Chronic Stress Induces Testicular Oxidative Damage Affects Rat Reproductive Behavior

Objectives: The psychological impact caused by social pressure has become the main factor affecting the decline of male sexual function and loss of libido.Oxidative damage damages germ cells,leading to sperm defects and reproductive dysfunction.Therefore,this study establishes a chronic stress model to research the effects of chronic stress on rat reproductive behavior,ultrastructure of testis cell and oxidative damage,to explore the mechanism of chronic stress causing reproductive dysfunction in rats.Methods: 24 six-week-old male Sprague-Dawley rats were randomly divided into control group and stress group.The chronic stress model was established in the control group and the chronic psychological stress group to give rats 5 weeks chronic unpredictable stress.The weight gain and open field experimental behavior indexes of rats in the chronic stress group and the control group was used to test whether the chronic stress model was successfully established.Sexually motivated behaviors are detected by a preference behavior detection device,and sexual mating behaviors are detected by the contact response of rats and female rats to explore whether the animal’s reproductive behavior is affected by chronic stress.After the behavior tests,hematoxylin-eosin staining and transmission electron microscopy were used to further study the changes in testicular cell structure.Further,the level of oxidative stress in testicular tissue was analyzed by detecting superoxide dismutase,catalase,nitric oxide synthase,nitric oxide and malondialdehyde in testicular tissue.Results:(1)Chronic stress caused male SD rats to lose weight gain,reduce their activity in the center of the open field.The chronic psychological stress rat model was successfully established.(2)Chronic stress leads to a decrease in the scores of male rats’ preference for female rats in estrus and female rats between estrus,a decrease in approaching behavior to female rats,and a weakened sexual desire.During sexual mating behavior,the duration of male rats’ proximity to female rats decreases and mating ability is weakened.(3)In the chronic stress group,the testicular tissue cell structure of rats is loose,the number of cell layers is significantly reduced,the order is disordered,the number of sperm in the cavity is reduced,the number of cells in the middle layer is significantly reduced,and the distribution is uneven.(4)Chronic stress causes swelling of the mitochondria of mesenchymal cells,supporting cells,and spermatogenic cells,damage to the mitochondrial cristae structure,and vacuoles.Among them,spermatogenic cells are the most damaged under chronic stress.(5)Chronic stress leads to the increase of nitric oxide synthase,nitric oxide,and malondialdehyde content in the testis tissues of rats.Conclusion: Chronic stress is one of the reasons that induce reproductive behavior disorder in male rats,and this reproductive behavior disorder may be related to the oxidative damage of testicular tissue.