Objective    To study the effect of high-glucose peritoneal dialysate (4.25%) on expression of  transforming growth factor-β1(TGF-β1) in peritoneum mesothelial cells (PMC) and the interfering role of chitosan.     Methods    PMC (second generation)

identified by their morphology and immunohistochemistry

were divided into group A (control group)

group B

group C and group D

which were cultured with DMEM/F12

DMEM/F12 +4.25% glucose peritoneal dialysate

DMEM/F12 + 4.25% glucose peritoneal dialysate +1.2 mg/L chitosan

and DMEM/F12+4.25% glucose peritoneal dialysate + 0.4 mg/L chitosan

respectively. RNA and protein were extracted from PMC

respectively

24 and 48 h after culture. Expression of TGF-β1 mRNA and protein in PMC was detected by RT-PCR and Western blot analysis

respectively.     Results    The expression level of TGF-β1 mRNA and protein in PMC was higher after than before 4.25% glucose stimulation

and reached its peak at 24 and 48 h of culture

in groups A and B

respectively (P0.05). Chitosan significantly up-regulated the expression of TGF-β1 mRNA and protein in PMC while it significantly down-regulated the expression of TGF-β1 mRNA at 24 h of culture. The expression of TGF-β1 mRNA was 2.51-fold

2.13-fold

1.68-fold higher in group B than in groups A

C

and D (P0.05). Chitosan significantly decreased the expression of TGF-β1 protein at 48 h of culture. The expression of TGF-β1 protein was 1.85-fold

1.52-fold

1.24-fold lower in group B than in groups A

C

and D (P0.05). Chitosan inhibited the expression of TGF-β1 protein in a concentration-dependent manner.     Conclusion    High glucose peritoneal dialysate (4.25%) can up-regulate the expression of TGF-β1 mRNA and protein in PMC. Chitosan can inhibit the expression activity of TGF-β1 during peritoneal fibrosis.