Distinct expression of Tim-3 during different stages of rat experimental autoimmune neuritis

Experimental autoimmune neuritis (EAN) is a well-known animal model of human demyelinating polyneuropathies and is characterized by inflammation and demyelination in the peripheral nervous system. Tim-3 had been identified as a Th1-specific marker negatively regulating autoimmunity or inflammatory diseases. Here we have studied by immunohistochemistry the spatiotemporal accumulation of Tim-3(+) cells in sciatic nerves of EAN rats, particularly focusing on its association with alternatively activated macrophages. Our results showed that time course of Tim-3(+) cell accumulation correlated positively with disease progression of EAN; but distinct major cellular resources of Tim-3 were observed at different disease stages of EAN: during the early phase of EAN, the main cellular resource were T cells, but at the peak and during recovery phase of EAN, Tim-3 was mostly expressed on CD68(+) macrophages or CD163(+) cells. Further investigation suggested that accumulation of CD163(+) cells, particularly their relative abundances to activated macrophages at different time points, were in accordance with the recovery from EAN. Therefore, Tim3(+) cells might include a distinct macrophage population, which may be involved in anti-inflammatory effect and recovery from EAN.