Antioxidants in experimental ischemia-reperfusion injury of the testis: Where are we heading towards?

The protective effect of pregabalin and xanthenone on testicular ischemia/reperfusion injury in rats

BACKGROUND

Torsion of the spermatic cord is a hazardous and common urologic issue. The current work evaluates the possible protective effect of pregabalin (PGB) and xanthenone (XAN) in testicular ischemia/reperfusion injury induced by testicular torsion/detorsion in rats.

MATERIALS AND METHODS

Seven groups of adult male Wistar albino rats were allocated randomly into seven groups, namely, sham control, torsion/detorsion (T/D), PGB 50 mg/kg, PGB 100 mg/kg, XAN 1 mg/kg, XAN 2 mg/kg, and PGB 50 mg/kg plus XAN 1 mg/kg groups. Serum cholesterol and testosterone levels were determined. Also, the levels of malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide (NO), superoxide dismutase (SOD), tumor necrosis factor-α (TNF-α), nuclear factor kappa B (NF-қB), angiotensin (Ang) II, Ang-(1-7), and angiotensin-converting enzyme2 (ACE2) were assessed in testicular tissue. Immunohistochemical analysis of heme oxygenase-1 (HO-1) and caspase-3 was performed. Finally, the histopathological examination of the testicular tissues was performed.

RESULTS

The PGB 50 mg/kg, PGB 100 mg/kg, XAN 1 mg/kg, XAN 2 mg/kg, and PGB 50 mg/kg plus XAN 1 mg/kg groups showed a significant decrease in serum cholesterol, MDA, NO, TNF-α, NF-қB, and Ang-II levels coupled with a significant increase in both testosterone and ACE2 expression. Furthermore, all test groups showed a significant improvement in the histopathological picture with a reduction in caspase-3 and an increase in HO-1 immunoexpression in testicular tissue.

CONCLUSION

PGB and XAN may have promising effects on preventing testicular T/D injury through antioxidant, anti-inflammatory, and antiapoptotic actions.

Activation of SIRT1/Nrf2/HO-1 and Beclin-1/AMPK/mTOR autophagy pathways by eprosartan ameliorates testicular dysfunction induced by testicular torsion in rats

Testicular torsion carries the ominous prospect of inducing acute scrotal distress and the perilous consequence of testicular atrophy, necessitating immediate surgical intervention to reinstate vital testicular perfusion, notwithstanding the paradoxical detrimental impact of reperfusion. Although no drugs have secured approval for this urgent circumstance, antioxidants emerge as promising candidates. This study aspires to illustrate the influence of eprosartan, an AT1R antagonist, on testicular torsion in rats. Wistar albino rats were meticulously separated into five groups, (n = 6): sham group, eprosartan group, testicular torsion-detorsion (T/D) group, and two groups of T/D treated with two oral doses of eprosartan (30 or 60 mg/kg). Serum testosterone, sperm analysis and histopathological examination were done to evaluate spermatogenesis. Oxidative stress markers were assessed. Bax, BCL-2, SIRT1, Nrf2, HO-1 besides cleaved caspase-3 testicular contents were estimated using ELISA or qRT-PCR. As autophagy markers, SQSTM-1/p62, Beclin-1, mTOR and AMPK were investigated. Our findings highlight that eprosartan effectively improved serum testosterone levels, testicular weight, and sperm count/motility/viability, while mitigating histological irregularities and sperm abnormalities induced by T/D. This recovery in testicular function was underpinned by the activation of the cytoprotective SIRT1/Nrf2/HO-1 axis, which curtailed testicular oxidative stress, indicated by lowering the MDA content and increasing GSH content. In terms of apoptosis, eprosartan effectively countered apoptotic processes by decreasing cleaved caspase-3 content, suppressing Bax and stimulating Bcl-2 gene expression. Simultaneously, it reactivated impaired autophagy by increasing Beclin-1 expression, decreasing the expression of SQSTM-1/p62 and modulate the phosphorylation of AMPK and mTOR proteins. Eprosartan hold promise for managing testicular dysfunction arising from testicular torsion exerting antioxidant, pro-autophagic and anti-apoptotic effect via the activation of SIRT1/Nrf2/HO-1 as well as Beclin-1/AMPK/mTOR pathways.

