Acellular porcine corneal matrix as a carrier scaffold for cultivating human corneal epithelial cells and fibroblasts in vitro

AIM：To investigate the feasibility of corneal anterior lamellar reconstruction with human corneal epithelial cells and fibroblasts,and an acellular porcine cornea matrix（APCM） in vitro.·METHODS：The scaffold was prepared from fresh porcine corneas which were treated with 0.5%sodium dodecyl sulfate（SDS）solution and the complete removal of corneal cells was confirmed by hematoxylin-eosin（HE）staining and 4’,6-diamidino-2-phenylindole（DAPI）staining.Human corneal fibroblasts and epithelial cells were cultured with leaching liquid extracted from APCM,and then cell proliferative ability was evaluated by MTT assay.To construct a human corneal anterior lamellar replacement,corneal fibroblasts were injected into the APCM and cultured for 3d,followed by culturing corneal epithelial cells on the stroma construction surface for another 10d.The corneal replacement was analyzed by HE staining,and immunofluorescence staining.·R ESULTS：Histological examination indicated that there were no cells in the APCM by HE staining,and DAPI staining did not detect any residual DNA.The leaching liquid from APCM had little influence on the proliferation ability of human corneal fibroblasts and epithelial cells.At 10d,a continuous 3 to 5 layers of human corneal epithelial cells covering the surface of the APCM was observed,and the injected corneal fibroblasts distributed within the scaffold.The phenotype of the construction was similar to normal human corneas,with high expression of cytokeratin 12 in the epithelial cell layer and high expression of Vimentin in the stroma.·CONCLUSION：Corneal anterior lamellar replacement can be reconstructed in vitro by cultivating human corneal epithelial cells and fibroblasts with an acellular porcine cornea matrix.This laid the foundation for the further transplantation in vitro.

Construction of a full-thickness human corneal substitute from anterior acellular porcine corneal matrix and human corneal cells

AIM: To construct functional human full-thickness corneal replacements.METHODS: Acellular porcine corneal matrix(APCM) was developed from porcine cornea by decellulariztion. The biomechanical properties of anterior-APCM(AAPCM) and posterior-APCM(PAPCM) were checked using uniaxial tensile testing. Human corneal cells were obtained by cell culture. Suspending ring was designed by deformation of an acupuncture needle. MTT cytotoxicity assay was used to check the cytotoxicity of suspending ring soaking solutions. A new three-dimensional organ culture system was established by combination of suspending ring, 48-well plate and medium together. A human full-thickness corneal substitute was constructed from human corneal cells with AAPCM in an organ coculture system. Biochemical marker expression of the construct was measured by immunofluorescent staining and morphological structures were observed using scanning electron microscopy. Pump function and biophysical properties were examined by penetrating keratoplasty and follow-up clinical observations.RESULTS: There were no cells in the AAPCM or PAPCM, whereas collagen fibers, Bowman's membrane, and Descemet's membrane were retained. The biomechanical property of AAPCM was better than PAPCM. Human corneal cells grew better on the AAPCM than on the PAPCM.There was no cytotoxicity for the suspending ring soaking solutions. For the constructed full-depth human corneal replacements keratocytes scattered uniformly throughout the AAPCM and expressed vimentin. The epithelial layer was located on the surface of Bowman's membrane and composed of three or four layers of epithelial cells expressing cytokeratin 3. One layer of endothelial cells covered the stromal surface of AAPCM, expressed Na+/K+ATPase and formed the endothelial layer. The construct was similar to normal human corneas, with many microvilli on the epithelial cell surface, stromal cells with a long shuttle shape, and zonula occludens on the interface of endothelial cells. The construct withstood surgical procedures during penetrating keratoplasty. The corneal transparency increased gradually and was almost completely restored 7 d after surgery.CONCLUSION: AAPCM is an ideal scaffold for constructing full-thickness corneal replacement, and functional human full-thickness corneal replacements are successfully constructed using AAPCM and human corneal cells.

