The influence of Saw palmetto extract on immune function in GL261 glioma

Objective To investigate the effect of saw palmetto extract (SR) on GL261 glioma in rats and immune system. Methods The 40 rats were divided into 4 groups randomly, one was the control group without tumor (n=10), the other 30 rats were given subcutaneous inoculation of tumor cells and then divided into 3 groups: tumor-bearing group (n=10), low dose SR group (n=10), and high dose SR group (n=10). After 1 weeks feeded, the rats of SR groups were given the saw palmetto extract, low dose group 50 mg/kg once a day every other day and 300 mg/kg of high dose group every other day. The tumor-bearing groups received the same dose of distilled water. After 4 weeks feeding, we measured the tumor weight and the inhibition rate was calculated. The tumor cell apoptosis was detected by TdT mediated dUTP nick-end labeling (TUNEL) staining. The splenic T lymphocyte proliferation was tested by methyl thiazolyl tetrazolium (MTT). Results ⑴ The SR groups compared to tumor group, the tumor weight was significantly reduced (F=62.678, P=0.000). The tumor inhibition rate was significantly higher in high dose group. ⑵ The apoptosis of tumor cells in tumor-bearing group was significantly less than SR groups and the apoptosis was significantly increased after treatment with SR , especially in high dose SR group(F=1.287E3, P=0.000). ⑶ Compared to SR groups and control group, T lymphocyte proliferation of tumor-bearing group reduced obviously. After treated with SR, T lymphocyte proliferation significantly increased and was higher in high-dose group (F=103.565, P=0.000). Conclusions Saw palmetto extract can activate T lymphocytes and induce apoptosis to tumor cells. Its function was related to SR concentration. Key words: Plant extracts /PD; Glioma/IM/DT