| 目的：研究外源性尿激酶型纤溶酶原激活剂（uPA）及其抑制剂PAI-1对小鸡形觉剥夺性近视眼（FDM）形成的影响，探讨TGF-beta在FDM形成中的作用及其可能的作用机制。
方法：随机选取1 d龄来亨雏鸡100只进行单眼遮盖（MD）以制备FDM动物模型。按照干预方法不同又随机均分为uPA组、纤溶酶原激活剂抑制剂1（PAI-1）组、PBS组与阴性对照组4组，前3组在MD同时分别球后注射uPA 500U/50ml、PAI-1 50U/50ml、PBS 50ml，每日1次。阴性对照组仅予以单纯遮盖。同时随机选1 d龄来亨雏鸡100只分别进行上述干预处理作为各自对照组。于实验前、14 d后每组随机抽取10只小鸡分别采用A超及带状视网膜检影镜检测实验眼眼轴长度及屈光度变化。快速摘除眼球，取后极部巩膜，冰冻切片，采用常规HE染色法进行组织病理学检查，免疫组化法检测后极部巩膜TGF-β1表达，逆转录聚合酶链反应（RT-PCR）一步法检测TGF-β1 mRNA表达变化。
结果：对MD眼，uPA可明显抑制其眼轴延长及近视屈光度增加，与阴性对照组、PBS组比较差别有统计学意义（P<0.01），而PAI-1无明显作用（P>0.05）；对正常非遮盖眼，uPA可抑制其眼轴延长及远视屈光度降低（P<0.05），而PAI-1却具显著促进作用（P<0.01）。组织病理学结果显示，单纯MD眼后极部巩膜纤维层明显变薄与纤维化，而软骨层相对增厚。uPA干预组与正常小鸡相似，而PAI-1干预组与FDM相似；免疫组化结果表明，正常小鸡后极部巩膜可检测到较丰富的TGF-β1阳性表达，而FDM组明显降低，特别是邻近脉络膜处、纤维层与软骨层交界处最明显。uPA干预后TGF-β1阳性表达信号显著增加，而PAI-1干预组显著减弱；RT-PCR检测发现，单纯MD组TGF-β1表达较正常对照组显著降低（P<0.01）。与阴性对照组、PBS组比较，uPA干预可明显上调MD眼TGF-β1 mRNA表达（P<0.01），且对正常小鸡亦存上调作用（P<0.05），而PAI-1仅对正常小鸡起下调作用（P<0.01），对MD眼无作用。
结论：uPA可显著抑制小鸡FDM形成，其作用机制极可能与诱导后极部巩膜内源性TGF-β1表达与活化密切相关。
关键词：形觉剥夺性近视眼，尿激酶型纤溶酶原激活剂，TGF-b1，巩膜
Influnce of Change in inner Transforming Growth Factor-beta1 expression on Posterior Sclera Induced by Urokinase Pasminogen Activator and its inhititor PAI-1 Administered Retra-orbitally on the Development of Chick Form-deprivation Myopia.
Objective: To clarify whether change of inner Transforming growth factor-beta1(TGF-β1) expression on posterior sclera, which was induced by urokinase pasminogen activator(uPA) or plasminogen activator inhibitor-1 (PAI-1) administered retraorbitally, was the key step for the development of chick form-deprivation myopia(FDM).
Methods: 100 one-day-old Lethorn chicks chosen randomly were covered monocularly with plastic goggles to establish the animal model of FDM with which various methods were performed to interferenc. According to the interferences the chicks were divided into uPA group, PAI-1 group, PBS group and negative control group. In the former three groups uPA(500U/50ml), PAI-1 (50U/50ml) and sterile PBS(50ml) were retra-orbitally injected respectively, and meanwhile chicks only monocularly covered were as the negative control. Another 100 one-day-old Lethorn chicks treated simularly were act as control for each group metioned above. Each experimental group have 25 chicks. Before and after 14 days’ experiment, 10 chicks were chosen randomly from each group to measure changes in axial length and diopter degrees by A ultrasonography and streak retinoscopy respectively. After that, killing the chicks to acquire the posterior sclera. changes in histology were observed by H.E dying, changes in TGF-beta1 protein was evaluated by immunohistochemistry, and changes in TGF-β1 mRNA level was measured by one-step reverse transcriptase polymerase chain reaction (RT-PCR).
Results: Form deprivation could stimulate the axial lengthening excessively which resulted in high myopia consequently. Daily administration of uPA 500U/50ml could not only inhibit the development of FDM, axial lengthening and reduction of hyperopic degrees in normal non-covered eyes also be postponed. One the contrary, little effect of PAI-1 injected daily on the development of FDM was found, and it could only stimulate axial extending and make the hyperopic diopters decrease in non-covered normal eyes. Histology had shown that the posterior sclera of normal chicks included two parts: the inner cartilage and the outer fibrile. In pure FDM group the former would thicken and while the later become thinner and fibrilized magnificently, which would also be observed in groups interferenced with PAI-1. What be seen in groups treated by uPA was similar to that in non-covered normal group. Immunohistochemistry had shown that abundant positive dying messenger for TGF-β1 could be found in the posterior sclera, especially adjacent to uvies membrane in normal non-covered eyes, and while in this region which would be reduced much more in pure FDM group. After injecting uPA both in normal non-coverd groups and in covered ones the positive messenger for TGF-β1 increased magnificently, and while administration of PAI-1 would be on the contrary. The content of TGF-beta messenger RNA (mRNA) was reduced heavily in FDM eyes compared with non-deprived eyes(P<0.01), which would disappear almost completely after daily administration of uPA, while PAI-1 could only have an inhibit effect on that in non-covered eyes.
Conclusion: Through inducing inner TGF-β1 expression on the posterior sclera uPA could almost inhibit the development of chick FDM, which suggested that change in inner TGF-β1 expression on posterior sclera be a key step for development of chick FDM.
Key words：form-deprivation myopia, urokinase pasminogen activator, TGF-beta1; sclera.
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