Bisphenol A (BPA) and diethylstilbestrol (DES) have been reported to cause sperm toxicity. To identify an earlier marker of toxicity of environmental substances or food additives, this study determined whether the levels of reactive oxygen species (ROS) in sperms could serve as indices for the prediction of sperm toxicity and quality. Male Wistar rats were given drinking water containing various doses of BPA or DES for 8 weeks. Some rats were treated with 0.45% N-acetyl cysteine (NAC) for 2 days prior to the administration of DES or BPA. Administration of BPA or DES to rats for 1 week dose-dependently increased the production of ROS, even at doses and time points which had no effect on sperm motility. 4-Hydroxy-2-nonenal modified proteins increased in sperms 8 weeks after BPA or DES treatment. NAC reversed oxidative stress and prevented the loss of sperm function in the DES or BPA-treated group. During observation, changes in the sperm motility, sperm count and morphology were not correlated to the increase in ROS levels. These results suggest that ROS levels may be used as an early indicator of sperm count and quality decreases which result from chronic toxicity.

We investigated the effect of bisphenol A (BPA) on oxidative stress and tau-related proteins in adult rat brains. BPA (10 mg/L) was administered to rats for eight weeks through their drinking water. The reactive oxygen species (ROS) scavenging capacity for hydroxyl radicals in the plasma was reduced after two weeks. In the hippocampus, four and eight weeks of BPA increased the ratio of oxidized DJ-1/DJ-1 (PARK7). The ratio of phosphorylated-GSK3β/GSK3β and phosphorylated-AKT/AKT increased after one week of BPA treatment. The ratio of phosphorylated JNK/JNK and phosphorylated-ERK/ERK increased after eight weeks of BPA; the elevation could be related to tau phosphorylation. Protein phosphatase 2A (PP2A) in the hippocampus decreased after eight weeks of BPA treatment. At that time, SOD1 was significantly induced, but no changes in SOD2 expression were apparent in the hippocampus. Furthermore, the ratio of phosphorylated-tau (PHF-1, Ser396/ Ser404) to total tau level did not change. However, PHF-1 or other sites of tau could be phosphorylated after eight weeks in the hippocampi of rats. BPA induced systemic oxidative stress and could change ROS-induced signaling pathways in the brain. These results suggest that mitochondrial dysfunction possibly is not responsible for oxidative stress and neurodegeneration due to low doses of BPA.

High-intensity exercise in athletes results in mainly the production of excess reactive oxygen species (ROS) in skeletal muscle, and thus athletes should maintain greater ROS scavenging activity in the body. We investigated the changes in six different ROS-scavenging activities in athletes following high-intensity anaerobic exercise. A 30-s Wingate exercise test as a form of high-intensity anaerobic exercise was completed by 10 male university track and field team members. Blood samples were collected before and after the exercise, and the ROS-scavenging activities (OH•, O₂•⁻, ¹O₂, RO• and ROO•, and CH₃•) were evaluated by the electron spin resonance (ESR) spin-trapping method. The anaerobic exercise significantly increased RO• and ROO• scavenging activities, and the total area of the radar chart in the ROS-scavenging activities increased 178% from that in pre-exercise. A significant correlation between the mean power of the anaerobic exercise and the ¹O₂ scavenging activity was revealed (r = 0.72, p < 0.05). The increase ratio in OH• scavenging activity after high-intensity exercise was significantly greater in the higher mean-power group compared to the lower mean-power group (n = 5, each). These results suggest that (i) the scavenging activities of some ROS are increased immediately after high-intensity anaerobic exercise, and (ii) an individual’s OH• scavenging activity responsiveness may be related to his anaerobic exercise performance. In addition, greater pre-exercise ¹O₂ scavenging activity might lead to the generation of higher mean power in high-intensity anaerobic exercise.