Fragmentation of sperm DNA. Is there a connection with basic sperm parameters and age?
Introduction. TStandard sperm examination, performed according to WHO guidelines, remains the main method of assessment of male fertility. At the same time, this research method has a number of significant limitations, including a low predictive value regarding the outcomes of assisted reproductive technologies (ART) programs and the outcome of naturally occurring pregnancies. The limitations of standard sperm examination dictate the need for additional methods for assessing male fertility. The most promising and widely used test is the assessment of the level of sperm DNA fragmentation. Aim. To evaluate the associations between the levels of sperm DNA fragmentation and the age of the patients along with the following parameters used as a part of standard sperm analysis: semen volume, total number of spermatozoa, percentages of progressively-mobile, non-progressively-mobile and immobile forms, percentages of morphologically normal forms and the forms bearing head defects within the structure of total number of morphological anomalies, as well as semen leukocyte count. Materials and methods. Study materials were the examination results from 121 males aged from 21 to 53 years old (mean age 32.7±4.5 years old), undergoing an examination within the Clinical Institution «Mother and Child - Yaroslavl» during a time period from January 2019 until April 2020. Standard sperm analysis procedures were carried out according to latest edition of WHO Guidelines (2010). The determinations of germ cell DNA fragmentation levels were performed using the TUNEL method. Results. The test results have revealed a weak negative relation between the sperm DNA fragmentation (%) and the percentage of progressively-mobile forms (%) - r = -0.26 (p <0.01). The correlation of sperm DNA fragmentation with age and other parameters was considered statistically insignificant. The second stage of the analysis have demonstrated that the increased degree sperm DNA fragmentation is 1.8-fold more often found in the patients having signs of astenozoospermia (23.6%) comparing to the patients showing normal degree of spermatozoa mobility (13.1%), (p <0.05). Conclusions. The level of sperm DNA fragmentation correlates with the percentage of progressively-mobile forms of spermatozoa (negative relation) and no correlations were found with other semen parameters and with the age. The rates of increased levels of sperm DNA fragmentation are 1.8-fold more often found in as-tenozoospermia patients comparing to the patients showing normal degrees of spermatozoa mobility.