[Histochemical and electron microscopic study of the formation of trabecular meshwork and changes of glycosaminoglycans].

The development of iridocorneal angle and trabecular tissue was investigated histochemically and electron microscopically. Sixty-three human eyes at from 5 to 22 weeks of gestation were used in this study. For identifying glycosaminoglycans, alcian blue staining and enzyme digestion methods with hyaluronidase and chondroitinase AC and ABC were carried out light microscopically. Electron microscopically, specimens were stained with ruthenium red. In the early stage from 8 to 10 weeks, mesenchymal cells between the primordium of the cornea and the iris became elongated and connected with one another. Desmosome-like junctional complexes were observed in these cells. Schlemm's canal and para-canalicular tissue were observed at 20 weeks and the structure of the meshwork became similar that of adults. From findings of enzyme digestion methods, glycosaminoglycans in trabecular tissue seemed to be mainly hyaluronic acid in the early stage, which was replaced by chondroitin sulfate and dermatan sulfate afterwards. Substances positive for ruthenium red, which seemed to be glycosaminoglycans, was observed in intercellular spaces electron microscopically. They decreased according to development. These findings indicated that the beginning of aqueous outflow might be related to the decrease of glycosaminoglycans in trabecular tissue.