Probucol Reduces Testicular Torsion/Detorsion-Induced Ischemia/Reperfusion Injury in Rats

Pathophysiology and management of testicular ischemia/reperfusion injury: Lessons from animal models

Testicular torsion is a urological emergency that involves the twisting of the spermatic cord along its course. Compelling pieces of evidence have implicated oxidative stress-sensitive signaling in pathogenesis of testicular I/R injury. Although, surgical detorsion is the mainstay management; blockade of the pathways involved in the pathogenesis may improve the surgical outcome. Experimental studies using various testicular I/R models have been reported in a bid to explore the mechanisms associated with testicular I/R and evaluate the benefits of potential therapeutic measures; however, most are limited by their shortcomings. Thus, this review was intended to describe the details of the available testicular I/R models as well as their merits and drawbacks, the pathophysiological basis and consequences of testicular I/R, and the pharmacological agents that have being proposed to confer testicular benefits against testicular I/R. This provides an understanding of the pathophysiological events and available models used in studying testicular I/R. In addition, this research provides evidence-based molecules with therapeutic potentials as well as their mechanisms of action in testicular I/R.

Testicular torsion in vivo models: Mechanisms and treatments

BACKGROUND

Testicular torsion is a condition in which a testis rotates around its longitudinal axis and twists the spermatic cord. This in turn results in a significant decrease in blood flow and perfusion of testicular tissue. During Testicular torsion, the testicular tissue is affected by ischemia, heat stress, hypoxia, and oxidative and nitrosative stress. The testicular torsion should be considered an emergency condition and surgical intervention (testicular detorsion ) as the sole treatment option in viable cases involves counter-rotation on twisted testes associated, when possible, to orchipexy, in order to avoid recurrence. Possible testicular detorsion side-effects occur due to reperfusion and endothelial cells injury, microcirculation disturbances, and intense germ cells loss.

OBJECTIVES

To discuss testicular torsion surgery-based methods, different time frames for testicular torsion induction, and the associated pathophysiology by emphasizing cellular and molecular events as well as different therapeutic agent applications for testicular torsion.

MATERIALS AND METHODS

We reviewed all original research and epidemiological papers related to testicular torsion condition.

RESULTS

Testicular torsion causes germ cell necrosis, arrested spermatogenesis, and diminished testosterone levels, with consequent infertility. Among different involved pathophysiological impacts, testicular torsion/detorsion-induced ischemia seems to play the key role by leading the tissue toward other series of events in testis. Numerous studies have used adjuvant antioxidants, calcium channel blockers, anti-inflammatory agents, or vasodilating agents in order to decrease these effects.

DISCUSSION AND CONCLUSION

To the best of our knowledge, no previously conducted study examined therapeutical agents' beneficial effects post clinical I/R condition in humans. Different agents targeting different pathophysiological conditions were used to ameliorate the ischemia/reperfusion-induced condition in animal models, however, none of the administrated agents were tested in human cases. Although considering testicular detorsion surgery is still the golden method to reverse the testicular torsion condition and the surgical approach is undeniable, the evaluated agents with beneficial effects, need to be investigated furthermore in clinical conditions. Thus, furthermore clinical studies and case reports are required to approve the animal models proposed agents' beneficial impacts.

Oct4 reduction contributes to testicular injury of unilateral testicular torsion in mice model and apoptotic death of Sertoli cells through mediating CIP2A expression

