目的：研究清眩润目饮对蒸发过强型干眼模型兔的作用机制和疗效。

方法：将25只雄性健康日本大耳白兔随机分为5组：空白对照组、模型组、西药组、高剂量清眩润目饮组、低剂量清眩润目饮组。空白对照组不做任何处理，采用改良睑板腺口灼烧法制备兔蒸发过强型干眼模型； 造模后，高、低剂量组每天分别予27.2mg/kg、6.8mg/kg的清眩润目饮灌胃，模型组每天以等量生理盐水灌胃，西药组以妥布霉素地塞米松眼膏1滴，1次/d点双眼，各组连续给药28d。各组分别在实验前第14d、实验前第7d、造模后当天、造模后第7d、造模后第14d，对全部实验兔行Schimer Ⅰ试验(SchimerⅠ test，SⅠt)和泪膜破裂时间(break-up time，BUT)测定。造模后15d以过量麻醉法处死动物，制备兔角结膜组织切片，采用苏木精-伊红染色法，观察各组兔角膜组织形态变化； 采用ELISA法检测兔角结膜中TNF-α、IL-1、IL-6的浓度含量。

结果：(1)BUT、SⅠt：造模后7d，西药组、高、低剂量清眩润目饮组的BUT、SⅠt较造模时均有不同程度的改善(P<0.05)； 西药组、高、低剂量清眩润目饮组与模型组比较，差异均有统计学意义(P<0.05)。(2)TNF-α、IL-1、IL-6：ELISA法检测显示，模型组兔角结膜中的TNF-α、IL-1、IL-6浓度含量明显高于空白对照组，西药组和高、低剂量组兔角结膜中的TNF-α、IL-1、IL-6浓度明显低于模型组，差异均有统计学意义(均P<0.05)，且高剂量组作用优于西药组。(3)病理组织学检查：造模后14d，空白对照组角膜上皮分层好，基底部细胞排列呈柱状，靠近角膜上皮呈鳞状改变，结膜可见完整的上皮层和结膜下组织层，杯状细胞排列紧密； 模型组角膜上皮层细胞数减少甚至剥脱缺失，基质层分层紊乱，结膜上皮细胞层不规则脱失，杯状细胞大量减少； 西药组、高剂量组兔角膜形态接近正常组，结膜杯状细胞数量与空白对照组无明显差异。

结论：清眩润目饮可以通过下调蒸发过强型干眼兔角膜和结膜中TNF-α、IL-1、IL-6的表达而抑制炎症反应，从而改善眼表症状，增加泪液分泌，延长泪膜破裂时间。

METHODS: Totally 25 healthy male Japanese white rabbits were randomly divided into 5 groups: control group, model group, western medicine group, high dose of Qingxuan decoction group, low dose of Qingxuan decoction group. The blank control group did not do any treatment. The improved dry eye model of rabbit was prepared by the improved method of glandular burning of the eyelid plate. The high and low dose group were given daily 27.2mg/kg, 6.8mg/kg Qingxuan decoction by gavage. The model group was intragastric with the same amount of normal saline every day. The western medicine group with tobramycin and dexamethasone ophthalmic ointment 1 drops, once a day. The treatment were administered continuously for 28d. At 14d before the experiment, 7d before the experiment, 7d after the model, and 14d after the model, all the rabbits were tested by Schimer Ⅰ test(SⅠt)and break-up time(BUT). On the 15d after modeling, the animals were sacrificed by excessive anaesthesia. Rabbit ocular surface tissue sections were prepared. Hematoxylin-eosin staining method was used to observe the corneal morphological changes in each group. The concentrations of TNF-α, IL-1 and IL-6 in the ocular surface of rabbits were detected by ELISA.

RESULTS:(1)BUT, SⅠt: 7d after the model had been prepared, BUT and SⅠt of the model group and the western medicine group, high dose and low dose of Qingxuan decoction group was improved(P<0.05); Those of western medicine group, high dose and low dose of Qingxuan Decoction group compared with the model group, were significantly different(P<0.05).(2)TNF-α, IL-1, IL-6: The ELISA assay showed that TNF-α and IL-1, IL-6 concentration in the model group rabbits was significantly higher than those of the control group, TNF-α and IL-1, IL-6 concentration in western medicine group and high dose group of rabbits was significantly lower than those in the model group, the differences were statistically significant(P<0.05), and in high dose group the effect was better than that of Western medicine group.(3)Histopathological examination: on the 14d after the model, the corneal epithelium in the blank control group was stratified well. The cells in the base were columnar, near the surface, the cornea epithelium showed a squamous change. Conjunctiva showed complete epithelial layer and subconjunctival tissue layer, and goblet cells arranged closely. The number of corneal epithelial cells in model group was reduced or even stripped, and the matrix layer was disorder; Irregular loss of conjunctival epithelial cell layer and a large decrease in goblet cells. The corneal morphology of the rabbits in the western medicine group and the high dose group was close to the normal group, and the number of conjunctival goblet cells was not significantly different from that in the blank control group.

CONCLUSION: The expression of Qingxuan decoction can inhibit the inflammatory reaction through down-regulation of TNF-α and IL-1, IL-6 and in evaporative dry eye rabbit cornea and conjunctiva, so as to improve the ocular symptoms, increase tear secretion, prolong the time of BUT.