Roles of fibrin deposition and protease activated receptor-1 in renal cytokine/chemokine production and inflammatory cell infiltration in rats of different ages

The present study aimed to investigate the roles of fibrin deposition and protease activated receptor-1 (PAR-1) in renal cytokine/chemokine production and inflammatory cell infiltration in rats of different ages. Acute inflammation was induced by lipopolysaccharide (LPS) in rats which were then treated with tranexamic acid (TA), TA+urokinase (UK) or TA+low-molecular-weight heparin (HP). Fibrin deposition, inflammatory cells and expressions of PAR-1, monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule 1 (ICAM-1) were detected. A reduction in fibrin deposition and PAR-1 expression in the LPS+TA+HP group was associated with decreased infiltration of inflammatory cells and down-regulated expressions of MCP-1 and ICAM-1. In the LPS+TA+UK group, the fibrin deposition, but not the PAR-1 expression, was reduced, However, the infiltration of inflammatory cells decreased and the expressions of MCP-1 and ICAM-1 down-regulated. There were significant differences in the fibrin deposition, infiltration of inflammatory cells and expression of PAR-1, MCP-1 and ICAM-1 between young and old rats undergoing the same treatment. These findings demonstrated that fibrin deposition plays more important roles than PAR-1 dose in cytokine/chemokine production and inflammatory cell infiltration in vivo, and ageing may deteriorate the fibrin deposition-induced production of cytokines/chemokines and infiltration of inflammatory cells.