The role of growth factors in human sperm parameters: A review of in vitro studies

In vitro sperm preparation/incubation and cryopreservation are associated with oxidative stress as the main cause of sperm damage, and different strategies are used to improve sperm quality in in vitro conditions to treat male infertility. Growth factors (GFs) are biological molecules that play different roles in various cellular processes such as growth, proliferation, and differentiation. Many studies have shown that GFs and their receptors are expressed in the male reproductive system. In vitro supplementation of GFs to improve sperm parameters has yielded useful results. There are many studies on the effects of GFs on sperm quality improvement and subsequent assisted reproductive technology results. Hence, this study will review the in vitro results of various GFs including brain-derived neurotrophic factor, nerve growth factor, fibroblast growth factor, insulin-like growth factor I, and vascular endothelial growth factor to improve sperm quality.