Syringic acid ameliorates ischemia/reperfusion-induced testicular injury in rats via suppressing of HMGB1/NF-κB axis and endoplasmic reticulum stress

PURPOSE

To investigate the possible protective role of syringic acid on torsion/detorsion-induced testicular injury using biochemical and histopathological approaches for the first time.

METHODS

A total of 24 rats were divided into 4 groups: sham control, torsion/detorsion, torsion/detorsion + syringic acid (50 mg/kg and 100 mg/kg). Tissue malondialdehyde, total oxidant status and total antioxidant status levels were determined using colorimetric methods. Tissue 8-hydroxy-2'-deoxyguanosine, superoxide dismutase, catalase, high mobility group box 1, nuclear factor kappa B protein 65, tumor necrosis factor-alpha, interleukin-6, myeloperoxidase, 78-kDa glucose-regulated protein, activating transcription factor-6, C/EBP homologous protein and caspase-3 levels were determined using commercial enzyme-linked immunosorbent assay kits. Johnsen's testicle scoring system was used for histological evaluation.

RESULTS

Compared with the control group, the levels of oxidative stress, inflammation, endoplasmic reticulum stress and apoptosis were significantly increased in the torsion/detorsion group (p < 0.05). Syringic acid administrations statistically significantly restored these damage in a dose dependent manner (p < 0.05). Moreover, it was found that the results of histological examinations supported the biochemical results to a statistically significant extent.

CONCLUSION

The overall results suggest that syringic acid emerges as a potential compound for the treatment of testicular torsion and may be subject to clinical trials.

Vanillic acid attenuates testicular ischemia/reperfusion injury in rats

Background

Testicular torsion is an important pediatric problem and ischemia/reperfusion injury (IRI) is involved in its etiopathogenesis. Vanillic acid (VA) is a phenolic acid has strong antioxidant properties. To our knowledge, the ability of VA to reduce testicular IRI has not been previously investigated. It was therefore aimed to evaluate whether VA had a beneficial effect against testicular IRI model in rats for the first time. Twenty-four rats were segregated into four groups: sham control, torsion/detorsion (T/D), T/D + VA (50 mg/kg and 100 mg/kg). The levels of testicular oxidative stress, inflammation, endoplasmic reticulum (ER) stress and apoptosis markers were determined using colorimetric methods. Hematoxylin–eosin staining method was used in the histopathological evaluation.

Results

Oxidative stress, inflammation, ER stress and apoptosis levels were significantly higher in testicular tissues of rats with only IRI model (p < 0.05). VA applications improved these injuries in a dose-dependent manner (p < 0.05). Moreover, it was found that the results of histological examinations supported the biochemical results to a statistically significant extent.

Conclusions

It was revealed that VA application can remove testicular IRI for the first time. This testicular protective efficacy of VA needs to be supported by more extensive preclinical studies.

Glutamine prevents upregulation of NF-kB signaling and caspase 3 activation in ischaemia/reperfusion-induced testicular damage: An animal model

AIM

Testicular ischaemia/reperfusion (I/R) injury is a major consequence of testicular torsion with possible attendant risk of male infertility. Glutamine, on the other hand, is a known antioxidant with anti-inflammatory potential. The present study evaluated whether or not glutamine would improve I/R-induced testicular injury in torsion/detorsion (T/D). The possible associated mechanisms were also investigated.

METHODS

Wistar rats were randomly allotted into four groups (n = 10); sham-operated, glutamine-treated, T/D, and T/D + glutamine. Testicular torsion was induced and reperfusion established after two and a half hour under ketamine/xylazine anaethesia. Glutamine was administered one hour before reperfusion and continued daily for 3 days. At the end of the study, animals were euthanized, blood samples obtained, epididymal sperm suspension collected, and the testes harvested for biochemical and histopathological assays using established methods.

RESULTS

Glutamine prevented T/D-driven I/R-induced reduced sperm quality, impaired testicular histoarchitecture, and suppressed circulating testosterone. Also, glutamine abated I/R-induced oxidative stress (evidenced by reduced hydrogen peroxide and MDA generation and enhanced concentrations and activities of antioxidants), inflammation (evidenced by suppression of TNF-α and IL-1β), and apoptosis (evidenced by reduced DNA fragmentation) by down-regulating NF-kB and caspase 3 activity.

