What causes DNA Fragmentation?
Sperm DNA damage may occur by any of these processes
- Apoptosis during formation of sperm cells
- Defective chromatin condensation during maturation of sperm
- Oxidative stress during the transport of sperm cells through the male genital tract.
In men, the major contribution is sperm in fertility. The factors for sperm DNA fragmentation is oxidative stress, which can be associated with one or more of the following:
- Infection
- Pyrexia
- Elevated testicular temperature
- Recreational drugs
- Smoking
- Alcohol
- Stress
- Diet
- Environmental and occupational pollutants
- Advanced chronological age
- Varicocele
How is the test done?
The interior of a sperm cell contains genetic material which mixes with the egg cell DNA for successful fertilization and normal embryo development. If the fertilizing sperm has high DNA fragmentation it may not fertilize with the egg.
In short it may lead to male subfertility, IVF failure and miscarriage. Routinely a semen analysis does not check the percentage of fragmentation in DNA. It requires a special test which can differentiate between normal and fragmented DNA.
A number of sperm DNA fragmentation tests are available at present. These are available at reproductive health hospitals and fertility centers. Some of them are:
- Sperm chromatin dispersion (SCD)
- Single cell gel electrophoresis assay (SCGE) or the comet assay
- Sperm chromatin structure assay (SCSA)
- Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay.