L-alanyl-glutamine dipeptide pretreatment attenuates ischemia-reperfusion injury in rat testis

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.

Effect of sunitinib on testicular oxidative and proinflammatory damage induced by ischemia-reperfusion in rats

INTRODUCTION

This study aimed to biochemically and histopathologically investigate the effect of sunitinib on oxidative testicular damage induced by ischemia/reperfusion in rats.

MATERIAL-METHOD

Experimental animals were divided into three groups of six rats each: testicular torsion-detorsion (TTD), sunitinib+testicular torsion-detorsion (STD), and sham control (SC). Sunitinib (25mg/kg) was administered orally to the STD group by gavage. Normal saline (0.9% NaCl) was administered orally to the TTD and control groups as the solvent. One hour after administration of sunitinib and 0.9% NaCl, all animal groups were done torsion-detorsion. Then, all the rats were killed by high-dose anesthesia, and their testicles were removed. Biochemical and histopathological examinations were performed on the removed testicular tissues.

RESULTS

Malondialdehyde; it was observed that the results in the STD group were close to those of the SC group and statistically significant lower compared to the TTD group (p=0.001). The glutathione values were statistically significantly higher in the STD group compared to the TTD group (p<0.001). Nuclear factor kappa B values, revealing a statistically significant difference between the TTD and STD groups (p<0.001). The TNF-α levels were measured and indicating that the results of the STD group were statistically significantly lower than those of the TTD group (p<0.001). Histopathologically, animal tissues given sunitinib were observed to resemble normal tissues.

CONCLUSION

Sunitinib was shown to prevent histopathological changes in testicular tissue against ischemia/reperfusion damage.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Protective effect of oltipraz in testicular ischaemia/reperfusion injury: An experimental study

Testicular torsion is an emergency urological disease, and the treatment is immediate surgery. Despite emergency surgery, testicular damage may occur due to reperfusion. Therefore, a medical treatment to prevent this damage may be a rational idea. We aimed to evaluate the protective effect of oltipraz in testicular ischaemia/reperfusion damage. Twenty-eight Wistar-Albino rats were randomly divided into four groups. In ischaemia/reperfusion group, testicular torsion was executed, and orchiectomy was done 4 hr after detorsion with no treatment. Second group performed torsion; intraperitoneal 50 mg/kg oltipraz was applied 30 min before detorsion, and orchiectomy was performed 4 hr after detorsion. Third group applied torsion; intraperitoneal 150 mg/kg oltipraz was applied 30 min before detorsion, and orchiectomy was performed 4 hr after detorsion. Last one was the sham group. We evaluated tissue malondialdehyde (MDA), transforming growth factor-β1 (TGF-β1), superoxide dismutase (SOD), reduced glutathione (GSH) and Johnsen testicular biopsy score. There was a significant decrease in TGF-β1, GSH and MDA values in oltipraz treatment groups compared with ischaemia/reperfusion group. Oltipraz treatment has significant protective effect in testicular ischaemia/reperfusion damage. However, more clinical studies are needed to demonstrate appropriate dose and its effects.

Protective roles of bioactive peptides during ischemia-reperfusion injury: From bench to bedside

Ischemia-reperfusion (I/R) is a well-known pathological condition which may lead to disability and mortality. I/R injury remains an unresolved and complicated situation in a number of clinical conditions, such as cardiac arrest with successful reanimation, as well as ischemic events in brain and heart. Peptides have many attractive advantages which make them suitable candidate drugs in treating I/R injury, such as low toxicity and immunogenicity, good solubility property, distinct tissue distribution pattern, and favorable pharmacokinetic profile. An increasing number of studies indicate that peptides could protect against I/R injury in many different organs and tissues. Peptides also face several therapeutic challenges that limit their clinical application. In this review, we present the mechanisms of action of peptides in reducing I/R injury, as well as further discuss modification strategies to improve the functional properties of bioactive peptides.

Mechanisms of testicular torsion and potential protective agents

Testicular torsion is a urological emergency most commonly seen in adolescence, involving a decrease in blood flow in the testis resulting from torsion of the spermatic cord that can result in gonad injury or even loss if not treated in time. Testicular ischaemia-reperfusion injury represents the principle pathophysiology of testicular torsion, with ischaemia caused by twisting of the spermatic cord, and reperfusion on its subsequent release. Many cellular and molecular mechanisms are involved in ischaemia-reperfusion injury following testicular torsion. Studies have investigated the use of pharmacological agents as supportive therapy to surgical repair in order to prevent the adverse effects of testicular torsion. Numerous substances have been proposed as important in the prevention of post-ischaemia-reperfusion testicular injury. A range of chemicals and drugs has been successfully tested in animal models for the purpose of mitigating the dangerous effects of ischaemia-reperfusion in testis torsion.