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Thioredoxin-1 (Trx1) has cardioprotective effects on ischemia/reperfusion (I/R) injury, although its role in ischemic postconditioning (PostC) in middle-aged mice is not understood. This study aimed to evaluate if combining two cardioprotective strategies, such as Trx1 overexpression and PostC, could exert a synergistic effect in reducing infarct size in middle-aged mice. Young or middle-aged wild-type mice (Wt), transgenic mice overexpressing Trx1, and dominant negative (DN-Trx1) mutant of Trx1 mice were used. Mice hearts were subjected to I/R or PostC protocol. Infarct size, hydrogen peroxide (H 2 O 2) production, protein nitration, Trx1 activity, mitochondrial function, and Trx1, pAkt and pGSK3β expression were measured. PostC could not reduce infarct size even in the presence of Trx1 overexpression in middle-aged mice. This finding was accompanied by a lack of Akt and GSK3β phosphorylation, and Trx1 expression (in Wt group). Trx1 activity was diminished and H 2 O 2 production and protein nitration were increased in middle-age. The respiratory control rate dropped after I/R in Wt-Young and PostC restored this value, but not in middle-aged groups. Our results showed that Trx1 plays a key role in the PostC protection mechanism in young but not middle-aged mice, even in the presence of Trx1 overexpression. [Display omitted] • Postconditioning and Trx-1 overexpression cannot reduce infarction in middle age. • Postconditioning and Trx-1 overexpression trigger similar intracellular mechanisms. • In middle age, a redox imbalance takes place. [ABSTRACT FROM AUTHOR]

The aim of this work was to quantify NO, O and ONOO production during heparin-induced capacitation of cryopreserved bovine spermatozoa. A time dependent hyperbolic increase was observed for heparin-dependent capacitation, O uptake, and NO production. Conversely, O production was increased during the first 15 min of incubation, showing a decrease from this time until 45 min. At 15 min of heparin incubation, a threefold increase in O consumption (5.9 ± 0.6 nmol/min × 10 cells), an enhancement in NO release (1.1 ± 0.2 nmol/min × 10 cells), and a five-fold increase in O production (1.3 ± 0.07 nmol/min × 10 cells), were observed. Peroxynitrite production rate was estimated taking into account NO and O generation and the second-order rate constant of the reaction between these species. To conclude, heparin-induced capacitation of cryopreserved bovine spermatozoa activates (i) mitochondrial O uptake by high ADP levels due to increased energy requirements, (ii) NO production by a constitutive NOS and (iii) O production by a membrane-bound NAD(P)H oxidase. The products of both enzymes are released to the extracellular space and could be involved in the process of sperm capacitation. [ABSTRACT FROM AUTHOR]