DNA Fragmentation
& Sperm Oxidative Damage

In addition to the age of the woman, the male factor plays an equally important role in the cases of karyotypically abnormal fetuses.

DNA Fragmentation & Sperm Oxidative Damage

Apart from the age of the woman, the male factor plays an equally important role in the cases of karyotypically abnormal fetuses. In everyday practice, we encounter cases even with normal parameters of the sperm diagram, where the sperm DNA has lesions that in the literature are largely related to the creation of genetically problematic embryos.
The genetic integrity of the sperm is assessed by the DFI sperm analysis using the Flow Cytometry / TUNNEL assay and is necessary for the development of the normal fetus. The fragmentation of genetic material in the sperm undermines significantly the chance of a successful pregnancy and increases the risk of miscarriage, regardless the way of conception (i.e. naturally or through assisted reproduction), thus causing male infertility. In addition, due to the limited levels of antioxidant defense and a unique, limited mechanism for detecting and repairing DNA damage, sperm is particularly vulnerable to oxidative stress.

The 8–OhdG sperm test allows the calculation of the levels of 8–OHdG (8–hydroxy–deoxyguanosine) which is a by–product of DNA degeneration due to oxidative stress and is detected by flow cytometry inside the sperm. Oxidative stress is a major cause of defective sperm function that causes DNA damage, in addition to fragmentation, and is thus associated with male infertility or miscarriages.

However, according to the above information on the changes in the sperm DNA, it should be taken into consideration that we do not cite these two types of sperm damage as causes of infertility and relapses. It is more practical to consider these lesions as the result of more central causes, such as chronic inflammation of the male genital tract, or habits such as smoking or substance use, or conditions, such as obesity, varicose veins or various endocrine or metabolic diseases. After all, in many cases, these DNA lesions disappear permanently or for long periods. Thus, by measuring the DNA damages, vital information can be taken on whether to proceed to the assisted reproduction or whether these should be corrected first.

Woman’s age must always be considered. After all, we all need to be reminded that the concerned part is the couple and not each individual alone. It should be noted that the role of eggs (ova), in addition to the structural involvement of the zygote is to correct the sperm’s DNA lesions, since mature spermatozoa have reduced DNA repair capacity. We therefore emphasize that the corrective capacity of the eggs (ova) decreases with woman’s age. So, as we can not increase the egg’s repair capacity, we must offer the woman the best possible sperm DNA quality, regardless of the reduced corrective abilities of the female’s gametes. We know that if genetic abnormalities of the zygpte are not corrected, then cell divisions are not promoted and this is another dimension in genetic causes, beyond the pathology of karyotypes.


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