方法：健康雌性SD大鼠36只随机分为4组，实验组为三组，分别给予右侧泪腺注射0.1mL 1.25、5、10mU的BTX-B溶液，对照组右侧泪腺注射0.1mL生理盐水，分别在第3、7、14、28d行泪液实验Ⅰ(SⅠt)、角膜荧光素染色(FL)检查。另选取32只大鼠，随机分为两组，实验组大鼠右侧泪腺注射0.1mL 1.25mU的BTX-B溶液，分别于第3、7、14、21、42d时选取5只实验大鼠摘除泪腺组织，采用免疫荧光法和Western-blot 法对Lacritin蛋白进行定性和定量检测，组织病理学检测采用常规HE染色。

结果：模型制备中三个实验组均在第3d开始出现泪液分泌减少和角膜上皮损害，但两两之间差异无统计学意义(P>0.05)，7d时达到高峰，14d时好转，28d时泪液分泌恢复正常，但角膜上皮仍见损伤。实验组和对照组大鼠泪腺组织中均仅见腺泡细胞表达Lacritin蛋白，实验组大鼠Lacritin蛋白含量明显下降，自第3d开始出现，7d时达到高峰，14d时好转，28d时开始恢复，42d时达到正常。

结论：泪腺注射1.25mU的BTX-B溶液可成功建立SD大鼠干眼模型，可见泪液分泌减少、角膜上皮损伤等干眼体征，可为干眼的发病机制和实验性治疗研究提供实验依据和基础； Lacritin蛋白仅在泪腺腺泡细胞中表达，其含量与泪液分泌量和干眼程度呈同步变化，可为干眼程度评价标准的完善提供新的依据。

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.