The effect of poly (adenosine diphosphate-ribose) polymerase inhibitors on biochemical changes in testicular ischemia-reperfusion injury

4'-O-methylbavachalcone alleviates ischemic stroke injury by inhibiting parthanatos and promoting SIRT3

Cerebral ischemia-reperfusion injury (CIRI) can induce massive death of ischemic penumbra neurons via oxygen burst, exacerbating brain damage. Parthanatos is a form of caspase-independent cell death involving excessive activation of PARP-1, closely associated with intense oxidative stress following CIRI. 4'-O-methylbavachalcone (MeBavaC), an isoprenylated chalcone component in Fructus Psoraleae, has potential neuroprotective effects. This study primarily investigates whether MeBavaC can act on SIRT3 to alleviate parthanatos of ischemic penumbra neurons induced by CIRI. MeBavaC was oral gavaged to the middle cerebral artery occlusion-reperfusion (MCAO/R) rats after occlusion. The effects of MeBavaC on cerebral injury were detected by the neurological deficit score and cerebral infarct volume. In vitro, PC-12 cells were subjected to oxygen and glucose deprivation/reoxygenation (OGD/R), and assessed cell viability and cell injury. Also, the levels of ROS, mitochondrial membrane potential (MMP), and intracellular Ca2+ levels were detected to reflect mitochondrial function. We conducted western blotting analyses of proteins involved in parthanatos and related signaling pathways. Finally, the exact mechanism between the neuroprotection of MeBavaC and parthanatos was explored. Our results indicate that MeBavaC reduces the cerebral infarct volume and neurological deficit scores in MCAO/R rats, and inhibits the decreased viability of PC-12 cells induced by OGD/R. MeBavaC also downregulates the expression of parthanatos-related death proteins PARP-1, PAR, and AIF. However, this inhibitory effect is weakened after the use of a SIRT3 inhibitor. In conclusion, the protective effect of MeBavaC against CIRI may be achieved by inhibiting parthanatos of ischemic penumbra neurons through the SIRT3-PARP-1 axis.

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.

Acetyl-11-keto-β-boswellic acid prevents testicular torsion/detorsion injury in rats by modulating 5-LOX/LTB4 and p38-MAPK/JNK/Bax/Caspase-3 pathways

AIMS

Testicular torsion/detorsion (T/D) is a critical medical condition that necessitates prompt surgical intervention to avoid testicular atrophy and infertility. The use of natural compounds may protect against the associated detrimental oxidative stress and inflammatory responses. Interestingly, acetyl-11-keto-β-boswellic acid (AKBA), the main active constituent of Boswellia resin, has shown potent inhibitory effect on 5-lipoxygenase enzyme which converts arachidonic acid into inflammatory mediators. Therefore, this study was conducted to assess the protective mechanisms by which AKBA may protect against testicular T/D injury in rats.

MAIN METHODS

Male rats were randomly distributed into five groups: Sham, AKBA (50 mg/kg, p.o.), unilateral testicular T/D, AKBA at two dose levels (25 or 50 mg/kg for 15 successive days) followed by T/D. Histological examination and Johnsen's score were performed to assess testicular injury and perturbations in spermatogenesis. Biochemical parameters included markers of testicular function (serum testosterone), oxidant/antioxidant status (malondialdehyde, glutathione), inflammation (5-lipoxygenase, leukotriene-B4, myeloperoxidase, interleukin-1β, interleukin-6), apoptosis (Bax, Bcl2, caspase-3), DNA integrity (quantitative DNA fragmentation, DNA laddering, PARP-1), energy production (ATP), in addition to p38 MAPK and JNK protein expression.

KEY FINDINGS

In a dose dependent manner, AKBA significantly inhibited testicular T/D-induced upregulation of 5-LOX/LTB4 and p38-MAPK/JNK/Bax pathways and their associated downstream inflammatory and apoptotic cascades. These effects were accompanied with ATP replenishment and DNA preservation, resulting ultimately in salvage of the testis.

SIGNIFICANCE

Unprecedentedly, the present mechanistic study revealed the pathways by which AKBA may inhibit testicular T/D injury and offered a novel protective approach that may attenuate the severity of this condition.

Dexmedetomidine protects mice against myocardium ischaemic/reperfusion injury by activating an AMPK/PI3K/Akt/eNOS pathway

Acute myocardial ischaemia/reperfusion (MIR) injury leads to severe arrhythmias and has a high rate of lethality. In the present study, we aim to determine the effect of dexmedetomidine (Dex) on heart injury parameters following MIR surgery. We examined the effects of Dex on heart function parameters and infarct size following MIR surgery. Proinflammatory cytokines, oxidative products and anti-oxidative enzymes in the myocardium were measured to evaluate the anti-inflammatory and anti-oxidative effects of Dex. The role of the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)/phosphatidylino-sitol 3-kinase (PI3k)/Akt/endothelial nitric oxide synthase (eNOS) pathway was investigated using their inhibitors. The alteration of haemodynamic parameters, histopathological results, and infarct size caused by MIR was attenuated by Dex. The interleukine-1 beta (IL-1β), IL-6, tumour necrosis factor-a (TNF-α) and myeloperoxidase (MPO) were all significantly decreased. Anti-oxidative enzymes superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) were restored by Dex. Oxidative products8-OHdG, MDA and protein carbonyl were all decreased by Dex (P<.05). Dex activated AMPK expression, eNOS and Akt phosphorylation. The influence of Dex on cardiac function was reversed by the inhibitors of the eNOS, AMPK and PI3K/Akt pathways. These results indicate that Dex protected the cardiac functional, histological changes, inflammation and oxidative stress induced by MIR. Our results present a novel signalling mechanism that Dex protects MIR injury by activating an AMPK/PI3K/Akt/eNOS pathway.

