The protective effects of Achyranthes bidentata polypeptides in an experimental model of mouse sciatic nerve crush injury.

We have separated the active polypeptides from aqueous extracts of Achyranthes bidentata Blume (ABPP), a commonly prescribed Chinese medicinal plant with a range of pharmaceutical properties. We investigated the effects of ABPP administration on peripheral nerve regeneration in a mouse sciatic nerve crush injury model. After nerve crush, the mice received daily tail vein injections of 1, 4, and 16 mg/kg of ABPP, 65 microg/kg of methylcobalamin, and vehicle saline, respectively, over a 21-day period. At 1, 3, 6, 9, 12, 15, 18 and 21 days after nerve crush, the animals were subjected to walking track analysis for evaluating the sciatic functional index (SFI) values. At day 21 the animals were anesthetized, and the compound muscle action potential and nerve conduction velocity were respectively recorded. After the animals were killed, the sciatic nerve was examined with immunohistochemistry and electron microscopy, and gastrocnemius muscle was analyzed with Masson trichome staining. The results indicated that treatment with ABPP at a dose range (1-16 mg/kg) promoted histological regeneration and functional recovery of the injured sciatic nerve and its target muscle, yielding a desired efficacy greater than that by vehicle treatment and close to that by methylcobalamin (65 microg/kg). These findings suggest that plant polypeptides, ABPP, may be a potential agent in ameliorating of neuropathy caused by sciatic nerve crush.