Semiquantitative analysis of tight-junction associated Occludin in healthy human gingiva

Objectives: To quantity the expression of occludin, tight-junction-associated proteins in healthy human gingival epithelium. Patients and methods: The expression of Occludin were analyzed in histologically evaluated, healthy gingival samples obtained from five young patients prior to surgical removal of impacted mandibular third molar. The expression of Occludin tight junction protein was quantified in different epithelial cell layers. The digital images captured from the stained samples were optimized and converted by Adobe Photoshop software to grayscale TIFF files. The semiquantitative analysis of Occludin expression was performed by using ImageQuant software (Molecular Dynamics). The background was eliminated by a threshold set up. On the images in each cell layers we set up 10 randomly selected polygonal areas with equal size and average pixel intensities of each polygons were determined. The mean of and standard deviation of grayscale intensities was calculated and plotted on graph. The Statistica 6.1 software (Statsoft Inc., Tulsa, USA) was used for statistical analysis. The statistical significance was determined by ANOVA probe and Tukeys post-hoc test. Results: The expression of Occludin was elevated significantly in the basal cell layer of gingival epithelium. Conclusion: The polymorphonuclear leucocyte migration into the periodontal tissues and through the junctional epithelium into the crevice area is crucial to the defence of the periodontium. In cell culture the Occludin modulates the transepithelial migration of neutrophils. The cells of the junctional epithelium are morphologically and structurally most similar to the basal cells in the stratified oral epithelium. Our results suggest that Occludin takes part in defence of the periodontium.