Scientists have found that sperm DNA from the testicles of many infertile men is as good as that of ejaculated sperm of fertile men. This may explain a major cause of male infertility and opens the possibility of using sperm taken directly from the testicles of these men; to overcome their infertility. Infertility is a major public health issue.
For decades, fertility testing for men has relied almost solely on a basic semen analysis, which examines sperm concentration, morphology and motility. This suggests that a semen analysis is inadequate when it comes to evaluating male fertility potential. More recently, there is a growing recognition of the need for better sperm quality testing.
A spermatozoon joins an ovum to form a zygote. A zygote is a single cell, with a complete set of chromosomesthat normally develops into an embryo. Sperm cells contribute approximately half of the nuclear genetic information to the diploid offspring excluding, in most cases, mitochondrial DNA. In mammals, the sex of the offspring is determined by the sperm cell: a spermatozoon bearing a X chromosome will lead to a female XX offspring, while one bearing a Y chromosome will lead to a male XY offspring.
Sperm DNA integrity is vital for successful fertilization, embryo development, pregnancy, and transmission of genetic material to the offspring. DNA fragmentation is the most frequent DNA anomaly present in the male gamete that has been associated to poor semen quality, low fertilization rates, impaired embryo quality, and preimplantation development and reduced clinical outcomes in assisted reproduction procedures. This work summarizes the causes of fragmentation in the spermatic DNA, and its relation with seminal parameters, male aging, and results in assisted reproduction procedures.
Conventional semen analysis only studies spermatozoa concentration, motility and morphology. It is an incomplete study, as it omits analysis of one of the most important parameters, the integrity of the DNA molecule. In this way, normal spermatozoa create halos formed by loops of DNA at the head of the sperm, which are not present in those with damaged DNA.
Skip to main content. A study published in Clinical Chemistry earlier this month has linked sperm with more DNA damage to repeated miscarriages. Recurring miscarriages, defined as three or more consecutive miscarriages before 20 weeks of pregnancy, occur in percent of couples.
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