ATP-MgCL2 reduces intestinal permeability during mesenteric ischemia

ATP-MgCl2 has been demonstrated to have beneficial attributes in numerous models of organ ischemia. In this study we examined whether ATP-MgCl2 could decrease permeability in ischemic segments of rat ileum. Ileal segments (nonischemic and ischemic) from the same rat were cannulated and perfused, and the plasma to lumen clearance of 51Cr-EDTA was measured. Ischemia increased permeability from a baseline value of 0.59 +/- 0.14 (mean +/- SEM in ml/min/g dry wt of intestine) to 1.10 +/- 0.14 at 90 min (n = 12), significantly higher than that of the nonischemic segments (0.55 +/- 0.07) at 90 min (P < 0.05). This was associated with a significant reduction in blood flow from 0.84 +/- 0.08 (n = 4) (mean +/- SEM ml/min/g wet wt of intestine) to 0.16 +/- 0.06 (n = 4) (P < 0.05) as measured by labeled microspheres. Rats receiving ATP-MgCl2 (100 micromol) (n = 8) pretreatment showed no increase in clearance over 90 min (baseline 0.69 +/- 0.07; 90 min 0.70 +/- 0.07) and no significant difference in blood flow from untreated ischemic segments (0.21 +/- 0.9) (n = 4). Tissue ATP levels determined enzymatically were significantly reduced by 5 min postischemia to 4.19 +/- 0.35 (n = 7) (P < 0.05) from a control value of 6.77 +/- 0.77 micromol/g dry wt (n = 14). ATP levels remained depressed at 30 min (3.45 +/- 0.35) and 90 min (3.38 +/- 0.26). ATP-MgCl2 treatment did not significantly alter these tissue ATP levels. These data indicate that ATP-MgCl2 prevents the increase of 51Cr-EDTA permeability during ischemia without alterations in tissue ATP levels or increases in intestinal blood flow.