Effect of extract of ginkgo biloba leaves on proliferation of SCs cultured in vitro

OBJECTIVE: To investigate the effect of extract of ginkgo biloba leaves (EGb50) on the proliferation of SCs cultured in vitro. METHODS: The SCs were isolated from 3-day-old SD rats' sciatic nerves by the method of enzyme gradation digestion (n=20) and the purified 2nd passage of SCs were divided into 2 groups: the experimental group, in which SCs were cultured in FBS-DMEM medium with EGb50 (terminal concentration: 50 microg/mL); the control group, in which SCs were cultured in the FBS-DMEM medium without EGb50. The absorbance (A) value was detected by the 2, 3-bis- (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) method 1, 3, 5, 7 and 9 days after culture, then the growth curves was drawn. Cell cycle was detected by flow cytometry (FCM). Disintegration per minute (DPM) of SCs was detected by the method of 3H-thymine nucleoside (3H-TdR) 2 and 3 days after culture and nerve growth factor (NGF) synthesis in SCs culture media was detected by ELISA method. RESULTS: Most SCs were spindle-shaped with a purity above 90%. XTT detection showed that A value of SCs in the control group was gradually increased 3 days after culture, reached the peak 5 days after culture and gradually decreased from then; the A value in the experimental group experienced the similar changes, but it was higher than that in the control group at each time point (P < 0.01). 3H-TdR showed that the DPM of the experimental group was 1 961.78 +/- 231.13 and 4 601.51 +/- 605.08 at 2 and 3 days after culture, while for the control group, the A value was 1347.15 +/- 121.57 and 3740.42 +/- 158.73 at the same time point, indicating a significant difference between two groups (P < 0.01). FCM observation indicated that the SCs proliferation index of the experimental group and the control group was 18.6% +/- 3.2% and 9.7% +/- 2.9%, indicating a significant difference between two groups (P < 0.01). ELISA observation showed that the NGF concentration in the experimental and the control group was (0.0656 +/- 0.0039) ng/mL and (0.0386 +/- 0.0036) ng/mL, indicating a significant difference (P < 0.01). CONCLUSION: EGb50 is capable of enhancing the proliferation of SCs cultured in vitro, which may be one of the important mechanisms to promote peripheral nerve regeneration.