Lentiviral-mediated growth-associated protein-43 modification of bone marrow mesenchymal stem cells improves traumatic optic neuropathy in rats

The aim of the present study was to examine the effect of growth-associated protein-43 (GAP-43) on bone marrow mesenchymal stem cell (BMSC) differentiation in a rat model of traumatic optic neuropathy (TON). GAP-43 and short hairpin (sh)RNA-GAP-43 were inserted into pGLV5 and pGLV3 lentiviral vectors, respectively. The stable control, GAP-43-overexpression and GAP-43-knockdown cell lines (GFP/BMSCs, GAP-43/BMSCs and shGAP-43/BMSCs, respectively) were established. The expression of GAP-43, neuron-specific enolase (NSE), nestin, neurofilament (NF), neuron-specific nuclear-binding protein (NeuN) and βIII-tubulin were detected in the GAP-43/BMSCs and shGAP-43/BMSCs with retinal cell-conditioned differentiation medium using semi-quantitative polymerase chain reaction (PCR), western blotting and cell immunofluorescence. In addition, the BMSCs were observed under fluorescence microscopy. The Sprague-Dawley rat models of TON were established and identified by retrograde labeling of retinal ganglion cells (RGCs) with fluoroGold (FG). The lentiviral-mediated GAP-43-modified BMSCs were then transplanted into the rat model of TON. The expression of GAP-43 was detected in the retinal tissues using qPCR and western blotting. The histopathology of the retinal tissues was observed using hematoxylin and eosin (H&E) staining. The GAP-43/BMSCs exhibited positive expression of NSE, NF, nestin and βIII-tubulin, and exhibited a neuronal phenotype. The shGAP-43/BMSCs markedly inhibited expression of NeuN, NSE, NF, nestin and βIII-tubulin induced by retinal cell-conditioned differentiation medium. The FG staining revealed that the number of labeled RGCs were significantly decreased in the TON model rats, compared with normal rats (P<0.05). The H&E staining revealed that the degree of pathological changes was improved in the GAP-43/BMSC group, compared with the GFP/BMSC and shGAP-43/BMSC groups. In conclusion, GAP-43 promoted BMSC differentiation into neuron-like cells, and intravitreally injected GAP-43/BMSCs promoted the process of nerve repair in a rat model of TON.