RESUMO
BACKGROUND: Human β-defensin is mainly located in various tissues epidermis or epithelium, also exists in ocular surface, but its ocular surface and its role of ocular surface diseases remain poorly understood.OBJECTIVE: To observe the distribution of human β-defensins in ocular surface tissue, and to analyze their potential effects on ocular surface disease. DESIGN, TIME AND SETTING: In vitro controlled observation with regard to ocular surface tissue was performed at the Central Laboratory, Xinhua Hospital, Medical College of Shanghai Jiao Tong University and Cell Biochemistry Institute, Chinese Academy of Sciences Shanghai Branch, between October 2006 and December 2007.MATERIALS: A total of 18 inflammatory conjunctival specimens consisted of 6 pterygium surface bulbar conjunctiva, 4 bulbar conjunctival cysts, 4 acid burn conjunctiva, 2 thermal burn conjunctiva and 2 conjunctival granuloma; 15 inflammatory corneal specimens included 6 viral keratitis, 4 fungal keratitis, 3 bacterial keratitis and 2 eye removal following corneal perforation; 9 cadaver normal bulbar conjunctiva samples, 8 cadaver normal corneal samples. METHODS: RT-PCR method and immunohistochemistry were applied to detect human β-defensin expression in 50 samples. MAIN OUTCOME MEASURES: Distribution and location of human β-defensin proteins in normal and inflammatory ocular surface tissues. RESULTS: RT-PCR showed that human β-defensin 1 and human β-defensin 3 were positive in all of the tested samples, whereas human β-defensin 2 existed in a majority of inflammatory ocular surface tissues and no expression was observed in normal ocular surface tissues. Immunohistochemistry analysis revealed most of inflammatory ocular surface tissues expressed human β-defensins 1 and 2, distributing in epithelial cell layer and predominantly in basal lamina, occasionally infiltration of stromal cells was observed, only a small number of human β-defensin 2 expression was absent; normal cornea and conjunctiva samples presented with human β-defensin 1 expression, distributing in epithelial cells and predominantly in basal lamina, only few expressed human β-defensin 2.CONCLUSION: Human β-defensin 1 and 3 appear to be constitutively expressed in surface epithelial cells and basal lamina of normal and inflammatory ocular surface tissues, while human β-defensin 2 may be induced to express in the majority of inflammatory ocular surface tissues. Three human β-defensins expression plays a pivotal role in preventing ocular surface infection and promoting ocular surface injury repair.