Association of the PPARγ/PI3K/Akt pathway with the cardioprotective effects of tacrolimus in myocardial ischemic/reperfusion injury

Myocardial ischemia/reperfusion injury (MIRI) induces severe arrhythmias and has a high risk of mortality. The aim of the present study was to investigate the effect of tacrolimus on arrhythmias, cardiac function, oxidative stress and myocardium apoptosis induced by MIRI, and to elucidate the underlying mechanism. The effects of MIRI and tacrolimus on arrhythmias, cardiac function parameters, myocardial oxidative stress and apoptosis were investigated in a rat model of MIRI. The phosphorylation of peroxisome proliferator‑activated receptor γ (PPARγ) and protein kinase B (Akt) was investigated via western blotting. After rats were treated with inhibitors of PPARγ/phosphoinositide 3‑kinase (PI3K)/Akt, cardiac function parameters were measured. The results demonstrated that the MIRI procedure induced arrhythmias and significant impairment of cardiac function, oxidative stress and apoptosis in cardiomyocytes (P<0.05). Tacrolimus significantly alleviated the arrhythmias and impairment of cardiac function and inhibited the oxidative stress and apoptosis in cardiomyocytes (P<0.05). The phosphorylation of PPARγ and Akt was significantly activated by tacrolimus, whereas inhibitors of PPARγ/PI3K/Akt significantly abolished the effects of tacrolimus (P<0.05). Together, these results suggest that tacrolimus may protect rats from MIRI through activation of the PPARγ/PI3K/Akt pathway.

Comparison of combined antioxidants and thymoquinone in the prevention of testis ischemia - reperfusion injury

We aimed to compare the preventive effects of combined antioxidants (CA1, 2) with a single antioxidant drug (thymoquinone; TQ) on experimental testis Ischemia/Reperfusion (I/R) injury. Thirty-five adult male Wistar rats were divided into five groups of seven rats each: control, testis I/R, testis I/R + CA1, testis I/R + CA2, and testis I/R + TQ. After 1 h of testicular ischemia, reperfusion was achieved by detorsion for 4 h. Antioxidants were intraperitoneally administered for 30 min prior to reperfusion. All rats were sacrificed 4 h after reperfusion to evaluate the tissue levels of malondialdehyde (MDA) and total antioxidant status (TAS) and the immunohistochemical evaluation of tissue inducible and endothelial nitric acid synthase (iNOS, eNOS) and apoptosis protease-activating factor 1 (APAF-1). MDA levels were lower and TAS values were higher in the I/R + antioxidant groups than in the I/R group (p < 0.05). iNOS and eNOS levels in the I/R + antioxidant groups were also lower than those in the I/R group (p < 0.05). There were no significant differences between the CA groups and the TQ group according to aforementioned parameters. In addition, tissue APAF-1 values were significantly higher in the I/R group than in the other groups. However, there was a significant difference between the TQ and CA groups in APAF-1 levels, which were highest in the TQ group (p < 0.05). Although TQ alone increased TAS values and reduced tissue iNOS and eNOS levels, combined antioxidant treatment may more effectively reduce apoptosis and increase preventive effects in testis I/R injury.

The efficiency of Poly(ADP-Ribose) Polymerase (PARP) cleavage on detection of apoptosis in an experimental model of testicular torsion

The aim of this study was to evaluate the histopathological and apoptotic changes occurring in the rat ipsilateral and contralateral testes, after experimental spermatic cord torsion, and to explore and the role of poly(ADP-ribose) polymerase (PARP) cleavage in testicular torsion-detorsion injury. A total of 37 Wistar albino rats were subjected to 720° unilateral spermatic cord torsion for 1, 2 and 4 h, followed by 4-h reperfusion, or else to a sham operation (control group). Histology of the testicle was evaluated using haematoxylin-eosin (H&E) staining and Johnsen's scoring system. Germ cell apoptosis was evaluated via active caspase-3 immunostaining, and PARP expression levels were evaluated via Western blotting. The mean Johnsen's tubular biopsy scores (JTBS) of the ipsilateral testicles were lower for all torsion groups than for the controls (P < 0.05), but the JTBS of the contralateral testicles were only lower in the 4-h torsion group (P < 0.05). The mean apoptosis score (AS) of the ipsilateral and contralateral testicles was significantly higher in the torsion groups than in the sham group. AS increased correlatively with torsion time, in both testicles. The effect of testicular torsion on PARP cleavage was time dependent, with the highest effect observed after 4 h of testicular torsion (P < 0.05). Testicular torsion caused time-dependent histological changes, apoptosis and increases in PARP cleavage. Our results suggest that testicular torsion-detorsion injury caused cell damage and germ cell apoptosis that apparently involved cleavage of PARP. Increased PARP cleavage could, in turn, lead to enhanced apoptosis.