This study explored the mechanism of ipsilateral testis injury after ipsilateral testicular torsion detorsion (T/D) and the potential testis-protective part of the octamer-binding transcription factor 4 (Oct4)-cancerous inhibitors of protein phosphatase 2A (CIP2A) axis in a T/D animal model and in ischemia-reperfusion (IR)-treated testicular Sertoli TM4 cells. Quantitative Polymerase chain reaction (PCR) and western blot (WB) confirmed the downregulation of both CIP2A and Oct4 expression in the testicular tissue from T/D mice compared with sham-operated mice. T/D model was then established in mice with upregulated Oct4 expression in the testis. Oct4 elevation restored CIP2A expression in testes after T/D treatment. Furthermore, we observed that an increase in Oct4 ameliorated the testicular damage caused by torsion in the testis. Biochemical analysis indicated that T/D treatment increased serum anti-sperm antibody levels, but reduced testosterone levels. Meanwhile, in testicular tissue, reactive oxygen species (ROS), malondialdehyde (MDA), and activity of testicular myeloperoxidase (MPO) enzymes were promoted, while glutathione peroxidase activity (GPx) was decreased by T/D injury. Notably, testicular Oct4 restoration partially counteracted the effect of T/D treatment on these biochemical indices. Hypoxia/reoxygenation (HR) treatment was applied to TM4 cells to mimic TT injury in vitro. A gain-of-function study showed that Oct4 overexpression partly counteracted the promoting role of HR in cell damage, apoptosis, and oxidative stress in TM4 cells. These observations provide novel insights into the possible biochemical mechanism underlying the mediation of the Oct4-CIP2A axis in T/D injury.

Adipose Mesenchymal Stromal Cell-Derived Exosomes Prevent Testicular Torsion Injury via Activating PI3K/AKT and MAPK/ERK1/2 Pathways

Adipose mesenchymal stromal cell-derived exosomes (ADSC-Exos) have shown great potential in the treatment of oxidative stress induced by ischemia-reperfusion injury. However, alleviation of testicular torsion injury by ADSC-Exos has not been reported. Therefore, we investigated the protective effect of ADSC-Exos against testicular torsion-detorsion injury. ADSC-Exos were isolated by ultracentrifugation and injected into torsion-detorsion-affected testes of rats. H&E staining and sperm quality were used to evaluate the therapeutic effects of ADSC-Exos, and tissue oxidative stress was measured by determining MDA and SOD levels. In addition, TUNEL staining and immunohistological analysis (Ki67, Cleaved Caspase-3, IL-6, IL-10, CCR7, and CD163) were used to clarify the effects of ADSC-Exos on spermatogenic cell proliferation, apoptosis, and the inflammatory microenvironment in vivo. Possible signaling pathways were predicted using sequencing technology and bioinformatics analysis. The predicted signaling pathways were validated in vitro by assessing the proliferation (EdU assay), migration (transwell assay and scratch test), and apoptosis (flow cytometry, TUNEL staining, and western blotting) of spermatogenic cells. The results showed that ADSC-Exos alleviated testicular torsion-detorsion injury by attenuating oxidative stress and the inflammatory response. In addition, ADSC-Exos promoted the proliferation and migration of spermatogenic cells and inhibited their apoptosis by activating the PI3K/AKT and MAPK/ERK1/2 signaling pathways.

Salidroside Exerts Beneficial Effect on Testicular Ischemia-Reperfusion Injury in Rats

Testicular torsion-detorsion results in testicular ischemia-reperfusion injury, which is associated with overgeneration of reactive oxygen species. Salidroside, a major bioactive ingredient extracted from Rhodiola rosea, has strong antioxidant activity. The purpose of this study was to examine the effect of salidroside on testicular ischemia-reperfusion injury. Sixty rats were randomly separated into 3 experimental groups: group A = sham-operated control; group B = testicular ischemia-reperfusion; and group C = testicular ischemia-reperfusion treated with salidroside. The rats in the sham-operated control group received all surgical procedures except testicular torsion-detorsion. The testicular ischemia-reperfusion group underwent 2 hours of left testicular torsion followed by detorsion. The rats in the salidroside-treated group received the same surgical procedure as in testicular ischemia-reperfusion group, but salidroside was injected intraperitoneally at reperfusion. Testicular malondialdehyde content (a reliable index of reactive oxygen species) and protein expression of superoxide dismutase and catalase which are primary antioxidant enzymes in testes were measured at 4 hours after reperfusion. Testicular spermatogenesis was evaluated at 3 months after reperfusion. The malondialdehyde content increased significantly, while superoxide dismutase and catalase protein expression and testicular spermatogenesis reduced significantly in ipsilateral testes of testicular ischemia-reperfusion group, as compared with sham-operated control group. Therapy with salidroside significantly reduced malondialdehyde content and significantly enhanced superoxide dismutase and catalase protein expression and spermatogenesis in ipsilateral testes, as compared with testicular ischemia-reperfusion group. The present findings indicate that treatment with salidroside ameliorates testicular ischemia-reperfusion injury by reducing reactive oxygen species level by upregulating superoxide dismutase and catalase protein expression.

