Bo Ram Hwang

Sexual activity counteracts the suppressive effects of chronic stress on adult hippocampal neurogenesis and recognition memory

Adult neurogenesis can be influenced by a variety of factors. Stress is one of the most potent inhibitors of hippocampal neurogenesis. Stress effects on adult hippocampal neurogenesis are affected differently by environmental factors, including social interaction. Sexual behavior between males and females in a social context has been suggested to influence neurogenesis and enhance hippocampal cell proliferation. However, the mechanisms of action of sexual interaction, the possible changes relative to stress state, and its effects on learning and memory remain uncertain. The current study examined the influence of sexual interaction on neurological responses in adult male mice and the function of sexual interaction relative to recognition memory in stress states. Changes in the expression of neurotrophic and transcription factors were assessed in reference to stress and/or sexual behaviors. The survival of newly generated cells and their rate of differentiation into neurons were determined in the hippocampus of chronically stressed and/or sexually experienced mice. Finally, to evaluate whether sexual experience alters adult hippocampal function, we tested learning and memory in a recognition memory task. The results demonstrated that sexual activity increased the expression of brain-derived neurotrophic factor, tyrosine kinase B, and cAMP response element-binding factor. Furthermore, the results supported the view that sexual interaction could be helpful for buffering adult hippocampal neurogenesis and recognition memory function against the suppressive actions of chronic stress.

Protective effect of pterostilbene on testicular ischemia/reperfusion injury in rats

PURPOSE To evaluate protective effect of pterostilbene against testicular ischemia/reperfusion (I/R) injury, which results in increased formation of oxidative stress, leading to testicular apoptosis and impaired spermatogenesis. METHODS Thirty two pubertal male Sprague-Dawley rats weighing 180-220g were selected and randomly divided into the following four groups: group A (normal control group), group B (sham-operated group), group C (induced I/R injury group), group D (induced I/R injury group receiving pterostilbene treatment). Johnsens scores and mean seminiferous tubule diameters were evaluated for histopathologic assessment; germinal cell apoptosis was evaluated by the transferase dUTP nick end labeling (TUNEL) assay and immunohistochemistry for caspases. Malondialdehyde (MDA) levels were assessed as an indicator of oxidative stress and total antioxidant capacity (TAC) was measured. RESULTS Germ cell apoptosis and MDA level significantly increased whereas TAC significantly decreased in group C; moreover, abnormal morphology and impaired spermatogenesis were observed in group C. In contrast, treatment with pterostilbene inhibited lipid peroxidation and apoptosis induced by ROS and restored the antioxidant capacity in group D. CONCLUSIONS These results show that treatment with pterostilbene may be a promising therapy for testicular I/R injury.