羊膜匀浆提取液对大鼠角膜碱烧伤后血管内皮生长因子及血管细胞黏附分子-1表达的作用

Effect of amniotic membrane extract on the expressions of vascular endothelial growth factor and vascular cell adhesion molecule-1 after coneal alkali burn in rats

目的观察羊膜匀浆提取液(amniotic membrane extract,AME)对角膜碱烧伤后不同时期血管内皮生长因子(VEGF)及血管细胞黏附分子-1(VCAM-1)在角膜表达的作用,初步探讨AME抑制角膜新生血管(CNV)形成的机制。方法 SD大鼠36只,中度碱烧伤法建立角膜碱烧伤动物模型,随机分成AME低浓度A组、中浓度B组、高浓度C组和对照组,每组9只。A、B、C三组分别予以80、160、320 mg/L AME滴眼,对照组行磷酸盐缓冲液(PBS)滴眼。分别于碱烧伤后每天裂隙灯下观察CNV情况,并于7、14、28 d计算CNV面积,角膜HE染色观察角膜病理改变,免疫组化法检测角膜组织中VEGF及VCAM-1的阳性表达率。结果角膜HE染色显示,大鼠角膜碱烧伤后,各时间点A、B、C三组角膜水肿情况、角膜溃疡及CNV均较对照组减轻,且C组好于B组,B组好于A组。大鼠角膜碱烧伤后各时间点CNV面积,A、B、C三组均明显小于对照组(P均<0.05),且随AME剂量增加而减少,各组间两两比较差异均有统计学意义(P均<0.05)。各时间点,A、B、C组VEGF和VCAM-1阳性表达率均明显低于对照组(P均<0.05),且随AME剂量增加而减少,各组间两两比较差异均有统计学意义(P均<0.05)。结论 AME对角膜碱烧伤后CNV的形成具有抑制作用,且随AME剂量增加,抑制作用增强。其可能机制是AME抑制了角膜碱烧伤后VEGF及VCAM-1在角膜的表达。

Objective To observe the effect of amniotic membrane extract （AME） on the expressions of vascular endothe- lial growth factor （VEGF） and vascular cell adhesion molecule -1 （VCAM-1） in cornea at different periods after corneal alkali burn to preliminarily investigate the mechanism of AME inhibiting corneal neovascularization （CNV） formation. Methods Corneal moderate alkali burn animal model was established in 36 SD rats. The rats were randomly divided into low concentration AME group （ group A）, middle concentration AME group （ group B ）, high concentration AME group （group C） and control group （n = 9, each）. The eye drops of 80,160 and 320 mg/L AME were given for dropping eyes in groups A, B, C, respectively, and phosphate buffer （PBS） eye drops were given for dropping eyes in control group. Corneal general condition was observed under the slit lamp every day, and CNV growth area was calculated at 7-, 14- and 28-day re- spectively after alkali burn. Corneal HE staining was used to observe the pathological changes of cornea. Immunohistochem- istry was used to detect the positive expression rates of VEGF and VCAM-1 in corneal tissue. Results Corneal HE staining showed that corneal edema, corneal ulcer and CNV at each time point after corneal alkali burn in groups A, B and C were relieved compared with control group,which were in group C better than those in group B and were in group B better than those in group A. CNV areas at each time point after corneal alkali burn in groups A, B and C were all significantly less than those in control group and decreased with the increase of AME dosage, and there were significant differences for pairwise comparison among groups A, B, C （ all P 〈 0. 05 ）. Positive expression rates of VEGF and VCAM-1 at each time point in groups A, B and C were significantly lower than those in control group and decreased with the increase of AME dosage, and there were significant differences for pairwise comparison among groups A, B, C （ all P 〈 0.05 ）. Conclusions AME has an inhibitory effect on the formation of CNV after corneal alkali burn, and the inhibitory effect increases with the in- crease of AME doses. It is the possible mechanism that AME can inhibit the expressions of VEGF and VCAM-1 in cornea tissues after corneal alkali bum.