Remote limb ischaemic conditioning produces cardioprotection in rats with testicular ischaemia-reperfusion injury.

NEW FINDINGS: What is the central question of this study? Can remote limb ischaemic conditioning produce cardioprotection in rats with testicular ischaemia-reperfusion injury? What is the main finding and its importance? Testicular ischaemia-reperfusion (TI/R)-injured rats were predisposed to myocardial reperfusion-induced atrioventricular block. Remote limb ischaemia preconditioning and postconditioning protected TI/R hearts against ischaemia-provoked ventricular arrhythmia and ultimately reduced the incidence of sudden cardiac death, with a possible role of c-Jun N-terminal kinase inhibition and connexin 43 activation. ABSTRACT: Remote ischaemic conditioning can protect hearts against arrhythmia. Testicular ischaemia-reperfusion (TI/R) injury is associated with electrocardiographic abnormalities. We investigated the effect of remote limb ischaemia preconditioning (RIPre) and postconditioning (RIPost) on arrhythmogenesis in TI/R rats, and determined the potential role of c-Jun N-terminal kinase (JNK)/connexin 43 (Cx43) signalling. Rats were randomized to sham-operated, control, TI/R, RIPre and RIPost groups. TI/R rats were more predisposed to myocardial reperfusion-induced atrioventricular block (AVB). RIPre and RIPost reduced the incidence of sudden cardiac death (SCD) or AVB, and duration of ventricular tachyarrhythmias during myocardial reperfusion. RIPre and RIPost decreased myocardial I/R-induced phosphorylation level of JNK, while preserving myocardial Cx43 expression in TI/R rats. Taken together, TI/R rats were predisposed to myocardial reperfusion-induced AVB. RIPre and RIPost protected TI/R hearts against ischaemia-provoked ventricular arrhythmia and ultimately reduced the incidence of SCD by suppressing JNK activation and restoring Cx43 expression.

Metformin decreases testicular damages following ischaemia/reperfusion injury in rats.

The effects of metformin on a testicular torsion injury in adolescent rat testis after I/R were evaluated in the present study. Forty adolescent rats were divided into five groups with eight rats per group: a control group; a sham-operated group; an ischaemia group, where torsion was applied for 4 hr and testis was examined immediately after detorsion; an I/R group, where torsion was applied for 4 hr and the testis was examined 4 hr after detorsion; and an I/R + M group, where the metformin (300 mg/kg) administration was added to the identical procedures used for the I/R group. Spermatogenesis, basal membrane integrity and cleaved caspase-3 expression were assessed. The I/R + M group had a significantly higher Johnsen score than the I/R group (7.9 ± 0.1 vs. 7.5 ± 0.2; p < .001; F-value = 14.2). Failure of basal membrane integrity was highest in the ischaemia group (45 ± 5) compared to the other groups (control group, 20 ± 5; sham-operated group, 16.6 ± 2.8), but not different between the I/R + M (31.6 ± 12.5) and the I/R groups (25 ± 3.5). Cleaved caspase-3 expression was highest in the ischaemia group (73.5 ± 0.7), and significantly lower in the I/R + M group (33.4 ± 0.9) than the I/R group (58.5 ± 0.2; p < .05; F-value = 7.6). Metformin decreases testicular damage by exerting protection against the harmful effects of I/R on spermatogenesis and alleviating apoptosis in adolescent rat testis.

Sitagliptin protects male albino rats with testicular ischaemia/reperfusion damage: Modulation of VCAM-1 and VEGF-A.

Twisting of the spermatic cord is considered a popular problem in the urological field, which may lead to testicular necrosis and male infertility. Sitagliptin, a glucose-lowering agent, proved to have a vindicatory function in myocardial and renal ischaemia/reperfusion (I/R), but its role in testicular I/R has not yet been studied. The current work investigates its capability to recover the testicular I/R injury with shedding more light on the mechanism of its action. Four groups were used: sham, sham pretreated with sitagliptin, I/R and sitagliptin/I/R-pretreated groups. The outcomes proved that I/R significantly decreased the serum testosterone, with a major increase in oxidative, inflammatory and nitrosative stress, along with a reduction in testicular vascular endothelial growth factor-A level with marked germinal cell apoptosis. However, pretreatment with sitagliptin significantly reversed the profound testicular I/R damaging effects, on the basis of its antioxidant, anti-inflammatory and anti-apoptotic activities with the ability of recuperation of the testicular vascularity.