Protective effect of Salvia miltiorrhiza aqueous extract on myocardium oxidative injury in ischemic-reperfusion rats

Salvia miltiorrhiza has strong antioxidative activity. They may have a strong potential as cardioprotective agents in ischemic-reperfusion injury. Experiments were carried out in Sprague-Dawley rats with myocardium ischemia reperfusion (IR). Myocardial injuries during IR were determined by changes in electrocardiogram analysis of arrhythmias, antioxidant enzyme activities, AST, CK-MB, lactate dehydrogenase (LDH) levels, and myocyte apoptosis. Results showed that S. miltiorrhiza aqueous extract (SAME) pre-treatment significantly decreased the ST-segment (ΣST120) and myocardium MDA, AST, CK-MB, lactate dehydrogenase (LDH) levels, increased myocardium antioxidant enzyme activities, and inhibit myocardium cell apoptosis. Furthermore, the SAME pre-treatment significantly upregulated p-JAK2 and p-STAT3 protein expression, decreased myocardium TNF-α and IL-6 concentrations in IR rats. The levels of TNF-α and IL-6 were positively correlated with the changes in myocardium p-JAK2 and p-STAT3 protein expression levels in IR rats. It can be concluded that the SAME pre-treatment has anti-ischemic and anti-apoptosis activity in heart IR rats. SAME pre-treatment protects heart against IR injury, at least in part, through its stimulating effects on injury-induced deactivation of JAK2/STAT3 signaling pathway.

Contemporary review of testicular torsion: new concepts, emerging technologies and potential therapeutics

Testicular torsion is one of the few emergencies in pediatric urology which requires an accurate and timely diagnosis in order to avoid testis loss. It is not an uncommon event affecting a young male population. In fact, testicular torsion is more common than testicular tumors for this same age group, yet testicular torsion has not been given the public attention it deserves as a male health risk. In this review we highlight the new information published over the past four years regarding testicular torsion. We will discuss a variety of topics associated with torsion including: medical legal issues, etiology and genetics, imaging diagnostics, innovative surgical techniques, management controversies, fertility, and new drug therapies.

Inhaled hydrogen gas therapy for prevention of testicular ischemia/reperfusion injury in rats

PURPOSE

This study evaluated whether 2% hydrogen (H(2)) gas therapy protects against testicular ischemia/reperfusion injury which results in increased formation of reactive oxygen species and/or reactive nitrogen species, leading to testicular apoptosis and impaired spermatogenesis.

METHODS

Pubertal six-week-old Spraque-Dawley rats were assigned to 5 groups (10 animals/group) as follows: group A was a sham operated group; groups B, C, D, and E underwent 5 hours of left testicular ischemia followed by 0, 30, 60, and 120 minutes of 2% H(2) gas therapy, respectively. Histological analysis was performed to verify structure and morphology of the testes and to investigate Johnsen scores, mean seminiferous tubule diameter, and the number of germ cell layers to classify spermatogenesis. Germ cell apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling assay and Bax/Bcl-2 ratio real-time polymerase chain reaction. We also investigated malondialdehyde levels as an indicator of lipid peroxidation.

RESULTS

Compared to the sham group (A), germ cell apoptosis and lipid peroxidation in the ischemia group (B) were significantly increased with abnormal morphology and impaired spermatogenesis. In contrast, amelioration of testicular damages was evident in the H(2) therapy groups (C, D, and E).

CONCLUSIONS

Our results showed that inhalation of 2% H(2) gas may be a promising therapy with anti-apoptotic and anti-oxidant properties in cases of testicular ischemia/reperfusion injury.

Effects of 3-aminobenzamide on unilateral testicular ischemia–reperfusion injury: What is the role of PARP inhibition?

The therapeutic effects of poly(adenosine diphosphate-ribose) polymerase inhibition by 3-aminobenzamide (3-AB) were investigated in testicular ischemia–reperfusion (I/R) injury, using sperm analysis and histopathological and biochemical examinations, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities and reduced glutathione (GSH) levels. Male rats were divided into 3 groups: sham (n = 12), I/R (n = 12), and I/R with 3-AB (I/R–3-AB) (n = 12). The left testicular artery was occluded for 1 h, followed by 24 h (for biochemical and histopathological examinations) and 30 days (for sperm analysis) of reperfusion. 3-AB treatment intraperitoneally 10 min prior to and 1 h after reperfusion increased the I/R-induced decrease in sperm motility in both testes and reduced the increased abnormal sperm rates in the ipsilateral testis. However, 3-AB treatment failed to prevent the I/R-induced decrease in sperm concentration in both testes. SOD and CAT activities did not change in any group. GSH-Px activity and GSH levels were increased by I/R. 3-AB treatment reversed the I/R-induced increase in GSH-Px activity, similar to the level in sham rats, but did not alter GSH levels. 3-AB treatment significantly increased the I/R-induced decrease in histopathologic score. In conclusion, 3-AB treatment has potential biochemical and histopathological benefits beyond improving sperm quality and may have the potential to decrease damage from testicular torsion.

