The benzene impact on programmed death of sperm cell

Introduction. Benzene and its derivatives enter organism from the natural environment are the sources of constant health danger, including reproductive system disorders. 

Purpose of the study. In vitro study of the modifying effect of benzene on the indices controlling the apoptosis of sperm cells.

Materials and methods. The study includes data on 27 men from 41 to 51 years of age, apparently healthy, not in contact with harmful factors, and living in relatively favourable conditions. Using flow cytometry in the ejaculated semen, we determined CD25⁺ and CD95⁺ markers, p53, bax, caspase-3 activity, percentage of AnnexinV-FITC⁺PI^–, and AnnexinV-FITC⁺PI⁺-spermatozoa. The seminal fluid samples were incubated with benzene at a concentration of 0.001 µg/ml (experimental samples) for 72 hours at 37°C to evaluate the effect of aromatic hydrocarbons on the indices controlling the apoptosis. Sperm samples incubated under identical conditions without benzene addition were used as control samples.

Results. p53 content, caspase-3 activity, and the number of dead male germ cells (AnnexinV-FITC⁺PI⁺-spermatozoa) were found to decrease statistically significantly (p=0.023–0.026) in experimental semen samples after the addition of benzene (by 50% of the initial levelon average). At the same time, the addition of benzene to the ejaculated semen samples did not change the early activation profile of gametes (according to CD25⁺ criteria), cells readiness to start FAS-dependent apoptosis (CD95⁺), and the number of spermatozoa marked for death by apoptosis (AnnexinV-FITC⁺PI^–-spermatozoa). 

Conclusion. The results of immunological testing demonstrated that in vitro system benzene inhibits apoptosis and interferes with gamete life cycle . On the example of benzene, it was been demonstrated that haptenic contamination could alter sperm fertility associated with an imbalance of proapoptotic factors and impair ed male reproductive system function. The indices of programmed cell death bax, p53, caspase-3, CD25-positive, FAS-positive, AnnexinV-FITC⁺PI^–-sperm, and AnnexinV-FITC⁺PI⁺-sperm in the ejaculate are recommended for diagnosis and monitoring of sperm fertility disorders.

Contribution:

Dolgikh O.V. — research concept and design, editing;

Dianova D.G. — research concept and design, text writing;

Alikina I.N. — collection and processing of the material;

Krivtsov A.V. — statistical processing.

All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.

Conflict of interest. The authors declare no conflict of interest.

Acknowledgement. The study had no sponsorship. The work was carried out on the topic from the Research Plan of the Federal State Budgetary Institution "Federal Research Center for Medical and Preventive Technologies of Public Health Risk Management" "Study of reproductive disorders in men associated with exposure to harmful and hazardous production factors and substantiation of molecular genetic markers for their diagnosis", No. НОКР AAAAA-A20-120080790015-5.

Received: July 27, 2021 / Accepted: September 28, 2021 / Published: October 31, 2021