Summary

Tight junctions (TJs) provide a barrier function, inhibitsolute and water flow through the paracellular space.Aim: Analysis of the expression pattern of the TJ-moleculesoccludin (OCLN), claudin-1 (CLDN-1), -3 (CLDN-3), and -5 (CLDN-5) on mRNA and protein level inpatients with oedema, venous leg ulcers and healthycontrols. Material, methods: Biopsy specimens weretaken in healthy individuals and in patients before andfour weeks after compression therapy. The expressionof mRNA was determined by densitometry after usingreverse transcriptase and polymerase chain reaction(RT-PCR), the expression of protein after western blotfrom tissue specimens. Results: Quantification revealeda diminished expression for CLDN-1 (p <0.01) andCLDN-5 (p <0.01) in patients with chronic venous insufficiencyin comparison with healthy controls on mRNAas well as protein level. No statistical differences weredetected for OCLN and CLDN-3 between the oedemagroup and healthy controls. There was a significantlyelevated expression (p <0.01) on mRNA and proteinlevel between the leg ulcer group and healthy controlsfor OCLN and CLDN-3. Densitometric quantificationrevealed a more significantly elevated expression(p <0.01) for CLDN-1 and CLDN-5 on mRNA andprotein level after four weeks of compression therapyin comparison with that prior to treatment for the groupwith oedema as well as for the group suffering from legulcer. Conclusion: Compression therapy tightens theparacellular barrier via elevated expression of specificTJs. It prevents the progression of chronic venous insufficiencybecause its effect on permeability preventing theentrance of fluid into the perivascular tissue.