Oxidative stress and iron metabolism in human sperm

Abstract

Infertility is a global problem in couples. The decrease in sperm quality and function might be related to intrinsic and extrinsic factors, which ultimately converge on inducing oxidative stress (OS) in male gametes. Seminal plasma (SP) contains a large amount of antioxidants which protect sperm against OS. The iron in semen has a great influence on male fertility. Its transport, celluar uptake and storage depend on Transferrin (Tf), the cell membrane receptor for Transferrin (RTf) and Ferritin (FN), respectively. An isoform found in SP, testicular transferrin (TfT), is essential for spermatogenesis. The objective was to evaluate the antioxidant capacity of metalloproteins in SP involved in iron metabolism. A total of 328 semen samples from patients from the Urology Service of Eva Perón School Hospital (Granadero Baigorria) and Centenario Hospital (Rosario) (n=166) and healthy volunteers (n=162) were studied. Of these participants, 204 met the inclusion criteria. Semen samples were analyzed according to WHO criteria (2010-2021). Measurement of Fe and total proteins was carried out by colorimetric method, FN was measured by immunoturbidimetric method. ELISA technique was used for measuring the Tf concentration in SP. To measure OS we used 3 techniques: MOST test, (TBARs) technique and determination of total nitrite production by colorimetric method. Concentration of nitrites vs TfT showed an inverse relationship (R2=0,921; M= -0,7057; p<0,05). For abnormal MOST values (less than or equal to 0.39), the seminal Tf values were mostly below the mean value found in our population (5 mg/dL). An inverse relationship was seen between lipid peroxidation and TfT. (R2=0,4869; M=-0,0028). Our data suggest that TfT may fulfill an antioxidant role in the testis. It is necessary to study a greater number of patients and discriminate them by pathology in order to conclude which OS measurement technique is the most appropriate to assess male reproductive function.