AIM: To establish dry eye model of rats induced by botulinum toxin B(BTX-B)and provide the basis for the pathogenesis and experimental treatment of dry eye caused by inflammation.

METHODS: Thirty-six healthy female SD rats were selected and divided into four groups randomly, and the experimental group included three groups, which were individually injected 0.1mL 1.25, 5, and 10mU BTX-B solution on the right lacrimal gland; the control group was injected 0.1mL normal saline on the right lacrimal gland, then received Schirmer Ⅰ test(SⅠt)and examination of corneal fluorescein(FL)staining respectively at the 3, 7, 14 and 28d. The other 32 rats were selected and divided into two groups randomly, the rats in the experimental group were injected 0.1mL 1.25mU BTX-B solution on the right lacrimal gland and then five rats were randomly chosen to be removed lacrimal gland tissue respectively at the 3, 7, 14, 21, 42d. The Lacritin protein was detected in the qualitative and quantitative way by immunofluorescence and Western-blot, and the histopathological test was received by routine HE staining.

RESULTS: The three groups in the experimental group during the preparation of the model appeared that tear secretions decreased and corneal epithelium got damaged at 3d, but there was no significant difference for each other of two changes(P>0.05). The change was reached the peak at 7d and improved at 14d. The tear secretions returned to normal level at 28d, but the damage of corneal epithelium was still existed. The expression of Lacritin protein was only observed in acinar cells of both experimental group and control group, and the content of Lacritin protein in the experimental group decreased significantly. The decreasing situation appeared at 3d, reached the peak at 7d, improved at 14d, began to recover at 28d, and returned to the normal level at 42d.

CONCLUSION: Dry eye model of SD rats can be successfully established by lacrimal gland injection of 1.25mU BTX-B solution, with symptoms of dry eyes such as tear secretions reducing and corneal epithelial injury, which can provide experimental basis and foundation for the research on the pathogenesis and experimental treatment of dry eye. Lacritin protein only expresses in acinar cells of lacrimal gland, and the content of Lacritin protein has a synchronous change with tear secretions and degree of dry eye, which provides a new basis for perfecting the standards on evaluating the degree of dry eye.