泵功能评估;采用人角膜缘干细胞（LSCs）来源的条件培养基培养hESCs 12 d,诱导其分化人角膜上皮样细胞并筛选鉴定,将其与APCM构建的角膜上皮植片移植于LSC失代偿动物模型的角膜缘,观察其眼表修复能力。结果诱导的人角膜内皮样细胞表达内皮细胞相关标记物vimentin、N-cadherin、Na+/K+ATP酶和ZO-1。构建的角膜内皮植片能够促使角膜内皮功能失代偿动物的角膜逐渐恢复透明。构建的角膜上皮细胞植片具有4～5层细胞复层结构,类似于正常角膜上皮,且能够一定程度上修复LSC失代偿动物模型眼表。结论采用hESCs诱导分化来源的细胞与APCM构建的人角膜内皮植片和人角膜上皮植片具有类似于正常角膜的功能,为全层生物角膜的构建提供了良好的实验和理论基础,具有良好的临床应用前景。     

Delay of corneal epithelial wound healing and induction of keratocyte apoptosis by platelet-activating factor

PURPOSE: To examine the role of the lipid mediator platelet-activating factor (PAF) in epithelial wound healing. METHODS: A 7-mm central de-epithelializing wound was produced in rabbit corneas, and the tissue was incubated with 125 nM carbamyl PAF (cPAF), an analogue of PAF. Rabbit corneal epithelial and stromal cells were also cultured in the presence of cPAF. Cell adhesion, proliferation, and migration assays were conducted. Apoptosis was assayed by TUNEL staining on preparations of corneal tissue sections and in cells in culture. RESULTS: Twenty-four hours after injury, 50% of the wounded area was covered by new epithelium, whereas only 30% was covered in the presence of cPAF. At 48 hours, the epithelium completely closed the wound, but only 45% of the original wound was covered in corneas treated with cPAF. Similar inhibition of epithelial wound closure was found with human corneas incubated with PAF in organ culture. Moreover, addition of several growth factors involved in corneal wound healing, such as epidermal growth factor, hepatocyte growth factor, and keratinocyte growth factor, could not overcome the inhibitory action of PAF in wound closure. Three PAF antagonists, BN50727, BN50730, and BN50739, abolished the effect of PAF. A significant increase in TUNEL-positive staining occurred in corneal stromal cells (keratocytes), which was inhibited by preincubating the corneas with PAF antagonists. However, no TUNEL-positive staining was found in epithelial cells. TUNEL-staining results in cultured stromal cells (keratocytes) and epithelial cells in first-passage cell culture were similar to those in organ-cultured corneas. In addition, PAF caused 35% to 56% inhibition of adhesion of epithelial cells to proteins of the extracellular matrix: collagen I and IV, fibronectin, and laminin. There were no significant changes in proliferation or migration of epithelial cells induced by the lipid mediator. CONCLUSIONS: The results suggest PAF plays an important role in preventing corneal wound healing by affecting adhesion of epithelial cells and increasing apoptosis in stromal cells. PAF antagonists could be of therapeutic importance during prolonged ocular inflammation, helping to avoid loss of corneal transparency and visual acuity.     

The effect of neurotransmitters on rabbit cornea]

PURPOSE: To ascertain the effect of neurotransmitters added to the culture medium of rabbit corneal epithelium and stromal cells. METHOD: The corneal epithelium and stromal cells were cultured in RCGM medium. Three neurotransmitters were added to the medium : substance P, acetylcholine, and vasoactive-intestinal peptide (VIP). RESULTS: Proliferation of epithelial cells significantly increased after incubation for 24 hours with substance P (p < 0.05). There was no change in proliferation after addition of acetylcholine or VIP. The extension of epithelial cell layer increased after addition of substance P but not after addition of acetylcholine or VIP. No change was induced in proliferation of stromal cells or extension of the stromal cell layer after addition of any one of the three substances. CONCLUSION: Substance P stimulates the proliferation of corneal epithelial cells when added to the culture medium.     

CD40 expression in normal human cornea and regulation of CD40 in cultured human corneal epithelial and stromal cells

PURPOSE: To determine whether CD40-CD40 ligand (CD40L) interaction plays a role in corneal inflammatory responses, the expression of CD40 and CD40L on normal human cornea was investigated. In addition, using cultured human corneal epithelial (HCE) and human corneal stromal (HCS) cells, the regulation of CD40 expression in human corneal cells investigated, including that induced by proinflammatory cytokines such as interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha. METHODS: Frozen optimal cutting temperature (OCT) compound-embedded sections of corneal tissues obtained from 18 normal human corneas were examined by an immunoperoxidase staining technique with anti-CD40 and anti-CD40L monoclonal antibodies (mAbs). Also, cultured HCE and HCS cells, with IFN-gamma (250-1000 U/mL) or TNF-alpha (500-4000 U/mL) treatment for 1 to 4 days and with no treatment, were stained by the immunofluorescence technique with mAbs and analyzed by flow cytometry. RESULTS. The area of positive staining for CD40 showed a topographical difference. The limbal epithelial cells were predominantly positive for CD40. Positive staining was also found to a lesser extent on the cells in the basal layer of peripheral corneal epithelium. Epithelial cells of the central cornea showed no immunoreactivity for CD40. Corneal stromal cells were negative for CD40 in most of the donor tissues (positive: 5 of the 18 corneas). Endothelial cells were distinctly negative for CD40. Cultured HCE cells were also positive but decreased in positive cell number with lengthening culture period. None or less than 5% of the cultured HCS cells were CD40 positive. IFN-gamma enhanced CD40 expression on both cell types. In contrast, TNF-alpha enhanced CD40 on HCE but not on HCS cells. No component cells of normal human cornea or cultured HCE and HCS cells showed immunoreactivity for CD40L. CONCLUSIONS: In the human cornea, CD40 is expressed predominantly on limbal epithelial cells and also on cultured HCE cells with high proliferative potential. In addition, the expression of CD40 is induced on cultured HCE and HCS cells differentially by proinflammatory cytokines, such as IFN-gamma and TNF-alpha.     

