The passage of abnormal spermatozoa through the uterotubal junction of the mouse

Abstract

Adult female mice of an outbred strain and of the inbred C57BL strain were naturally or artificially inseminated with spermatozoa from 6 to 14 wk old males belonging to 2 inbred strains, C57BL and KE. Several hr after insemination, the females were killed and examined for the percentage of spermatozoa with morphologically abnormal heads found in the uterus and in the oviducal flushings. According to the degree of abnormality, misshapen spermatozoa were divided into 5 classes. In young KE males, large spermatozoa were observed and designated as diploid. The proportion of abnormal forms in the uterus depended on the strain and on the age of the males, and was highest in the group inseminated with spermatozoa from young C57BL strain mice. The proportion of abnormal spermatozoa in the oviducal flushings was greatly reduced, although positively related to the percentage of abnormalities in the uterus. This applied particularly to slight abnormalities, their percentage being about 3 times higher in the uterus than in the oviduct. Spermatozoa with severe abnormalities were either not found in the oviduct or their proportion was reduced more than 10 times. The uterotubal junction appears to function as a barrier against morphologically abnormal spermatozoa, especially against severely deformed ones, although its selective action is not absolutely effective. (13 references)