Semaglutide early intervention attenuated testicular dysfunction by targeting the GLP-1-PPAR-α-Kisspeptin-Steroidogenesis signaling pathway in a testicular ischemia-reperfusion rat model

Testicular torsion is a serious emergency and a well-known cause of male infertility. It represents 10 %-15 % of scrotal diseases in children. Kisspeptin (KISS1) is a hormone secreted from the hypothalamic nuclei and testis, but its role in testis is not fully understood. Semaglutide is a novel antidiabetic glucagon-like peptide 1 (GLP-1) analog. Hence, we designed the current study to elucidate the possible ameliorative effect of semaglutide on ischemia/reperfusion-induced testicular dysfunction in rats and highlight the role of the testicular GLP-1/PCG-1α-PPAR-α-KISS1 signaling pathway. We randomly divided 50 male Sprague Dawley into five equal groups (10 rats each): SHAM, exendin 9-39 -treated (EX), testicular torsion/detorsion (T/D), testicular torsion/detorsion and semaglutide-treated (SEM + T/D), and testicular torsion/detorsion, exendin, and semaglutide-treated (EX + SEM + T/D). We quantified serum follicle-stimulating hormone, luteinizing hormone, total testosterone, testicular oxidative stress markers, testicular gene expression of GLP-1/KISS1 pathway-related genes (KISS1, KISS1R, GLP-1, GLP-1R, PGC-1α, PPAR-α), steroidogenesis pathway-related genes (STAR, CYP11A1, CYP17A1, HSD17B3, CYP19A1), HO-1, Nrf-2, and testicular protein expression of HIF-1α, TNF-α, NF-κβ, Caspase-3, FAS, proliferating cell nuclear antigen, and KISS1 through testicular histopathology and immunohistochemistry assays. Testicular torsion/detorsion markedly elevated proapoptotic, proinflammatory, and oxidative stress marker levels, noticeably downregulating the expression of GLP-1/KISS1 and steroidogenesis pathway-related proteins. Semaglutide administration significantly ameliorated all these deleterious effects. Nevertheless, injecting exendin, a GLP1-R antagonist, before semaglutide abolished all the documented improvements. We concluded that semaglutide ameliorated ischemia/reperfusion-induced testicular dysfunction by modulating the GLP-1/PGC-1α-PPAR-α/KISS1/steroidogenesis signaling pathway, improving testicular oxidative state, and suppressing testicular inflammation and apoptosis.

Apoptotic balance during testicular detorsion after one hour induced torsion in rats

Testicular torsion (TT) is an emergency complication that leads to oxidative stress and adversely affects spermatogenesis. Although immediate treatment consists of testicular detorsion (TD) to reverse TT-induced ischemia, mechanisms underlying recovery have yet to be fully understood. The current study aimed to investigate TD effects after a one-hour experimental TT by evaluating testicular antioxidant status and apoptosis-related proteins. Forty male Wistar rats were submitted to TT by testicular rotation, for one hour. Following TT, 32 rats were submitted to TD for 1, 2, 4, and 8 h (N = 8/group), the other 8 rats euthanized as TT-only. For controls, 8 rats were sham-operated. Testicular tissues were aseptically dissected for biochemical, histopathological, and immunohistochemistry analyses. The TD groups, especially after 4 h of TD, exhibited diminished MDA and increased TAC and GPX levels in testicular tissue. Levels of p53 and Caspase-3 were down-regulated in T1D4 and T1D8 groups versus torsion group. Bcl-2 was increased in T1D4 and T1D8 groups compared to the TT group. Moreover, spermatogenesis was recovered in T1D4 and T1D8 groups compared to the TT group. It can be concluded that after 1 h TT in rats, at least 4 h post-TD is needed for testicular tissue to initiate recovery.

