| dc.description.abstract | Round Spermatid Injection (ROSI) is widely considered as an alternative infertility
treatment for men who do not be able to produce mature sperm due to some
reasons related abnormal spermatogenesis (Tanaka, et al., 2018). However, the
successful rate of blastocyst formation which leads to significantly low birth rate
from such procedure is being recorded with unexplained underlying mechanisms
that might be due to abnormal epigenetic modifications based on previous
researches on inbred and hybrid mouse strains (Kishigami S, et al., 2004; Ohta
H, et al., 2009; Ogonuki N, et al., 2011). Nevertheless, study of Round Spermatid
Injection (ROSI) on ICR strain- an outbred mouse species, has not been conducted
yet despite its strong characteristics for oocyte manipulation. Therefore, in this
project, the objective is to establish an effective ROSI system on this mouse strain,
as well as to investigate the preimplantation development of embryos injected
with testicular round spermatids from the zygote to the blastocyst stage in
comparison with Intracytoplasmic Sperm Injection (ICSI) embryos - a control
group. The results indicated that ROSI embryos have similar ability of developing
into blastocysts as ICSI embryos, although the significant lower embryonic cell
number in DAPI stained blastocysts count. Interestingly, the injection of only
round spermatid nucleus resulted in the correlation between pronuclear formation
to the late-stage development in ICSI group was just slightly higher than the
ROSI-generated oocytes, with 93% and nearly 83% in turn. Moreover, DAPI
staining pictures of embryos from both groups showed that round spermatid -
derived oocytes possessed quite similar morphology and nuclei quality as those in
ICSI embryos at various stages in terms of preimplantation developmental
competence. On the other hand, the examination of Histone H3K9 Methylation
expression pointed out the significantly-remaining methylation status of male
pronucleus of ROSI zygotes at 6 hour after activation of injected oocytes which
directly contradicted to the demethylated status in ICSI male pronucleus at the
same time interval. Accordingly, to sum up, in this study, we successfully
established the effective ROSI procedure on ICR mouse strain that generated
similar embryonic developmental competence with other mouse strains.
Additionally, we discovered the remain methylation of ROSI male pronucleus at
the 6-hour zygote stage that possibly affected the abnormal paternal
reprogramming at the preimplantation development of embryos. | en_US |
