Teratozoospermia: Its association with sperm DNA defects, apoptotic alterations, and oxidative stress

Abstract

This study was carried out to evaluate the level of nuclear sperm DNA damage in men with isolated polymorphic teratozoospermia and examining its relationship with apoptosis and oxidative stress. A total of 89 subjects were divided into two groups: men with isolated teratozoospermia (n = 69) and men with normal semen parameters (n = 20) as controls. Sperm DNA breaks were determined by using acridine orange staining. The proportion of viable spermatozoa with mitochondrial transmembrane depolarization was detected by fluorescence microscopy through the use of MitoPTJC-1 staining method. Bivariate Annexin V/6-CFDA analysis was then set out in order to measure the percentage of both viable and dead spermatozoa with phosphatidylserine (PS) externalization. Seminal antioxidant profile (reduced glutathione (GSHr); oxidized glutathione (GSSG); glutathione S-transferase (GST)) and total protein sulfhydryl (P-SH) concentrations were measured spectrophotometrically. Men with isolated teratozoospermia, when compared to controls, showed significantly increased level of single sperm DNA breaks and higher proportions of spermatozoa with phosphatidylserine externalization and mitochondrial depolarization. Among the differently studied oxidative stress seminal parameters, the rates of seminal GSHr, GST, and P-SH were significantly decreased in the teratozoospermic group. However, the seminal rates of GSSG and GST have decreased, but only GST did not show a significant difference. Interestingly, significant correlations were found between the studied apoptotic markers and the rate of atypical sperm forms with the incidences of head abnormalities. Furthermore, positive inter-correlations were found between sperm DNA defects, impaired seminal antioxidant status, and the apoptotic sperm markers. Such data provide clear evidence that the apoptotic alterations are closely correlated to abnormal sperm morphology and DNA damage. Moreover, decreased seminal antioxidant profile may be a crucial factor involved in the mechanism of sperm cell death-mediated DNA breaks in teratozoospermic semen.

Keywords: DNA damage; mitochondrial depolarization; phosphatidylserine externalization; seminal antioxidant status; teratozoospermia.