Fig. 7

Model describing how obesity induces sperm infertility. During the process of sperm maturation in the epididymis, the sperm function can be modulated by changes in the expression levels of exosomes, which are mainly secreted by the EECs lining the lumen of caput epididymis. Obesity can alter the epididymal microenvironment by increasing the OS and ROS generation. Such changes upregulate the stress-induced ER response in the EECs. Furthermore, ER stress can alter the quantities and contents of the exosomes in the epididymal fluid which may affect the sperm function, finally leading to male subfertility or infertility