Comparison of the chloride channel activator lubiprostone and the oral laxative Polyethylene Glycol 3350 on mucosal barrier repair in ischemic-injured porcine intestine

AIM: To investigate the effects of lubiprostone and Polyethylene Glycol 3350 (PEG) on mucosal barrier repair in ischemic-injured porcine intestine. METHODS: Ileum from 6 piglets (approximately 15 kg body weight) was subjected to ischemic conditions by occluding the local mesenteric circulation for 45 min in vivo. Ileal tissues from each pig were then harvested and mounted in Ussing chambers and bathed in oxygenated Ringer's solution in vitro. Intestinal barrier function was assessed by measuring transepithelial electrical resistance (TER) and mucosal-to-serosal fluxes of 3H-mannitol and 14C-inulin. Statistical analyses of data collected over a 120-min time course included 2-way ANOVA for the effects of time and treatment on indices of barrier function. RESULTS: Application of 1 μmol/L lubiprostone to the mucosal surface of ischemic-injured ileum in vitro induced significant elevations in TER compared to non-treated tissue. Lubiprostone also reduced mucosal-to-serosal fluxes of 3H-mannitol and 14C-inulin. Alternatively,application of a polyethylene laxative (PEG,20 mmol/L) to the mucosal surface of ischemic tissues significantly increased flux of 3H-mannitol and 14C-inulin. CONCLUSION: This experiment demonstrates that lubiprostone stimulates recovery of barrier function in ischemic intestinal tissues whereas the PEG laxative had deleterious effects on mucosal repair. These results suggest that,unlike osmotic laxatives,lubiprostone stimulates repair of the injured intestinal barrier.

Gastro protective properties of the novel prostone SPI-8811 against acid-injured porcine mucosa

AIM:To evaluate the protective properties of novel prostone ClC-2 agonist SPI-8811 in porcine model of gastric acid injury. METHODS:Porcine gastric mucosa was mounted in Ussing chambers and injured by bathing mucosal tissues in an HCl Ringer's solution (pH = 1.5) with or without SP1-8811 (1 μmol/L), cystic fibrosis transmem-brane conductance regulator (CFTR) inhibitor (inhibitor 172, 10 μmol/L, apical) and ClC-2 inhibitor ZnCl 2 , 300 μmol/L, apical), on the apical surface of tissues. Transepithelial resistance and mucosal-to-serosal 3 H-mannitol fluxes were measured over a 90-min period. Tissues were analyzed by morph metric techniques, Immunofluorescence and by western blots. RESULTS:Compared with control tissues, acid exposure decreased transepithelial electrical resistance (TER) and increased 3 H-mannitol flux. Pretreatment of gastric mucosa with SPI-8811 was protective against acid-induced decreases in TER (TER, 50 Ω . cm 2 vs 100 Ω . cm 2 ) and abolished increases in flux ( 3 H-mannitol flux, 0.10 μmol/L . cm 2 vs 0.04 μmol/L . cm 2 ). Evidence of histological damage in the presence of acid was markedly at- tenuated by SPI-0811. Immunofluorescence and western analysis for occludin revealed enhanced localization to the region of the tight junction (TJ) after treatment with SPI-8811. Pretreatment with the ClC-2 inhibitor ZnCl 2 , but not the selective CFTR inhibitor 172, attenuated SPI-8811-mediated mucosal protection, suggesting a role for ClC-2. Prostone may serve both protective and reparative roles in injured tissues. CONCLUSION: ClC-2 agonist SPI-8811 stimulated enhancement of mucosal barrier function by protecting TJ protein occludin in porcine gastric mucosa and thus protected the gastric acid injury in porcine stomach.