Protective effect of ischaemic post-conditioning on ipsilateral and contralateral testes after unilateral testicular ischaemia-reperfusion injury

The protective effect of L-arginine, tadalafil, and their combination in rat testes after ischemia and reperfusion injury

INTRODUCTION

Nitric oxide (NO) plays an important role in the ischemia and reperfusion process. In this study, we aimed to examine the effect of L-arginine, tadalafil, and their combination for prevention of the ischemia reperfusion injury after testis torsion in rats.

METHODS

A total of 40 adult, male Sprague-Dawley rats were allocated into five groups. Three hours of left testicular torsion was performed in each group, excluding the control group. While the ischemia reperfusion (I/R) group had no treatment, I/R + Arg group received L-arginine, I/R + Td group received tadalafil and I/R + Arg + Td group received tadalafil and L-arginine 30 minutes before the detorsion. Then the left testis was untwisted for four hours of reperfusion. After bilateral orchiectomy, lipid peroxidation (LPx) and glutathione (GSH) activities were examined in testicular tissue. Spermatogenesis was evaluated with Johnsen's score.

RESULTS

LPx levels of the I/R group were found to be significantly higher than for groups that received drugs for both testes (p<0.001). GSH levels of the combination group were higher than I/R group in ipsilateral testis (p<0.01) and it was significantly higher than other groups for contralateral testis (p<0.001 for I/R group, p<0.01 for I/R + Arg, p<0.05 for I/R + Td). Mean Johnsen's score of the I/R group was found to be significantly lower than treatment groups in ipsilateral testis (p<0.001 for I/R + Arg + Td group, p<0.01 for other treatment goups) and contralateral testis (p<0.001). The mean Johnsen score of the combination group was significantly higher than that of other treatment groups in ipsilateral testis (p<0.05) and it was significantly higher than in the I/R + Td group in the contralateral testis (p<0.05).

CONCLUSIONS

L-arginine, tadalafil, and combination of these two molecules showed protective effect against ischemia/reperfusion injury for both testes after unilateral testis torsion.

Protection from ischemia by preconditioning, postconditioning, and combined treatment in rabbit testicular ischemia reperfusion injury

This study aimed to investigate the protection of ischemic preconditioning (IPreC), ischemic postconditioning (IPostC) and combined treatment on ischemia reperfusion injury (IRI) of testis. A rabbit testicular ischemia reperfusion (IR) model was established with determining of rabbit serum testosterone, nitric oxide (NO), malondialdehyde (MDA), protein carbonyl (PC), superoxide dismutase (SOD), myeloperoxidase (MPO), glutathione peroxidase (GSH-Px), and tissues pathology. After IR, the NO, MDA, PC, SOD, MPO, and GSH-Px expression significantly increased in torsive testis, and significantly decreased after IPreC, IPostC, and combined treatment in torsive testis when compared to contralateral testis. In torsive testis, testicular tissues was severely damaged with spermatogenic cells disappearing, and were filled with light eosin edema liquid. Cell apoptosis index significantly increased, and the ratio of Bcl-2/Bax significantly decreased. After IPreC, IPostC, and combined treatment, testicular tissues were restored to normal, cell apoptosis index significantly decreased, and the ratio of Bcl-2/Bax significantly increased. It indicates that IPreC, IPostC, and combined treatment has an obvious protective effect on testicular IRI, by decreasing the oxidative stress index and cell apoptosis, provides a significant reference for the treatment of testicular torsion induced infertility, and exhibits a great value in clinical applications.

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.

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.

