Abstract: Objective　To investigate the effect of Puerarin on the expression of iNOS, CGRP and PI3K/Akt signaling pathway in spinal anterior horn following brachial plexus root avulsion injury (BPRAI).  Methods　Fifty SD rats were randomly divided into a normal group, a model group, a low-dose group, a middle-dose group and a high-dose group with 10 rats in each group. BPRAI modeling was made in the model group, low-dose group, middle-dose group and high-dose group by avulsing the anterior roots and transecting posterior roots of right C5~7 segment of spinal nerve. Puerarin was injected intraperitoneally in the low-dose group, middle-dose group and high-dose group after the operation at doses of 50, 100 and 200 mg·kg-1·d-1 respectively. The normal group and model group were given intraperitoneal injection of saline of equal volume for 4 weeks. Nissl staining, immunofluorescence and Western blot were used to observe the survival rate, the expression of iNOS and CGRP of alpha motorneurons (α-MNs), and PI3K/Akt pathway related proteins in the spinal cord on the injured side.    Results    At the 4th week, low, middle and high doses of Puerarin could inhibit the loss of α-MNs (P<0.05 or P<0.01); middle and high doses of Puerarin could inhibit the expression of iNOS (P<0.05); high doses of Puerarin could significantly promote the expression of CGRP protein (P<0.05 or P<0.01); low, middle and high doses of Puerarin could significantly inhibit the expression of p-Akt1/2/3 (P<0.01).  Conclusions    Puerarin can ameliorate the death of alpha-MNs induced by BPRAI. The protective effect of Puerarin may be related to its inhibition of iNOS expression and promotion of CGRP expression, and PI3K/Akt signaling pathway is involved in its regulation.

Key words: Puerarin; ,  Brachial plexus root injury; ,  Alpha motorneurons; ,  iNOS; ,  CGRP; ,  PI3K/Akt