Cell viability and extracellular matrix synthesis in a co-culture system of corneal stromal cells and adipose-derived mesenchymal stem cells

AIM：To investigate the impact of adipose-derived mesenchymal stem cells（ADSCs） on cell viability and extracellular matrix（ECM） synthesis of corneal stromal cells（CSCs）. METHODS：ADSCs and CSCs were obtained from the corneas of New Zealand white rabbits and indirectly cocultured in vitro. The proliferative capacity of CSCs in the different groups was assessed by CCK-8 assays. Annexin V-fluorescein isothiocyanate（FITC）/proliferation indices（PI） assays were used to detect the apoptosis of CSCs. The expression levels of matrix metalloproteinase（MMP）, such as MMP1, MMP2, MMP9, and collagens were also evaluated by Western blot. RESULTS：ADSCs significantly promoted proliferation and invasion of CSCs in the indirect co-culture assays. The co-cultural group displayed much higher ability of proliferation, especially under the co-culture conditions of ADSCs for 3d, compared with that CSCs cultured alone. The PI of CSCs in the co-culture system were increased approximately 3-8-fold compared with the control group. A significant change was observed in the proportions of cells at apoptosis（early and late） between the negative control group（6.34% and 2.06%） and the ADCSs-treated group（4.69% and 1.59%）. The expression levels of MMPs were down regulated in the co-culture models. Compared with the control group, the decrease intensities of MMP-1, MMP-2 and MMP-9 in CSCs/ADSCs group were observed, 3.90-fold, 1.09-fold and 3.03-fold, respectively. However, the increase intensities of collagen type（I, II, III, IV, and V） in CSCs were observed in CSCs/ADSCs group, 3.47-fold,4.30-fold, 2.35-fold, 2.55-fold and 2.43-fold, respectively, compared to that in the control group. The expressions of aldehyde dehydrogenase and fibronectin in CSCs were upregulated in the co-culture models.CONCLUSION：ADSCs play a promotive role in CSCs＇ growth and invasion, which may be partially associated with MMPs decrease and collagens increase, resulting in a positive participation in the plasticity and ECM synthesis of CSCs. This provided a new insight into the extensive role of ADSCs in CSCs and a potential molecular target for corneal therapy.

Corneal matrix repair therapy with the regenerating agentin neurotrophic persistent epithelial defects

Citation： Utine CA, Engin Durmaz C, Koqak N. Corneal matrix repair therapy with the regenerating agent in neurotrophic persistent epithelial defects, lntJOphthalmo12017;10（12）：1935-1939

Preliminary studies of constructing a tissue-engineered lamellar corneal graft by culturing mesenchymal stem cells onto decellularized corneal matrix

AIM:To construct a competent corneal lamellar substitute in order to alleviate the shortage of human corneal donor.METHODS:Rabbit mesenchymal stem cells(MSCs)were isolated from bone marrow and identified by flow cytometric,osteogenic and adipogenic induction.Xenogenic decellularized corneal matrix(XDCM)was generated from dog corneas.MSCs were seeded and cultured on XDCM to construct the tissueengineered cornea.Post-transplantation biocompatibility of engineered corneal graft were tested by animal experiment.Rabbits were divided into two groups then underwent lamellar keratoplasty(LK)with different corneal grafts:1)XDCM group(n=5):XDCM;2)XDCM-MSCs groups(n=4):tissue-engineered cornea made up with XDCM and MSCs.The ocular surface recovery procedure was observed while corneal transparency,neovascularization and epithelium defection were measured and compared.In vivo on focal exam was performed 3 mo postoperatively.RESULTS:Rabbit MSCs were isolated and identified.Flow cytometry demonstrated isolated cells were CD90 positive and CD34,CD45 negative.Osteogenic and adipogenic induction verified their multipotent abilities.MSC-XDCM grafts were constructed and observed.In vivo transplantation showed the neovascularization in XDCMMSC group was much less than that in XDCM group postoperatively.Post-transplant 3-month confocal test showed less nerve regeneration and bigger cell-absent area in XDCM-MSC group.CONCLUSION:This study present a novel corneal tissue-engineered graft that could reduce post-operatively neovascularization and remain transparency,meanwhile shows that co-transplantation of MSCs may help increase corneal transplantation successful rate and enlarge the source range of corneal substitute to overcome cornea donor shortage.