Blocking of the ATP sensitive potassium channel ameliorates the ischaemia-reperfusion injury in the rat testis

There is increasing evidence that the effects of administered ATP sensitive potassium (KATP ) channel openers or blockers during ischaemia are still controversial in many organs/tissues. Testicular torsion detorsion which causes ischaemia-reperfusion (IR) injury, cannot be predicted, thus an effective drug should be administered during or after the ischaemia. The aim of this study was to examine whether the administration of KATP channel openers or blockers during ischaemia ameliorates IR injury in the testis. Eight-week-old male Sprague-Dawley rats were subjected to 2 h right testicular ischaemia followed by 24 h reperfusion. The selective mitochondrial (mito) KATP channel blocker, 5-hydroxydecanoate (5-HD) (40 mg/kg), the non-selective KATP channel blocker glibenclamide (5 mg/kg), the selective mito KATP channel opener diazoxide (10 mg/kg) and the non-selective KATP channel opener cromakalim (300 μg/kg) were administered intraperitoneally 15 min prior to the ischaemia or 75 min after the induction of ischaemia. Tissue damage was evaluated by malondialdehyde concentration, myeloperoxidase activity, histological evaluation and TdT-mediated dUTP nick end labelling assay in the testis. There was a significant increase in oxidative stress, neutrophil infiltration, histological damage and apoptosis in the testicular IR model. A significant reduction in the testicular IR injury was observed with the administration of glibenclamide, but not 5-HD, diazoxide or cromakalim during ischaemia. The administration of non-selective KATP channel blocker glibenclamide ameliorated the testicular IR injury. On the other hand, the selective mito KATP channel blocker, 5-HD and KATP channel openers did not reduce the testicular IR injury. These data suggest that blocking of the membrane KATP channel may have a protective effect during the testicular ischaemia. Glibenclamide could be an effective drug to manage the post-ischaemic injury caused by the testicular torsion-detorsion.

Effects of ischaemic post-conditioning on the early and late testicular damage after experimental testis ischaemia-reperfusion

Ischaemic post-conditioning (IPostC) might represent an innovative surgical approach to protect organs from ischaemia and reperfusion (I/R) injury. We investigated the molecular mechanisms underlying the contrasting effects of IPostC on the early and late damage induced by testicular I/R injury. Testis I/R was induced by occluding the right testicular vessels using a clip. Male rats were divided into the following groups: sham, I/R and I/R + IPostC. In the I/R group, the clip was removed after 60 min of ischaemia, and reperfusion was allowed for 30 min, 1 and 30 days. In the I/R + IPostC group, three cycles of 30-sec reperfusion and 30-sec ischaemia were performed after 60 min of ischaemia and then reperfusion followed up for 30 min, 1 and 30 days. Following 30-min reperfusion, there was an increase in mitogen-activated protein kinases (MAPKs) in I/R rats; after 1 day of reperfusion, interleukin-6, tumour necrosis factor-α and nuclear factor-κB (NF-κB) expression were significantly increased; IκB-α expression reduced; and a marked damage in both testes was observed. IPostC inhibited MAPKs, cytokines and NF-κB expression, augmented IκB-α expression and decreased histological damage in testes subjected to I/R. After 30 days of reperfusion, I/R injury activated the apoptosis machinery, caused severe histological damage and reduced spermatogenic activity. By contrast, IPostC did not modify the apoptotic markers, the histological alterations as well as spermatogenic activity following 30 days of reperfusion. Our data demonstrate that IPostC protects the testis from the early damage induced by I/R injury, but it does not protect against the late damage.

Postconditioning with far-infrared irradiation increases heme oxygenase-1 expression and protects against ischemia/reperfusion injury in rat testis

AIMS

Studies have shown that heme oxygenase-1 (HO-1) has a protective role in the mechanism underlying hypoxic preconditioning. We used a far-infrared radiation (FIR) heater to investigate the postconditioning protective role of HO-1 against ischemia/reperfusion (I/R) injury in rat testis.

MAIN METHODS

Forty rats were used. Testis ischemia was mimicked by total obstructive clamping of testis vessels for 1, 2, or 4 h, and concomitant postconditioning with 30 min FIR or heat light during initially 30 min reperfusion. HO-1 expression and apoptosis of testis tissues were examined by immunohistochemistry and in situ terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay, respectively. HO-1 protein level and caspase-3 activity were analyzed by Western blotting.

