The effects of short-interval postconditioning in preventing testicular 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.

Long-term protective effects of the combination of intermittent reperfusion and hypothermia on reperfusion injury in an experimental testicular torsion model

INTRODUCTION

There are many significantfactors in testicular injury which determine the prognosis in testicular torsion. Reperfusion injury following detorsion also has a significant effect on testicular injury.This study was planned considering that with the implementation of intermittent reperfusion and hypothermia, reperfusion injury can be reduced, and such an application might have a positive effect on testicular tissue in the long term.

MATERIALS AND METHODS

Forty adult male rats were divided into five groups as follows: Sham(Sh)(n = 8), Torsion(T)(n = 8), Intermittent reperfusion(IR)(n = 8), Hypothermia(H)(n = 8), and Intermittent reperfusion+hypothermia(IR+H)(n = 8). Except forGroup Sh, the left testicle was taken out of the scrotum in all groups, rotated three times counterclockwise, fixed back in the scrotum, and left for four hours.After four hours, and just before reperfusion, the testicle's detorsion was performed while holding the vascular structures in the proximal part of the torsed segment with an atraumatic vessel clamp, and thus, not allowing reperfusion in Groups T, IR, H, and IR+H. In Group T, the clamp was released immediately. In Group H, an ice-bag cooling was performed around the testis, and the clamp was released when the tissue temperature was reached and kept constant at 4 °C. In Group IR, the clamp was released, allowing reperfusion of five seconds, followed by reclamping, providing an ischemic status for ten seconds; this procedure was repeated ten times. In Group H+IR,an ice-bag cooling was performed around the testis, and the clamp was released when the tissue temperature was reached and kept constant at 4 °C. Then, reperfusion was applied for 5 s, followed by 10 s ischemia with reclamping. This procedure was repeated ten times.Tissue blood flow was provided for60 days of reperfusion in all groups. After 60 days, both testicles were excised under anesthesia in all living rats, and samples ofthe left testicle werereserved for biochemical and pathological examinations. At the end of the procedure, all animals were sacrificed by a high dose of anesthesia.

RESULTS

It was biochemically and histopathologically determined that the tissues were preserved in the experimental groups compared to Group T, which was statistically significant (p < 0.05).However, no experimental group's superiority over each other was determined both biochemically and histopathologically (p > 0.05).

CONCLUSION

Our long-term experimental study revealed that all methods were protective in testicular torsion. The authors believe that these methods can be applied in clinical practice because of their ease of application and no additional cost. On the other hand, the results of our study should further be supported by other experimental studies.

Comparison of the effects of intermittent reperfusion and hypothermia in preventing testicular ischemia-reperfusion injury in the testicular torsion model in rats

INTRODUCTION

Reperfusion injury after detorsion in testicular torsion is a clinical problem. This study was planned to investigate the protective effect of intermittent reperfusion in hypothermia-applied testicles.

MATERIALS AND METHODS

A total of 40 adult male rats were used, and 5 groups were created: sham (Sh; n = 8), torsion (T; torsion-detorsion) (n = 8), intermittent reperfusion (IR; n = 8), hypothermia (H; n = 8), and intermittent reperfusion+hypothermia (H+IR; n = 8). The left testicle was removed in all groups except in the Sh group, and it was rotated 3 times counterclockwise, fixed in the scrotum, and left for 4 h. After 4 h, the testicle was detorsioned in the groups T, IR, H, and H+IR. During detorsion, an atraumatic vessel clamp was applied in the proximal part of the vascular structures to prevent any reperfusion of the testicle. The clamp was opened immediately in the group T. In the group IR, the clamp was opened, a reperfusion of 5 s was applied; then, the clamp was closed again, and ischemia was created for 10 s; this procedure was repeated 10 times. In the group H, an ice bag cooling was performed around the testis. The tissue temperature was kept constant at 4 °C using a digital thermometer control. The testicle was cooled using an ice bag in the group H+IR; the same procedure was applied to the IR group. In all groups, reperfusion was performed for 1 h at the end of these procedures. The left testicle was removed from all rats; a portion of each testicle was separated for biochemistry testing, and some was separated for histopathological evaluation. At the end of the procedure, intracardiac blood was taken to examine oxidative stress parameters. At the end of the procedure, all animals were sacrificed after administration of a high dose of anesthesia.

RESULTS

The authors observed that the tissue was preserved in the experimental groups and this was statistically significant (p<0.05). It was detected that the tissues were also histopathologically and significantly preserved in the groups IR, H, and H+IR. However, both biochemically and histopathologically, there was no superiority of hypothermia, intermittent reperfusion, or combined application (p>0.05).

