Benzolamide perpetuates acidic conditions during reperfusion and reduces myocardial ischemia-reperfusion injury

• Published in: Journal of applied physiology (1985) 2018-08, Vol.125 (2), p.340-352
• Main Authors: Ciocci Pardo, Alejandro, Díaz, Romina G, González Arbeláez, Luisa F, Perez, Nestor G, Swenson, Erik Richard, Mosca, Susana M, Alvarez, Bernardo V
• Format: Article
• Language: English
• Subjects: Acidity; Acidosis; AKT protein; Calcium (intracellular); Calcium (mitochondrial); Calcium homeostasis; Calcium ions; Carbonic anhydrases; Glycolysis; Heart attacks; Homeostasis; Immunoblotting; Infarction; Injury prevention; Intracellular; Ischemia; Kinases; Membrane potential; Membranes; Mitochondria; Muscle contraction; Muscles; Myocardial ischemia; pH effects; Phosphorylation; Prolongation; Protein kinase C; Recovery; Reperfusion
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00957.2017

During ischemia, increased anaerobic glycolysis results in intracellular acidosis. Activation of alkalinizing transport mechanisms associated with carbonic anhydrases (CA) leads to myocardial intracellular Ca increase. We characterize the effects of inhibition of CA with benzolamide (BZ) during cardiac ischemia-reperfusion (I/R). Langendorff perfused isolated rat hearts were subjected to 30 min of global ischemia and 60 min of reperfusion. Other hearts were treated with BZ (5 μM) during the initial 10 min of reperfusion or perfused with acid solution (AR, pH 6.4) during the first 3 min of reperfusion. P38MAPK, a kinase linked to membrane transporters and involved in cardioprotection, was examined in hearts treated with BZ in presence of the P38MAPK inhibitor SB202190 (10 μM). Infarct size (IZ) and myocardial function were assessed, and phosphorylated forms of P38MAPK, Akt and PKCε were evaluated by immunoblotting. We determined the rate of intracellular pH (pH ) normalization after transient acid loading in the absence and presence of BZ or BZ+SB202190, in heart papillary muscles (HPM). Mitochondrial potential (∆ψm), Ca retention capacity and Ca -mediated swelling following I/R were also measured. BZ, similarly to AR, reduced IZ, improved post-ischemic recovery of myocardial contractility, increased phosphorylation of Akt, PKCε, and P38MAPK, and normalized mitochondrial ∆ψm and Ca homeostasis; effects abolished following P38MAPK inhibition. In HPM, BZ slowed pH recovery; an effect which was restored after P38MAPK inhibition. We conclude that, prolongation of acidic conditions during reperfusion by BZ could be responsible for the cardioprotective benefits of reduced infarction and better myocontractile function, through P38MAPK-dependent pathways.