Objective: To assess effects of hyperosmolarity, high glucose concentration, and low pH with or without lactate sodium at the level of antioxidant mechanisms, such as the concentration of total intracellular glutathione (GSH/GSSG), the activity of catalase (CAT) and total superoxide dismutase (SOD) in mesothelial cells (MC) in vitro.
Methods: HPMC were obtained from omentum from nonuremic donors. The effect of pH (5.2-7.3) with or without sodium lactate (35 mM/L) was tested in Earle's salt after 30 min exposure, whereas the osmotic and metabolic effects of glucose, glycerol, mannitol, and amino acids were studied in a medium with 10% FCS after 4, 24, 72 and 104 h of exposure. The activity of antioxidant mechanisms was determined by spectrophotometry.
Results: In the cells exposed to Earle's salt pH 5.2 with lactate, the GSH/GSSG level, and CAT and SOD activity were substantially reduced. After 4 h of exposure, glycerol, glucose and mannitol increased the GSH/GSSG content in MC; after 24 h only glucose slightly increased the GSH/GSSG level.
Conclusion: We conclude that although low pH with high lactate concentration decreased the activity of all studied antioxidant mechanisms in MC, the clinical relevance of these observations needs to be studied further.
Abbreviations: MC - mesothelial cells; GSH/GSSG - total intracellular glutathione; CAT - catalase; SOD - superoxide dismutase; FCS - fetal calf serum; PD - peritoneal dialysis.
key words: peritoneal dialysis, inflammation, mesothelial cells, osmotic agents, antioxidants

Keywords: osmotic agents, mesothelial cells, Peritoneal Dialysis