Changes of matrix metalloproteinases in the stroma after corneal cross-linking in rabbits

AIM:To observe changes in the content of matrix metalloproteinases(MMPs)in the corneal stroma after corneal cross-linking(CXL)in rabbits,and further explore the corneal pathophysiological process after CXL.METHODS:Forty-two rabbits(42 eyes)were randomly divided into seven groups.One group served as the control group,while the other six groups were treated with CXL.The concentrations of MMPs in corneal stroma were evaluated through parallel reaction monitoring at baseline and 3,7,15,30,90,and 180 d after treatment.RESULTS:The levels of MMP-2 in the corneal stroma of rabbits were 0.76±0.07,2.78±1.39,4.12±0.69,2.00±0.29,2.00±0.30,1.22±0.18,and 1.35±0.18(10^(-9)mol/g)at baseline and 3,7,15,30,90,and 180 d after treatment,respectively.The contents of tissue inhibitor of metalloproteinase-1(TIMP-1)were 1.83±0.26,7.94±0.58,6.95±2.64,3.81±0.48,3.07±0.92,1.72±0.19,and 1.69±0.74(10^(-9)mol/g),respectively.The ratios of MMP-2/TIMP-1 were 0.42±0.33,0.36±0.20,0.62±0.10,0.54±0.15,0.68±0.13,0.71±0.10,and 0.68±0.09,respectively.After CXL,the expression of MMP-2 and TIMP-1 in the rabbit corneal stroma was initially increased and subsequently decreased.The levels of MMP-2 remained higher than those recorded at baseline 180 d after treatment,but it was not statistically significant.The levels of TIMP-1 returned to baseline levels at 90 d after treatment.The ratio of MMP-2/TIMP-1 started to rise from 7 d after CXL.It was significantly higher than that calculated at baseline 30-180 d after CXL.The results for MMP-1,-3,-7,-9,-13,and TIMP-2 were negative.CONCLUSION:CXL can lead to changes in the content of MMP-2 and TIMP-1 in the rabbit corneal stroma.The ratio of MMP-2/TIMP-1 remains higher versus baseline,indicating that MMP-2 is involved in the corneal pathophysiological process after CXL.

Alarmins from conjunctival fibroblasts up-regulate matrix metalloproteinases in corneal fibroblasts

AIM:To explore the effects of alarmins produced by necrotic human conjunctival fibroblasts on the release of matrix metalloproteinases(MMPs)by human corneal fibroblasts(HCFs).METHODS:A necrotic cell supernatant(NHCS)was prepared by subjecting human conjunctival fibroblasts to three cycles of freezing and thawing.The amounts of interleukin(IL)-1βand tumor necrosis factor(TNF)-αin NHCS were determined by enzyme-linked immunosorbent assays.HCFs exposed to NHCS or other agents in culture were assayed for the release of MMPs as well as for intracellular signaling by immunoblot analysis.The abundance of MMP m RNAs in HCFs was examined by reverse transcription and real-time polymerase chain reaction analysis.RESULTS:NHCS increased the release of MMP-1 and MMP-3 by HCFs as well as the amounts of the corresponding m RNAs in the cells.NHCS also induced activation of mitogen-activated protein kinase(MAPK)signaling pathways mediated by extracellular signal-regulated kinase(ERK),p38,and c-Jun NH2-terminal kinase(JNK)as well as elicited that of the nuclear factor(NF)-κB signaling pathway by promoting phosphorylation of the endogenous NF-κB inhibitor IκB-α.Inhibitors of MAPK and NF-κB signaling as well as IL-1 and TNF-αreceptor antagonists attenuated the NHCS-induced release of MMP-1 and MMP-3 by HCFs.Furthermore,IL-1βand TNF-αwere both detected in NHCS,and treatment of HCFs with these cytokines induced the release of MMP-1 and MMP-3 in a concentration-dependent manner.CONCLUSION:Alarmins,including IL-1βand TNF-α,produced by necrotic human conjunctival fibroblasts triggered MMP release in HCFs through activation of MAPK and NF-κB signaling.IL-1βand TNF-αare therefore potential therapeutic targets for the amelioration of corneal stromal degradation in severe ocular burns.

