Protective effect of remote ischemic postconditioning in rat testes after testicular torsion/detorsion

Aloperine protects the testis against testicular ischemia/reperfusion injury in rats

BACKGROUND

Testicular torsion/detorsion can cause testis loss and infertility. Aloperine is a major active alkaloid extracted from Sophora alopecuroides Linn. It has been shown to have organ-protective effects. However, the effects of aloperine on the testis and its underlying mechanisms remain unclear.

OBJECTIVES

This study investigated the effect of aloperine on testicular torsion/detorsion injury in rats.

MATERIALS AND METHODS

Male Sprague-Dawley rats were randomized to the sham-operated (sham), testicular I/R (TI/R), or aloperine preconditioning (ALOPre) or postconditioning (ALOPost) groups. All rats except for the sham-operated rats were subjected to 3 h of right spermatic cord torsion (720°, clockwise), followed by 3 h of detorsion. Aloperine (10 mg/kg) was intravenously administered before testicular torsion (ALOPre) or at the onset of testicular detorsion (ALOPost). The therapeutic efficacy of aloperine was evaluated by histological analysis, oxidative stress evaluation, inflammatory response examination, apoptosis analysis, protein analysis, and immunohistological assessment.

RESULTS

Compared with TI/R, aloperine protected both the ipsilateral and contralateral testes against unilateral testicular I/R, as evidenced by a reduced testicular weight to body weight (TW/BW) ratio (ALOPre: p = 0.0037; ALOPost: p = 0.0021) and volume (ALOPre: p = 0.0020; ALOPost: p = 0.0009), less structural damage with better Johnsen (ALOPre: p = 0.0013; ALOPost: p = 0.0021), and Cosentino scores (ALOPre: p < 0.0001; ALOPost: p < 0.0001), increased mean seminiferous tubule diameter and mean seminiferous tubule epithelial height, decreased testicular apoptosis, and less oxidative stress and inflammatory response. In addition, aloperine significantly stimulated the phosphorylation of signal transducer and activator of transcription (STAT)-3 in the ipsilateral testes following detorsion. Administration of Ag490 suppressed STAT-3 phosphorylation, thereby abrogating the protective effects exerted by aloperine on the ipsilateral testis.

DISCUSSION AND CONCLUSION

Aloperine has a strong testicular protective effect on the ipsilateral and contralateral testes after testicular torsion/detorsion. This aloperine-induced ipsilateral testicular protection is mediated via the STAT-3 signaling pathway.

Remote Ischemic Postconditioning Improve Cerebral Ischemia-Reperfusion Injury Induced Cognitive Dysfunction through Suppressing Mitochondrial Apoptosis in Hippocampus via TK/BK/B2R-Mediated PI3K/AKT

