The sperm DNA fragmentation index (DFI) plays a crucial role in assessing the male infertility in prediction of outcomes in assissted reproductive technology (ART). DNA refers to deoxyribonucleic acid in all living organisms, including sperms, it is a carrier of genetic information.as the name says, sperm DNA fragmentation refers to the amount of genetic damage in the DNA of sperm. Sperm is the powerhouse of genetic materials that are carried to the body of the female. The fragmentation of the sperm DNA fragmentation is one of the leading causes of male fertility. Sometimes, while the motility, quantity and quality of the sperm are fine, failed pregnancy can also be a result abnormal genetic composition of sperm. Some research even suggests that the egg cell or ovum itself has the ability to repair the DNA of the sperm during fertilization but such cases are rare.
FACTORS AFFECTING SPERM DNA FRAGMENTATION :
Though there are no exact causing factors for sperm DNA fragmentation, they are caused most likely by oxidative stress or faulty DNA repair mechanisms. Here are some other factors affecting DNA fragmentation of sperm.
1. DRUG ABUSE
2. OBESITY
3. SMOKING
4. AGEING
5. UNHEALTHY ENVIRONMENT
6. HIGH FEVER
HOW TO PERFORM DNA FRAGMENTATION TEST?
A mere semen analysis is not enough to detect the abnormalities. Specific tests are designed for the same. One of the most commonly used tests is SCSA. SCSA stands for sperm chromatin structure analysis. In this test, the sperm is made to come in contact with a certain chemical dye. If the sperm is broken, its DNA turns red. Similarly, if the sperm is healthy or normal, its DNA turns green. Then the ratio of the red to green sperm cells is calculated with the help of a specially built software and computer. In this way DFI (DNA fragmentation index) is calculated. Some Research shows ICSI improves embryonic developmental potential for sperm samples that display this type of DNA fragmentative production. Reactive oxygen species have a seriously deleterious effect on sperm DNA. They lead to formation of 8-oxo-7, 8-dihydro-2 –deoxyguanosine , the major oxidative product of sperm DNA. This compound causes fragmentation and therefore has a mutagenic effect. During the process of fertilization, factors in the oocyte cytoplasm should theoretically repair any decays in the integrity of sperm DNA. The DNA repair capacity is decreased with age. In the absence of repair, such DNA lesions have profound effects on cell viability and have the potential of oncogenic transformation. Numerous controversial studies have evaluated the efficacy of antioxidants in the treatment of male infertility. The majority agree that these treatments result in only partial success.
HOW TO PREDICT DNA FRAGMENTATION TEST?
1. If the DFI is less than or equal to 15% the results lie between excellent to good.
2. If the DFI is greater than 15% to less than 25%, the results lie between good to fair
3. If the DFI is greater than or equal to 25% to less than 50%, the results lie between fair to poor.
4. If the DFI is greater than or equal to 50%, the results are very poor.
WHAT DOES TESTING FOR SPERM DFI INVOVE AND WHO SHOULD PERFORM DNA FRAGMENTATION INDEX TEST?
There are many different procedures for sperm DNA fragmentation, but most commonly used ones are the sperm chromatin structure assay (SCSA), the single-cell gel electrophoresis assay (COMET), and the sperm chromatin dispersion test (SCD). These tests provide the information approximately about the DNA damage present in a semen sample. Testing the sample for sperm DNA fragmentation index is typically performed at an outside laboratory using a semen sample obtained through ejaculation. Despite many other studies investigating the utility of these DNA fragmentation tests, the 2013 American society for reproductive medicine practice (ASRM) committee opinion concluded that there was no enough data to support a consistent relationship increased DNA fragmentation testing alone can predict pregnancy rates in the context of fertility treatment, and routine testing is not recommended at this time. As always, there are selective population for which this testing would be useful, and a reproductive urologist would be able to determine if this additional information would be helpful in formulating a treatment plan
CAN WE TREAT SPERM DNA FRAGMENTATION?
Given that new sperm is created every 72 days, decreasing exposure to oxidative stress may decrease the degree of sperm DNA fragmentation present. Methods to reduce the oxidative stress:
. varicoceles should be evaluated by a urologist to determine whether surgical repair is necessary.
. Avoid hot tubs and tight-fitting underwear.
. Eat healthful diet, full of fruits and vegetables, and rich in antioxidants. Exercise regularly.
. Avoid Smoking and illicit drugs. Limit alcohol intake. Have a urologist look over your medication list to determine if any medications need to be switched or adjusted.
. Consider the use of supplements containing vitamins and antioxidants.
