尿素酶在眼组织中的表达及泪膜尿素减少与干眼症的关系分析

Expression of urease in ocular tissues and the correlation between the reduction of lacrimal film urea and xerophthalmia

目的探讨尿素酶在泪腺和眼表组织表达,尿素是组成泪膜重要组成成分。方法选取2011年3月至2013年3月20例干眼症患者,58例正常患者。通过RT-PCR和免疫组化染色测定泪腺和眼表组织尿素酶(精氨酸酶-1,2和鲱精胺酶)表达。共收集38例眼泪、房水、血清样本。结果精氨酸酶-1,2和鲱精胺酶在所有眼组织表达,除精氨酸酶-1在角膜无表达。眼泪尿素浓度与房水和血清尿素浓度无相关性(r=0.13,P=0.58;r=0.45,P=0.05),房水尿素浓度与血清尿素浓度具有明显相关性(r=0.7,P=0.0001)。干眼症眼泪尿素浓度明显低于正常对照组(P<0.0001)。结论眼泪中尿素酶能够独自生成尿素,使尿素浓度维持泪膜结果具有重要作用。

Objective To investigate the expression of urea enzymes in lacrimal gland and ocular surface tissues,and urea is important component of lacrimal film. Methods Twenty patients with xerophthalmia from March 2011 to March 2013 were enrolled as observation group,and 58 healthy subjects were served as control group. The urease levels including arginase1,2 and agmatinase in lacrimal gland and ocular surface tissues were detected by RT-PCR and immunohistochemistry. A total of 38 specimens were collected including tear fluid,aqueous humour and serum. Results The enzymes including arginase 1,2 and agmatinase were expressed in all the ocular tissues,except for arginase 1 without expression in cornea. The concentration of urea in tear fluid was not correlated to that in aqueous humour and serum（ r = 0. 13,P 〉0. 05; r = 0. 45,P = 0. 05）,however,the concentration of urea in aqueous humour was closely related with that in serum（ r = 0. 7,P = 0. 01）. The concentration of urea in observation group was significantly lower than that in control group（ P 〈0. 01）. Conclusion The urease in tear fluid can produce urea independently,which plays an important role in maintaining lacrimal film at a certain concentration of urea.