In vitro and in vivo effects of Ginkgo biloba extract EGb 761 on seeded Schwann cells within poly(DL-lactic acid-co-glycolic acid) conduits for peripheral nerve regeneration

This study investigated the effects of Ginkgo biloba (EGb 761) extract on seeded Schwann cells within poly(DL-lactic acid-co-glycolic acid) (PLGA) conduits by in vitro and in vivo trials for peripheral nerve regeneration. The seeding efficiency of Schwann cells in serum-deprived culture medium, which simulated the environment of mechanical trauma on an injured nerve site, was improved by adding different dosages of EGb 761 (0,1,10,20,50, 100, 200 mug/mL). The analytical results showed enhanced cell attachment and survival, reduced LDH release and increased MTT values, particularly in the range 10-100 mug/mL. The PLGA nerve conduits, seeded with Schwann cells (6x10(3) cells) and filled with gelatin containing EGb 761 (0,10,50, 100 mug/mL) were implanted to 10-mm right sciatic nerve defects in rats. Autograft; was performed as another control. Electromyography was assessed based on the motor unit action potential (MUAP) and fibrillation potential (Fib) at 2, 4, and 6 weeks during all periods. The specimens of the experimental and control groups were harvested for histological analysis at 6 weeks after surgery. The Fib was found to gradually decay, and the MUAP was found not to be present until 4 weeks after surgery. Meanwhile, the experimental groups were all statically better than the control group (without EGb 761) and autografts were observed at 6 weeks, especially at the concentration of 10 mug/mL, where there was higher amplitude of MUAP and a significantly larger number of myelinated axons. This study concluded that a proper concentration of EGb 761 (10-50 mug/mL) promoted seeding efficiency of Schwann cells in a tissue-engineered PLGA conduit. Addition of EGb 761 in Schwann cells-seeded conduit could increase the total number of myelinated axons in nerve regeneration and improve peripheral nerve functional recovery.