米诺环素对碱烧伤大鼠角膜新生血管生成的影响及其作用机制

目的 探讨米诺环素对碱烧伤大鼠角膜新生血管生成的影响及其作用机制.方法 选取SPF级健康SD 大鼠72 只(取右眼为实验眼),从中随机选取24 只(24 眼)作为空白对照组(不做任何干预),其余48 只采用1 mol.L-1 NaOH 浸润过的实验滤纸建立角膜碱烧伤模型,然后随机分为溶剂对照组和米诺环素组,每组24 只...

Effect of minocycline on corneal neovascularization after alkali burns and its mechanisms

Objective　To investigate the effect of minocycline and its mechanism on corneal neovascularization after alkali burns.Methods　Totally 72 healthy SD rats with SPF grade were selected (right eyes were selected as the experimental ones). Twenty-four ones among of 72 rats were selected randomly as the control group (they got not treatment), and the remaining 48 ones were burned by filter paper infiltrated 1 mol·L^-1 NaOH to create the model of cornea with alkali burn, then were divided into solvent group and minocycline group, and each group had 24 rats (24 eyes). The rats of the solvent group were given intraperitoneal injection with 9 g·L^-1 saline solution (10 mL·kg^-1) and the ones of the minocycline group were given intraperitoneal injection with minocycline solution (45 mg·kg^-1). Afterwards 6 rats were randomly selected from each group on day 1, 4, 7 and 14 after alkali burns successively, and the anterior segments of their eyes were observed by slit lamp, then the lengths and growth area sizes of corneal neovascularization were calculated at each time point. The inflammation of cornea was detected by Hematoxylin and Eosin (HE) staining.Results　During the whole experiment, the rats in the control group had clear cornea and no corneal neovascularization. On day 4, 7 and 14 after alkali burns, corneal neovascularization could be observed in both minocycline group and solvent group, and the lengths and the area sizes of corneal neovascularizationin the minocycline group were less than that in solvent group, and the differences were statistically significant (all P<0.01). HE staining showed that the rats in the control group had clear corneal structure, orderly epithelial cells and no vascular structure. On the 4th, 7th and 14th day after alkali burns, the number of inflammatory cells in each visual field (×200) of the solvent group compared with minocycline group were (119.83±7.28) cells vs. (81.83±8.30) cells, (92.50±7.34) cells vs. (42.33±9.11) cells, and (48.33±7.76) cells vs. (16.67±4.93) cells, and the differences between the two groups at each time point were statistically significant (all P<0.01). Compared with the control group, the relative expression levels of iNOS and Arg-1 mRNA in the solvent group increased on day 1, 4, 7 and 14 day after alkali burns (all P<0.05). Compared with the solvent group, the relative expression of iNOS mRNA in the minocycline group significantly decreased on the 4th and 7th day after alkali burns (all P<0.05), while there was no statistically significant difference between the two groups on the 1st and 14th day after alkali burns (both P>0.05). Compared with the solvent group, the relative expression of Arg-1 mRNA in the minocycline group significantly decreased on the 14th day after alkali burns (P<0.01), while there was no significant difference between the two groups on the 1st, 4th, and 7th day after alkali burns (all P>0.05). The relative expression ratios of Arg-1 and iNOS mRNA in the solvent group were 0.73±0.14, 0.82±0.90 and 1.71±0.21 on the 4th, 7th and 14th days after alkali burns, respectively, which was statistically significant compared with that of the control group (all P<0.01). The relative expression of Arg-1 was positively correlated to the length and area size of corneal neovascularization in the solvent group, and the correlation coefficient were 0.898 (P=0.000) and 0.781 (P=0.000). The cumulative optical density values of TNF-α and CD206 protein expression in solvent group were higher than those in minocycline group on the 7th and 14th day after alkali burns (all P<0.05).Conclusion　The polarization of macrophages regulates the formation of corneal neovascularization after alkali burns, and minocycline can reduce corneal neovascularization after alkali burns by regulating the polarization of macrophages.