DISCUSSION

Both hypothermia and intermittent reperfusion alone protect tissue from IR damage. But no studies have been found in which these applications were used together. And as a result of this work, the combination of both methods did not show superiority over the effect they showed when they were used separately. The authors think that these methods can be applied clinically because of their ease of application and no additional costs; however, it should be supported by other studies.

Optimized postconditioning algorithm protects liver graft after liver transplantation in rats

BACKGROUND

Ischemia reperfusion injury (IRI) causes postoperative complications and influences the outcome of the patients undergoing liver surgery and transplantation. Postconditioning (PostC) is a known manual conditioning to decrease the hepatic IRI. Here we aimed to optimize the applicable PostC protocols and investigate the potential protective mechanism.

METHODS

Thirty Sprague-Dawley rats were randomly divided into 3 groups: the sham group (n = 5), standard orthotopic liver transplantation group (OLT, n = 5), PostC group (OLT followed by clamping and re-opening the portal vein for different time intervals, n = 20). PostC group was then subdivided into 4 groups according to the different time intervals: (10 s × 3, 10 s × 6, 30 s × 3, 60 s × 3, n = 5 in each subgroup). Liver function, histopathology, malondialdehyde (MDA), myeloperoxidase (MPO), expressions of p-Akt and endoplasmic reticulum stress (ERS) related genes were evaluated.

RESULTS

Compared to the OLT group, the grafts subjected to PostC algorithm (without significant prolonging the total ischemic time) especially with short stimulus and more cycles (10 s × 6) showed significant alleviation of morphological damage and graft function. Besides, the production of reactive oxidative agents (MDA) and neutrophil infiltration (MPO) were significantly depressed by PostC algorithm. Most of ERS related genes were down-regulated by PostC (10 s × 6), especially ATF4, Casp12, hspa4, ATF6 and ELF2, while p-Akt was up-regulated.

CONCLUSIONS

PostC algorithm, especially 10 s × 6 algorithm, showed to be effective against rat liver graft IRI. These protective effects may be associated with its antioxidant, inhibition of ERS and activation of p-Akt expression of reperfusion injury salvage kinase pathway.

Short-interval postconditioning protects the bowel against ischaemia-reperfusion injury in rats

Objective

Acute mesenteric ischaemia leads to intestinal damage. Restoration of blood flow results in further damage to tissue, which is called reperfusion injury. This study aimed to investigate the protective effects of short-interval postconditioning and to determine the optimal interval for reperfusion in an experimental rat model of intestinal ischaemia.

Methods

Forty adult male Wistar rats were grouped as follows: sham (Sh), ischaemia + reperfusion (IR), ischaemia + postconditioning for 5 seconds (PC5), ischaemia + postconditioning for 10 seconds (PC10), and ischaemia + postconditioning for 20 seconds (PC20). For postconditioning, 10 cycles of reperfusion (5, 10, or 20 seconds) interspersed by 10 cycles of 10 seconds of ischaemia were performed. Blood glutathione reductase (GR) and glutathione peroxidase (GPx) levels were measured. Intestinal tissue damage was assessed histopathologically.

Results

GR levels were significantly higher in the PC5 group than in the IR group (37.7 ± 9.0 vs. 18.5 ± 2.0 min/g Hb). GPx levels were significantly higher in the PC10 group than in the IR group (43.2 ± 9.2 vs. 15.9 ± 4.6 U/g Hb). The histopathological score was significantly lower in the PC5 group (1.1 ± 0.1) than in the IR group (2.1 ± 0.2).

Conclusion

Short-interval postconditioning reduces reperfusion injury in the ischaemic bowel and the optimal interval for reperfusion is 5 seconds. The long-term effects of short-interval postconditioning and the optimal reperfusion interval in intestinal ischaemia–reperfusion in rats need to be investigated.

Oxidant and antioxidant status in experimental rat testis after testicular torsion/detorsion

BACKGROUND

The aim of this study was to determine oxidative stress (OS) parameters after testicular torsion/detorsion in adult rats.

MATERIALS AND METHODS

In this experimental study, male adult Wistar rats were divided into four groups, each consisting of seven animals: group I-one hour right testicular torsion with subsequent orchiectomy, group II-one hour right testicular torsion followed by detorsion, group III-unilateral right-sided orchiectomy without previous torsion and group IV-control. After 30 days, bilateral orchiectomies were performed in rats with both testes and unilateral orchiectomies in rats with single testicles. Parameters of OS were determined in testicular tissue and in plasma.

