The relationship between sperm DNA fragmentation, free radicals and antioxidant capacity with idiopathic repeated pregnancy loss

Abstract

More than two consecutive miscarriages in less than 20 weeks of gestation is defined as recurrent spontaneous miscarriage. Various causes such as uterine anatomical anomalies, genetic factors, and infectious and endocrine disorders have been reported for RPL. However, approximately 50% of the causes are unknown, which can be due to male factors. Several studies have been done on semen parameters to determine the unknown causes and risk factors for miscarriages, however, only studying common semen parameters have not been sufficient. In this study, the relationship between sperm DNA fragmentation, the amount of free radicals, and total antioxidant capacity (TAC) in semen have been considered as a risk factor for spontaneous miscarriage. Semen samples were collected from 42 men whose partners had a history of spontaneous miscarriage and 42 fertile men as the control group. Volume, pH, viscosity, concentration, and motility of semen, as well as sperm morphology were measured. Sperm DNA fragmentation was analyzed by the sperm chromatin structure assay (SCSA) and TUNEL methods, the amount of sperm free radicals was measured by the luminescence method and the total amount of semen antioxidant was measured using the TAC kit. The results have shown that sperm motility in the experimental group was significantly less than the control group (P = 0.001). The percentage of sperm DNA fragmentation and the amount of free radicals in the experimental group were significantly higher than the control group (P < 0.001). The total amount of antioxidant was lower in the experimental group compared to the control. Spouses of men with lower sperm motility and higher DNA fragmentation had a higher chance of spontaneous miscarriage when compared to the control group. The results of this study support the hypothesis that sperm DNA fragmentation is a major contributor to spontaneous miscarriage. The relationship between SDF, ROS and TAC with RPL.

Keywords: DNA fragmentation index (DFI); Radical oxidative stress (ROS); Repeated pregnancy loss (RPL); Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL); Total antioxidant capacity (TAC).