The effect of cervical mucus on measurable Feulgen DNA content of human spermatozoa.

The DNA content of morphologically normal Feulgen-stained human spermatozoa (SP) without and with vacuoles was determined by visible light absorption at 560 nm. In an experimental device designed according to the sperm penetration meter of Kremer, sperm penetration into cervical mucus (CM) was allowed to take place for a 60-min period. Smears of the native and mucus-penetrated spermatozoa were applied to glass slides and fixed in a mixture of methanol, formalin, and acetic acid for 1 h. Hydrolysis was performed in 1 N HCl. The slides were stained using hematoxylin. Bull spermatozoa stored at -96 degrees C were applied as an internal standard to ach slide. Of a total of 1,464 spermatozoa measured, 485 came from the ejaculate, 491 had travelled through the cervical mucus for a distance of 15-30 mm, and 193 had migrated for 31-45 mm. The remaining 295 bull spermatozoa were also measured. It was found that after cervical mucus passage the content of Feulgen DNA material measured changed in two different ways: in some of the samples the Feulgen DNA content increased with passage through the cervical mucus, whereas in other samples the Feulgen DNA content decreased during cervical mucus passage. As in the ejaculate, we found a marked variation of the DNA content of spermatozoa after CM passage. The filtering effect of the CM on pathologic SP was not complete.