Development of the Human Foetal Vitreous Body

Abstract

Only few biochemical data are available on the development of the vitreous body. Balazs, Laurent & Laurent (1959) measured the concentrations of ascorbic acid, hexosamine, hexuronic acid, ester sulfate, protein nitrogen, hydroxyproline and calcium in the developing cattle vitreous body from 2 month-old embryos to 10-year-old adult animals. Bembridge & Pirie (1951) measured the total nitrogen and the hexosamine concentration in the rabbit vitreous humour during the first weeks after birth. T o the best of our knowledge similar biochemical analyses have not been carried out on the human foetal vitreous body.As an opportunity arose to examine fresh human foetal eyes, we decided to perform as many relevant analyses as possible. This proved, however, to be a difficult task owing to the very small size and the limited number of eye balls which was available. For these reasons the accuracy of some of the results is not quite up to the standard we should have wanted, but owing to the uniqueness of the material we decided to publish them along with the other more reliable results. Methods MaterialThis comprises eyes from 22 human foetuses removed by caesarean section in connection with legal abortion, and 1 foetus delivered by spontaneous abortion. The eyes were excised and frozen at -20' C within 20 minutes post partum.Received May 16th 1968. Bekzempelse. This investigation was supported by a grant from Landsforeningen ti1 Krzeftens PreparationThe anterior segment and the sclera-choroid-retina were carefully removed from the frozen vitreous body under a dissection-microscope. The vitreous bodies of the various age groups were pooled, and afber thawing, spun for 2 hours at 105 000 X g in a Beckman Spinco preparatory ultracentrifuge at 4' C.The supernatants were carefully decanted off and the sediment pellets were saved for hydroxyproline determination.The centrifuged vitreous samples were dialyzed against destilled water for 2 hours at 37" C in a microdialysis apparatus (Kunz, Copenhagen).All analyses had to be done on much smaller volumes than described by the authors of the methods used. Control determinations on test solutions of various concentrations gave satisfactory results in spite of the reduction in volume. In most instances the samples were diluted with destilled water in order to obtain a sufficient amount to work with.The spectrophotometric readings were performed on a Zeiss PMQ I1 spectrophotometer using semimicro quartz cells. Analyses