Serum-induced collagen gel contraction

• Purpose: To understand the molecular events underlying disease-related vitreous gel contraction, the effect of serum components on collagen was investigated. • Methods: Bovine vitreous or dermal collagen was incubated with a mixture of transglutaminase (TG; factor XIIIa) and fibronectin (FN), and the biochemical changes of collagen were monitored by gel electrophoresis. In addition, serum-induced changes in the volume of the collagen gel were monitored. • Results: Gel electrophoresis revealed a new high-molecular-weight band (Mr 240 000) presumably due to intermolecular cross-links of collagen peptides and FN. The serum components also were shown to cause a significant decrease in the volume of the collagen gel. • Conclusion. Collagen gel contraction could be attributed to the collagen-FN-collagen cross-links catalyzed by TG.