Remote ischemic postconditioning (RIPostC) is known to improve motor function recovery in animal models, but its efficacy in alleviating cognitive impairment caused by ischemic stroke remains unclear. This study aims to investigate the beneficial role of RIPostC in recovering cognitive impairment induced by cerebral ischemia-reperfusion injury (CIRI). Building upon our previous research findings, we proved that the TK/BK/B2R pathway is crucial for understanding the crosstalk between cognitive impairment and RIPostC. Additionally, in vitro experiments were conducted using the oxygen glucose deprivation/re-oxygenation (OGD/r) HT-22 cell model, which revealed that the mechanism by which RIPostC suppressed mitochondrial apoptosis was mainly through the activation of the B2R/PI3K/AKT signaling pathway, thereby protecting neurons in the ischemic hippocampus from ischemic damage. To investigate the effect of RIPostC on cognitive function recovery following ischemic stroke, we established a rat model using left middle cerebral artery occlusion reperfusion (MCAO/r). 48 h after MCAO/r, rats were subjected to 3 circles of RIPostC therapy daily for 12 consecutive days. HOE140 was used to antagonize the bradykinin 2 receptor (B2R). Cognitive function was assessed using a modified neurological severity score, the Morris water maze, and the novel object recognition test. Local infarct volume in the hippocampus was measured through MRI scanning. The apoptosis rate of hippocampal neurons was quantified using TUNEL staining. Protein expression levels of kallikrein (TK) and mitochondrial apoptosis-related proteins, Cyt c, Bcl-2, Bax, cleaved caspase-3, and cleaved caspase-9, were detected in ischemic hippocampal tissue using Western blot (WB). The expression of bradykinin (BK) in serum and the ischemic penumbra was measured using an enzyme-linked immunosorbent (ELISA) assay. In the cell experiments, the HT-22 cell line and OGD/r model were used to simulate in vitro hippocampal ischemia. WB was performed to detect the expression of apoptosis-related proteins and PI3K/AKT pathway proteins. The apoptosis rate of HT-22 cells was detected using Annexin-V/PI flow cytometry and a cell viability kit. JC-1 staining and reactive oxygen species staining were used to evaluate mitochondrial condition. The PI3K/AKT pathway was inhibited using LY294002. RIPostC significantly upregulated the concentrations of TK and BK in the ischemic hippocampus. Behavioral function tests demonstrated that daily RIPostC therapy for 12 days significantly promoted cognitive function recovery in MCAO/r rats. Through MRI analysis, we found that RIPostC therapy effectively reduced the infarct volume in the hippocampus. Additionally, TUNEL staining and WB results of apoptosis-related proteins showed that RIPostC therapy significantly reduced apoptosis of hippocampal neurons. However, the therapeutic effect of RIPostC was reversed by the B2R antagonist HOE14, indicating that the TK/BK/B2R pathway mediated the neuroprotective effect of RIPostC. Cell experiments further confirmed that BK/B2R significantly attenuated mitochondrial apoptosis induced by ischemia-hypoxia injury in HT-22 cells. In vivo and in vitro results from WB demonstrated that the BK/B2R pathway activated the PI3K/AKT signaling pathway. Finally, the PI3K inhibitor LY294002 reversed the anti-apoptotic effect induced by BK/B2R. RIPostC therapy effectively inhibited mitochondrial apoptosis of hippocampal neurons and significantly alleviated cognitive dysfunction associated with CIRI by regulating the TK/BK/B2R-medated PI3K/AKT pathway. In conclusion, RIPostC represents a promising therapeutic strategy for combating cognitive dysfunction by inhibiting cell apoptosis in hippocampus. Moreover, our results suggest that RIPostC may have a broader protective effect against apoptosis in other ischemia-reperfusion-related diseases.

Effect of sulforaphane on testicular ischemia-reperfusion injury induced by testicular torsion-detorsion in rats

Testicular ischemia-reperfusion induces enhanced concentration of reactive oxygen species. The increased reactive oxygen species harm cellular lipids, nucleic acids, proteins, and carbohydrates, and ultimately cause testicular injury. Sulforaphane, a kind of natural dietary isothiocyanate, exists predominantly in some cruciferous vegetables, like broccoli and cabbage. It can protect tissues from oxidative stress-induced damage. Herein, we analyzed the effectiveness of sulforaphane in treating ischemia-reperfusion injury occurring after testicular torsion-detorsion. Male rats (n = 60) were grouped as follows: sham-operated group, unilateral testicular ischemia-reperfusion group, and unilateral testicular ischemia-reperfusion group receiving sulforaphane treatment at 5 mg/kg. No testicular torsion-detorsion was performed in the sham group. Unilateral testicular ischemia-reperfusion model was created by detorsion after 2 h of left testicular torsion. In the sulforaphane-treated group, intraperitoneal sulforaphane (5 mg/kg) was administered at left testicular detorsion. Biochemical assay, Western blot, and hematoxylin and eosin staining were used to evaluate testicular malondialdehyde content (an important marker of reactive oxygen species), protein levels of superoxide dismutase and catalase (intracellular antioxidant defense mechanism), and testicular reproductive function, respectively. In testicular tissues, malondialdehyde content was significantly promoted, while protein levels of superoxide dismutase and catalase, and testicular reproductive function were significantly reduced in ipsilateral testes by testicular ischemia-reperfusion. Nevertheless, sulforaphane administration partially reversed the effect of testicular ischemia-reperfusion on these indexes. It can be concluded that sulforaphane elevates protein levels of superoxide dismutase and catalase, and suppresses reactive oxygen species content, thereby preventing ischemia-reperfusion injury in testis.

