目的：研究甘草甜素(Gly)对小鼠角膜急性碱烧伤后角膜新生血管(CNV)的抑制作用。

方法：采用碱烧伤法制备小鼠碱烧伤模型60只，随机平均分为Gly组和PBS组，分别隔天结膜下注射2g/L Gly溶液或PBS溶液，共14d。裂隙灯显微镜下观察角膜炎症反应和CNV。实验结束后取角膜行HE染色法和免疫组织化学法CD34及髓过氧化物酶(MPO)染色并计算角膜微血管密度(MVD)及中性粒细胞数。

结果：造模后第7、14d Gly组CNV面积分别是4.16±0.00、7.33±0.13mm²，显著低于PBS组(7.58±0.20、9.24±0.08mm²，均P<0.05)。HE病理染色显示正常小鼠角膜结构完整，未见新生血管形成及炎症细胞浸润； Gly组角膜新生血管数量及炎症细胞浸润较少，胶原排列较规则，而PBS组角膜基质中可见大量炎症细胞浸润及新生血管。免疫组织化学CD34染色结果显示Gly组MVD为11.13±1.46条/mm²，显著低于PBS组(34.08±2.46条/mm²，P<0.001)； 免疫组织化学MPO染色结果显示Gly组中性粒细胞计数为每200倍视野17.50±1.98个，明显少于PBS组(59.56±4.79个，P<0.001)。

结论：Gly能减轻小鼠角膜急性碱烧伤模型中的角膜炎症反应，并抑制角膜新生血管形成，这为临床上有效防治角膜新生血管类疾病提供了一种新的思路。

METHODS: Corneal neovascularization was established in mice by alkali burn. Sixty mice were then randomly distributed into normal group, Gly group and phosphate buffer solution(PBS)group. The mice were treated with subconjunctival injection of 2g/L Gly solution or vehicle alone every other day for 14d. Corneal inflammation and neovascularization were monitored with a slit lamp microscope. At the end of treatment, the corneas were harvested for hematoxylin-eosin(HE)staining as well as immunohistochemical of CD34 and myeloperoxidase(MPO)staining, microvessel density(MVD), neutrophils were then calculated.

RESULTS: At the 7 and 14d, the CNV area of Gly group were 4.16±0.00 and 7.33±0.13mm² respectively, which were lower than those in PBS group(7.58±0.20 and 9.24±0.08mm²; all P<0.05). The HE pathological staining showed that there were no changes in morphology as well as no neovascularization or inflammatory cell infiltration in the cornea of control group. In the Gly group, blood vessels and inflammatory cell infiltration nearly diminished with collagen in normal shape. While in the PBS group, extensive infiltration of inflammatory cells and neovascularization was examed in the corneal stroma. The immunohistochemical CD34 staining performed that the MVD in the Gly group was 11.13±1.46 bars per square millimeter, which was lower than that in PBS group(34.08±2.46)bars per square millimeter(P<0.001). Additionally, the immunohistochemical MPO staining showed that the number of neutrophils in Gly group was 17.50±1.98 cells per 200-fold field of view, lower than that in PBS group(59.56±4.79, P<0.001).

CONCLUSION: Gly can eliminate corneal inflammation and inhibit corneal neovascularization in mice with acute corneal alkali burn, which provides a new idea for clinical prevention and treatment of corneal neovascularization.