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1.
AIM: To evaluate the histological changes after transepithelial corneal crosslinking (CXL) using partial thickness excimer laser ablation or epithelial ethanol application in an experimental rabbit study.METHODS: Right eyes of twenty-four rabbits were studied. Four eyes received total epithelial debridement (group I). Four eyes received partial thickness epithelial ablation with excimer laser (group II). Twelve eyes were treated with different durations (30s and 60s) and concentrations (18% to 48%) of ethanol (group III). Riboflavin was applied for 30min intervals along with topical proparacaine drops with benzalkonium chloride, and 370 nm irradiation was performed for 30min, while riboflavin was instilled every 3min. Four eyes (group IV) received 48% ethanol for 30s without riboflavin and irradiation. Eyes were collected after 24h and examined histologically.RESULTS: All eyes in group I showed keratocyte loss in the superficial 300 μ of corneal storma. In group II, 1-4 layers of epithelium were preserved and no keratocyte loss occurred. In group III, CXL after treatment with ethanol up to 24% concentration and up to 60s revealed no keratocyte loss. CXL after treatment with 48% and higher ethanol concentrations yielded keratocyte loss in the superficial 200 μ to 300 μ of cornea.CONCLUSION: Incomplete excimer laser ablation of the epithelium or treatment with ethanol up to 24% concentration and up to 60s duration yielded no stromal keratocyte loss. To get the same histological appearance seen in epithelial debridement group, partial thickness excimer laser epithelial ablation or ethanol application is not adequate for transepithelial CXL.  相似文献   

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Wang Y  Zhao KX  Su LY  Wang LJ  Geng WL  Jin Y 《中华眼科杂志》2005,41(6):498-504
目的探讨准分子激光角膜上皮瓣下磨镶术(LASEK)中乙醇对角膜伤口愈合过程的影响。方法24只健康白兔(48只眼)分为两组,一只眼行机械去上皮法,另一只眼应用20%乙醇30s去除角膜上皮,行相同方案的准分子激光切削,同时设立正常对照组。观察角膜基质浅层角膜细胞数量和形态变化;RTPCR法及免疫组化法检测正常对照组及手术组术后1d、1周、1个月、3个月转化生长因子β1(TGFβ1)和碱性成纤维细胞生长因子(bFGF)的表达情况并做分析。结果术后1d,乙醇组和机械组兔角膜TGFβ1和bFGFRTPCR表达较正常对照组下降;1周两组较正常对照组升高(P<0.01),乙醇组高于机械组(P<0.01);术后1个月达高峰(P<0.01),但乙醇组与机械组比较差异无统计学意义(P>0.05);术后3个月,TGFβ1、bFGFRTPCR产物明显下降,两组之间比较或与正常对照组比较差异无统计学意义(P>0.05)。浅层基质内角膜细胞数量乙醇组与TGFβ1和bFGF的相关系数分别为0.744,0.738;机械组分别为0.664和0.785。结论TGFβ1、bFGF在伤口愈合过程中的表达呈现“减少增多正常”动态过程;20%乙醇在LASEK早期对角膜伤口愈合存在一定影响,但极其短暂。手术中应用是相对安全的。  相似文献   

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PURPOSE: The transplantation of retinal pigment epithelial (RPE) cells is a possible therapy for degenerative diseases of the retina. However, the immune response and the subsequent rejection of the allografts are major problems in this field. We investigated the effect of pro-inflammatory factors on the cytokine and chemokine mRNA expression of human RPE cells during long-term observations in vitro. METHODS: Human RPE cells were cultured in the presence of tumor necrosis factor-alpha (TNF-alpha, 10 ng/ml), interferon-gamma (IFN-gamma, 1000 U/ml) or with a combination of both up to 96 hours. Cells were harvested and total RNA was isolated. The changes in expression of mRNA coding for RANTES, the interleukines (IL)-6, 8, 10, 15, IFN-gamma, monocyte chemotactic protein-1 (MCP-1) and transforming growth factor-beta1 (TGF-beta1) during the stimulation were investigated using the ribonuclease protection assay. RESULTS: IL-10 and IFN-gamma mRNA were detected in neither unstimulated nor stimulated cells. Human RPE cells constitutively express the mRNA for IL-6, MCP-1, IL-8, IL-15, TGF-beta1 and, at very low levels, for RANTES. The TGF-beta1 mRNA expression was not influenced by either stimulation. The mRNA of the other factors was up-regulated for 24-48 h dependent on the stimulation. CONCLUSIONS: Human RPE cells are able to increase their mRNA expression for the detected cytokines in response to the pro-inflammatory factors which are detectable in the rejection process. These up-regulated cytokines themselves are known to be involved in several inflammatory and immunological processes, suggesting their role in the rejection of transplanted RPE allografts.  相似文献   

