Effect of 4.25% peritoneal dialysis solution on CD40 expression in rat peritoneal mesothelial cells

AIM:To investigate the effect of 4.25%peritoneal dialysis solution (PDS) on CD40 expression in rat peritoneal mesothelial cells so as to reveal the potential mechanisms by which CD40-CD40 ligand (CD40L) interaction may be involved in the inflammation of peritoneal membrane. METHODS:Rat peritoneal mesothelial cells (MC) were harvested from the peritoneal cavity and maintained under defined in vitro conditions. Expression of CD40 on MC under normal culture or stimulation with 4.25%PDS or 4.25%PDS+IFN-γ was detected by RT-PCR and FACS analyses. After activation of CD40 on MC with CD40 mAb, the expression of intercellular adhesion molecule-1 (ICAM-1) on MC was analyzed by FCAS. RESULTS:MC cultured in vitro expressed CD40 constitutively. 4.25%PDS markedly up-regulated the expression of CD40 mRNA and its protein. The expression of CD40 mRNA and its protein following stimulation with 4.25%PDS+IFN-γ was significantly higher than 4.25%PDS alone. The expression of ICAM-1 on MC was significantly increased after activation of CD40 with CD40mAb.CONCLUSIONS: MC functionally express CD40.The up-regulated CD40 expression on MC fol owing stimulation with 4.25%PDS may play an important role in local peritoneal defense mechanisms and may be involved in the chronic inflammatory process of the peritoneum.