KEY FINDINGS

There was less apoptotic activity in rat testis after FIR, as determined by TUNEL assay. Higher HO-1 protein expression was observed by immunohistochemistry and Western blotting (p<0.01) in testis cells after FIR postconditioning. In contrast, caspase-3 activity was significantly higher in heat light groups, as compared with FIR groups (p<0.01).

SIGNIFICANCE

FIR postconditioning attenuated I/R injury in rat testis by inducing HO-1 expression, which might have a protective role in testis apoptosis after I/R injury.

Comparison of the protective effect of dipyridamole and acetylsalicylic acid on long-term histologic damage in a rat model of testicular ischemia-reperfusion injury

PURPOSE

Ischemia reperfusion injury arising from testicular torsion results in a loss of spermatogenesis and a significant increase in germ cell apoptosis. We investigated the effects of dipyridamole and acetylsalicylic acid (ASA), 2 well-known platelet inhibitors, on testicular ischemia reperfusion injury.

METHODS

Thirty adult male Sprague-Dawley rats were randomly divided into 5 groups (n = 6 for each group): control, sham-operated, torsion/detorsion (T/D), T/D + dipyridamole, and T/D + ASA. Testicular ischemia was achieved by rotating the left testis 720° clockwise for 2 hours. Thirty minutes before torsion, 10 mg/kg dipyridamole was injected transperitoneally in the T/D + dipyridamole group, and 100 mg/kg ASA was injected transperitoneally in the T/D + ASA group. Sixty days after the initial surgical procedure, ipsilateral orchiectomies were performed for histopathologic examination to determine Johnsen's mean testicular biopsy score (MTBS), mean seminiferous tubular diameter (MSTD), and apoptotic index (AI) in all groups.

RESULTS

Unilateral testicular torsion-detorsion led to a significant decrease in Johnsen's MTBS and MSTD values in the ipsilateral testis and a significant increase in AI values of the T/D group. There were no significant differences between the T/D + dipyridamole and control groups in terms of MSTD and MTBS values. Although an amount of improvement exits in T/D + ASA group, there were significant differences between the T/D + ASA and control group MSTD and MTBS values. There was no significant difference between the T/D + dipyridamole and control groups in terms of AI values (P > .05), but the differences between the T/D + ASA and control groups were significant despite a slight decline in AI values of the T/D + ASA group.

CONCLUSIONS

Our findings show that the use of dipyridamole before testicular reperfusion has a potentially protective effect against long-term injury in testicular ischemia reperfusion injury.

Long-term effects of the testicular torsion on the spermatogenesis of the contralateral testis and the preventive value of the twisted testis orchiepididymectomy

PURPOSE: To determine whether the testicular torsion causes long-term effects on the spermatogenesis of the contralateral testis, and whether the orchiepididymectomy of the twisted testis could prevent them, using specific spermatogenesis parameters to elucidate the conflicting results in the literature. METHODS: Seventy-four pubertal male Wistar rats were randomly selected. The experimental group consisted of 40 rats, divided into four subgroups, submitted to 1.080 degrees counterclockwise left testicular torsion and its scrotal fixation at the beginning of the experiment, and left orchiepididymectomy at one, five, ten and 90 days, respectively. The control group consisted of 24 rats, divided into four sham operation control subgroups. An additional control subgroup consisted of the ten remaining rats, submitted only to the left orchiepididymectomy at the beginning. At 90 days, the contralateral testes of the experimental and control subgroups were collected for the evaluation of their spermatogenesis parameters: testicular weight, seminiferous tubular diameter, Johnsen score and differential counting of the germ cells. RESULTS: No statistically significant differences were observed among the experimental and control subgroups for all of the spermatogenesis parameters of the contralateral testes. CONCLUSIONS: Testicular torsion does not cause long-term effects on the spermatogenesis of the contralateral testis in pubertal rats, and the orchiepididymectomy of the twisted testis is not necessary for preventive purposes for the contralateral spermatogenesis.