生物工程角膜板层角膜移植在真菌性角膜溃疡患者中的应用

目的探讨生物工程角膜板层角膜移植在真菌性角膜溃疡患者中的有效性及安全性。方法选取44例真菌性角膜溃疡患者为研究对象,根据使用的角膜材料分为生物工程组[采用脱细胞猪角膜基质(APCM)进行板层角膜移植,20例]和人供体组(采用人供体角膜材料进行板层角膜移植,24例)。比较两组术后不同时间角膜植片透明度评分、最佳矫正视力(BCVA)和术后角膜上皮愈合时间、术后并发症及复发率。结果术后1、3、6、12个月,随着时间的延长两组角膜植片透明度评分均逐渐降低,术后1、3、6个月生物工程组角膜植片透明度评分高于人供体组(P<0.05),但术后12个月两组角膜植片透明度评分比较,差异无统计学意义(P>0.05)。术后3、6、12个月,随着时间的延长两组患眼BCVA均逐渐增加,但生物工程组患眼术后3、6、12个月的BCVA均低于人供体组(P<0.05);两组角膜上皮愈合时间及术后角膜上皮愈合延迟、角膜植片排斥、角膜植片溶解、新生血管长入角膜植片4项并发症发生率和术后复发率比较,差异无统计学意义(P>0.05)。结论以APCM为材料进行板层角膜移植治疗真菌性角膜溃疡临床效果好,安全性高,可作为生物工程角膜应用于角膜病致盲的治疗。

塞来昔布固体脂质纳米粒对兔角膜重度热烧伤行穿透性角膜移植术后CNV、MMP-2的影响

目的观察塞来昔布(celecoxib,CXB)固体脂质纳米粒(solid lipid nanoparticles,SLN)对兔角膜重度热烧伤(severe corneal thermal burn,SCTB)行穿透性角膜移植术(penetrating keratoplasty,PKP)后角膜新生血管(corneal neovascularization,CNV)及基质金属蛋白酶2(matrix metalloproteinase-2,MMP-2)浓度的影响,探讨CXB-SLN对兔SCTB的作用机制。方法取36只新西兰白兔,恒温烧灼器制作兔SCTB模型(左眼),随机分为对照组、PKP组、CXB-PKP组,每组12只。对照组、PKP组球结膜下注射9 g/L的生理盐水0.1 ml,CXB-PKP组球结膜下注射1 g/L的CXB-SLN 0.1 ml。PKP组、CXB-PKP组于造模后第3天行PKP治疗。观察3组白兔术后角膜一般情况并记录术后10、20、40天CNV面积。在术后20、40天各组随机选择6只兔处死。采用酶联免疫吸附试验(enzyme-linked immunosorbent assay,ELISA)检测角膜上清液中MMP-2浓度,并分析CNV面积与MMP-2的相关性。结果术前3组白兔角膜均可见角膜缘充血明显,角膜烧伤区水肿,混浊,伴角膜上皮层坏死、剥脱。术后对照组可见角膜混浊逐渐加重呈瓷白色混浊,PKP组与CXB-PKP组可见角膜植片均成活,角膜透明度尚可。术后10、20、40天,CXB-PKP组CNV面积小于PKP组(P均<0.05),PKP组CNV面积小于对照组(P均<0.05)。术后20和40天角膜上清液MMP-2的浓度,CXB-PKP组低于PKP组,PKP组低于对照组(P均<0.05)。术后20、40天,CNV面积与MMP-2浓度呈正相关(r=0.742,P<0.001;r=0.827,P<0.001)。结论CXB-SLN对兔SCTB后的CNV具有明显抑制作用,可减轻角膜混浊,其机理可能与MMP-2的下调有关,能够为SCTB后行PKP创造有利条件。

Construction of eukaryotic plasmid expressing human TGFBI and its influence on human corneal epithelial cells