Paeonol protects against testicular ischaemia-reperfusion injury in rats through inhibition of oxidative stress and inflammation.

Ischaemia-reperfusion (IR) is the most common form of testicular injury that results in oxidative damage and inflammation ending by subinfertility. Paeonol, a natural phenolic compound, exhibits antioxidant and anti-inflammatory effects. Thus, the present study investigated the role of paeonol in rat testicular IR injury. Thirty adult Wistar rats were randomly divided into five groups; sham, sham treated with paeonol, IR injury, and IR pre-treated with paeonol at low and high doses. Serum testosterone and testicular levels of malondialdehyde and reduced glutathione (GSH) besides superoxide dismutase (SOD) activity were determined. Gene quantifications for tumour necrosis factor-α (TNF-α), hypoxia-inducible factor-1α (HIF-1α) and heat shock protein 70 (HSP70) were also assessed. Histopathological pictures and the immunohistochemical expression of testicular nuclear factor erythroid 2-related factor 2 (Nrf2), interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) were shown. Pre-treatment with paeonol prevented the drop in serum testosterone, alongside with improvement of testicular malondialdehyde and GSH levels plus SOD activity. Paeonol regained the normal spermatogenesis with prevention of IR-induced increase in TNF-α, HIF-1α and HSP70 gene expression besides IL-1ß and IL-6 immunostaining and reduction in Nrf2 protein expression. Paeonol exerted a dose-dependent beneficial effect on testicular IR injury. This effect was achieved by its antioxidant and anti-inflammatory effects.

HO-1 attenuates testicular ischaemia/reperfusion injury by activating the phosphorylated C-jun-miR-221/222-TOX pathway.

Aims: Heme oxygenase (HO-1) affords protection against ischaemia/reperfusion (I/R) injury; however, its effects on testicular I/R injury remain poorly explored. Herein, we aimed to examine the effects of HO-1 on testicular I/R injury and elucidate the underlying mechanism. Methods: Using the TALEN technique, we knocked out the HO-1 gene from rats. In vivo: Thirty hmox+/+ and 30 hmox-/- rats were randomly assigned to six groups: sham-operated (sham), I/R (the left testicle torsion/detorsion) 0 d,I/R 1d, I/R 3d, I/R 7d and I/R 28d. In vitro: GC-1 were suffered from: control,H/R (oxygen-deprivation/reoxygenation),H/R + HO-1 siRNA,H/R + c-Jun siRNA or H/R + HO-1 siRNA + c-jun.We performed immunofluorescence and immunohistochemistry experiments to detect HO-1 nuclear translocation. Flow cytometry was used to detect cell apoptosis and analyse the cell cycle. High-resolution miRNA, mRNA sequencing, reverse transcription-quantitative PCR, and western blotting were performed to identify testicular I/R injury-related genes strongly conserved in HO-1 knockout rats. A double luciferase reporter assay was performed to verify the relationship between C-jun and miR-221/222. Main findings: In vivo, HO-1 improved the pathological damage induced by testicular I/R. In GC-1 cells, we confirmed the nuclear translocation of HO-1 and its protective effect against hypoxia/reoxygenation (H/R) damage. Accordingly, HO-1 protein itself, rather than heme metabolites, might play a key role in testicular I/R. Gene sequencing was performed to screen for miR221/222 and its downstream gene, thymocyte selection-associated high mobility group box (TOX). HO-1 increased c-Jun phosphorylation in the H/R group, knocked down c-Jun in GC-1 cells, and decreased miR-221/222 expression. Inhibition of HO-1 expression decreased the expression of c-Jun and miR-221/222, which was rescued by adding c-Jun. Dual-luciferase reporter assay confirmed the interaction between c-Jun and miR-221/222. Conclusions: HO-1 could exert a protective effect against testicular I/R via the phosphorylated c-Jun-miR-221/222-TOX pathway.