Lectin staining of saccharides in the normal and hypothyroid developing organ of Corti

Abstract

Lectin staining has been used to detect mono- and oligosaccharides in normal and hypothyroid developing organs of Corti in the rat. Eight developmental stages were studied (1, 5, 8, 10, 15, 20, 50 and 60 days after birth). Congenital hypothyroidism was induced by oral administration of propylthyouracil to pregnant rats. Labelling of the tectorial membrane with 3 lectins, Ulex europaeus agglutinin-I (UEA-I), Lens culinaris agglutinin (LCA) and Ricinus communis agglutinin-I (RCA-I) showed no significant differences between normal and hypothyroid animals. Staining with peanut agglutinin (PNA) showed that the hypothyroid adult tectorial membrane (but not the normal one) possesses the disaccharide galactose+ N-acetyl galactosamine. Phaseolus vulgaris agglutinin-L (PHA-L) labels the whole tectorial membrane in both groups of animals, but the staining is more intense in the hypothyroid one for a narrow band of oligosaccharide located just between the tectorial membrane and the underlying organ of Kölliker. Both soybean agglutinin (SBA) and succinylated wheat germ agglutinin (WGA) stain the tectorial membrane as well as the cytoplasm of the cells constituting the inner portion of the organ of Kölliker; this latter feature disappears in the normal animals about the 8th postnatal day, but it is abnormally preserved until the 60th postnatal day in the hypothyroid ones. In the adult hypothyroid animals, 3 of the lectins (LCA, PHA-L and WGA) stain extracellular conglomerates located under the synaptic pole of the outer hair cells.