The effects of N-acetylcysteine on testicular damage in experimental testicular ischemia/reperfusion injury

PURPOSE

The aim of this study to evaluate the effects of N-acetylcysteine (NAC) on testicular damage in a rat testicular ischemia-reperfusion (I/R) injury model.

METHODS

Thirty male Wistar albino rats were divided into five groups. Group 1: sham control, Group 2: torsion (T), Group 3: torsion/detorsion (T/D), Group 4: the early NAC treatment plus T/D, 20 mg/kg of NAC was given intravenously 60 min before detorsion; Group 5: the late NAC treatment plus T/D, 20 mg/kg of NAC was given intravenously 5 min before detorsion. After torsion (2 h) and detorsion (2 h), bilateral orchiectomies were performed to determine the tissue levels of malondialdehyde (MDA) or more exactly thiobarbituric acid reactive substance (TBARS), myeloperoxidase activity and histopathological changes.

RESULTS

The most significant increase in the mean TBARS level and decrease in the mean seminiferous tubular diameter, germinal epithelial cell thickness values in bilateral testes were observed in T/D group rather than other groups. TBARS levels of early NAC treatment group were significantly lowered and histological parameters of spermatogenesis were significantly improved in bilateral testes when compared with T and T/D groups.

CONCLUSION

Our results suggest that the early administration of NAC may have a protective effect in the rat experimental testicular T/D models.

Protective effect of trapidil on long-term histologic damage in a rat model of testicular ischemia-reperfusion injury

OBJECTIVES

Trapidil is an antianginal compound with a broad spectrum of pharmacological activities. In recent years, it has been used successfully to decrease ischemia-reperfusion injury in several organ systems. We evaluated the effect of trapidil on the long-term histologic damage in testicular ischemia-reperfusion injury.

METHODS

Adult male Wistar rats were divided into three groups of six rats each. One group underwent 2 h of testicular torsion; one received pretreatment with trapidil before detorsion; and one group underwent sham operation. All rats underwent bilateral orchiectomy 60 days after the experiment. The mean seminiferous tubular diameter, germinal epithelial cell thickness, and mean testicular biopsy score were determined by histological examination of each testis.

RESULTS

Testicular torsion-detorsion caused a significant decrease in the mean seminiferous tubular diameter, germinal epithelial cell thickness, and mean testicular biopsy score in the ipsilateral testes, but not in the contralateral testes. The animals treated with trapidil had a significant increase in these histological parameters as compared to the torsion-detorsion group.

CONCLUSION

Trapidil administration before reperfusion may have the potential to decrease the long-term histologic damage that occurs after experimental testicular torsion. Trapidil is used as an antianginal drug and additional clinical studies are required to elucidate the protective role of trapidil in patients with testicular torsion.

Effect of 3-amino benzamide, a poly(adenosine diphosphate-ribose) polymerase inhibitor, in experimental caustic esophageal burn

INTRODUCTION

The enzyme poly(adenosine diphosphate-ribose) polymerase affects the repair of DNA in damaged cells. However, its activation in damaged cells can lead to adenosine triphosphate depletion and death. This study was designed to investigate the efficacy of 3-amino benzamide (3-AB), a poly(adenosine diphosphate-ribose) polymerase inhibitor, on the prevention of esophageal damage and stricture-formation development after esophageal caustic injuries in rat.

MATERIALS AND METHODS

Forty-five rats were allocated into 3 groups: sham-operated, untreated, and treated groups. Caustic esophageal burn was created by instilling 15% NaOH to the distal esophagus. The rats were left untreated or treated with 3-AB 10 mg/kg per day intraperitoneally. All rats were killed on the 28th day. Efficacy of the treatment was assessed by measuring the stenosis index and histopathologic damage score and biochemically by determining tissue hydroxyproline content, superoxide dismutase (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA), and protein carbonyl content (PCC) in esophageal homogenates.

RESULTS

Treatment with 3-AB decreased the stenosis index and histopathologic damage score seen in caustic esophageal burn rats. Hydroxyproline level was significantly higher in the untreated group as compared with the group treated with 3-AB. Caustic esophageal burn increased MDA and PCC levels and also decreased SOD and GPx enzyme activities. On the contrary, 3-AB treatment decreased the elevated MDA and PCC levels and also increased the reduced SOD and GPx enzyme activities.

CONCLUSION

3-Amino benzamide has a preventive effect in the development of fibrosis by decreasing tissue damage and increasing the antioxidant enzyme activity in an experimental model of corrosive esophagitis in rats.

The protective effect of erythropoietin infusion on testicular torsion/detorsion: an experimental study

INTRODUCTION

The aim of the present study was to evaluate the effects of erythropoietin (EPO) on the histopathology of testes after unilateral testicular torsion and detorsion.

