Abstract: Objective To determine the effects of polypeptides of Achyranthes bidentata Blume (ABPP) on neurite growth in cultured hippocampal neurons of rats. Methods The cell activity of rat hippocampal, neurons with ABPP was tested with MTT. After 24 hours of incubation with different concentrations (0.1 mg/L, 0. 5 mg/L, 1.0 mg/L)of ABPP, the hippocampal neurons were photographed by TCS SP2 confocal microscope with fluorescent immunocytochemistry, and the neurite length was analyzed using the Image-Pro Express software. Real-time fluorescence quantitative RT-PCR was performed to examine the mRNA levels of GAP-43 and NF-H after 6 hour with different concentrations of ABPP. Western blotting was performed to further examine the protein levels of GAP-43 and NF-H in cultured hippocampal neurons after 24 hours incubation with different concentrations of ABPP. Results ABPP promoted the neurite growth of cultured hippocampal neurons. Real-time fluorescence quantitative RT-PCR showed that the mRNA level of GAP-43 and NF-H in cultured hippocampal neurons was up-regulated by ABPP in a dose dependent manner. Meanwhile, fluorescent immunocytochemistry and Western blotting showed that the protein level of GAP-43 and NF-H were up-regulated by ABPP. Conclusion ABPP could promote the neurite growth and modulate the expression of GAP-43 and NF-H in cultured hippocampal neurons, which maybe have something to do with ERK pathway.

Key words: Polypeptides ofEM>Achyranthes bidentata/EM> Blume, Hippocampal neurons, GAP-43, NF-H, Fluorescence immunohistochemistry, Realtime PCR, Western blotting, Rat