Male fertility is evaluated by sperm count, motility and morphology. This becomes a part of routine semen analyses. The basic semen analysis may provide useful information regarding male fertility potential. Sperm concentration, motility and morphology have been correlated with fertilization rates as a result of normal development during sperm production in the testes, normal maturation in epididymis and normal seminal plasma constituents. Abnormal sperm quality has been linked to several infertility problems. In certain cases, the initial semen examination can reveal some radical forms of sperm dysfunction, eg. azoospermia or globozoospermia that have serious negative consequences to natural conception. However limitations still exist in finding a cause of male infertility and a normal sperm parameter does not necessarily guarantee satisfactory fertilizing potential. An estimated 15% of men with normal basic semen analysis profiles have nonetheless been associated with infertility. A specialised test of sperm is checking sperm DNA damage measured by DNA fragmentation which may be linked to negative clinical outcomes. Recently there has been growing interest in the use of DNA integrity as a marker of male infertility.
DNA damage may exert its effect at different stages of the reproductive procedure, beginning from the pre-implantation development of the embryo to the achievement and sustaining of pregnancy and finally the creation of healthy offspring. An inverse relationship has been reported between the likelihood of achieving pregnancy either by natural intercourse or by application of ART and the presence of high sperm DNA fragmentation levels. Men with abnormal semen parameters have a higher risk of high levels of DNA fragmentation. Men with infertility have increased levels of fragmented sperm DNA and vice versa. Abnormal chromosome rate which triggers DNA fragmentation is higher in poor quality sperm samples. Research has shown that Sperm nuclear DNA fragmentation has been positively correlated with lower fertilization rates in IVF, impaired implantation rates, an increased incidence of abortion and disease in offspring. For example, a study investigated correlation of fertilization rate with sperm DNA fragmentation in A 85 couples undergoing infertility treatment with IVF/ICSI. The result has shown that fertilization rate was inversely correlated with DNA fragmentation. In addition, the slower embryo development and worst morphology on day 6 was correlated with higher sperm DNA fragmentation. There was a negative correlation between DNA fragmentation and the implantation rate. Analysis from a study including 2969 couples has shown that there was a significant increase in miscarriage in patients with high DNA damage compared with those with low DNA damage.
As mentioned above, sperm DNA damage is a useful biomarker for male infertility diagnosis and prediction of assisted reproduction outcomes. It shows more promise than conventional semen parameters from a diagnostic perspective. Another recent study has shown that it is associated with reduced fertilization rates, embryo quality and pregnancy rates, and higher rates of spontaneous miscarriage and childhood diseases; A study involved in 2,756 couples, 965 pregnancies has also shown that high-level sperm DNA fragmentation has a detrimental effect on outcome of IVF/ICSI, with decreased pregnancy rate and increased miscarriage rate. The analysis by type of procedure (IVF vs. ICSI) indicated that high sperm DNA damage was related to lower pregnancy rates in IVF but not in ICSI cycles, whereas it was associated with higher miscarriage rates in both IVF and ICSI cycles.
Sperm DNA damage is often the result of increased oxidative stress in the male reproductive tract, the potential contribution of antioxidant therapy. Do you know that acupuncture improves sperm quantity and quality? Acupuncture could reduce oxidative damage and is a potential useful therapy to treat sperm DNA damage.
References
Muriel et al Fertil Steril (2006) 85:371-83
Robinson et al HumRepord (2012) 27:2908-17
Zhao et al Fertil Steril (2014) 102:998-1005
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