Vascular smooth muscle cells (VSMCs) were prepared from thoracic aortas of male Sprague-Dawley rats by the explant method to observe VSMC proliferation via phosphoinositide 3 kinase (PI3K)/Akt signaling transduction pathway induced by apelin-13. Expression of PI3K, phospho-PI3K, phospho-Akt, ERK1/2, phospho-ERK1/2 and cyclin D1 was detected by western blot analysis. Results showed that apelin-13 promoted the expression of phospho-PI3K and phospho-Akt in dose- and time-dependent manner. PI3K inhibitor LY294002 significantly decreased the express...