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目的:研究TGF—β1短期眼部应用对兔角膜碱烧伤后整合素β1表达和角膜上皮愈合的影响,探求其对角膜碱烧伤的治疗作用。方法:制备大耳自家兔角膜碱烧伤模型,一组给予TGF—β1(浓度为200ng/m1)局部滴眼,每日3次,连续7日;另一组给予PBS溶液代替,处理相同。于角膜碱烧伤后每13观察角膜上皮愈合面积,并于烧伤后6h、1d、3d、7d和14d5个时间点应用免疫组化方法检测TGF—β1实验组与PBS组角膜整合素β1表达情况。结果:烧伤后4d、10d、11d、12d和14d实验组和对照组上皮愈合率比较,差异有统计学意义(P〈0.05),两组随着上皮修复过程的进行,整合素B1的表达均逐渐增加,烧伤后7d、14d两个时间点实验组和对照组整合素B1平均灰度值比较,差异有显著性(P〈0.05)。结论:TGF—β1在活体实验中能促进整合素β1的表达,而后者的增加可以促进角膜上皮细胞向损伤区域的移行和粘附,从而减少碱烧伤愈合过程中上皮再次脱落现象,有利于创伤愈合。  相似文献   

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Chang SW  Wang YH  Pang JH 《Cornea》2006,25(1):78-84
PURPOSE: To investigate the effect of corneal epithelium on the viability of corneal stromal keratocytes in Optisol-GS. METHODS: After sterilization, corneoscleral buttons were excised and stored in Optisol-GS for various time periods. Group 1 corneas (n = 40) underwent mechanical corneal epithelial debridement before storage while group 2 corneas (n = 40) were stored with intact epithelium. Changes in corneal thickness, keratocyte density, and keratocyte apoptosis were investigated immediately, at 4 hours, and on days 1, 2, 3, 5, 7, and 14 in the preservation medium. The differences between group 1 and 2 corneas were analyzed. RESULTS: Corneal thickness increased significantly in the second week of preservation in both groups, though more substantially in group 1. Significant corneal epithelial apoptosis was noticed in the first week in group 2 corneas. Corneal stromal keratocyte density decreased with prolonged preservation time. DNA laddering was detected by ligation-mediated polymerase chain reaction throughout the experiment periods in both groups, but the increase of keratocyte apoptosis was more significant after 5 days of preservation, especially in group 1. CONCLUSIONS: Stromal keratocytes underwent apoptosis in Optisol-GS. The absence of corneal epithelium during preservation further increased the stromal keratocyte apoptosis.  相似文献   

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PURPOSE. Incisional or ablation injury to the corneal stroma is repaired by deposition of a fibrotic tissue produced by activated keratocytes, whereas cells lost from the underlying stroma after epithelial abrasion are simply replaced by keratocyte replication without expression of fibrotic markers. The purpose of this study was to investigate mechanisms that determine this differential keratocyte response. METHODS. A penetrating keratectomy rabbit model was adapted for mice to study the fibrotic repair response. A mouse epithelial abrasion model was applied to study the stromal cell replacement response. A primary rabbit corneal cell culture model and an organotypic culture model were also used. RESULTS. When the epithelium was prevented from resurfacing the cornea after penetrating keratectomy, expression of fibrotic markers was considerably reduced. TGF-beta2 was determined to be a major substance produced by corneal epithelial cells capable of inducing the fibrotic phenotype. In the intact mouse cornea, TGF-beta2 was confined to the uninjured epithelium, but was released into the stroma during fibrotic repair. By contrast, TGF-beta1 was never found in the epithelium. When epithelial cells were cultured on a basement-membrane-like gel or allowed to deposit their own basement membrane in organotypic culture, TGF-beta2 production was reduced. Return of a basement membrane after wounding in vivo correlated with loss of the fibrotic phenotype. In the epithelial debridement injury model in which the basement membrane was left intact, TGF-beta2 remained confined to the corneal epithelium, consistent with the absence of a fibrotic phenotype. CONCLUSIONS. These data suggest that integrity of the basement membrane is a deciding factor in determining the regenerative character of corneal repair.  相似文献   

