Objective      To determine the effect of apelin on the proliferation and apoptosis in rat ovarian granulosa cells (GCs) in vitro.       Methods      SD rat ovarian GCs were isolated and primary cultured

and then cultured with apelin at a concentration of 10

-8

mol/L for 12

24 and 48 h respectively

and then tested by MTT assay and flow cytometry (Annexin/PI). RNA interference (RNAi) was used to down-regulate the expression of APJ in GCs. PI3K/Akt inhibitor LY294002 and HIMO were used to determine the role of the signaling pathway. Western blotting was employed to determine the expression of cell a

poptosis-related proteins.       Results      Apelin of 10

-8

mol/L promoted the proliferation and anti-apoptosis in GCs (

P

0.05). Apelin activated the phosphorylation of Akt

while APJ-siRNA

inhibitor LY294002 and HIMO abolished apelin-induced activation of Akt. Western bloting showed that apelin enhancecd the expression of Bcl-2 but suppressed the expression of Bax

Bad

and Foxo3a (

P

0.05). The effects were blocked by APJ-siRNA

inhibitor LY294002 and HIMO (

P

0.05).       Conclusion      Apelin promotes the proliferation and suppresses the apoptosis in GC via the PI3K/Akt signaling pathway.