MATERIALS AND METHODS

Twenty-five male Sprague-Dawley rats weighing 120 g were used in this study. The rats were randomly divided into three groups, a sham group consisting of five rats and the other two groups consisting of ten rats. In group 1 (sham group), right orchiectomy with no additional intervention was performed. In group 2 (T/D group), torsion was created by rotating the testis 720 degrees in a clockwise direction for 4 h. After a 4-h torsion period, the right testis was detorted and replaced into the scrotum for 4 h. After the torsion, 0.5 cc 0.9% NaCl solution was injected once and three times in a week (total 12 doses). In group 3 (T/D + erythropoietin; EPO group), the same surgical procedure was done as in group 1, but EPO 1,000 IU/kg was injected just before the detorsion and three times in a week. At the end of each procedure, bilateral orchiectomies were performed for the histopathological examinations in all groups.

RESULTS

We examined the testes weight, vascularization of the region between the seminiferous tubules, percentage of necrotic seminipherous tubules, and maturation of spermatogenesis in terms of necrosis, sertoli cells, maturation arrest of spermatogenesis, hypospermatogenesis, and normal spermatogenesis of torsioned testis tissues with and without EPO treatment. Extremely significant differences in testicular weight were observed in group 1 compared to groups 2 and 3 (P < 0.001).

CONCLUSION

Administration of EPO significantly influenced the rescue of testicular function by preserving the intact seminiferous tubular morphology, lowering the percentage of necrotic seminipherous tubules, and significantly reducing histological damage (P < 0.05).

Novel pharmacological approaches to the treatment of renal ischemia-reperfusion injury: a comprehensive review

Renal ischemia-reperfusion (I-R) contributes to the development of ischemic acute renal failure (ARF). Multi-factorial processes are involved in the development and progression of renal I-R injury with the generation of reactive oxygen species, nitric oxide and peroxynitrite, and the decline of antioxidant protection playing major roles, leading to dysfunction, injury, and death of the cells of the kidney. Renal inflammation, involving cytokine/adhesion molecule cascades with recruitment, activation, and diapedesis of circulating leukocytes is also implicated. Clinically, renal I-R occurs in a variety of medical and surgical settings and is responsible for the development of acute tubular necrosis (a characteristic feature of ischemic ARF), e.g., in renal transplantation where I-R of the kidney directly influences graft and patient survival. The cellular mechanisms involved in the development of renal I-R injury have been targeted by several pharmacological interventions. However, although showing promise in experimental models of renal I-R injury and ischemic ARF, they have not proved successful in the clinical setting (e.g., atrial natriuretic peptide, low-dose dopamine). This review highlights recent pharmacological developments, which have shown particular promise against experimental renal I-R injury and ischemic ARF, including novel antioxidants and antioxidant enzyme mimetics, nitric oxide and nitric oxide synthase inhibitors, erythropoietin, peroxisome-proliferator-activated receptor agonists, inhibitors of poly(ADP-ribose) polymerase, carbon monoxide-releasing molecules, statins, and adenosine. Novel approaches such as recent research involving combination therapies and the potential of non-pharmacological strategies are also considered.

Effect of melatonin on testicular ischemia/reperfusion injury in rats: is this effect related to the proinflammatory cytokines?

OBJECTIVE

To determine whether the protective effect of melatonin in testicular ischemia/reperfusion (IR) injury is mediated by the proinflammatory molecules.

DESIGN

Experimental study.

SETTING

University pharmacology laboratory.

ANIMAL(S)

Fifty-six 8-week-old male Wistar albino rats.

INTERVENTION(S)

Left testicular artery and vein was occluded for 1 hour, followed by 3 hours or 24 hours of reperfusion. Melatonin (10 mg/kg IP) or vehicle (1% ethanol in saline) was given 10 minutes before ischemia.

MAIN OUTCOME MEASURE(S)

Malondialdehyde (MDA), protein carbonyl (PC) content, myeloperoxidase (MPO) activity, and proinflammatory cytokines TNF-alpha, IL-1beta, and IL-6 were examined in testicular tissue after 3 hours of reperfusion. Histologic examination was made after 24 hours of reperfusion.

RESULT(S)

The MDA, PC, and MPO levels in testicular tissue increased significantly after IR, but the proinflammatory cytokine levels did not change. Melatonin treatment decreased lipid and protein oxidation and ameloriated histopathologic alterations induced by IR without any change in proinflammatory cytokine levels.

CONCLUSION(S)

The protective effect of melatonin on IR-induced testiculary injury is related to its antioxidant properties but not to proinflammatory cytokines.

