AIM: To study the mechanism and effect of Qingxuan decoction on evaporative dry eye in rabbit model.

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.