Explanation of 'Essence and Blood from the Same Source' in Theory of Chinese Medicine from the Roles of Vascular Endothelial Growth Factor in Spermatogenesis

: 'Essence and blood from the same source', as one of basic theories of Chinese medi- cine (CM), is important for syndrome typing and clinical medication. Vascular endothelial growth factor (VEGF) can be produced and secreted in Leydig cells and Sertoli cells, which can not only promote the formation of new blood vessels, but also regulate synthesis of testosterone and the proliferation and dif- ferentiation of germ cells. The roles of VEGF in the spermatogenesis reveal scientific connotations of 'essence and blood from the same source', and it plays an important role in guiding clinical practice of CM.