FIGURE 8.

Aldose reductase-dependent protection of the ischemic heart by carnosine. A, changes in developed pressure in isolated mouse hearts subjected to 30 min of ischemia followed by 45 min of reperfusion. In the carnosine-treated group the hearts were continuously perfused with 1 mm carnosine before induction of ischemia and during reperfusion. Data are the mean ± S.E.; n = 4–7 hearts/group; *, p < 0.01 versus WT without carnosine or AR-null hearts with and without carnosine. B, levels of total released lactate dehydrogenase (LDH) (i) and CK (ii) in post-ischemic myocardial effluent collected from WT and AR-null hearts treated with and without carnosine. Data are expressed as the mean ± S.E.; n = 4–7 hearts/group. *, p < 0.01 versus WT without carnosine. C, Western blots from Langendorff-perfused hearts from WT and AR-null mice subjected to either 30 min of perfusion (P) or perfusion followed by 30 min of ischemia (i). At the end of the protocol, proteins from the heart homogenates were separated by SDS-PAGE and immunoblotted with anti-protein-carnosine antibody. Relative intensity of immuno-reactive bands of 45 (ii), 37 (iii), and 30 (iv) kDa was measured and normalized to total protein in the gel measured by Amido Black staining. Data are expressed as the mean ± S.E.; *, p < 0.01 versus perfused hearts; #, p < 0.01 versus WT ischemic hearts (n = 3–4 mice).