枸橼酸-磷酸氢二钠缓冲液冲洗对小鼠急性角膜化学伤眼表的保护作用

Protective effects of citric acid-disodium hydrogen phosphate rinsing solution on ocular surface of mice with acute chemically induced corneal burns

背景角膜化学性烧伤后即刻进行眼部冲洗是防止化学性物质进一步损伤眼组织的关键步骤，而理想的冲洗液才能有效地中和化学物质，改善患眼的预后。 目的评价自制的枸橼酸－磷酸氢二钠缓冲液、枸橼酸－磷酸氢二钠－氯化钾缓冲液对小鼠急性角膜酸、碱烧伤的治疗效果。 方法配制pH值为7.4的枸橼酸－磷酸氢二钠缓冲液（缓冲液1）和枸橼酸－磷酸氢二钠－氯化钾缓冲液（缓冲液2）。采用计算机取随机数方法将120只6～8周龄清洁级雄性C57小鼠随机分为酸烧伤模型组和碱烧伤模型组，分别用1 mol/L硫酸和0.15 mol/L氢氧化钠滤纸贴附于中央角膜制备急性角膜酸、碱烧伤模型，造模后即刻按照亚分组分别用40 ml缓冲液1、自来水、缓冲液2进行冲洗，未冲洗的模型鼠作为对照。分别于造模后和冲洗后3、7、14 d在裂隙灯显微镜下按照角膜混浊程度进行评分，并观察各组小鼠角膜上皮荧光素染色阳性率、角膜新生血管和角膜溃疡发生率。 结果角膜酸烧伤后3、7和14 d，缓冲液1冲洗组、自来水冲洗组和缓冲液2冲洗组角膜混浊评分为1分的眼数均明显多于不冲洗组，差异均有统计学意义（均P〈0.01）；角膜酸烧伤后3 d，缓冲液1冲洗组角膜混浊度为1分的眼数明显多于自来水冲洗组和缓冲液2冲洗组，差异均有统计学意义（χ2＝11.000，P＝0.001; χ2＝4.000，P＝0.046）；角膜酸烧伤后7 d，缓冲液1冲洗组角膜混浊度为1分的眼数明显多于自来水冲洗组，差异具有统计学意义（χ2＝6.000，P＝0.014）；角膜酸烧伤后14 d，缓冲液1冲洗组、自来水冲洗组和缓冲液2冲洗组不同角膜混浊评分的眼数差异均无统计学意义（均P〉0.05）。碱烧伤后3、7、14 d，缓冲液1冲洗组、自来水冲洗组和缓冲液2冲洗组角膜混浊度评分为1分和2分的眼数均明显多于不冲洗组，差异均有统计学意义（均P〈0.01）。角膜酸烧伤后7 d，缓冲液1冲洗组、自来水冲洗组和缓冲液2冲洗组角膜溃疡发生率分别为7%、27%和13%，均明显低于不冲洗组的73%，差异均有统计学意义（P＝0.000、0.027、0.003）；角膜碱烧伤后3、7、14 d角膜溃疡发生率比较，差异均无统计学意义（均P〉0.05）。角膜酸烧伤后14 d，不冲洗组角膜新生血管发生率为50%，而缓冲液1冲洗组、自来水冲洗组和缓冲液2冲洗组小鼠未见角膜新生血管。角膜碱烧伤后各组小鼠在各时间点均未发现角膜新生血管。 结论pH值为7.4的枸橼酸－磷酸氢二钠缓冲液对急性角膜酸、碱烧伤进行即刻冲洗均有较好的治疗效果，冲洗液中是否添加氯化钾对预后无明显影响。

BackgroundImmediately ocular rinsing is a key step for the prevention of eye tissue damage after acute chemical burns.A good ophthalmic rinsing solution can neutralize chemical substance and improve the prognosis of patients. ObjectiveThis study attempted to evaluate the therapeutic effect of self-made citric acid-disodium hydrogen phosphate buffer and citric acid-disodium hydrogen phosphate-potassium chloride buffer on corneal chemical burns in mice. MethodsCitric acid-disodium hydrogen phosphate buffer solution （solution 1） and citric acid-disodium hydrogen phosphate-potassium chloride buffer solution （solution2） with the pH 7.4 were prepared.One hundred and twenty clean male C57 mice aged 6-8 weeks were randomized to two groups, and filter papers containing 1 mol/L H2SO4 or 0.15 mol/L NaOH were attached to the central corneas of the right eyes to create the acid or alkali burning models.Then the eyes were immediately rinsed by 40 ml solution 1, tap water or solution 2 according to the grouping and the model eyes without rinsing served as the control group.The corneal opacity was examined by slit lamp microscope and scored in 3, 7 and 14 days after modeling.The percentages of corneal fluorescein staining, corneal neovascularization and corneal ulcer were analyzed.The study protocol was approved by Experimental Animal Ethic Commission of Second Military Medical University. ResultsIn the corneal acid burning models, the number of eye with corneal opacity scored 1 in the solution 1 group, tap water group and solution 2 group was significantly more than that in the non-rinsing group in 3, 7 and 14 days after modeling （all at P〈0.01）; In 3 days after modeling, the numbers of eye scored 1 were more in the solution 1 group than those in the tap water group and solution 2 group （χ2=11.000, P=0.001; χ2=4.000, P=0.046）. There were no differences in the eye number of different corneal opacity scores in 14 days after acid burning （all at P〉0.05）. In 3, 7 and 14 days after corneal alkali burning, the number of eyes with corneal opacity scored 1-2 was significantly increased in the solution 1 group, tap water group and solution 2 group compared with non-rinsing group （all at P〈0.01）. The percentage of corneal ulcer in the solution 1 group, tap water group and solution 2 group was 7%, 27% and 13%, respectively, which was significantly lower than 73% in the non-rinsing group（P=0.000, 0.027, 0.003）, and no significant differences were seen in various time points after corneal alkali burning （all at P〉0.05）. Corneal neovascularization occurred in 50% mice in non-rinsing group in 14 days after acid burning.However, no neovascularization was seen in the mice of the solution 1 group, tap water group and solution 2 group in both acid and alkali burning mice. ConclusionsCitric acid-disodium hydrogen phosphate buffer （pH 7.4） appears to be an effective emergency rinsing solution for corneal chemical burns and the rinsing solution with or without potassium chloride is not obviously affected to the prognosis of corneal chemical burns in the mice.