ABSTRACT
The aim of the present study was to investigate the putative role and underlying mechanisms of insulinlike growth factor 1 (IGF1) in mediating neuroplasticity in rats subjected to partial dorsal root ganglionectomies following electroacupuncture (EA) treatment. The rats underwent bilateral removal of the L1L4 and L6 dorsal root ganglia (DRG), sparing the L5 DRG, and were subsequently subjected to 28 days of EA treatment at two paired acupoints, zusanli (ST 36)xuanzhong (GB 39) and futu (ST 32)sanyinjiao (SP 6), as the EA Model group. Rats that received partial dorsal root ganglionectomies without EA treatment served as a control (Model group). Subsequently, herpes simplex virus (HSV)IGF1, HSVsmall interfering (si) RNAIGF1 and the associated control vectors were injected into the L5 DRG of rats in the EA Model group. HSVIGF1 transfection enhanced EAinduced neuroplasticity, which manifested as partial recovery in locomotor function, remission hyperpathia, growth of DRGderived spared fibers, increased expression of phosphorylated (p) phosphatidylinositol 3kinase (PI3K) and Akt, and increased pPI3K/PI3K and pAkt/Akt expression ratios. By contrast, HSVsiRNAIGF1 treatment attenuated these effects induced by HSVIGF1 transfection. The results additionally demonstrated that HSVIGF1 transfection augmented the outgrowth of neurites in cultured DRG neurons, and interference of the expression of IGF1 retarded neurite outgrowth. Cotreatment with a PI3K inhibitor or Akt siRNA inhibited the aforementioned effects induced by the overexpression of IGF1. In conclusion, the results of the present study demonstrated the crucial roles of IGF1 in EAinduced neuroplasticity following adjacent dorsal root ganglionectomies in rats via the PI3K/Akt signaling pathway.