Abstract:

BACKGROUND: Astragalus or olfactory ensheathing cell (OECs) transplantation alone can promote survival of various neurons and functional improvement of injured spinal cord. The clinical effect of astragalus in combination with OECs transplantation remains unclear.
OBJECTIVE: To observe the effect of astragalus on the proliferation of OECs and the secretion of neurotrophic factors. 
METHODS: OECs of SD rats, 24 hours old, were isolated and cultured, and identified by immunohistochemistry. OECs at culture day 8 were seeded in polylysine-coated 96-well plate and incubated in 5% CO₂ at 37 ℃ for 24 hours, followed by   2 mg/L, 20 mg/L, 200 mg/L, 2 g/L, 20 g/L astragalus injection for 24 hours. MTT and flow cytometry were used to assess the effects of astragalus in promoting OECs proliferation; enzyme linked immunoassay (ELISA) was used to measure the content of neurotrophic factors. Serum culture medium was served as negative control. 
RESULTS AND METHODS: Compared with the negative control group, 2 and 20 mg/L astragalus injection significantly promoted OECs proliferation (P < 0.05, P < 0.01). The result of flow cytometry showed that astragalus could promote OECs in G1 stage and reduce the percentage of cells in S and G2 stages, but the difference was not significant (P > 0.05). However, astragalus injection at each mass concentration significantly reduced the number of OECs (P < 0.05). Moreover, 2 mg/L astragalus injection significantly promoted in vitro neurotrophic factor levels in OECs. Results show that astragalus injection in combination with OECs can promote recovery of spinal cord injury.