NS398对白介素1α诱导兔角膜基质细胞环氧化酶2表达的抑制

目的探讨氮-2,环己氧-4,硝基苯-甲基磺胺（NS398）对白介素1α（IL-1α）诱导的兔角膜基质细胞环氧化酶2（COX-2）表达的影响。方法体外培养兔角膜基质细胞,实验组分别以含0、25、50、100、200μmol／LNS398的培养液孵育2h后加入IL-1α诱导COX-2表达,24h后实时荧光定量聚合酶链反应（Real-Time PCR）检测兔角膜基质细胞中COX-2基因表达的差异,四甲基偶氮唑盐（MTT）比色法检测不同浓度NS398对细胞生长的影响,并与对照组进行比较。结果Real—Time PCR结果显示IL—1α诱导后24h各组COX-2 mRNA表达量差异有统计学意义（F=988．45,P〈0．01）;对照组与各实验组以及各实验组之间COX-2 mRNA表达量进行多重比较可见,0μmol／LNS398浓度组与对照组之间差异无统计学意义（q=1．3322,P〉0．05）,其他NS398浓度组与对照组相比差异均有统计学意义（q=34．7896,48．3298,65．8010,70．8131,P〈0．01）,随培养液中NS398浓度的增加,IL-1α刺激后兔角膜基质细胞中COX-2 mRNA表达量不断下降（q=36．1218,49．6620,67．1332,72．1453,13．5402,31．0114,36．0235,17．4712,22．4833,5．0121,P〈0．01）;MTT法检测结果显示,100μmol／L、200μmol／L的NS398对兔角膜基质细胞生长均有明显的抑制作用（q=12．7693,20．9087,P〈0．01）。结论NS398能够有效抑制IL-1α诱导的兔角膜基质细胞COX-2的表达,但超过一定浓度会对细胞产生明显毒性作用。     

柔红霉素对人晶体上皮细胞生长抑制和角膜内皮细胞毒性试验研究

目的：研究柔红霉素对体外培养人晶体上皮细胞增殖的抑制作用和对角膜内皮细胞的毒性，探索使用柔红霉素预防后发障的适宜浓度，方法：第三代人晶 皮细胞接种于24孔培养板内，24h后加入不同浓度柔红霉素作用10min后，吸出药物并冲洗后再培养48h，细胞计数，原代培养角加入膜内皮细胞，加入不同浓度柔红霉素作用10min，观察细胞生长形态学变化，结果：柔红霉素依浓度梯度抑制晶体上皮细胞增殖，其LD50为4．9ug/ml，10ug/ml以下浓度对角膜内皮细胞无损害，结论：柔红霉素有可能作为预防后发障的辅助药物之一，选择适宜浓度是防止其对其他组织产生毒性的关键。     

Increased apoptosis and abnormal wound-healing responses in the heterozygous Pax6+/- mouse cornea

PURPOSE: Corneal wound healing involves a cascade of interactions between the epithelium and stroma. Pax6 is upregulated, and early events include epithelial cell migration and apoptosis of superficial keratocytes. The mouse heterozygous Pax6 (Pax6+/-) corneal phenotype mimics human aniridia-related keratopathy (ARK), and some aspects of wound healing have been shown to be abnormal, including matrix metalloproteinase (MMP)-9 expression. The purpose of this study was to test whether the Pax6+/- genotype affects corneal wound-healing responses, including stromal cell apoptosis, epithelial cell migration rate, and MMP secretion in culture. METHOD: Pax6+/- and wild-type (Pax6+/+) mice were killed and their corneas wounded by epithelial debridement. Whole eyes were cultured in organ culture and corneal epithelial healing rates and keratocyte apoptosis were quantified by topical fluorescein staining and TUNEL, respectively. Dissociated corneal epithelial cells from Pax6+/- and wild-type mice were cultured, and the activities of secreted MMP-9 were determined by zymography. RESULTS: Wound-healing rates during the first 6 hours were significantly faster for larger wounds and for Pax6+/- corneas. Compared with wild-type, wounded Pax6+/- eyes showed significantly more stromal cell apoptosis, and cultured Pax6+/- corneal epithelial cells produced lower MMP-9 activity. CONCLUSIONS: The cumulative effect of abnormal wound-healing responses, characterized by increased stromal cell apoptosis and reduced levels of MMP-9 secretion may contribute to the corneal changes in the Pax6+/- mice. Possible contributions of elevated stromal cell apoptosis and other abnormal wound-healing responses to ARK are discussed.