Hyaluronidase function and effect: which statement is true?

• A. It slows absorption by increasing tissue density
• B. It reduces diffusion by thickening interstitial space
• C. It acts as a vasoconstrictor at the injection site
• D. It loosens proteins in tissues by breaking them down, increasing absorption

Answer: (D)

Hyuluronidase increases absorption by altering the extracellular matrix to allow better diffusion of injected substances. It does this by enzymatically breaking down hyaluronic acid, a key component of the connective tissue matrix. When hyaluronic acid is degraded, the interstitial space becomes less viscous and more permeable, so the injected drug can spread more widely and be absorbed faster. This explains why the statement that it loosens tissue by breaking down matrix components and increases absorption is true. It does not slow absorption or act as a vasoconstrictor, and its primary target is hyaluronic acid rather than proteins in the tissue, so its effect is to facilitate diffusion and absorption.