Improvement of human ovulatory cervical mucus by alpha-amylase. Effect on spinability and crystallization in vitro.

Alpha-amylase can modify ovulatory cervical mucus in vitro, changing both its structure and an essential rheological parameter, spinability. After 5 min at alpha-amylase concentrations above 4.6 mg/ml, spinability was greatly reduced or even non-existent because of the total liquefaction of the mucus. These concentration levels also induced breakdown of the solid phase of the hydrogel, producing more or less marked abnormalities in mucus crystallization after air drying. In the presence of the highest alpha-amylase concentrations (greater than or equal to 37.5 mg/ml) dendrites could not be formed and only sodium chloride crystals were visible at high magnification under a scanning electron microscope. In the 75 to 1.2 mg/ml concentration range, where alpha-amylase has a significant action on cervical mucus, there was an overall decrease in average spinability as the enzyme concentration fell. The action of the enzyme was greater after 10 min than after 5 min reaction time. For the 10-min reaction time interval, the activity could be adjusted using a squared polynominal regression, whereas for the 5-min reaction time interval a linear regression was a suitable model of enzymatic activity. In the 4.6 to 1.2-mg/ml concentration range, adjustment on a linear model showed that there was a significant effect of alpha-amylase concentration and reaction time on mucus spinability. Statistical analysis of the dose-effect data was compatible with the structural changes in dried cervical mucus demonstrated by scanning electron microscopy.