The Expression Of Dectin-1 In Corneal Epithelium Of Fungal Keratitis

Objective:To observe the expression of dendritic cell-associated C-type lectin-1 (dectin-1) in corneal epithelium of fungal keratitis and compare with the expression of dectin-1 in normal corneal epithelium, then study the effect of fungal on the expression of dectin-1 in corneal epithelium.Materials and methods:A total of 20 patients (20 eyes) suffered from fungal keratitis that underwent penetrating keratoplasty (PKP) at the Affiliated Hospital of Qingdao University Medical College from July 2010 to December 2012 composed experimental group.20 cases of healthy donor corneas were used as corneal graft and the rest of the peripheral corneal tissues were control group. The two groups’corneal epithelium was scraped. Real-time quantitative reverse transcription-polymerase chain reaction (real-time RT-PCR) was applicated in the detection of mRNA expression of dectin-1 receptor in corneal epithelium of two groups.72 Wistar rats were randomly divided into two groups. The first group of 54 rats (54 eyes) were used for real-time RT-PCR:Group A1 was blank control group (6 eyes). Group B1 was negative control group (24 eyes) and group C1 was fungal keratitis experimental group (24 eyes). The right eyes of fungal keratitis experimental group were experimental eyes. After the epithelium of central cornea was scraped, aspergillus fumigatus hyphae-laden contact lenses covered in fungal keratitis experimental eyes, and the left eyes of negative control group covered with contact lenses only. The expression of dectin-1 and toll-like receptor 4 (TLR4) receptors in corneal epithelium of group B1 and C1 (at 4h,8h,16h,24h) were detected. The second group of 18 rats were used for immunohistochemistry (6 eyes each):Group A2 was blank control group. Group B2 was negative control group and group C2 was fungal keratitis experimental group. The expression of dectin-1 and toll-like receptor 4 (TLR4) receptors in corneal epithelium of group B2 and C2 (at 24h) were detected.Results:mRNA of dectin-1 expressed in corneal epithelium of normal persons and patients with fungal keratitis. Dectin-1 and TLR4 receptors expressed in the corneal epithelium of blank control and negative control eyes of rats, and the expression of dectin-1 and TLR4 receptors in the two groups did not have significantly statistical difference (F=1.325, P=0.288; F=0.455, P=0.768). Compared with blank control eyes, the expression of dectin-1 and TLR4 receptor in corneal epithelial of fungal keratitis experimental eyes elevated (F=74.679, P=0.000; F=30.225, P=0.000). In fungal keratitis experimental eyes, mRNA expression of dectin-1 receptor began to increase after stimulation of 8h (P=0.000), and protein expression increased after stimulation of 24h (t=-27.983, P=0.000); mRNA expression of TLR4 receptor began to increase after stimulation of 4h (P=0.001), and protein expression elevated after stimulation of 24h (t =-30.650, P=0.000).Conclusion:Dectin-1 receptor expressed in corneal epithelium of normal persons and patients with fungal keratitis. Dectin-1 receptor expressed in rat corneal epithelium, and aspergillus fumigatus hyphae stimulation can elevate the expression of dectin-1 receptor in corneal epithelium. Dectin-1 may serve as pattern recognition receptor to participate in the innate immune response of fungal keratitis.