Hyaluronan, hydration and flow conductivity of rat dermis.

We have measured the flow conductivity, kappa/eta, of discs of rat dermis with and without digestion with hyaluronidase. We found no significant difference between the flow conductivity of hyaluronan digested (kappa/eta = 5.56 +/- 2.74 cm4/dyne.s (n = 13)) and untreated tissue (kappa/eta = 6.03 +/- 3.15 cm4/dyne.s (n = 13)). For the first time in such experiments the overall tissue hyaluronan content as well as the difference in concentration of this material across tissues subjected to conditions of flow was measured. Similarly, the overall hydration and the difference in fluid content across the tissue is also reported. We have demonstrated that approximately 99% of the tissue hyaluronan was digested as a result of activity of the enzyme. No difference in hyaluronan across the tissue was found in the flow experiments (i.e., with or without digestion). We found significant change in the overall tissue hydration for controls and for either of the two types of flow experiments performed. Likewise, we found significant hydration differences across the tissues under both types of flow conditions. A trend in decreasing hydration associated with digestion of hyaluronan in the flow experiments was found.