THE DISTRIBUTION OF FIBRONECTIN AND P-COMPONENT IN DESCEMETS-MEMBRANE- AN IMMUNOELECTRON MICROSCOPIC STUDY

Descemet's membrane consists of two zones, the 'anterior banded zone' which contains wide-spaced collagen and the amorphous 'posterior non-b anded zone'. It is attached anteriorly to the corneal stroma by a narr ow transitional zone termed the 'interfacial matrix', The distribution of fibronectin and P component within the different layers of Desceme t's membrane was investigated using an ultrastructural immunogold tech nique. Seven normal human corneas from an eye bank and one specimen fr om an orbital exenteration were examined. Fibronectin was predominantl y present in the posterior part of the posterior non-banded zone and i n the anterior banded zone. The anterior part of the posterior non-ban ded zone contained less fibronectin. P component was present throughou t the anterior banded and posterior non-banded zones. There was a shar p demarcation at the interfacial matrix since neither substance was ob served in the corneal stroma. The differences shown in the distributio n of fibronectin and P component within Descemet's membrane may have r esulted from their binding to other substances or alternatively from d ifferences in the quantities laid down during the evolution of this ba sement membrane.