RESULTS

Plasma concentrations of advanced oxidation protein products (AOPP) and thiobarbituric acid reactive substances (TBARS) were higher (p<0.05 and p<0.01, respectively), whilst the plasma concentration of the total sulfhydryl (T-SH)-groups was lower (p<0.05) in group I compared to the control group. Group II had higher plasma concentrations of AOPP compared to group IV (p<0.05), as well as significantly increased TBARS and decreased T-SH-group levels compared to groups III (p<0.05 and p<0.01, respectively) and IV (p<0.01, for both parameters). There were significant differences in OS markers between the ipsilateral and contralateral testis, as well as significant correlations among levels of both plasma and tissue markers of OS.

CONCLUSION

The increase in TBARS levels seen throughout the experimental period indicated that OS development was caused by ischemia/reperfusion in the testicular tissue. The oxidant-antioxidant system of the testicular tissue was altered during torsion as well as detorsion.

Beneficial effects of taurine and carnosine in experimental ischemia/reperfusion injury in testis

PURPOSE

Testicular torsion can be thought of as an ischemia/reperfusion (I/R) injury to the testis. This study aimed to investigate the effects of taurine (TAU) and carnosine (CAR), which are strong antioxidants, on experimental testicular I/R injury model.

METHODS

Male Wistar albino rats were divided into four groups with eight animals in each. A sham operation was performed in group 1. To create testicular I/R, the left testis was torsioned 720° for 2 h followed by 2 h of detorsion. Groups 2 (I/R), 3 (I/R + TAU) and 4 (I/R + CAR) received intraperitoneal saline, TAU (250 mg/kg) and CAR (250 mg/kg), respectively, 1 h before detorsion. Thiobarbituric acid reactive substances (TBARS), diene conjugate (DC), protein carbonyls (PC), nonprotein sulfhydryl (NPSH), and vitamin C levels were measured in testis tissues as well as superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. Histopathological evaluation was also performed.

RESULTS

TBARS, DC, and PC levels were significantly increased in I/R group. TAU and CAR did not alter TBARS levels, but decreased the elevated DC and PC levels. There were no changes in testicular NPSH levels, SOD, and GPx activities in all groups; however, vitamin C significantly decreased in I/R group. CAR treatment was found to increase vitamin C levels as compared to I/R group. Histopathologically, both I/R + TAU and I/R + CAR groups showed significant increase in testicular spermatogenesis in comparison to I/R group.

CONCLUSION

Our results indicate that TAU and CAR reduces oxidative stress and may have a protective role in testicular I/R injury.

The long-term protective effects of short-interval postconditioning in testicular ischemia-reperfusion injury in rats

AIM

Even with prompt diagnosis and treatment, testicular torsion may lead to infertility and atrophy after testicular salvage. The aims of this study were to investigate the long-term protective effects of short-interval postconditioning on testicular atrophy and to optimize the reperfusion period.

MATERIALS AND METHODS

Forty adult male rats were divided into 5 subgroups: sham operated; torsion + detorsion; torsion + postconditioning, 5 seconds (PC5); torsion + postconditioning, 10 seconds; and torsion + postconditioning, 20 seconds. Torsion was created by rotating the left testis 1080° counterclockwise and then fixing the testis to the scrotum with 3 sutures. Torsion was maintained for 4 hours. The testicular artery was visualized, and an atraumatic vascular clamp was applied to prevent reperfusion in all study groups. Detorsion of the testis was then performed. In the torsion + detorsion group, the clamp was released just after detorsion. In all the other intervention groups, the subsequent procedures were repeated 10 times. In the PC5 group, the clamp was released for 5 seconds and applied for 10 seconds; in the torsion + postconditioning, 10 seconds group, the clamp was released for 10 seconds and applied for 10 seconds; and in the torsion + postconditioning, 20 seconds group, the clamp was released for 20 seconds and applied for 10 seconds. Then, reperfusion was allowed. After 60 days, rats in all study groups were killed, both testes were removed, and the histopathology was evaluated. The χ(2) test was used for statistical analysis.

RESULTS

Compared with the other groups, the extent of tissue injury determined by histopathologic grades according to Cosentino et al (J Androl. 1986;7:23-31) was significantly less in group PC5 (P < .05).

CONCLUSION

We conclude that short-interval postconditioning can protect against long-term testicular reperfusion injury. Furthermore, the optimal time for reperfusion during postconditioning was 5 seconds in our rat model of testicular torsion. This technique seems easily applicable, and evidence suggests that similar techniques may be useful during testicular surgery.