Effects of Dioxin on DNA Damage in the Testes of Adult Male Mice

Background: Given the importance of environmental factors and the impact of environmental pollutants, such as dioxins, on organ systems, especially the reproductive system, it is necessary to study these issues and the mechanisms of their effects.  Objectives: This study aimed to investigate the effects of different doses of dioxins on DNA damage in the testes of adult male mice.  Methods: In this experimental study, ۳۲ male Naval Medical Research Institute (NMRI) rats were randomly divided into four groups: The control group received normal saline, and the dioxin groups were treated with different doses (۰.۱, ۰.۵, and ۱ µg/kg) for two weeks. Apoptosis in the testes was then examined using a TUNEL assay kit. Results: The mean number of TUNEL-positive spermatogonia cells was ۵.۹۱±۵.۲۸ in the dioxin group ۱, ۷.۲۰±۱۰.۰۳ in the dioxin group ۲, and ۸.۷۳±۴.۶۳ in the dioxin group ۳, which was higher than that in the control group (۰.۱۶±۰.۴۰; P=۰.۰۷۳, P=۰.۰۳۴, and P=۰.۰۰۷, respectively).  The mean number of TUNEL-positive spermatocyte cells was ۵.۱۶±۱.۹۹ in the dioxin group ۱, ۲.۵۰±۴.۶۲ in the dioxin group ۲, and ۳.۳۳±۲.۹۴ in the dioxin group ۳, which was higher than that in the control group (P=۰.۰۳۴, P=۰.۱۴, and P=۰.۰۳۷, respectively).  The mean number of TUNEL-positive spermatocyte cells in the dioxin group ۱ was significantly higher than that in the dioxin group ۲ (۲.۵۰±۴.۶۲, P=۰.۰۴۷).  The average number of TUNEL-positive spermatid cells was ۱۱.۵۸±۶.۹۰ in the dioxin group ۱, ۱۱.۱۰±۱۲.۱۹ in the dioxin group ۲, and ۱۰.۲۰±۷.۳۲ in the ۳-dioxin group, which was higher than that in the control group (۰.۱۶±۰.۴۰; P=۰.۰۰۸, P=۰.۰۱۴, and P=۰.۰۱۵, respectively).  Conclusion: The results of the present study showed that dioxin caused dose-dependent apoptosis in the testes.