Does in vitro capacitation alter chromatin stability of ejaculated human spermatozoa? cytochemical studies

Abstract

In vitro capacitation of human spermatozoa is commonly evaluated by the progressive motility percent. However its effects on sperm chromatin have hardly been studied. Our aim was to determine the extent to which in vitro capacitation with two treatments (B2 or human follicular fluid) alters the chromatin of human spermatozoa, by using two analytical methods, acridine orange staining and Feulgen-DNA cytophotometric measures. Ejaculates were obtained from 23 men participating in our in vitro fertilization program, and several measurements were made on the same ejaculate for each subject. No alteration was observed for the percent of native DNA after capacitation in B2, but spermatozoa incubation during the same time in human follicular fluid was followed by a significant decrease of the percent of native DNA (P less than 0.01). Feulgen-DNA content significantly increased after capacitation in either B2 or follicular fluid (P less than 0.05, P less than 0.001 respectively), and so did sperm nuclear surface area (P less than 0.001). In this study we observed a negative correlation between Feulgen-DNA content and fertilization rate (P less than 0.02). Moreover, the greater effects on Feulgen-DNA content were observed in men with abnormal sperm, whose spontaneous percent of native DNA was lower (P less than 0.05) and Feulgen-DNA content higher (P less than 0.05) than in men with normal sperm. These results indicate that capacitation in B2 as well as in human follicular fluid may alter the chromatin stability of human spermatozoa. Such results suggest a partial decondensation state of human spermatozoa during in vitro capacitation. However, beyond some level of decondensation, the fertilizing ability could be altered.

Sperm Chromatin Stability DuringIn VitroManipulation of Beef Bull Semen

“…2006; Liu and Baker 2007). In accordance with findings of previous studies (Royere et al. 1991; McNutt et al.…”

“…In addition, sperm treated with heparin penetrated a higher percentage of oocytes than sperm incubated (4 h) with 20% or 60% FF. In brief, a level of 20% FF is non‐physiological and may be incompatible with fertilization (Royere et al. 1991).…”

“…Furthermore, supplementation of boar semen with EDTA decreased DNA fragmentation rate in freeze-dried spermatozoa (Nakai et al 2007). On the other hand, treatment of human semen with FF decreased sperm chromatin stability (Royere et al 1991). In another study, addition of caffeine to human semen increased sperm chromosome aberrations (Genesca et al 1992).…”

“…2007). On the other hand, treatment of human semen with FF decreased sperm chromatin stability (Royere et al. 1991).…”

An Epididymis-Specific Secretory Protein HongrES1 Critically Regulates Sperm Capacitation and Male Fertility

“…It had been reported that the degree of DNA damage is clearly correlated with the impairment of embryo development and severe DNA damage cause male infertility [40]. Moreover, sperm capacitation could alter the chromatin stability, enhance remodeling asynchrony and result in delayed pronuclei formation and DNA synthesis [41], [42]. Our in vivo results showed that the prematurely capacitated sperm stemmed from knockdown of HongrES1 led to the reduction in fertility and somehow deformed appearance of fetuses and pups.…”