AIM: To detect the expression of transforming growth factor beta-induced gene (TGFBI) protein in human corneal tissue and overexpress it in the human corneal epithelial cells in order to discuss the function of TGFBI in the pathogenesis of corneal dystrophy. METHODS: Immunohistochemistry (IHC) was used to detect the expression of TGFBI in the human cornea tissue. TGFBI cDNA was obtained by reverse transcription-PCR from human corneal total RNA extracted from cornea transplant donor and cloned into pCMV-N-HA vector. The recombinant pCMV-N-HA-TGFBI plasmid transfected human corneal epithelial cells. Forty-eight hours later, mRNA and proteins were harvested from cells for real-time PCR analysis and western blot assay respectively. RESULTS: IHC indicated TGFBI mainly exist below the human corneal epithelium layer. Transfection of recombinant pCMV-N-HA-TGFBI into human corneal epithelial cells resulted in effective expression of TGFBI, as shown by increased mRNA level detected by real-time KR as well as increased protein level detected by Western blot. Meanwhile the result of real-time KR and Western blot shown the expression of MMP1,MMP3(matrix rnetalloproteinases MMP) increased while the expressin of TIMP1 (tissue inhibitors of matrix metalloproteinases TIMP) decreased. CONCLUSION: TGFBI mainly exists below the corneal epithelial layer, recombinant eukaryotic expression vector harboring human TGFBI cDNA was obtained and efficiently overexpressed in human corneal epithelial cells. Meanwhile the TGFBI overexpression in human corneal epithelial cells result in MMPI., MMP3 increasing and TIMP1 decreasing. The result might be helpful for studying the function and role of TGFBI in pathogenesis of corneal dystrophy.

猪脱细胞角膜基质组织结构特点与生物相容性研究

背景构建组织工程化角膜时，载体的选择十分重要。目前有多种载体可供选用，但脱细胞角膜基质是公认的较好载体。目的观察猪脱细胞角膜基质的组织结构特点，评价其与异种角膜基质和上皮细胞的生物相容性。方法取猪角膜组织进行组织块培养，经胰蛋白酶-EDTA酶消化角膜上皮、基质、内皮细胞，支架组织于-20℃冷冻干燥后灭菌保存。猪脱细胞角膜基质石蜡切片行常规苏木精一伊红染色，光学显微镜下观察组织的形态学特征；扫描电镜下观察其组织结构特点；并对其物理特性，如抗拉性、膨胀性、含水量和透明度进行评价。将猪脱细胞角膜基质移植到兔角膜基质层内，同时与体外培养的兔角膜上皮细胞共培养4周，分析其组织和细胞生物相容性。结果经酶消化处理后猪角膜组织中未见上皮、基质和内皮细胞，其胶原纤维直径大小、排列与正常角膜组织相同，抗拉性、膨胀性、含水量和透明度等物理特性与正常猪角膜相似。猪脱细胞角膜基质行异种兔角膜基质层间移植1周时可见轻度水肿，2周后水肿基本消退，4周时透明度较好。猪脱细胞角膜基质与兔角膜基质之间贴附良好，未见炎症反应及新生血管。兔角膜上皮细胞接种于猪脱细胞角膜基质上共培养4周后CK3表达阳性。猪脱细胞角膜基质脱水前与脱水2h、4h后及正常猪角膜基质间的抗拉性、膨胀性、含水量的差异均无统计学意义（P〉0．05），但脱水2h、4h后及正常猪角膜基质的透明度明显好于脱水前，差异均有统计学意义（P〈0．01）。结论猪脱细胞角膜基质组织结构与正常猪角膜相似，与兔角膜基质和上皮细胞具有良好的生物相容性。

不同方法处理的角膜脱细胞基质组织学生物特性的比较

目的:比较不同的角膜脱细胞基质方法,旨在选择最适合的脱细胞基质方法,制备成为组织工程角膜支架材料和角膜替代物的脱细胞基质。方法:分别用胰酶-曲拉通法、SDS-戊二醛法、胰酶-冷冻法等方法对角膜进行脱细胞处理,并对脱细胞彻底的基质进行力学特性、透光率的分析。结果:用胰酶-冷冻法获得的兔角膜全层和分层基质脱细胞最彻底,基质的结构未见明显破坏,脱细胞基质在生物力学特性上与正常角膜接近,透光率低于新鲜角膜。结论:用胰酶-冷冻法获得的脱细胞基质与自然角膜接近,可作为组织工程角膜支架材料和角膜替代物。

