The Histological Effects of Hyaluronic Acid and Hyaluronidase Injections on Skin: An Experimental Study

BACKGROUND Nonsurgical facial rejuvenation procedures are currently among the most popular areas of plastic, reconstructive, and aesthetic surgery. The goal of this study is to identify the effects of simultaneous hyaluronic acid and hyaluronidase injections into animal skin. This study is the first animal study in the literature showing the effects of hyaluronic acid and hyaluronidase simultaneous injection on skin. METHODS The study included 15 male and 15 female Wistar Albino rats. Four different areas were determined on the backs of the rats: a control area, an area for injection with hyaluronic acid, an area for injection with hyaluronic acid with hyaluronidase, and an area for injection with hyaluronidase only. The experiment was terminated at different times in these groups. After sacrification, the 4 regions were compared with each other under light microscope. RESULTS The results of this study demonstrate increases in dermis thickness, collagen density, and extracellular matrix density with injection of hyaluronic acid (81% vs 69.1%, p < .05), and hyaluronidase appears to antagonize these effects (52.5% vs 59.17%, p < .05). CONCLUSION Hyaluronic acid injections have positive effects on animal skin, while hyaluronidase can antagonize these effects. When hyaluronic acid and hyaluronidase are injected simultaneously into the animal skin, it is observed that the antagonizing effect of hyaluronidase is dominant from the first moment.