大气颗粒物PM10对小鼠泪膜功能和角膜上皮组织结构的影响

Influence of air pollutant PM10 on tear film and corneal epithelium in mice

摘要:

目的研究大气颗粒物PM10对小鼠泪膜功能和角膜上皮组织结构的影响。方法24 只雄性6～8周龄BALB/c 小鼠，随机分为A、B组，每组12 只。空白对照组6 只不作处理。B组采用5 mg/ml PM10点眼，A组采用无菌PBS 点眼，3 次/d。分别在干预前及干预第1、4 和7天进行实验小鼠泪膜功能相关检查，包括采用酚红棉线法检查泪液分泌量、泪膜破裂时间（BUT）、荧光素染色及荧光素染色评分（FL）。根据分组于相应时间点收集其角膜组织，行苏木精- 伊红染色及透射电子显微镜下观察角膜上皮组织结构变化。结果干预4 和7 d后，A组泪液分泌量、BUT、FL 较干预前无明显变化（P >0.05），而B 组泪液分泌量减少、BUT、FL 较干预前恶化（P <0.05）。点眼7 d后，A 组上皮细胞为（5±1）层，B 组为（7±1）层，差异有统计学意义（P <0.05）。电镜观察可见A 组角膜上皮微绒毛呈指状突起，微绒毛数量多，排列整齐；而B 组角膜上皮微绒毛减少、变短、排列紊乱。结论PM10会影响小鼠泪膜功能，小鼠泪液量分泌减少，泪膜稳定性下降；小鼠角膜上皮组织结构损坏。

Abstract:

Objective To investigate the influence of PM10 on tear film functions and corneal epithelium in mice. Method Totally 30 male BALB/c mice at the age of 6-8 weeks (30 eyes) were divided into 3 groups: group A (PBS eye drops,n = 12), group B (PM10 eye drops, n= 12) and blank control group ( n= 6). The group B used 5 mg/ml PM10 eye drops, 50 μl each time, 3 times a day, for 7 consecutive days. The group A used sterile PBS as eye drops, 3 times a day, for 7 consecutive days. The tear film function tests including tear secretion level, breakup time of tear film (BUT) and fluorescein staining and fluorescein staining score (FL) were performed before therapy and 1, 4 and 7 d after treatment. On the 7th d after treatment, the corneas of all the mice were collected for HE staining and ultrastructural examination under transmission electron microscope. Results On the 1st, 4th and 7th d after treatment, there was no statistical change in tear secretion level, BUT or FL in the group A (P > 0.05); but there were statistical changes in all items in the group B (P < 0.05). On the 7th d after therapy, the mean layers of corneal epithelial cells in the group A were significantly fewer than those in the group B (P < 0.05). Under electron microscope, the microvilli of corneal epithelium in the group A were finger-like and in regular arrangement; in contrast, a cluster of disordered, shorter and fewer microvilli was observed in the group B. Conclusions PM10 can influence tear film functions and damage corneal epithelial structure in mice.