g(m1)-ganglioside and Peripheral-Nerve-Injuries

Nerve growth factor (NGF) is widely used for repairing peripheral nerve injury because of its capability in dominating the survival, migration, proliferation, and differentiation of nerve cells. Monosialoganglioside (GM1), as another kind of nerve growth factor, works for regulating NGF function. In this study, GM1 and NGF were incorporated into the Poly(l-lactic acid-co-ε-caprolactone)/silk fibroin (PLCL/SF) nanofibers by the coaxial electrospinning. The fibers morphology and core–shell structure were characterized by SEM and TEM. The scaffolds demonstrated high tensile stress with good flexibility. In vitro cell viability studies indicated that the scaffolds incorporating both GM1 and NGF played a synergistic effect to enhance Schwann cells (SCs) proliferation and Pheochromocytoma (PC12) cells differentiation, in comparison to the scaffolds only incorporating NGF. Subsequently, the nanofibrous conduit scaffolds (NCSs) were evaluated in vivo in a rabbit sciatic nerve defect model. The NGF/GM1 incorporated NCSs group performed better nerve function recovery than single incorporated group, in consideration of the compound muscle action potential (CMAP) and nerve conduction velocity (NCV) results. Furthermore, hematoxylin and eosin (H&E) staining, toluidine blue (TB) staining, and transmission electron microscope (TEM) analysis displayed better nerve regeneration of NGF/GM1 incorporated NCSs both quantitatively and qualitatively. Therefore, the results indicated the dual neurotrophins-incorporated NCSs had potentials for the application in peripheral nerve repairing.

Topics: Animals; Electrochemical Techniques; G(M1) Ganglioside; Male; Nanofibers; Nerve Growth Factor; Nerve Regeneration; PC12 Cells; Peripheral Nerve Injuries; Rats; Schwann Cells; Sciatic Nerve; Tissue Scaffolds

1. Three-dimensional spatial patterns of changes in membrane-bound protein kinase C (PKC) were examined in the lumbar spinal cords (L1-L5) of rats with an experimental painful peripheral mononeuropathy. Painful peripheral mononeuropathy was produced by loosely ligating the rat's common sciatic nerve, resulting in chronic constrictive nerve injury (CCI). Changes in spinal cord membrane-bound PKC distribution were assayed by employing an established quantitative [3H]-phorbol-12,13-dibutyrate ([3H]PDBu) autoradiographic assay, which includes spinal cord sectioning, incubation of spinal cord sections with [3H]PDBu, production of autoradiographs, and computer-assisted image processing. 2. Sciatic nerve ligation induced demonstrable thermal hyperalgesia in response to radiant heat stimulation and spontaneous pain-related behaviors (such as lifting of the nerve-ligated hind paw) in CCI rats 3, 7, and 10 days after unilateral sciatic nerve ligation. 3. Consistent with behavioral changes, CCI rats examined 3 or 10 days after sciatic nerve ligation displayed a three-dimensional pattern of increased membrane-bound PKC in the lumbar spinal cord (L1-L5) strikingly different from that of sham-operated rats: in the dorsoventral dimension, reliable increases in membrane-bound PKC occurred mainly within spinal cord laminae I-IV and V-VI in CCI rats; in the ipsilateral-contralateral dimension, changes in membrane-bound PKC were seen on both sides of the spinal cord in CCI rats with reliably higher levels of membrane-bound PKC on the side ipsilateral than on the side contralateral to sciatic nerve ligation; in the rostrocaudal dimension, increases in membrane-bound PKC in the spinal cord dorsal horns of CCI rats extended from spinal segments L2-L5. 4. Both three-dimensional increases in spinal cord membrane-bound PKC and nociceptive behaviors (thermal hyperalgesia and spontaneous pain behaviors) in CCI rats were reliably reduced after three daily intrathecal treatments with 80 nmol GM1 ganglioside (a glycosphingolipid shown to prevent PKC translocation/activation), the first of which was given 1 h after sciatic nerve ligation. This reduction was seen 24 h but not 7 days after the last GM1 ganglioside treatment. 5. This three-dimensional increase in membrane-bound PKC in the spinal cord dorsal horn of CCI rats displayed high correlations with thermal hyperalgesia and with spontaneous pain-related behaviors in CCI rats observed both 3 and 10 days after sciatic nerve ligation.

Topics: Animals; Autoradiography; Blood Glucose; Deoxyglucose; Energy Metabolism; Functional Laterality; G(M1) Ganglioside; Hindlimb; Image Interpretation, Computer-Assisted; Male; Nociceptors; Pain Threshold; Peripheral Nerve Injuries; Peripheral Nerves; Phorbol 12,13-Dibutyrate; Protein Kinase C; Rats; Rats, Sprague-Dawley; Reaction Time; Sciatic Nerve; Spinal Cord; Synaptic Membranes; Thermosensing

Neuropathic pain following nerve injury is thought to involve central nervous system Ca(2+)-mediated neuronal plastic changes. This study provides evidence that induction and/or maintenance of post-injury neuropathic pain behaviors in the rat is associated with increases in membrane-bound protein kinase C (PKC), a Ca(2+)-dependent process known to mediate central nervous system neuronal plasticity. In addition, spinal cord administration of GM1 ganglioside, an intracellular inhibitor of PKC translocation/activation, reverses both increased levels of membrane-bound PKC and pain-related behaviors. Thus, persistent post-injury neuropathic pain may be mediated by the initiation of excitatory neuropathological processes resulting from an increase in membrane-bound PKC.

Topics: Animals; Behavior, Animal; G(M1) Ganglioside; Pain; Peripheral Nerve Injuries; Phorbol 12,13-Dibutyrate; Protein Kinase C; Rats; Spinal Cord