Etude cytophotométrique de l'ADN et des nucléoprotéines des spermatozoïdes du bélier : influence du séjour dans les voies génitales de la brebis

Abstract

Ejaculated ram spermatozoa were microspectrophotometrically observed as such (controls) or after incubation in the female genital tract (2 to 24 hrs). The nuclear DNA content, measured with UV light, did not significantly differ whether the spermatozoa were incubated in utero or not. However, quantitative measurements of various components, carried out with visible light on specifically stained cells, indicated that the sperm staining abilities were different. The Feulgen DNA increased in 60 p. 100 of the sperm samples incubated in utero. After the longest incubation periods, this was especially evident in 7 out of 8 ewes and 10 out of 10 ewes after 22 and 24 hrs, respectively. In these cases, the mean values for Feulgen DNA extinctions were increased by 21 and 29 p. 100. Most of the in utero-incubated samples (19/21) had the highest extinction values when stained with Fast Green for arginine-rich basic proteins. The nuclear area of in utero-incubated sperm was increased as compared to the non-incubated one. This increase was especially evident after an 18 to 24 hrs incubation. Differences in staining ability would be due to modifications in chromatin structure. The significance of these changes in relation to the preparation of spermatozoa for fertilization has been discussed. The appearance of abnormalities on some spermatozoa, seen after staining with Fast-Green, might indicate a deleterious effect of the uterine environment on already altered spermatozoa.