Figure 4
From: Hyperglycemia-induced diaphragm weakness is mediated by oxidative stress
PEG-SOD restores hyperglycemia-induced reductions in diaphragm permeabilized single fiber contractile force generation. Force pCa relationships in single permeabilized diaphragm fibers from control (black), hyperglycemia (red), hyperglycemia + PEG-SOD (blue), and hyperglycemia + denatured (heat inactivated) PEG-SOD groups (green) were evaluated at two weeks after administration of citrate buffer (controls) or streptozotocin (hyperglycemia) (n = 6 animals/group). A total of 15 fibers from each animal were assessed (90 fibers/experimental group, total 360 fibers). As shown, PEG-SOD substantially improved the force-pCa relationship in single permeabilized diaphragm fibers from hyperglycemic animals, whereas denatured PEG-SOD had no effect to restore single fiber force generating capacity (P < 0.001). PEG-SOD did not normalize glucose levels. These data suggest that inhibition of superoxide generation in the hyperglycemic diaphragm restores contractile protein function. PEG-SOD, polyethylene glycol superoxide dismutase.