Secretome of human amniotic membrane stem cells promote recovery and testicular functions through modulating SIRT1/NRF2/TNF-α pathway in mice testicular torsion: An experimental study

Background

Testicular ischemia/reperfusion injury, a significant result of testicular torsion, can lead to the risk of male infertility.

Objective

The current study aimed to evaluate the effect of human amniotic membrane-derived mesenchymal stem cells (hAMSCs) secretome on testicular torsion/detorsion (T/D) in mice.

Materials and Methods

All the experiments were performed in the Anatomy Department of Tehran University of Medical Sciences, Tehran, Iran, during the period of March 2023 to December 2023. 40 male NMRI mice (5-7 wk, 25-30 gr) were randomized into: 1) the sham group: mice received sham operations with no other interventions, 2) T/D group, 3) negative control group; torsion detorsion + intratesticular injection of Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12, and 4) the T/D group + hAMSCs secreted factors. Serum testosterone levels, hematoxylin and eosin staining, and sperm quality parameters were used to evaluate the therapeutic effects of hAMSCs secreted factors on the testicular structure and function. Tissue oxidative stress was measured by determining malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase-1. Nuclear factor erythroid 2-related factor 2, Kelch-like ECH-associated protein 1, NAD-dependent deacetylase sirtuin-1, tumor necrosis factor-alpha and tumor protein P53 mRNA expressions were assessed in testis via real-time polymerase chain reaction.

Results

The results showed that hAMSCs secreted factors alleviated testicular T/D injury by attenuating oxidative stress, inflammatory response, and apoptosis via modulating the sirtuin-1/ nuclear factor erythroid 2-related factor 2/tumor necrosis factor-alpha signaling pathway.

Conclusion

hAMSCs secreted factors increased antioxidative, anti-inflammatory, and antiapoptotic properties which consequently increased testosterone levels, spermatogenesis, and sperm quality parameters.

Remote liver ischemic preconditioning protects against renal ischemia/reperfusion injury via phosphorylation of extracellular signal-regulated kinases 1 and 2 in mice

Perioperative acute kidney injury (AKI), which is mainly mediated by renal ischemia‒reperfusion (I/R) injury, is commonly observed in clinical practice. However, effective measures for preventing and treating this perioperative complication are still lacking in the clinic. Thus, we designed this study to examine whether remote liver ischemic preconditioning (RLIPC) has a protective effect on damage caused by renal I/R injury. In a rodent model, 30 mice were divided into five groups to assess the effects of RLIPC and ERK1/2 inhibition on AKI. The groups included the sham-operated (sham), kidney ischemia and reperfusion (CON), remote liver ischemic preconditioning (RLIPC), CON with the ERK1/2 inhibitor U0126 (CON+U0126), and RLIPC with U0126 (RLIPC+U0126). RLIPC consisted of 4 liver ischemia cycles before renal ischemia. Renal function and injury were assessed through biochemical assays, histology, cell apoptosis and protein phosphorylation analysis. RLIPC significantly mitigated renal dysfunction, tissue damage, inflammation, and apoptosis caused by I/R, which was associated with ERK1/2 phosphorylation. Furthermore, ERK1/2 inhibition with U0126 negated the protective effects of RLIPC and exacerbated renal injury. To summarize, we demonstrated that RLIPC has a strong renoprotective effect on kidneys post I/R injury and that this effect may be mediated by phosphorylation of ERK1/2.

Pretreatment with remote ischemic conditioning attenuates testicular damage after testicular ischemia and reperfusion injury in rats

