DEFINITION OF SPERM DNA FRAGMENTATION
As the name suggests, sperm DNA fragmentation (SDF), refers to the breaks and lesions in the sperm’s genetic material.
The higher the number of lesions, the lower the integrity of the genetic material and the likelihood of a full term pregnancy.
It is a test that measures the entirety of the genetic material in a semen sample by analyzing fractures or lesions in the DNA chains of sperm.
DNA fragmentation in sperm is inversely proportional to its fertilization capacity, and therefore, the higher the rates of DNA fragmentation in a sperm sample, the lower the individual’s fertilization capacity.
Studies show that, approximately 1 in 4 infertile patients have higher levels of fragmentation and, for those with normal spermogram; the prevalence is approximately 1 in 10. Therefore, fragmentation of the DNA should be considered as an independent parameter and complementary to traditional spermogram and survival tests, which offers specialists’ very valuable additional information when they are offering treatment.
Currently, it has been established that values above a threshold, close to 30% of the DNA fragmentation, indicates that, the individual’s ability to fertilize might be compromised seriously.
Yes, DNA fragmentation levels may vary from one sample to another when it is obtained one or more weeks later.
In some cases, the oocyte may repair the sperm’s DNA damage that fertilized it. It depends on several factors:
• The type of the DNA damage.
• The percentage of the DNA of the affected sperm.
• The quality of the oocyte, since this will depend on whether the DNA damage in the sperm can be repaired or not. This parameter is generally related to the age of the patient.
Some studies indicate that treatment with antioxidants can significantly reduce the levels of DNA fragmentation. Even so, some patients may not respond to treatment, especially when DNA damage is induced by toxic factors or high temperatures that activate sperm caspases and endonucleases.
No, the Spermogram evaluates other parameters of the sperm sample such as sperm concentration, motility and morphology, but it does not take the integrity of the genetic material into account which a sperm DNA fragmentation test does.
The causes are numerous and can be intrinsic or induced by external factors.
Intrinsic factors include:
• Ineffective selection: The production of sperm is localized in the seminiferous tubules (testes) and in some cases, the sperm and their progenitor cells suffer from genetic alterations which result in DNA breaks. These are usually selected and eliminated, but if the mechanism of the selection process fails, sperm appear with the fragmented DNA in the ejaculate.
• Improper maturation: Sperms suffer from a maturation process in the epididymis known as epididymal maturation.
This maturation process involves the packaging of nuclear chromatin and the acquisition of sperm motility. If this process is not done correctly, damage can occur in the sperm DNA.
• Damage induced by radiotherapy/chemotherapy
• Occupational factors/ Radiations
• High fever.
• Higher temperatures.
• Inflammatory disease.
• Post-testicular oxidative stress
This test is recommended in the following cases:
• Idiopathic infertility (of unknown cause).
• After repeated failures of assisted reproduction techniques.
• Cases where poor embryonic quality has been observed.
• Patients who have suffered from repeated miscarriages.
• Men over 45 years of age.
• In cases of sperm freezing (it is verified that the frozen sample has acceptable levels of fragmentation).
• Fever in the last three months.
• Low fertilization rate.
• Genitourinary infections.
• People who smoke and are exposed to toxic substances in the environment.
In order to guarantee maximum reliability of the diagnosis, the sperm sample must be obtained by following these guidelines:
• Observe 24 hours of sexual abstinence, (unless otherwise indicated for low quality sperm samples).
• Place, the sample in a sterile vial.
• Obtain the sample by Masturbation, neither the interrupted coitus nor the use of commercial condoms being valid.
• Respect the hygienic conditions as much as possible, when obtaining the sample (wash your hands beforehand).
• Try that the sample is complete (that nothing falls outside the vial) because, if a large quantity fell outside, the sample would no longer be valid (if only a small fraction fell outside, it wouldn’t matter).
• If you have a fever within 7-10 days of obtaining the semen sample or taking antibiotics, you will need to contact the laboratory to reschedule the appointment.
There are several methods to measure the levels of fragmentation. In our center, we use the TUNEL test, which is the test recommended by the experts in DNA fragmentation studies.
Most fragmentation tests, including the SCSA test and the SCD test, measure the potential damage and susceptibility to DNA denaturalization, and for this, they have a very low level of prediction.
On the contrary, the TUNEL test measures actual damage and has great predictive value in assisted reproduction techniques. Currently, the recommended normality cut value for the TUNEL test is <15%.
To perform the TUNEL test, the sperm reacts with an enzyme, and the sperm with fragmented DNA will either show a light staining by field microscopy or fluorescent green color if observed by fluorescence microscopy.
Are you suffering from any of the above mentioned symptoms then it’s time for you to get the right consultation.
To get rid of all your infertility problems and to fulfill your parenthood dream, visit your nearest Indira IVF centre and get the right treatment.
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