Chemical Studies on Interstitial Fluid in the Hard Tissues

¹ Department of Medical Chemistry, University of Turku, Turku, Finland

A method has been developed for the separation of interstitial fluid by centrifugal force from the dentin and other hard tissues for their chemical description.

The interstitial tissue fluids were prepared from dentin (DIF) and costal cartilage CIF) of swine. The samples were analyzed chemically and compared with the blood serum from the same swine.

The tissue fluids from dentin and cartilage probably contain chondroitin sulfate and hyaluronic acid and probably contain a soluble collagen fraction, which were not found in serum. The starch gel electrophoresis of DIF and blood serum show quantitative and probably qualitative differences in the protein components.

The results show that the interstitial fluid from dentin and cartilage differ greatly from blood serum. It does not seem proper to consider interstitial fluids as ultrafiltrates of blood only. Obviously, DIF and CIF should not be classified as a distinct kind of tissue fluids but have to be regarded as the soluble ground substance of dentin and cartilage.