Testicular torsion is a urological emergency. However, surgical detorsion of the torsed spermatic cord can cause testicular reperfusion injury. Although remote ischemic preconditioning (RIPC) has been convincingly shown to protect organs against ischemia/reperfusion (I/R) injury, little is known regarding the effect of RIPC on testicular torsion/detorsion-induced reperfusion injury. Therefore, we aimed to evaluate the effect of RIPC on testes after testicular I/R injury in a rat model in vivo. Male Sprague-Dawley rats were randomly classified into 4 groups: sham-operated (sham), testicular I/R (TI/R), or remote liver (RIPC liver) and limb (RIPC limb) ischemic preconditioning groups. Testis I/R was induced by 3 h of right spermatic cord torsion (720° clockwise), and reperfusion was allowed for 3 hours. In the RIPC group, four cycles of 5 min of ischemia and 5 min of reperfusion were completed 30 min prior to testicular torsion. The ERK1/2 inhibitor U0126 was administered intravenously at the beginning of reperfusion (1 mg/kg). The testes were taken for the oxidative stress evaluations, histology, apoptosis, immunohistochemical and western blotting analysis. Remote liver and limb ischemic preconditioning attenuated ipsilateral and contralateral testicular damage after testicular I/R injury. For example. RIPC reduced testicular swelling and oxidative stress, lessened structural damage, and inhibited the testicular inflammatory response and apoptosis. Furthermore, RIPC treatment enhanced testicular ERK1/2 phosphorylation postI/R. Inhibition of ERK1/2 activity using U0126 eliminated the protection offered by RIPC. Our data demonstrate for the first time that RIPC protects testes against testicular I/R injury via activation of the ERK1/2 signaling pathway.

MiR-195-5p is involved in testicular ischemia/reperfusion injury by directly targeting PELP1 and regulating spermatogonia pyroptosis

BACKGROUND AND OBJECTIVE

Ischemia/reperfusion injury (IRI), which is characterized by testicular torsion and causes permanent impairment of spermatogenic function, is linked with pyroptosis. Studies have implicated endogenous small non-coding RNAs in IRI development across various organs. In this study, we elucidated the mechanism underlying miR-195-5p's action in regulating pyroptosis in testicular IRI.

METHODS

We established two models, namely a testicular torsion/ detorsion (T/D) mouse model and an oxygen-glucose deprivation/reperfusion (OGD/R)-treated germ cell model. Hematoxylin and eosin staining was performed to evaluate the testicular ischemic injury. The expression of pyroptosis-related proteins and reactive oxygen species production in testis tissues were detected using Western blotting, quantitative real-time PCR, malondialdehyde and superoxide dismutase assay kits and immunohistochemistry. Cell viability and cytotoxicity were evaluated using CCK-8 and LDH assays, whereas expression patterns of inflammatory proteins were measured using ELISA, immunofluorescence, and western blot assays. miR-195-5p interaction with PELP1 was validated by conducting the luciferase enzyme reporter test.

RESULTS

Pyroptosis-related proteins NLRP3, GSDMD, IL-1β, and IL-18 were significantly upregulated following testicular IRI. A similar pattern was observed in the OGD/R model. miR-195-5p was significantly downregulated in mouse IRI testis tissue and OGD/R-treated GC-1 cells. Notably, miR-195-5p downregulation promoted whereas its upregulation attenuated pyroptosis in OGD/R-treated GC-1 cells. Furthermore, we found that PELP1 is a miR-195-5p target. miR-195-5p attenuated pyroptosis in GC-1 cells by inhibiting PELP1 expression during OGD/R, and this protective effect was blocked upon miR-195-5p downregulation. Collectively, these results indicated that miR-195-5p inhibits testicular IRI-induced pyroptosis by targeting PELP1, suggesting that it has the potential to serve as a novel target for the future development of therapies for testicular torsion.

Baicalein Alleviates Testicular Ischemia-Reperfusion Injury in a Rat Model of Testicular Torsion-Detorsion

