Comparison of different chromatin staining techniques for bull sperm

Abstract

Morphological analysis of semen is a very important step in fertility assessment, but many semen defects are not detectable at the morphological level. These include pathological changes in sperm chromatin structure. During mammalian spermiogenesis, histone proteins associated with DNA structure are replaced by specific protamines, with which chromatin does not form nucleosomal complexes. In the fully developed, mature sperm, the histones are replaced with protamines. Disruptions of nucleoprotein structure can be treated as possible indicators of the biological value of spermatozoa. The experimental material consisted of sperm from one-and-a-half-year-old bulls, isolated post mortem from the tail of the epididymis. The smears were stained with silver nitrate (AgNO 3 ), acridine orange (AO), aniline blue (AB) and chromomycin A3 (CMA3). Sperm dimensions largely depend on individual variability among the bulls. In most cases, differences in sperm dimensions were identified between individuals, which was confirmed in the statistics. Sperm with elevated, abnormal histone levels were proportionally quite scarce (1.4 %). Studies of nuclear proteins in the context of infertility demonstrate the important influence of normal chromatin structure on sperm functions.

Evaluation of sperm chromatin structure in boar semen

“…Research conducted on young (1.5-year-old) bulls, from which sperm was isolated post mortem from the tail of the epididymis, also showed a slight deviation in the number of sperm cells with abnormally packaged genetic material (2). The present study shows that the quality of boar semen improves as sexual development progresses.…”

Differences in drone sperm morphometry and activity at the beginning and end of the season

“…Staining with silver nitrate also shows the heterogeneous structure of the sperm tail, which is probably linked to variation in the activity of mitochondria or mitochondrial derivatives. The use of silver nitrate staining to identify the sperm midpiece in other species has been described by Andraszek et al (13,14). A study by Collins and Donoghue (6) confirmed that it is useful to stain drone sperm cells using various techniques, because each technique can reveal different details of the sperm ultrastructure or defects in its morphological structure.…”

Unravelling how in vitro capacitation alters ram sperm chromatin before and after cryopreservation

“…[21][22][23][24][46][47][48] Sperm chromatin condensation can be evaluated rapidly with aniline blue (AB). This cytochemical dye selectively stains persisting lysine-rich histones 49,50 and has been widely used to identify an excessive histone retention in the chromatin of mature spermatozoa, which has been related to infertility, poor fertilization rates and morphological defects in the sperm head. 10,14,51 However, a lower sperm chromatin condensation detected with AB does not always involve an abnormal histone content.…”