中文摘要：

背景 多西环素是一种金属离子螯合剂和广谱抗生素,常用于眼表疾病的治疗. 目的 研究多西环素对体外培养的牛角膜肌成纤维细胞增生的影响,并探讨其作用机制.方法 收集6只新鲜牛角膜,分别用基础培养液配制的1.0g/L及2.0 g/L Ⅰ型胶原酶对牛角膜基质层进行二步法消化分离,制成细胞悬液后转入培养瓶中用RPMI-1640培养液（含质量分数10％胎牛血清）进行培养.取生长良好的细胞进行波形蛋白免疫细胞化学染色以确定所培养的细胞来自角膜基质层,在细胞传代培养的同时进行α-平滑肌肌动蛋白（α-SMA）免疫荧光细胞化学染色,呈阳性表现的细胞为角膜肌成纤维细胞.细胞培养36 h后培养液中不加入任何药物者为阴性对照组,阳性对照组细胞培养液中加入120 mg/L地塞米松,另分别在培养液中加入10、20、40、60、80 mg/L多西环素作为药物干预组.采用MTT比色法、流式细胞术测定各组干预24 h和48 h后角膜肌成纤维细胞的增生情况及细胞周期各时相的分布. 结果 体外分离培养的牛角膜肌成纤维细胞生长良好,免疫组织化学染色显示波形蛋白和α-SMA呈阳性反应,证实为角膜肌成纤维细胞.MTT比色法检测显示,随着多西环素质量浓度的增加,活性角膜肌成纤维细胞的数量逐渐下降,差异有统计学意义（F质量浓度=1233.778,P＜0.001）；随着药物作用时间的延长,活性角膜肌成纤维细胞的数量逐渐下降,差异有统计学意义（F时间=227.564,P＜0.001）；且两因素间的交互效应亦有统计学意义（F交互作用=51.656,P＜0.001）.流式细胞术细胞周期分析显示,10、20、40、60、80 mg/L多西环素作用24 h,G0-G1期角膜肌成纤维细胞率分别为82.85％、84.36％、85.18％、87.12％、89.31％,明显高于阴性对照组的63.89％,差异均有统计学意义（P＜0.05）,40 mg/L多西环素组G0-G1期角膜肌成纤维细胞率接近阳性对照组；10、20、

英文摘要：

Background Doxycycline is a broad spectrum antibiotic,and it is frequently used in the treatment of ocular surface diseases.Objective The purpose of the present study was to investigate the effect of doxycycline on the inhibition of cell proliferation in bovine corneal myofibroblasts in vitro and assess its contribution to ocular surface repairing mechanism.Methods Six fresh bovine corneas were collected.The corneal stromal layer was isolated by two-step method of 1.0 g/L and 2.0 g/L collegenase-1.Isolated cells were plated at mantaryay culture flask in 10% FBS of RPMI-1640.Vimentin and alpha-smooth muscle actin （α-SMA） organization were evaluated by immunocytochemistry,and the cells with influoresccence staining for vimentin and α-SMA were identified as the corneal myofibroblasts.Doxycycline at the concentrations of 10,20,40,60,80 mg/L was added to the medium,respectively,in different concentrations of doxycycline groups.Dexamethasone （120 mg/L）was used in the same way in the positive control group,and no drug was used in the negative control group.Cell proliferation was evaluated by MTT and the cell cycle was analyzed by BD FACScan flow cytometer assay 24 hours and 48 hours after addition of any drug.Results The cells grew well and showed the positive response for vimentin and α-SMA.MTT assay showed that the A570values of bovine corneal myofibroblasts were gradually declined with the increase of the concentration of doxycycline and lapse of active time,showing statistically significant difference （Fconcentration =1233.778,P〈0.001 ; Ftime =227.564,P 〈 0.001）.And the difference between the two factors was also statistically significant （Ftime＊concentration =51.656,P〈0.001）.Flow cytometry cell cycle analysis showed that 24 hours after 10,20,40,60,80 mg/L doxycycline treated,the perentage of of corneal myofibroblast cell in G0-G1 phase was 82.85%,84.36%,85.18%,87.12 % and 89.31%,showing significant increase in comparison with 63.89% of the negative control group （all P〈0.05）,and tha