种植人骨髓间充质干细胞的猪角膜板层移植治疗兔角膜损伤的初步研究

目的研究种植人骨髓间充质干细胞(MSCs)的猪角膜基质治疗兔角膜损伤的可能性。方法用全骨髓贴壁法分离纯化人MSCs并传代,流式细胞仪检测免疫表型及诱导成脂、成骨分化鉴定。12只新西兰白兔随机分为2组,实验组取第3代MSCs接种于去上皮的猪角膜基质上,培养4 d后移植到广泛损伤的兔角膜上,对照组单纯移植去上皮猪角膜基质。术后2、4、8周,取各实验眼行组织学检查,观察移植的MSCs及猪角膜基质的存活、转归及移植局部的反应。免疫组织化学、免疫荧光染色检测移植后角膜上皮细胞角蛋白12的表达。结果培养获得的MSCs中CD29阳性者占95.97%,CD44阳性者占96.49%,CD90阳性者占92.79%,CD105阳性者占94.66%,CD34阳性者占0.59%,CD45阳性者占0.36%,符合MCSs的免疫表型,并可以诱导成脂及成骨分化。实验组MSCs接种到去上皮猪角膜基质后贴附、生长迅速,术后植片在植床上存活良好,无排斥反应,角膜较对照组透明,新生血管少,而对照组在移植后发生排斥反应。实验组角膜免疫组织化学及免疫荧光染色均检测出CK12阳性细胞。结论种植MSCs的猪角膜基质移植到损伤兔角膜后可以存活,MSCs可以分化为角膜上皮样细胞,具有构建组织工程角膜的潜能。

CTGF对角膜成纤维细胞生物学功能的影响

目的 观察结缔组织生长因子(CTGF)对体外培养的角膜成纤维细胞增殖、向肌成纤维细胞转化和合成细胞外基质的影响。 方法 体外培养兔角膜成纤维细胞,经0.5、5、50和500 ng／mL CTGF处理24 h后,分别进行增殖细胞核抗原(PCNA)免疫组化染色、银染核仁组成区染色(AgNOR)、平滑肌肌动蛋白(α-SMA)免疫组化染色以及Ⅲ型胶原(CA-Ⅲ)、纤维连接蛋白(FN)和层黏蛋白(LM)免疫组化染色,检测CTGF对角膜成纤维细胞增殖、向肌成纤维细胞转化和细胞外基质合成的影响。 结果 与对照组相比,0.5、5、50和500 ng／mL的CTGF能剂量依赖性地促进角膜成纤维细胞PCNA表达,增加核仁银染颗粒数,促进α-SMA的表达,同时能促进角膜成纤维细胞CA-Ⅲ、FN和LM的合成(P<0.01)。结论 一定质量浓度的CTGF可能在角膜损伤修复过程中发挥重要作用。

基质金属蛋白酶在角膜疾病中的作用

MMP作为降解细胞外基质的酶家族。参与许多生理及病理过程。同样其在角膜表达水平的改变与许多角膜疾病密切相关。随着对其研究的不断深入,使得从一个新的角度来预防和治疗角膜疾病成为可能。所以十分有必要了解MMPs的结构、功能、生物合成的调节及其在角膜疾病中的作用。

脱细胞真皮基质在角膜中植入性的生物力学研究

对脱细胞真皮基质(acellular dermal matrix,ADM)囊袋植入兔角膜后的生物相容性、生物学转归及组织结构改变进行生物力学研究,以探讨其作为组织工程角膜支架材料的可行性.对ADM进行了系统的组织微观结构观察和植入性实验研究,组织结构观察包括HE染色、胶原染色、免疫荧光染色和透射电镜观察.在植入实验中,将ADM按不同预处理方法分为无干预组、脱水组和复水组,将3组ADM囊袋植入兔角膜,观察其术后不同时期在体和离体的生物相容性和组织学特性.结果发现:ADM由横纵交替、排列疏松的Ⅰ和Ⅲ型胶原纤维束构成,未见细胞结构;囊袋植入角膜后有不同程度的炎症反应,部分植片透明;组织学观察显示3组ADM植入角膜后均有细胞长入,并进行了胶原纤维重塑.研究工作表明,经适当预处理且结构致密的脱细胞真皮基质植入后可以长期稳定存留于角膜内,是一种比较理想的组织工程角膜支架.