CONCLUSION

For the first time, this study demonstrated that glutamine administration improved testicular I/R injury in T/D rat model by maintaining testicular redox balance, and testicular integrity and function via inhibition of I/R-induced upregulation of NF-kB signaling and caspase 3 activation.

Inhibition of keratinocyte ferroptosis suppresses psoriatic inflammation

Psoriasis is a common, chronic, and recurrent inflammatory disease. It is characterized by hyperproliferation and abnormal differentiation of keratinocytes. Keratinocyte death is also involved in many pathophysiological conditions and amplifies the inflammatory cascade. As a newly recognized form of cell death, ferroptosis is involved in several inflammatory diseases. In this study, we aimed to investigate a previously unrecognized role for ferroptosis in psoriasis. Ferroptosis is mediated by lipid peroxidation and iron overload. Compared with normal lesions, the mRNA expression of acyl-CoA synthetase long-chain family member 4 (ACSL4), prostaglandin-endoperoxide synthase 2 (PTGS2), and transferrin receptor (TFRC) were highly expressed in psoriatic lesions, with decreased levels of glutathione peroxidase 4 (GPX4), ferritin light chain (FTL), and ferritin heavy chain 1 (FTH1). The protein levels of ACSL4 and GPX4 were consistent with their mRNA levels. A similar tendency of ferroptosis was also observed in erastin-treated human primary keratinocytes and the Imiquimod (IMQ)-induced model of psoriasis. To investigate the correlation between inflammation and peroxidation, we analyzed single-cell RNA-sequencing data and identified 15 cell types. There was a high correlation between the activity of the lipid oxidation and the Th22/Th17 response in keratinocytes at a single-cell level. Moreover, ferrostatin-1 (Fer-1), a potent inhibitor of lipid peroxidation, suppressed ferroptosis-related changes in erastin-treated keratinocytes and alleviated psoriasiform dermatitis of IMQ-induced models. Additionally, Fer-1 blocked inflammatory responses in vitro and in vivo, reducing the production of cytokines including TNF-α, IL-6, IL-1α, IL-1β, IL-17, IL-22, and IL-23. This study revealed an expression pattern of ferroptosis in which specific molecules enhance inflammatory reactions in psoriasis.

Computational and Preclinical Evidence of Anti-ischemic Properties of L-Carnitine-Rich Supplement via Stimulation of Anti-inflammatory and Antioxidant Events in Testicular Torsed Rats

Ischemia-reperfusion injury is a urological emergency condition that could lead to necrosis, testicular damage subfertility, and infertility. The purpose of this study was to identify changes taking place in the rat testis at short-term (4 hr) as well as long-term (7 days) reperfusion following testicular torsion and to evaluate the effects of Proxeed Plus (PP), L-carnitine-rich antioxidant supplement, on preventing these changes using the biochemical parameters and histopathology. Thirty adult male rats were divided into five groups: in groups, 1-4 testicular ischemia was achieved by rotating the left testis 720° clockwise for 4 h and dividing into the sham, torsion/detorsion (T/D), T/D+1000 mg/kg BW PP, and T/D+5000 mg/kg BW PP groups, respectively. PP was administered intraperitoneally 30 min before detorsion while group 5 served as the normal control. All rats were sacrificed 4 h after detorsion. The same experimental design was set up, and animals were sacrificed after 7 days of detorsion. The testicular levels of human cyclooxygenase-2; tumor necrosis factor; interleukins-1β, 6, and 10; hydrogen peroxide; malonaldehyde; superoxide dismutase; catalase; glutathione transferase; glutathione peroxidase; glutathione reductase; and histopathological damage were evaluated. Our results revealed that rats in the torsion/detorsion group exhibited elevated testicular levels of oxidative markers and proinflammatory cytokines, low levels of antioxidant enzymes, and severe histological alterations relative to the control and sham groups. Treatments with 1000 and 5000 mg/kg BW of PP for 4 hr and 7 days significantly (p < 0.05) decreased the levels of the proinflammatory and oxidative markers while increasing the spermatogenesis, testicular levels of antioxidant enzymes, and anti-inflammatory cytokine (IL-10) in a dose-dependent manner. This suggested that PP exhibited anti-inflammatory and antioxidant activities against I/R testes thus serving as an effective supplement to protect against testicular assault.

