Effect of hyaluronate on physicochemical and biological properties of collagen solution which could be used as collagen filler

The effect of hyaluronate (HA) on the physiochemical and biological properties of collagen solution was examined for two preparations of collagen with different rates of fibril formation. The addition of HA to the collagen preparation with the slower rate of fibril formation caused a prominent acceleration of fibril formation. A differential scanning calorimetric measurement of the collagen preparation demonstrated a stabilizing effect of HA on collagen solution after incubation at 37 degrees C. Histochemical examination of rat dermis after injection of the collagen solution into the tissue revealed the migration of fibroblast-like cells into the region occupied by the injected collagen. The addition of HA to collagen preparation S (slower rate of fibril formation) shortened the time-to-appearance of fibroblast-like cells to a similar value to that observed when collagen preparation F (faster rate of fibril formation) was used. The timing of cell appearance was in accord with the rate of fibril formation in vitro. Fibrils newly formed by injected collagen might provide sites for cell attachment, migration and proliferation.