title: Increased peritoneal membrane permeability is associated with abnormal peritoneal surface layer.
abstract: OBJECTIVE
  We recently showed that the peritoneal surface layer may be an important barrier in modulating peritoneal membrane permeability. In the present study, we investigated the relationship between an increased peritoneal transport rate and the peritoneal surface layer.
  
  
  METHODS
  Male Sprague-Dawley rats (n = 8) received intraperitoneal injections of 4.25% glucose dialysate daily for 1 week. Forty-eight hours after the last injection, a 4-hour dwell study using 25 mL 4.25% glucose dialysate was performed in each rat. The results were compared with those from control rats that received no intraperitoneal injections (n = 8). The peritoneal fluid and small-solute transport characteristics were evaluated. The peritoneal surface layer was studied using an electron microscope. The phospholipids content of the dialysate was also evaluated.
  
  
  RESULTS
  Peritoneal fluid removal was significantly reduced in the daily injection group (30.6 +/- 1.3 mL) as compared with the control group (38.2 +/- 0.6 mL). The peritoneal fluid absorption rate and small-solute transport rate were also significantly higher in the daily injection group as compared with the control group. The amounts of phospholipids in the dialysate were significantly lower in the daily injection group--especially the quantity of phosphatidylcholine. However, lysophosphatidylcholine increased significantly in the daily injection group. Electron microscopy showed that the peritoneal surface layer was almost completely gone in the daily injection group, but that a dense and thick (average 4 microm) peritoneal surface layer was present on the top of the mesothelial cells in the control group.
  
  
  CONCLUSIONS
  Our results suggest that daily injection of hypertonic glucose dialysate significantly increased the peritoneal transport rate. The increased peritoneal transport rate was associated with a significant reduction in the peritoneal surface layer and the phospholipids content of the dialysis effluent.
authors.affiliation: Department of Nephrology, 1st Affiliated Hospital, Sun Yat-sen University of Medical Sciences, Guangzhou, PR China. wangta@gzsums.edu.cn
authors.forename: T
authors.initials: T
authors.lastname: Wang
authors.forename: H H
authors.initials: HH
authors.lastname: Cheng
authors.forename: S M
authors.initials: SM
authors.lastname: Liu
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: J L
authors.initials: JL
authors.lastname: Wu
authors.forename: W X
authors.initials: WX
authors.lastname: Peng
authors.forename: J H
authors.initials: JH
authors.lastname: Zhong
authors.forename: B
authors.initials: B
authors.lastname: Lindholm
mesh_terms: D000818:Animals; D001692:Biological Transport; D015314:Dialysis Solutions / Q000737:chemistry / Q000494:pharmacology; D004848:Epithelium / Q000648:ultrastructure; D005947:Glucose / Q000008:administration & dosage; D005950:Glucose Solution, Hypertonic / Q000494:pharmacology; D008297:Male; D008854:Microscopy, Electron; D010537:Peritoneum / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure*; D010539:Permeability; D010743:Phospholipids / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D015314:Dialysis Solutions; D005950:Glucose Solution, Hypertonic; D010743:Phospholipids; D005947:Glucose