7 research outputs found
Does human sperm nuclear DNA integrity affect embryo quality?
1016-1022Abnormalities in the male genome are a
clear potential reason for post fertilization failure. Male infertility may arise
due to high levels of loosely packaged chromatin and damaged DNA. The achievement
of a correct chromatin packaging level is essential for successful fertilization.
The chromatin contained in the nuclei of mammalian spermatozoa is an
extremely compact and stable structure.
The reports on mammalian spermatozoa indicate that available volume is insufficient
to contain sperm chromatin packed in nucleosoll1e like structure and thus is organized
in a special way. Different unique properties of sperm DNA like high degree of
inertness and stability, absence of transcription, replacement of somatic
histone by protamine etc have made the study
of sperm chromatin more interesting. Increased levels of sperm nuclear DNA damage
exist in infertile men with abnormal sperm parameters (i .e. concentration, motility
and morphology), and various assay techniques have been developed to evaluate sperm
chromatin maturity/DNA integrity. These assays are based on the facts that defects
in chromatin structure have been shown to lead to increased DNA instability and
sensitivity to denaturing stress. DNA integrity in the sperm is essential for the
accurate and successful transmission of genetic information. Importance of
sperm DNA has also become more obvious in the context of assisted reproductive techniques.
While recent
advances in assisted reproductive
technologies have made possible and practical for many infertile men to become father,
the risk of transmission of genetic mutation to the offspring, however, still remains.
Further research is necessary to devise techniques for identification and
selection of sperm with undamaged DNA for ICSI or to remove sperm with damaged
DNA from the semen sample to improve the pregnancy outcome in ICSI