Chemokine mRNA expression in the cauda equina of Lewis rats with experimental allergic neuritis

Chemokines play an important role in the migration of leukocytes to inflammatory sites. In this study, using the quantitative competitive reverse transcriptase PCR method, we analyzed sequential expression of certain chemokine mRNAs in the cauda equina (CE) of rats with experimental allergic neuritis (EAN). Interferon-gamma-inducible protein (IP)-10, monocyte chemotactic protein (MCP)-1, macrophage inflammatory protein (MIP)-1alpha, the regulated upon activation normal T cell expressed and secreted chemokine (RANTES), and lymphotactin were analyzed on days 0 (pre-immunization), 7 (preclinical stage), 10 (disease onset), 13 (clinical progression), 17 (disease peak), as well as on days 20, 24, and 34 post-immunization (p.i.) (recovery). MCP-1 message increased at the preclinical stage and peaked at day 17 p.i. The increase in the early stage was not detected in other tissues, indicating peripheral nerve-specific upregulation. MIP-1alpha and IP-10 messages surged at day 13, then returned to low in the recovery stage. RANTES message increased at day 13 and peaked at day 17 p.i.; however, unlike other chemokines, it showed a second peak of expression on day 24. Lymphotactin message was undetectable at any time point. MCP-1 protein was detected immunohistologically in endothelial cells at day 7 p.i. The sequential expression of these chemokines in relation to the inflammatory process in the nerve leading to demyelination is discussed.