Vitamin D3 Prevents the Deleterious Effects of Testicular Torsion on Testis by Targeting miRNA-145 and ADAM17: In Silico and In Vivo Study

Testicular torsion (TT) is the most common urological emergency in children and young adults that can lead to infertility in many cases. The ischemia-reperfusion (IR) injury due to TT has been implicated in the pathogenesis of testicular damage. The main pathological mechanisms of contralateral injury after ipsilateral TT are not fully understood. In the presented study, we investigated the molecular and microscopic basis of ipsilateral and contralateral testicular injury following ipsilateral testicular torsion detorsion (T/D) and explored the possible protective role of vitamin D3. The biochemical analysis indicated that IR injury following T/D significantly decreased the activity of testicular glutathione peroxidase (GPx) enzyme, level of serum testosterone, serum inhibin B, and expression of testicular miRNA145, while increased the activity of testicular myeloperoxidase (MPO) enzyme, level of testicular malondialdehyde (MDA), level of serum antisperm-antibody (AsAb), and expression of ADAM-17. The histological and semen analysis revealed that torsion of the testis caused damages on different tissues in testis. Interestingly, administration of vitamin D3 prior to the IR injury reversed the deterioration effect of IR injury on the testicular tissues as indicated by biochemical and histological analysis which revealed normal appearance of the seminiferous tubules with an apparent decrease in collagen fiber deposition in both ipsilateral and contralateral testes. Our results revealed that the protective effect of vitamin D3 treatment could be attributed to target miRNA145 and ADAM17 protein. To further investigate these findings, we performed a detailed molecular modelling study in order to explore the binding affinity of vitamin D3 toward ADAM17 protein. Our results revealed that vitamin D3 has the ability to bind to the active site of ADAM17 protein via a set of hydrophobic and hydrophilic interactions with high docking score. In conclusion, this study highlights the protective pharmacological application of vitamin D3 to ameliorate the damages of testicular T/D on the testicular tissues via targeting miRNA145 and ADAM17 protein.

Varenicline limits ischemia reperfusion injury following testicular torsion in mice

BACKGROUND

Torsion of the spermatic cord and the resulting testicular ischemia leads to the production of inflammatory cytokines and cell death due to impaired aerobic metabolism. Following reperfusion of the testis, a robust innate inflammatory response furthers tissue injury due to the production of reactive oxygen species and disruption of normal capillary function. Blunting the innate immune response with antioxidants, anti-inflammatory medications and targeted genetic interventions reduces long term testicular injury in animal models of torsion, however these approaches have limited clinical applicability. Mediated via α7 nACh receptors, the cholinergic anti-inflammatory pathway limits NFKB signaling and prevents renal fibrosis following warm renal ischemia. We identified varenicline as an FDA approved α7 nAChR agonist and hypothesized that varenicline administration would decrease long-term testicular atrophy and fibrosis in a murine model of testicular torsion.

METHODS

Using an established model, unilateral testicular torsion was induced in mature male CD1 mice by rotating the right testicle 720° for 2 h. In the treatment group, 4 doses of varenicline (1mg/grm) were administered via intraperitoneal injection every 12 h, with the first dose given 1 h after the creation of testicular torsion. The acute inflammatory response was evaluated 48 h following reperfusion of the testis. Long term outcomes were evaluated 30 days following testicular perfusion.

