[Immunohistologic studies of the vitreous humor]

Immunohistological staining of the vitreous is difficult because of its high water content. We present a method for immunohistological staining of celloidin-embedded eyes. Results from diabetic and non-diabetic eyes are demonstrated.

Diabetic and non-diabetic eyes were firstly immersed in formol and then slowly dehydrated using rising concentrations of glycerine (sink method). Subsequently, the whole globe was embedded in celloidin and cut into 200-micron sections. Control areas of interest were dissected from the 200 microns sections under a lightmicroscope. These specimens were then embedded in paraffin and cut into 7-micron sections. The 7-micron sections were immunohistochemically stained for type I-collagen, type IV-collagen, fibronectin and laminin.

This method makes immunohistochemical staining of the vitreous possible. Type IV collagen, laminin and fibronection were found at higher concentrations in diabetic eyes than in normal eyes. Type I collagen was detected in neither diabetic nor in normal eyes.

Our method of examination allows immunohistological staining of the vitreous in its place of origin. Although our method is time consuming, it has some advantages over biochemical analysis: Even minimal changes and their exact distribution can be detected. Our first results show that the vitreous is built up inhomogeneously and that pathological influence can cause structural changes.