Abstract
Abstract: :
Purpose: Ten days after optic nerve axotomy, microglia migrate to the nerve fiber layer. Their arrival is associated with ganglion cell loss. To examine the mechanism of microglial migration and the microglia-ganglion cell interaction, we measured chemokine mRNA in axotomized rat retinas. Method: Retinas were obtained from Lewis rats 3, 7 and 10 days after axotomy and mRNA was isolated from the retinas. The chemokines were examined by reverse transcription-polymerase chain reaction and semiquantiative polymerase chain reaction analysis. The chemokines examined include monocyte chemoattractant protein (MCP)-1, MCP-5, macrophage inflammatory protein (MIP)-1α, MIP-1ß, regulated on activation of normal T-cell-expressed and secreted (RANTES), interferon-γ-inducible protein, 10 kDa (IP-10) and fractalkine. Results: MCP-1, MIP-1α, MIP-1ß, and fractalkine mRNAs were significantly elevated from 3 to 10 days after axotomy (p<0.05). RANTES was significantly elevated 7 days after axotomy (p<0.05). IP-10 tends to elevate 10 days after axotomy . MIP-1ß and RANTES expression peaked 7 days after axotomy. MCP-5 was minimally affected. Conclusion: These results suggest that chemokines, especially MCP-1, MIP-1α, MIP-1ß, RANTES and fractalkine play major roles in the recruitment of microglia to the site of degenerating ganglion cells. The signal for chemokine generation may originate in ganglion cells.
Keywords: 380 cytokines/chemokines • 415 ganglion cells • 470 microglia