Sinapic acid reduces ischemia/reperfusion injury due to testicular torsion/detorsion in rats

This study aimed to investigate the protective effect of sinapic acid (SA) on biochemical and histopathological changes in an experimental testicular torsion-detorsion rat model. Twenty-four rats were randomised into four groups: sham group, ischemia/reperfusion (IR) group subjected to testicular torsion for 2 hr and then detorsion for 4 hr, and two groups treated with SA1 and SA2 (10 mg/kg and 20 mg/kg, by single intraperitoneal injection, 30 min before reperfusion). Serum testosterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were measured by an autoanalyzer, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), protein carbonyl (PC), and nitric oxide (NO) oxidative stress parameters by spectrophotometric methods, and tumour necrosis factor (TNF-α), interleukin-1 beta (IL-1β), and interleukin 6 (IL-6) parameters by the Elisa method. In addition, immunohistochemical and histopathological examinations were performed on testicular tissues. There was no significant difference between the groups in terms of serum testosterone, FSH and LH levels (p > .05). SA significantly reduced increased testicular damage, oxidative stress, inflammation, cell death and also restored decreased antioxidant enzyme activities (p < .05). Pre-treatment of rats with SA reduced testicular dysfunction and morphological changes IRI. SA's antioxidant, anti-inflammatory, and antiapoptotic properties were found to be protective against testicular IR.

Renal Protective Effect of Beluga Lentil Pretreatment for Ischemia-Reperfusion Injury

Materials and Methods

Mice were divided into four groups: normal, untreated, low- (2 mg), and high-dose (8 mg) beluga lentil treatment groups. Beluga lentil was orally administered for 2 weeks, followed by bilateral renal ischemia for 20 min and reperfusion for 30 min. Blood samples and kidney tissues were collected and analyzed to investigate renal function, histopathology, epithelial and endothelial cell damage, apoptosis, oxidative stress, and inflammatory responses.

Results

The pretreated groups maintained renal function, with significantly lower blood urea nitrogen (BUN) and creatinine levels, compared with the other groups. The histopathological analysis showed reduced proximal tubule injury and decreased injury-related molecule (kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL)) secretion in the pretreated groups compared with the other groups. Terminal deoxynucleotidyl transferase dUTP nick-end labeling- (TUNEL-) positive cells and the secretion of apoptosis-related molecules (Fas and caspase 3) were significantly reduced in the pretreated groups compared with the other groups. The pretreated groups showed positive microvessel-associated gene (cluster of differentiation (CD31)) expression and negative adhesion molecule (intracellular adhesion molecule 1 (ICAM-1)) expression. An antioxidant effect was observed in the pretreatment groups, with reduced malonaldehyde (MDA) expression and increased antioxidant enzyme (superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GPx)) secretion. In the pretreated groups, F4/80+ macrophages and CD4+ T cell infiltration were inhibited and proinflammatory cytokine (interleukin- (IL-) 1β, IL-6, and tumor necrosis factor- (TNF-) α) levels decreased; however, the levels of anti-inflammatory cytokines (transforming growth factor- (TGF-) β, IL-10, and IL-22) increased.

Conclusions

Beluga lentil pretreatment demonstrated protective effects against I/R-induced renal damage, via antiapoptotic, anti-inflammatory, and antioxidant activities.

Proxeed plus salvage rat testis from ischemia- reperfused injury by enhancing antioxidant's activities and inhibition of iNOS expression

Testicular torsion is an acute urological emergency condition that occurs due to obstruction of blood flow to the testicles which may result in ischemia and loss of testicular functions. This study examined the protective effects of Proxeed Plus (PP), a dietary supplement on testicular ischemia/reperfusion (I/R) injured rats using oxidative stress markers, hormonal levels, apoptotic parameters, histological and immunohistochemistry analysis at 4 h and after 7 days of reperfusion. The protective treatment of the I/R injured rats with PP at 1000 and 5000 mg/kg body weight (bw) resulted in significant increases in the serum and tissue antioxidative defense capacities (superoxide dismutase, reduced glutathione, catalase, glutathione-s-transferase, and glutathione peroxidase), sex hormones (luteinizing hormone, follicle-stimulating hormone, and testosterone), also reduce pro-oxidative markers (malondialdehyde and hydrogen peroxide), serum iNOS and apoptotic parameters (Caspase -3 and Caspase -9) in comparison to the results detected in the I/R untreated rats. It was also observed that PP ameliorated histological changes of I/R injured rats; increased spermatogenetic activity, seminiferous tubular diameter, Leydig cell mass, and reduced expressions of testicular inducible nitric oxide synthase (iNOS). Therefore, the therapeutic use of Proxeed Plus could be considered a promising approach in averting testicular damage against I/R injury.

