Morphological Alterations Of Peritoneum In Uremic Rats Undergoing Long-term Peritoneal Dialysis

Objective To investigate the damage of peritoneum upon uremic toxin,and the morphological alterations of peritoneum in uremic rats undergoing long-term peritoneal dialysis as well as the high glucose concentration dialysate.Methods Thirty male SD rats were randomly divided into control group (n= 7), NS group (n=11), and PD group (n=12). A 5/6 nephrectomy was carried out in group NS and PD rats, while rats of group C underwent sham surgery and left untreated.4 weeks postoperatively, rats of group NS and PD were started to treat with daily transcatheter injection of 20ml 0.9% sodium chloride or 4.25% peritoneal dialysate respectively for 6 weeks. Then the experiment was terminated for all groups. Parietal and visceral peritoneum were obtained for morphological examination, The expression of vascular endothelial growth factor(VEGF) and transforming growth factor beta1(TGF-β1) was investigated by immunohistochemistry and RT-PCR.Results As in the proceeding of the uremic model, nine rats of group NS and PD dropout due to death or obstruction of catheters, which lead to that only seven rats were left each group and were put into the analysis of result. It was revealed that the net ultrafiltration in group C, NS and PD were respectively (5.27±0.61) ml, (3.59±0.68) ml and (-0.53±1.04) ml. It was decreased in group NS and PD compared with group C, and decreased in group PD compared with group NS (P<0. 05). HE stain show the parietal thickness in group C, NS and PD were respectively (10.51±1.81)μm, (23.91±2.18)μm and (38.68±5.35)μm, the number of blood vessels in each group were (1.43±0.98), (3.71±1.11) and (8.14±1.57).They were significantly increased in group PD compared with group C and NS, and increased in NS group compared with group C (P<0.05).As the immunohistochemistry revealed,the positive cells of VEGF and TGF-β1 per high-power field were the most in group PD when compared with group C and group NS, and it was much more in group NS when compared with group C (P<0.05). The expression of VEGF and TGF-β1 mRNA were up-regulated in group PD compared with other two groups,and increased significantly in NS group compared with C group (P<0.05). Conclusion Both uremia and non-biocompatible peritoneal dialysate fluid exposure may lead to peritoneal angiogenesis, fibrosis, ultrafiltration failure, and ultimately drop out from peritoneal dialysis.