小鼠角膜碱烧伤行羊膜移植对MMP-9、TIMP-1在新生血管形成中的影响

目的探讨小鼠角膜碱烧伤行羊膜移植对基质金属蛋白酶9(matrixmetalloproteinase9,MMP9)、金属蛋白酶组织抑制剂1(tissueinhibitorofmetalloproteinase1,TIMP1)在新生血管形成中的影响以及MMP9及TIMP1在角膜新生血管形成中的作用。方法昆明小鼠40只,随机分为实验组和对照组,每只鼠均取右眼为实验眼。采用1mol·L-1NaOH溶液烧伤小鼠角膜,建立炎症性角膜碱烧伤动物模型。对实验组小鼠右眼角膜行羊膜移植,对照组不行羊膜移植。分别在羊膜移植后的0d、2d、7d、14d处死2组小鼠,摘除右眼球,行免疫组织化学染色并用计算机图像分析系统检测2组小鼠MMP9及TIMP1在角膜中的分布及其平均吸光度值的变化。结果免疫组化结果:对照组碱烧伤角膜后第2d,可见MMP9出现表达,第7dMMP9的染色较第2d增强,基质层可见大量新生血管,且血管内皮细胞可见表达,14d达高峰;TIMP1开始表达不明显,第7d出现表达,14d达高峰。羊膜移植组各时间点MMP9表达低于对照组,而TIMP1表达高于对照组。结论碱烧伤后小鼠角膜中MMP9表达增加,在新生血管形成的过程中起一定作用。羊膜可能具有抑制MMP9在碱烧伤小鼠角膜中表达的作用,而且羊膜同时促使TIMP1在后期表达水平升高,从而抑制MMP9的活性,抑制和减缓碱烧伤后角膜新生血管的发生和发展。

机械牵张对兔角膜成纤维细胞细胞外基质基因表达的影响

目的研究机械牵张与白介素-1β(IL-1β)联合作用对兔角膜成纤维细胞细胞外基质相关基因表达的影响。方法对原代提取的兔角膜成纤维细胞进行牵张幅度15%、频率0.1 Hz的周期性牵张12、24、36 h,同时给予IL-1β处理,采用实时荧光定量PCR检测细胞基质金属蛋白酶(MMPs)、基质金属蛋白酶的组织抑制剂(TIMP-1)和I型胶原α1(Collagen Iα1)mRNA表达变化水平。结果 IL-1β单独作用可以诱导角膜成纤维细胞MMP-1、MMP-3和MMP-9 mRNA表达;MMP-1和MMP-3 mRNA表达随时间而降低,MMP-9、TIMP-1、Collagen Iα1 mRNA则随时间而增加;IL-1β与机械牵张联合作用使MMP-1、MMP-3、MMP-9 mRNA表达水平上调,TIMP-1和Collagen Iα1 mRNA表达下调,且具有时间依赖。单独机械牵张使Collagen Iα1 mRNA表达下降,IL-1β与机械牵张联合作用使其表达进一步下调,且具有时间依赖性。结论机械牵张与炎性因子联合作用可加剧角膜组织破坏,促进角膜膨隆的发生发展。

角膜上皮细胞基底膜的研究进展

角膜上皮细胞基底膜是一层很薄的组织,它的结构与其他部位的基底膜既有相似之处,也有独特的地方,在角膜创伤修复中有着重要的作用。基底膜组织的破坏会导致一系列棘手的角膜病变,而近来对角膜上皮细胞基底膜的研究使我们在这些病变的治疗方面有了新的入手点。就近年来角膜上皮细胞基底膜的研究进展做一综述。

角膜新生血管与微环境研究进展

在多种病理状态下毛细血管由角膜缘向角膜中央生长形成角膜新生血管（CNV），CNV破坏角膜正常微环境，降低角膜透明性，严重影响视力，而且导致角膜移植术后角膜免疫排斥反应的发生。角膜新生血管的微环境包括炎性介质、细胞、细胞因子和细胞外基质（ECM）。近年来研究显示CNV处于周围复杂的微环境之中，角膜微环境变化与CNV具有密切关系。CNV形成过程中，角膜微环境发生一系列变化。本文就CNV与微环境变化作一综述。