The effect of caffeic acid phenethyl ester (CAPE) on histopathological changes in testicular ischemia-reperfusion injury

Testicular torsion causes an enhanced formation of reactive oxygen species which contributes to the pathophysiology of ischemia-reperfusion injury in the testis. We evaluated here the effect of caffeic acid phenethyl ester (CAPE), a new antioxidant and anti-inflammatory agent on histopathological changes in testicular ischemia-reperfusion injury. Adult male Wistar rats were divided into six groups of five each: control group 1 (n=5), sham operation group 2 (n=5), torsion/detorsion (T/D) group 3 (n=5), T/D+saline group 4 (n=5), T/D+CAPE group 5 (n=5) and T/D+CAPE group 6 (n=5). Group 1 served to determine baseline values of histopathological parameters, group 2 animals that underwent sham operation served as a control, while groups 3-6 animals were subjected to left unilateral torsion (2 h) and detorsion (24 h) periods. All the groups were sacrified 24 h later except group 6. CAPE was injected 2 days with the same dose to the group 6 and it was sacrified 48 h later. One testis removed and fixed in Bouin's solution. After routine tissue processing myeloperoxidase (MPO) and inducible nitric oxide synthase (iNOS) immunohistochemical methods were studied from paraffin embedded tissues. Treating rats with CAPE (applied at 10 micromol/kg, 30 min prior to T/D) attenuated the testicular injury and as well as the tissue levels of MPO. At the same time testis tissue showed a decrease in iNOS activity. Our results suggest that CAPE treatment have a protective role on testicular T/D and this effect may be due to inhibiting the neutrophil mediated cellular injury.

Protective effects of trapidil in ischemia-reperfusion injury due to testicular torsion and detorsion: An experimental study

OBJECTIVE

We aimed to detect the preventive effects of trapidil in ischemia-reperfusion (IR) injury due to testicular torsion and detorsion.

METHODS

Forty prepubertal albino rats were used. In the IR group, torsion was created by rotating the left testis over 2 h, and detorsion was done by untwisting the testis. Bilateral orchiectomies were performed after 4 h. In study group, 2-h torsion was performed and trapidil was administered as a single dose 1 h before detorsion. Bilateral orchiectomies were performed after 4 h. In the sham group, a sham operation was done. In the sham plus trapidil group, a sham operation was done and trapidil was administered as a single dose. Testicular tissue malondialdehyde (MDA), nitric oxide (NO) and total sulfhydryl (T-SH) levels were determined for each group. The grades of interstitial injury were determined in histopathologic examination.

RESULTS

The NO and MDA levels in the IR group were significantly higher than the study, sham and sham plus trapidil groups in the left testis (P<0.05, P<0.001 and P<0.001, respectively). A statistical difference was not found among study, sham and sham plus trapidil groups in the left testis in NO and MDA levels (P>0.05). The T-SH level in the study group was significantly higher than in the IR, sham and sham plus trapidil groups in left testis P<0.05). In the IR group (left testis), grade 1 interstitial injury was 30% (3/10), grade 2 injury was 60% (6/10) and grade 3 injury was 10% (1/10). In the study group (left testis), grade 1 interstitial injury was 30% (3/10) and there was no injury in 70% (7/10).

CONCLUSION

Trapidil decreased free oxygen radical formation in testicular torsion and detorsion, and attenuated histopathological damage in the ipsilateral twisted testis.

The effects of N-acetylcysteine on antioxidant enzyme activities in experimental testicular torsion

Testicular torsion is a serious problem in male children and, if not treated at the right time, can lead to subfertility and infertility. The main reason for testicular damage is ischemia-reperfusion injury. A number of chemical substances have been used to protect testes against ischemia-reperfusion injury in experimental animals. The possible protective effect of N-acetylcysteine on testicular tissue after testicular detorsion was examined in the current study. Twenty-four rats were divided into four groups: sham operation, torsion, detorsion, and NAC + detorsion groups (n = 6 for each group). Excluding sham operation group, the rats were subjected to unilateral torsion (720-degree rotation in clockwise direction). After torsion (5 h) and detorsion (2 h), unilateral orchidectomy was performed. Malondialdehyde levels and superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activities were determined in testicular tissue. Administration of N-acetylcysteine caused a decrease in malondialdehyde levels and an increase in glutathione peroxidase levels compared to detorsion group. The results suggest that N-acetylcysteine may be a potential protective agent for preventing the negative biochemical changes related to oxidative stress in testicular injury caused by testis torsion.

Allopurinol provides long-term protection for experimentally induced testicular torsion in a rabbit model

OBJECTIVE

To assess the effect of five antioxidants on exocrine function of rabbit testes retained in situ for 24 h and 3 months after experimental torsion.

MATERIALS AND METHODS

The left testes of peripubertal rabbits were clamped for 60 min, after which the clamps were removed and the testes allowed to reperfuse. The right testes served as internal controls. There were eight rabbits in each of the following experimental groups: (a) sham; (b) 60-min ischaemia followed by reperfusion; (c) 60-min ischaemia followed by left orchidectomy. In five further groups, rabbits were exposed to 60-min ischaemia followed by reperfusion, but received one of the following antioxidants before reperfusion: acetyl salicylic acid, ascorbic acid, allopurinol, quercetin or superoxide dismutase. Both testes were excised at 24 h or 3 months. The degree of lipid peroxidation, a measure of free radical damage, was assessed in testicular tissue homogenates by measuring the tissue levels of malondialdehyde (MDA). The Johnsen score was used to assess the morphological damage at 24 h and 3 months for each group.

