The effect of an orally administered proteolytic enzyme on the elasticity and viscosity of nasal mucus.

We have evaluated the effect of serratiopeptidase (SER), a proteolytic enzyme, on the elasticity and viscosity of the nasal mucus in adult patients with chronic sinusitis. SER was administered in a dose of 30 mg/day orally for 4 weeks. Nasal mucus was collected from the nasal cavities of each patient before (week 0) and 4 weeks after the start of the medication (week 4). The storage modulus (G') and the dynamic viscosity (eta') of each specimen of nasal mucus were determined by an oscillating sphere magnetic rheometer at frequencies of 0.5, 1, 5, 10 and 20 Hz at a constant temperature of 25 degrees C. The dynamic viscosity (eta') of the mucus at week 4 was significantly lower than that at week 0 (at frequencies of 5, 10 and 20 Hz). No significant differences were observed in the storage modulus (G') between the mucus at week 0 and week 4. SER reduced the viscosity but not the elasticity of the nasal mucus. These findings are discussed in relation to mucociliary clearance.