Human sperm bound to the zona pellucida have normal nuclear chromatin as assessed by acridine orange fluorescence

Abstract

Sperm binding to human ZP is highly selective for double stranded DNA. Sperm with single stranded or denatured DNA bind less or do not bind at all to the ZP, probably because of defects of motility and, more especially, morphology.

Could using the zona pellucida bound sperm for intracytoplasmic sperm injection (ICSI) enhance the outcome of ICSI?

“…14-17 The majority of sperm (average .92%) bound to the ZP have normal nuclear chromatin DNA. 17 These results suggest that the human ZP possesses the capacity to select normal functioning sperm and therefore, the ZP-bound …”

“…[10][11][12][13] For conventional IVF, it is adequate to inseminate oocytes using motile sperm selected by these methods since the sperm which fertilizes will be further selected through the biological process of spermoocyte interaction, especially sperm-ZP binding. [14][15][16][17] In contrast with conventional ICSI, this additional selection does not occur. The embryologists subjectively select a sperm based only on motility and gross morphology and it is very difficult to select a most competent sperm for injection of an oocyte, in particular for samples with high proportion of DNA damaged sperm.…”

“…Although the ability of sperm binding to the ZP is not necessary and likely only a viable sperm with normal DNA is needed for fertilization with ICSI, many previous studies showed clearly that the human ZP selectively binds sperm with normal morphology. [14][15][16][17] The majority of sperm (average .92%) bound to the ZP have normal nuclear chromatin DNA. 17 These results suggest that the human ZP possesses the capacity to select normal functioning sperm and therefore, the ZP-bound sperm should have a superior quality compared to the general population of motile sperm in medium or scientist subjectively selected motile sperm during conventional ICSI.…”

“…[14][15][16][17] The majority of sperm (average .92%) bound to the ZP have normal nuclear chromatin DNA. 17 These results suggest that the human ZP possesses the capacity to select normal functioning sperm and therefore, the ZP-bound sperm should have a superior quality compared to the general population of motile sperm in medium or scientist subjectively selected motile sperm during conventional ICSI. Thus the use of the ZP-bound sperm, a best proportion of sperm selected biologically through sperm-ZP interaction for ICSI, may produce higher embryo quality, implantation and clinical pregnancy rate than conventional ICSI, which uses a sperm subjectively selected by a scientist.…”

“…2,3 The ZP of immature oocyte has similar biological activity as the ZP of mature oocyte to bind sperm with normal morphology and normal DNA. 15,17 Therefore, the ZP-bound sperm can be prepared using patients' sibling immature oocytes. In patients without immature oocytes collected, it may be worthwhile using one mature oocyte (if .6 oocytes collected) to harvest the ZP-bound sperm.…”