RESULTS

48 h following reperfusion, the testis of animals treated with varenicline demonstrated a significant reduction in the inflammatory response as measured by the acute immune cell infiltrate, myeloperoxidase activity, concentration of reduced glutathione and expression of downstream NF-KB targets. 30 days following reperfusion, animals treated with varenicline, demonstrated decreased testicular atrophy (Summary Figure), fibrosis and expression of pro-fibrotic genes.

CONCLUSION

Activation of a central immunosuppressive cascade with varenicline after the onset of testicular torsion reduces ischemia reperfusion injury and prevents long term testicular atrophy and fibrosis. Further studies are needed to define the optimum dose and varenicline administration regimen. Our results suggest that varenicline offers a novel, FDA approved, adjunct to the current management of testicular torsion.

Leech therapy (Hirudo medicinalis) attenuates testicular damages induced by testicular ischemia/reperfusion in an animal model

BACKGROUND

Testicular torsion/detorsion triggers tissue ischemia/reperfusion, leading to reactive oxygen species overgeneration and apoptosis. The saliva of leeches is full of anti-inflammatory, anticoagulants, antioxidants, and antimicrobial agents. Therefore, this study aimed to assess the protective mechanism of leech therapy on testicular ischemia/reperfusion damage.

METHODS

18 adult male rats were randomly divided into three groups: 1-Sham-operated group (SO). 2-Torsion/detorsion (T.D) group: two hours of testicular torsion with two hours of testicular detorsion was performed. 3-Torsion/detorsion + Leech therapy (TDL) group. Sperm parameters (motility, vitality, morphology, and concentration), oxidative stress biomarkers (MDA, CAT, GPx, and TAC), histopathological factors (Mean seminiferous tubular diameter, Germinal epithelial cell thickness, Testicular capsule thickness, Johnson's score, and Cosentino's score), and immunohistochemical markers for apoptosis detection (Bax, Bcl-2, and Caspase-3) were measured.

RESULTS

There was a significant difference for all sperm parameters in the T. D group compared to the sham group. Leech therapy significantly increased progressive motility and normal morphology and reduced non-progressive motility. In the TDL group, MDA concentration significantly reduced, and levels of GPx, TAC, and CAT remarkably increased. All evaluated histopathological parameters in the TDL group significantly increased compared to the T. D group except for the testicular capsule thickness. T. D notably increased the expression of Bax and Caspase-3, while the treatment group slowed the rate of apoptosis compared to the control group. Bcl-2 expression in the T. D group was significantly lower than that in the sham group. Leech therapy increased the Bcl-2 expression.

CONCLUSION

Leech therapy attenuates damages to testicular tissue following torsion/detorsion due to its antioxidant, anti-inflammatory, and anti-apoptotic effects. Hence, it can be considered as an effective remedy for testicular ischemia/reperfusion.

Cross-link between mitochondrial-dependent apoptosis and cell cycle checkpoint proteins after experimental torsion and detorsion in rats

The current study assessed the cross-link between mitochondria-related apoptosis and cell cycle machinery systems during ischemia and reperfusion in a rat model of testicular torsion and detorsion. The Wistar male rats were divided into control, 1 h, 2 h, 4 h and 8 h testicular torsion-induced, and 1 h, 2 h, 4 h and 8 h testicular detorsion-induced groups. The Johnson's score was analyzed. The mRNA and protein contents of Bcl-2, Bax, Caspase-3, Cyclin D1, Cdk4, P21 and P53 were investigated by sqRT-PCR and immunohistochemical staining, respectively. The apoptosis index was analyzed by TUNEL staining. The mRNA levels of bax, p53, p21 and cyclin D1 were increased, and the mRNA levels of bcl-2 and cdk4 were decreased in torsion and reperfusion-induced groups, time-dependently. The caspase-3 mRNA was increased in torsion-induced and diminished in detorsion-induced groups. A time-dependent reduction in Bcl-2⁺, Caspase-3⁺, Cyclin D1⁺, Cdk4⁺ and P53⁺ and increment in P21⁺ cells distribution per mm² of tissue were revealed after torsion and detorsion. The apoptosis index was increased after torsion and decreased after detorsion. In conclusion, torsion-induced severe DNA damage stimulates the cyclin D1, p53 and p21 mRNA expression while more than 8 h is needed to reveal them as protein content in testicular tissue. About detorsion, decreased Cyclin D1 and Cdk4 proteins and the P53-induced transcriptional effect on p21 expression, stimulates the p21 bind to cdk4 and consequent failure in Cyclin D1/Cdk4 complex formation. This situation in association with apoptotic genes results in spermatogenesis failure.

