Properties of macrophages and lymphocytes appearing in rat renal fibrosis followed by repeated injection of cisplatin

Abstract

ABS TRACT. Properties of macrophages and lymphocytes appearing in renal fibrosis remains to be investigated. F344 rats were injected once a week with cisplatin (2 mg/kg body weight) for 8 weeks and examined at post-final injection weeks 1, 3, 6, 9, and 12. Rats developed progressive renal fibrosis at weeks 1 to 6 as fibrosis-progress phase, and subsequent amelioration at weeks 9 and 12. CD68 + M 1-macrophages and major histocompatibility complex (M HC) class II + macrophages remarkably increased persistently, whereas CD163 + M 2-macrophages slightly increased. M HC class II + /CD68 + and MHC class II + /CD163 + macrophages were present, indicating that M HC class II + macrophages might have both functions of M 1-and M2-macrophages. In the fibrosis-progress phase, interleukin (IL)-6, tumor necrosis factor (TNF)- and interferon (IFN)- for M 1-factors, and transforming growth factor (TGF)-1 and IL-10 for M 2-factors tended to increase; tissue injury by M 1 and fibrosis by M2 might have occurred simultaneously. Lots of CD4 + and CD8 + T cells appeared in close relation with M HC class II + macrophages, and mainly CD4 + T cells formed aggregations. In the lymphocyte aggregates collected by laser microdissection, expression of IL-17A (for Th17 cells) and forkhead box P3 (FoxP3) (for Treg) significantlyincreased at weeks 1 and 6, respectively; presumably, Th17 cells might be involved in tissue injury, whereas Treg might be related to fibrosis amelioration. These results suggested that macrophages and T cells may contribute interrelatedly to renal fibrosis.