The effect of glycosaminoglycans on the in vitro fibril formation of collagen type I and type III.

The effect of glycosaminoglycans (GAG) on the in vitro collagen fibril formation of type I and type III collagen extracted from rat skin was studied by measuring the optical absorbancy change of collagen-GAG solution during the fibrillary precipitation and following the electronmicroscopic structure of collagen fibrils. The main difference between type I and type III collagen was found in the kinetic of fibrillary precipitation mainly during the logarithmic growth ("log") period of fibril formation. Chondroitin sulphate-A (CSA) shortened this phase and affected especially type III collagen which has a longer "log" period. No difference was found in the electronmicroscopic structure of collagen fibrils. The supposed biological significance of the results is briefly discussed.