Background: Heterotypic (mixed) collagen fibrils that contain collagen types II, IX and V/XI have previously been identified in vitreous gel. The purpose of this study was to determine whether vitreous gel also contains type VI collagen microfibrils, as they are widely distributed in other tissues where they may play an important structural role.
Methods: Bovine and human vitreous gel was analysed by rotary shadowing electron microscopy after bacterial collagenase digestion and gel filtration chromatography. Bovine vitreous was extracted in 4 M guanidine hydrochloride, and following isopycnic centrifugation fractions were analysed by western blotting.
Results: Type VI collagen microfibrils were identified by electron microscopy in human and bovine vitreous. Type VI collagen was identified by western blot analysis.
Conclusion: Type VI collagen is present in vitreous and may participate in the structural assembly of the vitreous gel.