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PURPOSE: To evaluate the keratocyte apoptosis and effects of topical vitamin E on keratocyte apoptosis after photorefractive surgery. METHODS: Rabbits were divided into 7 groups, and all groups were compared with controls after epithelial scraping, epithelial scrape and photorefractive keratectomy (PRK) (traditional PRK), transepithelial PRK, production of a corneal flap with microkeratome and laser-assisted in situ keratomileusis (LASIK). The effects of topical Vitamin E treatment were investigated in the traditional PRK group. The terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labelling assay (to detect DNA fragmentation in situ) and light microscopy have been used to detect apoptosis in rabbit cornea. RESULTS: Transepithelial PRK induced minimal keratocyte apoptosis, less than in all other refractive surgical procedures. The greatest amount of keratocyte apoptosis was observed after traditional PRK (p = 0.001), therefore we tested the effects of topical vitamin E in this group. The number of apoptotic keratocytes significantly reduced after vitamin E therapy (p < 0.005). CONCLUSION: Keratocytes undergo apoptosis after refractive surgery in response to mechanical epithelial removal, preparing of corneal flap and excimer laser stromal photoablation. The topical application of vitamin E immediately after surgery can prevent keratocyte apoptosis, and this result suggests that free radicals may be partly responsible for keratocyte apoptosis after excimer laser keratectomy.  相似文献   

9.
AIM: To determine interleukin 8 (IL-8) and monocyte chemoattractant protein 1 (MCP-1) expression in response to mechanical injury in human retinal pigment epithelial (HRPE) cells. METHODS: Enzyme linked immunosorbent assay (ELISA) was performed to determine IL-8 and MCP-1 secretion by HRPE cells after mechanical denudation. IL-8 and MCP-1 mRNA expression by HRPE cells was assessed using semiquantitative RT-PCR. The effects of immunosuppressive drugs, dexamethasone (DEX) and cyclosporin A (CSA), as well as immunosuppressive cytokines, interleukin 4 (IL-4), interleukin 10 (IL-10), and interleukin 13 (IL-13), on chemokine expression in HRPE cells after denuding injury were analysed. RESULTS: Mechanical injury induced HRPE IL-8 mRNA and IL-8 secretion. Although MCP-1 mRNA was enhanced slightly after denuding injury, MCP-1 secretion was not increased. DEX and CSA inhibited HRPE chemokine expression after injury. IL-4 and IL-13 enhanced IL-8 and MCP-1 production by HRPE cells after injury while IL-10 had no effect. CONCLUSIONS: These results suggest that IL-8 may be involved in retinal inflammatory responses to injury and that DEX and/or CSA treatment may help control the inflammatory components of retinal diseases such as proliferative vitreoretinopathy.  相似文献   

10.
20%乙醇处理兔角膜后上皮增生和细胞凋亡的研究   总被引:4,自引:1,他引:3  
Sun LX  Wang Z  Yang B  Liu J  Qiu P  Chen JQ 《中华眼科杂志》2005,41(6):492-497
目的探讨准分子激光角膜上皮瓣下磨镶术(LASEK)中采用20%乙醇浸润兔角膜40s后角膜上皮增生和角膜细胞凋亡情况与机械刮除角膜上皮后的异同。方法实验组42只新西兰大白兔,用直径为8mm的LASEK专用角膜上皮刀切割角膜上皮,20%的乙醇浸润单眼40s,机械刮除对侧眼中央8mm直径的角膜上皮,随机分7组,于术后0、4h,1、3、5、8、30d取材;6只兔眼为空白对照。角膜冰冻切片,行Ki67免疫组化检查和TUNEL检测,计数角膜中央前基质细胞。结果乙醇浸润后5d中央角膜上皮增生达峰值,术后1d周边角膜上皮增生达峰值;术后4h上皮刀口下方局限的角膜基质细胞TUNEL染色阳性,数量最多;各组角膜中央前基质细胞计数和空白对照比差异无统计学意义(P=0.68)。机械刮除角膜上皮后3d周边角膜上皮增生达峰值,其高于乙醇浸润后角膜上皮的增生峰值;术后4h可见大量中央前基质细胞TUNEL阳性;术后1d中央前基质细胞数量最少(P<0.05)。结论与机械刮除角膜上皮相比,20%乙醇浸润40s对角膜损伤轻,恢复快,乙醇浸润后的角膜上皮对基质细胞有保护作用。  相似文献   

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