Milrinone ameliorates ischaemia-reperfusion injury in experimental testicular torsion/detorsion rat model

This experimental study aims to evaluate the efficacy of milrinone against ischaemia-reperfusion injury due to testicular torsion/detorsion. Group 1 was defined as the control group. Testicular torsion/detorsion model was performed in Group 2. Group 3 had similar procedures to the rats in Group 2. In addition, 0.5 mg/kg of milrinone was administered intraperitoneally immediately after testicular torsion in Group 3. Histopathological examinations indicated a dramatic improvement in terms of inflammation, haemorrhage, oedema, congestion, Cosentino and Johnson scores in Group 3 compared to Group 2 (p = .037, p = .045, p = .018, p = .040, p = .033 and p = .03 respectively). Blood biochemical analyses, superoxide dismutase (SOD), glutathione peroxidase (GSH-px) activity and total antioxidant status (TAS) levels increased significantly in Group 3 compared to Group 2 (p = .001, p = .024 and p < .001). Malondialdehyde (MDA), protein carbonyl (PC), interleukin 1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and total oxidant status (TOS) levels decreased in Group 3 compared to Group 2 (p = .001, p = .018, p < .001, p = .036 and p = .002 respectively). Tissue biochemical analyses determined an increase in SOD and GSH-px activity in Group 3 compared to Group 2, while PC and MDA levels were reduced (p = .001, p < .001, p = .038 and p < .001 respectively). Milrinone attenuates ischaemia-reperfusion injury that causes highly harmful effects due to testicular torsion/detorsion.

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.

Administration of Dexmedetomidine Does Not Produce Long-Term Protective Effect on Testicular Damage Post Testicular Ischemia-Reperfusion Injury

Background

After surgical correction of testicular torsion, up to 68% of ipsilateral testes undergo atrophy due to ischemia-reperfusion injury (IRI). Recent studies have shown that dexmedetomidine (Dex) alleviates IRI in various vital organs. However, those studies evaluated its protective effect on short-term reperfusion.

Purpose

We aimed to investigate whether Dex has a long-term protective effect against testicular injury after IRI.

Materials and Methods

A total of 24 New Zealand white rabbits were randomly divided into three groups (n = 8/group): the control group (saline-infused rabbits without IRI), the IRI group (saline-injected rabbits with IRI), and the Dex group (Dex-injected rabbits with IRI). The spermatic cord of rabbits in IRI and Dex groups was ligated for 4 h, and 1 h before reperfusion, Dex was administered intraperitoneally at a dose of 50 μg/kg body weight in group Dex, whereas saline was administered at the same dose to the IRI and control groups. Rabbits were kept alive for 4 weeks post reperfusion, then the testes were harvested, and the rabbits were euthanized.

Results

Four weeks post reperfusion, testicular volumes of the affected side decreased considerably in the IRI and Dex groups compared to the control group, with no significant difference between the IRI and Dex groups. Compared to the control group, the Johnson score and the mean seminiferous tubular diameters were significantly decreased in the IRI and Dex groups, but no significant differences were observed after administration of Dex. There were no significant differences in malondialdehyde and superoxide dismutase levels between the groups treated with and without Dex.

Conclusion

Dex administration 3 h after ischemia and 1 h before reperfusion did not demonstrate a significant protective effect against testicular injury 4 weeks after IRI in rabbits. Further research is needed to confirm the potential therapeutic effects of Dex by varying the experimental conditions.

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.

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.