Assessment of human sperm DNA integrity using two cytochemical tests: Acridine orange test and toluidine blue assay

Primary infertility affects approximately 15% of couples, with male factor infertility accounting for 50% of cases. Semen samples from 41 patients with asthenoteratospermia and 28 men with proven fertility were analysed according to World Health Organization guidelines. Abnormal sperm chromatin structure was assessed by toluidine blue assay (TBA), and DNA denaturation (DD) was detected by the acridine orange test (AOT). The mean (±SEM) rates of DD and abnormal chromatin structure were significantly higher in infertile subjects compared to fertile group respectively p = .003 and p < .001. A significant correlation was established between sperm DD and abnormal chromatin structure (R = .431, p < .001). Sperm DNA damage correlated significantly with abnormal morphology, sperm motility and necrozoospermia. Our study shows that men with increased levels of abnormal sperm chromatin structure have a high incidence of DNA denaturation and altered semen parameters. These findings suggest that male infertility has been linked to sperm DNA damage.