Testicular torsion/detorsion-induced ischemia/reperfusion injury is partly due to the overgeneration of reactive oxygen species. Baicalein, a main bioactive constituent derived from the dried root of Scutellaria baicalensis Georgi, possesses powerful antioxidative and anti-inflammatory properties. Therefore, we designed the research to explore the possible protective effect of baicalein against testicular ischemia-reperfusion injury. Sprague-Dawley rats were randomized into 4 groups, including control, testicular ischemia-reperfusion, testicular ischemia-reperfusion+vehicle injection, and testicular ischemia-reperfusion+baicalein therapy groups. The control group received surgical exposure of the left testis without torsion-detorsion. In the testicular ischemia-reperfusion group, the left testis underwent 720° counterclockwise torsion for two hours and then was allowed detorsion. Rats in the testicular ischemia-reperfusion+vehicle injection group received intraperitoneal injection of the vehicle at detorsion. In the baicalein-treated group, the intraperitoneal administration of baicalein dissolved in the vehicle was performed at detorsion. At four hours or three months following testicular detorsion, testicular tissues were removed to detect the levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) which can recruit neutrophils into the testis, myeloperoxidase activity (an index of neutrophil infiltration in the testis), protein expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in neutrophils which can catalyze reactive oxygen species production, malondialdehyde concentration (a common marker of reactive oxygen species), and spermatogenesis. Both testicular ischemia-reperfusion and testicular ischemia-reperfusion+vehicle injection significantly increased the TNF-α and IL-1β levels, myeloperoxidase activity, NADPH oxidase protein expression, and malondialdehyde concentration, while decreased spermatogenesis in ipsilateral testes. In contrast, baicalein administration remarkably reduced TNF-α and IL-1β levels, myeloperoxidase activity, NADPH oxidase protein expression, and malondialdehyde concentration and also elevated spermatogenesis in ipsilateral testes. The results of our experiment demonstrate that baicalein alleviates testicular ischemia-reperfusion injury by inhibiting TNF-α and IL-1β secretion, neutrophil infiltration in the testis, and NADPH oxidase protein expression in neutrophils to reduce reactive oxygen species production.

Oleuropein attenuates testicular ischemia-reperfusion by inhibiting apoptosis and inflammation

BACKGROUND

Ischemia-reperfusion injury (IRI) is the key reason of injury after testicular torsion and may eventually lead to male infertility. Oleuropein, a natural antioxidant isolated from Olea europaea, has shown beneficial effects in different models of ischemia. We evaluated the effects of oleuropein on testicular IRI and explored the underlying protective mechanisms.

METHODS

A mouse testicular torsion/detorsion (T/D) model and an oxygen-glucose deprivation/reperfusion (OGD/R) germ cell model were established and treated with oleuropein. H&E staining was used to evaluate testicular pathological changes. Apoptosis and apoptosis-associated protein levels in testis tissues were assessed by TUNEL staining, immunohistochemical staining and western blot. Apoptosis levels and apoptosis-associated protein levels in GC-1 were evaluated by flow cytometry, immunofluorescence and western blot. Oxidative stress levels were assessed by malondialdehyde (MDA) and superoxide dismutase (SOD) kits. Cell viability and inflammatory protein levels were evaluated by CCK-8 assay coupled with qRT-PCR.

RESULTS

Relative to the control group, SOD activity was markedly suppressed, while MDA, Bax, Caspase-3, TNF-α as well as IL-1β levels were significantly increased in the T/D model and OGD/R model. However, all of the aforementioned alterations were relieved by oleuropein treatment.

CONCLUSION

Our findings indicate that oleuropein may be a promising treatment option to attenuate testicular IRI via its anti-oxidant, anti-inflammatory as well as anti-apoptotic properties.

Ischemic limb preconditioning-induced anti-arrhythmic effect in reperfusion-induced myocardial injury: is it mediated by the RISK or SAFE pathway?

The mechanism for limb ischemic precondition (RLIPC)-induced suppression of reperfusion arrhythmia remains unknown. The purpose of this study was to examine the roles of the pro-survival reperfusion injury salvage kinase (RISK) and survivor activating factor enhancement (SAFE) pathways in this RLIPC-mediated antiarrhythmic activity. Male Sprague Dawley rats were assigned to sham-operated, control, or RLIPC groups. All rats except for the sham rats had 5 min of left main coronary artery occlusion with another 20 min of reperfusion. RLIPC was initiated by four cycles of limb ischemia (5 min) and reperfusion (5 min) on the bilateral femoral arteries. Hearts in every group were taken for protein phosphorylation analysis. RLIPC ameliorated reperfusion-induced arrhythmogenesis and reduced the incidence of sudden cardiac death during the entire 20-min reperfusion period (66.7% of control rats had SCD vs. only 16.7% of RLIPC-treated rats). RLIPC enhances ventricular ERK1/2 phosphorylation after reperfusion. RLIPC-induced antiarrhythmic action and ERK1/2 phosphorylation are abolished in the presence of the ERK1/2 inhibitor U0126. Limb ischemic preconditioning protects the heart against myocardial reperfusion injury-induced lethal arrhythmia. These beneficial effects may involve the activation of ERK1/2 in the RISK signaling pathway.