Protective effect of dipeptidyl peptidase-4 inhibitors in testicular torsion/detorsion in rats: a possible role of HIF-1α and nitric oxide

Spermatic cord torsion is a serious and common urologic emergency. It requires early diagnosis for prevention of subfertility and testicular necrosis. Vildagliptin and sitagliptin are anti-diabetic drugs of the dipeptidyl peptidase-4 (DPP-4) inhibitors that have a protective role against cerebral ischemic stroke and cardiac ischemia reperfusion. This study aimed to investigate the role and mechanism of action of vildagliptin and sitagliptin in a model of testicular ischemia/reperfusion injury by testicular torsion/detorsion (T/D). Testicular T/D was done and vildagliptin and sitagliptin were administered either alone or in combination with nitric oxide synthase (NOS) inhibitor. Serum total cholesterol and testosterone were measured, while in testicular tissue testosterone, malondialdehyde (MDA) level, total antioxidant capacity (TAC), nitric oxide level, caspase-3, superoxide dismutase (SOD), hypoxia-inducible factor-1α (HIF-1α), tumor necrosis factor-α (TNF-α) and endothelial NOS (eNOS), and inducible NOS (iNOS) and neuronal NOS (nNOS) were measured. Histopathology of testicular tissue was done. Vildagliptin and sitagliptin increased serum testosterone, expression, and activity of SOD and testicular TAC. It also reduced total serum cholesterol, testicular MDA, caspase-3, HIF-1α, TNF-α, and expression of eNOS, iNOS, and nNOS. Vildagliptin and sitagliptin also improved histopathological picture of testicular tissue. NOS inhibitor produced similar result to DDP-4 inhibitors; however, its co-administration augmented the effect of vildagliptin and sitagliptin on these parameters. DPP-4 inhibitors, vildagliptin, and sitagliptin were protective against testicular T/D-induced injury mostly by anti-oxidative stress, and anti-apoptotic and anti-inflammatory actions that was augmented by NOS inhibition with a possible role for HIF-1α expression.

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.

The protective effect of low-energy shock wave on testicular ischemia-reperfusion injury is mediated by the PI3K/AKT/NRF2 pathway

AIMS

Testicular ischemia-reperfusion (IR) injury is the primary pathophysiological consequence of testicular torsion. Low-energy shock wave (LESW) is an effective treatment for certain diseases. The present study investigated whether LESW could improve on testicular IR injury in rats and examined the involved mechanism.

MAIN METHODS

Testicular reperfusion was induced in rats after 1-h ischemia. The first LESW treatment was performed 30 min prior to testicular reperfusion, and then every other day for another 3 applications. LY294002 was applied to investigate the involved mechanism. Testicular morphological changes and malonaldehyde (MDA) level were respectively assessed by hematoxylin-eosin staining. Western blot and thiobarbituric acid method. Western blot, real-time quantitative PCR and immunohistochemistry were performed to assess the apoptosis, the activation of phosphatidylinositol-4,5-bisphosphate 3-kinase/protein kinase B (PI3K/AKT) pathway the nuclear factor erythroid 2-related factor 2 (NRF2) and vascular endothelial growth factor A (VEGF-A) level in the testis of rats.

KEY FINDINGS

LESW improved testicular IR injury in rats. Moreover, LESW upregulated the phosphorylation levels of AKT and glycogen synthase kinase 3β (GSK-3β). Also, it upregulated the levels of nuclear NRF2, heme oxygenase 1 (HO-1) and NAD(P)H quinone dehydrogenase 1 (NQO-1) in these rats. Nevertheless, LY294002 blocked these protective effects. LESW also upregulated VEGF-A level in rats with testicular IR injury.

SIGNIFICANCE

This study demonstrated that LESW could ameliorate testicular IR injury in rats, which might be attributed to the activation of PI3K/AKT/NRF2 pathway. These findings suggested the potential of LESW in the treatment of testicular torsion.