Chromosome analysis of mouse zygotes produced by intracytoplasmic injection of spermatozoa exposed to acrosome reaction inducing agents methyl-β-cyclodextrin and calcium ionophore A23187

Abstract

Purpose This study was performed to investigate whether removal of cholesterol from the plasma membrane and collapse of the acrosome can prevent structural chromosome aberrations of paternal origin in mouse zygotes produced by intracytoplasmic sperm injection (ICSI). Methods Mouse spermatozoa were treated with methyl-β-cyclodextrin (MβCD) to remove cholesterol from the plasma membrane and with calcium ionophore A23187 to collapse the acrosome. Chromosomes of zygotes derived from MβCD-and ionophore-treated spermatozoa were analyzed at the first mitotic metaphase. Results Both chemical agents effectively induced the acrosome reaction. Incidence of structural chromosome aberrations in ICSI zygotes derived from MβCD-treated spermatozoa was similar to that in zygotes produced by in vitro fertilization (IVF) with the same spermatozoa, but significantly lower compared to ICSI zygotes derived from acrosome-intact spermatozoa. Chromosome aberration rates in ICSI zygotes derived from ionophore-treated spermatozoa were evidently high compared to IVF zygotes. Conclusions Induction of the acrosome reaction through cholesterol efflux by MβCD can prevent chromosome aberrations of paternal origin, while use of ionophore to induce the acrosome reaction exerts detrimental effect on paternal chromosomes in ICSI zygotes.

Sperm capacitation pretreatment positively impacts bovine intracytoplasmic sperm injection

“…Therefore, upon MβCD treatment, cholesterol efflux from the sperm plasma membrane, which results in lipid raft movement and loosening of the lipid bilayer structure (Watanabe & Kondoh, 2011), may have supported the observed higher bovine sperm decondensation, and subsequent development, after ICSI. Indeed, the highest rate of embryonic development was observed in this group-a result also reported in a mouse ICSI model using the same sperm pretreatment (Tateno, 2010). Similar results were recently described using glutathione (Lee et al, 2015) and lysolecithin (Zambrano et al, 2016) as sperm pretreatments, confirming the positive effect of pretreatment in promoting DNA decondensation and pronucleus formation.…”

The Behavior and Acrosomal Status of Mouse Spermatozoa In Vitro, and Within the Oviduct During Fertilization after Natural Mating

“…The suspension was kept for 2 h at 378C under 5% CO 2 in air to capacitate the spermatozoa. Acrosome-reacted spermatozoa were obtained according to Tateno [22]. Briefly, epididymal spermatozoa were incubated in TYH for 5 min or 2 h, treated with 20 lM Ca 2þ ionophore (A23187) in 23 Ca 2þ TYH for 10 min, centrifuged, and allowed to swim out of the sperm pellet into 500 ll prewarmed TYH.…”

Risk of chromosomal aberration in spermatozoa during intracytoplasmic sperm injection

“…For example, induction of sperm capacitation [ 30 ] or the acrosome reaction [ 9 , 31 , 32 , 33 ] prior to ICSI was shown to improve the fertilization and/or development of the resultant zygotes. On the other hand, studies on mouse models revealed that the chromosomal integrity of zygotes derived from ICSI without any pretreatment of spermatozoa was impaired in comparison with that of zygotes derived from conventional IVF [ 12 , 34 , 35 ]. The damage was reduced by injecting spermatozoa cultured with bovine serum albumin or methyl-β-cyclodextrin [ 12 , 35 ], which triggered sperm capacitation due to cholesterol efflux on the plasma membrane [ 36 , 37 ].…”

“…On the other hand, studies on mouse models revealed that the chromosomal integrity of zygotes derived from ICSI without any pretreatment of spermatozoa was impaired in comparison with that of zygotes derived from conventional IVF [ 12 , 34 , 35 ]. The damage was reduced by injecting spermatozoa cultured with bovine serum albumin or methyl-β-cyclodextrin [ 12 , 35 ], which triggered sperm capacitation due to cholesterol efflux on the plasma membrane [ 36 , 37 ]. Similarly, the frequency of chromosomal aberrations originating from sperm was low when spermatozoa were treated with calcium ionophore A23187 to induce the acrosome reaction [ 35 ].…”

“…The damage was reduced by injecting spermatozoa cultured with bovine serum albumin or methyl-β-cyclodextrin [ 12 , 35 ], which triggered sperm capacitation due to cholesterol efflux on the plasma membrane [ 36 , 37 ]. Similarly, the frequency of chromosomal aberrations originating from sperm was low when spermatozoa were treated with calcium ionophore A23187 to induce the acrosome reaction [ 35 ]. These findings suggested that injection of non-capacitated and acrosome-intact spermatozoa resulted in the generation of chromosome-damaged embryos.…”