Objective   To study the effects of grape seed proanthocyanidin extract (GSPE) on the growth and apoptosis of the transplanted tumor of human ovary cancer in nude mice and to explore the implying molecular mechanism.   Methods   A human ovarian cancer model was established by subcutaneously human ovary cancer cell line SKOV3 into nude mice. The 24 mice were randomly and equally divided into 3 groups

the high-dose GSPE group (200 mg/kg

HD GSPE)

the low-dose GSPE group (100 mg/kg

LD GSPE) and the control group (Normal saline). GSPE solution or normal saline was intragastrically given to the mice at 10 mg/kg. Tumor volume and weight were measured. HE staining was used to observe the tumor cells morphology. Apoptosis of the tumor cells was analyzed by flow cytometry (FCM)

semi-quantitative RT-PCR was used to detect the mRNA expressions of Caspase-3 and Bax

and their protein expressions detected by Western blot analysis.   Results   The inhibitory rate in the HD and LD GSPE groups were 34.303% and 28.594% respectively

which was significantly higher than that in the control group (P0.01). The apoptotic rate in the GSPE groups were 67.965% and 24.650% respectively

which were significantly higher than that of the control group (P0.01). Semiquantitative RT-PCR and Western blot analysis showed that the mRNA and protein expressions of Caspase-3 and Bax were both up-regulated in GSPE groups in a dose-dependent manner.   Conclusion   GSPE inhibits the growth of ovarian cancer by inducing tumor cells apoptosis and inhibiting the growth of human ovarian cancer transplanted tumor in nude mice. Increased expressions of Bax and Caspase-3 may be related to the cell growth inhibition and to the apoptosis mediated by GSPE in vivo.