RESULTS

At 3 months twisted viable testes allowed to reperfuse had higher MDA levels than controls; the left testes of rabbits treated with allopurinol had significantly lower MDA levels than untreated rabbits and rabbits given other antioxidants. Rabbits given quercetin, ascorbic acid or superoxide dismutase had lower (but not significantly) left testicular MDA levels than untreated rabbits, while rabbits given acetyl salicylic acid had even higher levels. Allopurinol-treated rabbits had a Johnsen score of > 7.6 and those given other antioxidants had scores of < 7.6 at 3 months.

CONCLUSION

The twisted viable testis treated by orchidopexy contains high free radical levels at 3 months. Of the antioxidants studied, only allopurinol had a beneficial long-term effect, by significantly reducing testicular MDA levels at 3 months.

Protective effect of vascular endothelial growth factor on histologic changes in testicular ischemia-reperfusion injury

OBJECTIVE

To evaluate the efficacy of vascular endothelial growth factor (VEGF) on long-term histologic damage in testicular ischemia-reperfusion injury.

DESIGN

Controlled experimental study using rats.

SETTING

University of Mersin School of Medicine, Mersin, Turkey.

ANIMAL(S)

Sixteen adult male Wistar rats.

INTERVENTION(S)

Five rats underwent 2 hours of testicular torsion. Six rats received VEGF injection into the testis before detorsion. Five rats underwent sham operation.

MAIN OUTCOME MEASURE(S)

Mean seminiferous tubular diameter (MSTD), germinal epithelial cell thickness (GECT), mean testicular biopsy score (MTBS), and apoptosis (caspase-3-positive cells).

RESULT(S)

Testicular torsion-detorsion caused a significant decrease in MSTD, GECT, and MTBS and a significant increase in the mean value of caspase-3-positive cells in ipsilateral testes but not in the contralateral testes. The MSTD, GECT, and MTBS of the ipsilateral testes were significantly higher in the group treated with VEGF than in the torsion-detorsion group. The animals treated with VEGF had a significant decrease in the mean value of ipsilateral testicular caspase-3-positive cells compared with the torsion-detorsion group.

CONCLUSION(S)

Vascular endothelial growth factor might have a role in testicular damage caused by ischemia-reperfusion. Administering VEGF before reperfusion might have the potential to decrease the long-term histologic damage after testicular torsion.

Inhibition of poly(ADP-ribose) polymerase attenuates lung tissue damage after hind limb ischemia-reperfusion in rats

The objective of this study was to investigate the effects of 3-aminobenzamide (3-AB) on tissue damage in lung after hind limb ischemia-reperfusion (I/R), by assessing blood biochemical assay and histopathological analysis. Thirty-five adult Wistar rats were divided into five groups. After application of anaesthesia both hind limbs were occluded with tourniquets. Following ischemia period for 60 min, the tourniquets were removed allowing reperfusion for 120 min. The IR group received 0.5 ml of saline while the IR+AB group received 3-AB (10 mgkg(-1) intraperitoneally). The IR+DMSO group was given 0.5 ml 10% DMSO 30 min before the removal of the tourniquets. The control group received 0.5 ml saline and the AB group received 0.5 ml 3-AB (10 mgkg(-1)) intraperitoneally. At the end of the reperfusion period, mid-line sternotomy was performed. Blood samples were taken with cardiac puncture. Bronchoalveolar lavage (BAL) of the left lung was performed with saline. Right lung was preserved for histopathological evaluation and biochemical examination. Lung tissue malondialdehyde (MDA) and 3-nitrotyrosine levels, myeloperoxidase and Na+/K+ ATP-ase activities, wet to dry weight ratios, and plasma and BAL fluid MDA levels were determined. Histopathological evaluation was performed, too. Hind limb IR caused significant increase in the lung tissue 3-NT to total tyrosine ratio (p = 0.014), wet to dry weight ratio (p = 0.000), MPO activity (p = 0.000), and MDA levels (p = 0.000). The animals treated with 3-AB showed a statistically significant decrease in these values (p < 0.05). Na+/K+ ATP-ase activity which was found to be decreased significantly with IR, returned to near normal levels with 3-AB treatment. Additionally, lung tissue injury in IR group characterized with moderate interstitial congestion and neutrophil infiltration, showed remarkable amelioration following 3-AB treatment. Our results strongly support the view that poly(ADP-ribose) polymerase (PARP) plays an important role in the inflammatory process in hind limb I/R-induced lung injury and as a PARP inhibitor, 3-AB seems to have a potential to treat this inflammatory injury.

Neuroprotective effect of peroxynitrite decomposition catalyst and poly(adenosine diphosphate—ribose) polymerase inhibitor alone and in combination in rats with focal ischemia

Object. The authors evaluated the neuroprotective effect of 5,10,15,20-tetrakis(N-methyl-4′-pyridyl)porphyrinatoiron(III) (FeTMPyP), a peroxynitrite decomposition catalyst, and 1,5-isoquinolinediol (ISO), a poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitor, alone and in combination in rats with focal cerebral ischemia induced by middle cerebral artery occlusion (MCAO).

