Histochemistry and lectin histochemistry of the sclera and choroid in development of the eyes

Background and Sclera and choroid as external and middle tunic of the eye, originate from the mesenchyme surrounding the optic cup. Neural crest cells have major contribution in mesenchyme development. Main part of transmitter signals in eyes development are extracellular matrix components and cell surface glycoconjugates. The purpose of this study was to recognize extracellular matrix components and cell surface glycoconjugates during development of the sclera and choroid. Rat embryos from 11th to 20th day of gestation and newborns from 1st to 15th day were collected. Tissue sections histochemical staining and lectin histochemistry using PNÂ, BSÂ1-B4 and S/PNÂ techniques were carried out. Sections graded according to staining intensity. Statistical analysis of section showed significant differences only for neutral and carboxylated acidic glycose aminoglycan in studied days (mann-whitney P<0.05). Further more, surrounding optic cup mesenchyme reacts with high affinity to BSÂ1-B4. Ïn this way, presence of end sugar D-Gal in mesenchymal cells of this area was identified. The reaction of above mentioned mesenchyme to PNÂ lectin of end sugar D-Gal N-acetyle glucose amine was negative, but after using sialidase enzyme digestion method, some of the mesenchymal cells showed a week response to this lectin. Ïn this way, presence of acid sialic and end sugar Gal/GalNac could be shown in these cells. Çonclusion: Ït is concluded that, over-all, extracellular matrix changes and cell surface end sugars are part of mechanism responsible in control of morphogenesis in embryo during eye formation.