Methods. Male Sprague—Dawley rats were subjected to 2 hours of MCAO followed by 22 hours of reperfusion. Cerebral infarction and neurological deficits were estimated after ischemia. Intraperitoneal injections of FeTMPyP (1 and 2 mg/kg) and ISO (0.05 and 0.1 mg/kg) were administered alone or in combination in ischemic animals. The PARP activity in vehicle- and drug-treated groups was estimated using anti—poly(ADP-ribose) antibody in immunofluorescence and immunoblotting studies.

Two hours of MCAO and 22 hours of reperfusion produced significant cerebral infarction and neurological deficits. Treatment with FeTMPyP (1 and 2 mg/kg) and ISO (0.05 and 0.1 mg/kg) produced a significant reduction in cerebral infarction and neurological deficits. Combination therapy (2 mg/kg FeTMPyP and 0.1 mg/kg ISO) enhanced the inhibition of ischemic volume (77.81 ± 0.86%) compared with monotherapies (FeTMPyP 54.07 ± 5.6% and ISO 53.06 ± 3.88%). Immunoblotting and immunofluorescence studies showed PARP activation after ischemia, which was reduced by drug treatment.

Conclusions. Neuroprotection observed with FeTMPyP and ISO alone and in combination may be attributed to inhibition of the peroxynitrite—PARP cascade of cerebral ischemia/reperfusion injury.

Raxofelast, a hydrophilic vitamin E-like antioxidant, reduces testicular ischemia-reperfusion injury

Testis torsion is a surgical emergency that lead to permanent gonad damage. The damage has been ascribed to mechanisms of ischemia-reperfusion similar to other tissues. The mechanisms involved are different, but the lipid peroxidation of plasma membrane, caused by reactive oxygen species (ROS), generated particularly during reperfusion, is one of the most accredited. In the present study, we aimed to evaluate the effects of raxofelast, a vitamin E-like antioxidant with potent action and no systemic toxicity, on lipid peroxidation and histopathology in both testes after unilateral testicular torsion and detorsion. Adult male Wistar rats were subjected to total occlusion (3 h) of the left testis followed by 4 hours of reperfusion (TI/R). Sham testicular ischemia-reperfusion rats (SHAM TI/R) were used as controls. The animals were then randomized to receive either vehicle (1 ml/kg/i.p. of a dimetylsulphoxide/NaCl 0.9% 1:10 v/v solution, injected either 15 min before detorsion and 15 min after detorsion) or raxofelast (20 mg/kg i.p. 15 min before detorsion and 15 min after detorsion). Conjugated dienes (CD) levels, an index of lipid peroxidation, and testis histopathology were evaluated. Testicular ischemia reperfusion (TI/R) in untreated rats produced high testicular levels of CD (3.6+/-0.3 DeltaABS/g protein on the left side and 2.5+/-0.2 DeltaABS/g protein on the right side). Furthermore, histological examination revealed marked damage to the testis interstitium with severe haemorrhage and edema. The administration of raxofelast lowered CD levels (2.8+/-0.2 DeltaABS/g protein on the left side and 1.9+/-0.1 DeltaABS/g protein in the right side) and significantly reduced histological damage. These data suggest that the hydrophilic vitamin E-like antioxidants are good candidates for designing a novel therapeutic strategy to halt the oxidative stress that follows acute testis torsion.

Inhibition of poly(adenosine diphosphate-ribose) polymerase decreases long-term histologic damage in testicular ischemia-reperfusion injury

OBJECTIVES

To evaluate the effect of 3-aminobenzamide, an inhibitor of poly(adenosine diphosphate-ribose) polymerase (PARP), on the long-term histologic damage in testicular ischemia-reperfusion injury. PARP inhibitors have been used successfully to decrease ischemia-reperfusion injury in several organ systems.

METHODS

Adult male Wistar rats were divided into four groups of 7 rats each. One group underwent 2 hours of testicular torsion; one received pretreatment with vehicle (dimethyl sulfoxide) before detorsion; one received pretreatment with 3-aminobenzamide, an inhibitor of PARP, before detorsion; and one group underwent a sham operation. All rats underwent bilateral orchiectomy 60 days after the experiment. The mean seminiferous tubular diameter, germinal epithelial cell thickness, and mean testicular biopsy score were determined by histologic examination of each testis.

RESULTS

Testicular torsion-detorsion caused a significant decrease in the mean seminiferous tubular diameter, germinal epithelial cell thickness, and mean testicular biopsy score in the ipsilateral testes (P <0.001), but not in the contralateral testes. The animals treated with 3-aminobenzamide had a statistically significant increase in these histologic parameters compared with the torsion-detorsion group (P <0.01).

CONCLUSIONS

The results of this study show that PARP may have a role in the testicular damage caused by ischemia-reperfusion. Administering PARP inhibitors before reperfusion may have the potential to decrease the long-term histologic damage that occurs after testicular torsion.