Protective effect of pterostilbene on testicular ischemia/reperfusion injury in rats

The neuroprotective effect of pterostilbene on oxaliplatin-induced peripheral neuropathy via its anti-inflammatory, anti-oxidative and anti-apoptotic effects: Comparative study with celecoxib

BACKGROUND

Oxaliplatin is one of the first-line drugs in solid tumors treatment. However, neuropathy is a devastating side effect leading to poor compliance and treatment cessation.

AIM

The current study explored pterostilbene plausible neuroprotective effects aiming to ascertain the potential mechanisms involved in relieving oxaliplatin-induced peripheral neuropathy (OIPN) and investigating whether pterostilbene and celecoxib combination could show better relief.

MAIN METHODS

Rats were divided into six groups; control, pterostilbene (40 mg/kg/day, p.o. for 5 weeks), oxaliplatin (4 mg/kg, i.p. twice per week for 4.5 weeks), celecoxib (30 mg/kg/day, p.o. for 5 weeks) and combination of pterostilbene and celecoxib. Behavioral tests and histopathological analysis of sciatic nerves were done. MAPKs, cytokines, COX-2, and PGE₂ gene and protein expressions were estimated using qRT-PCR, western, and ELISA techniques. Malondialdehyde (MDA) and total antioxidant capacity (TAC) were assessed by colorimetric assay while apoptotic markers by immunohistochemical analysis and qRT-PCR.

KEY FINDINGS

The study revealed that pterostilbene and celecoxib averted oxaliplatin-induced behavioral and motor impairments along with restoration of histopathological changes. Moreover, pterostilbene and celecoxib have significantly attenuated sciatic nerve: p38 MAPK, JNK, ERK1/2, NF-κB, COX-2, PGE₂, TNF-α, and interleukins levels. Pterostilbene and celecoxib have reduced caspase-3, Bax, and MDA while increasing Bcl-2 level and TAC.

SIGNIFICANCE

Altogether, Pterostilbene mitigates OIPN by interrupting the vicious cycle of inflammation, oxidation, and apoptosis. Furthermore, pterostilbene and celecoxib show comparable attenuation on MAPKs cascades, inflammatory cytokines, oxidative and apoptotic markers. Likewise, co-administration of pterostilbene and celecoxib shows further relief of neuropathic pain.

Effects of L-carnitine and betamethasone on ischemia-reperfusion injuries and sperm parameters following testicular torsion in a rat model

Testicular torsion is a consequence of spermatic cord twisting which causes progressive damage to the structure of the testis and reduces sperm quality and usually results in infertility. In the present study, with the assumption of the protective effects of L-carnitine and betamethasone against ischemia-reperfusion (IR) injuries, their effects on twisted testicles were evaluated and compared. Twenty Wistar rats were randomly divided into four groups and used in this study. Except for the Sham (S) group, testicular IR was induced surgically in three other groups, including Control (C), Betamethasone (BM), and L-carnitine (LC) groups. Betamethasone and L-carnitine were injected before detorsion in the BM and LC groups, respectively. After twelve hours of reperfusion, the testicles were detached, and prepared for sperm parameters evaluation such as sperm count, motility, viability, morphology, and chromatin quality, and histopathologic evaluations, including mean seminiferous tubular diameter (MSTD), germinal epithelial cell thickness (GECT), and Johnsen's mean testicular biopsy scoring (MTBS). The MSTD, GECT, and healthy sperms in the C group were significantly lower than the other groups, while the BM and LC groups were significantly different from others in MTBS. The number of sperms and sperm motility in the BM group was significantly higher than the C group. Sperm viability in the BM and LC groups were significantly higher than the C group. The results of this study showed that both L-carnitine and betamethasone similarly can be effective in treating testicular IR injuries.

Pterostilbene alleviates hydrogen peroxide-induced oxidative stress via nuclear factor erythroid 2 like 2 pathway in mouse preimplantation embryos

Pterostilbene (PTS) in blueberries is a phytoalexin with antioxidant properties. PTS exerts strong cytoprotective effects on various cells via Nuclear Factor Erythroid 2 like 2 (NFE2L2) pathway. We evaluated the antioxidant PTS treatment in mouse preimplantation embryos. In vitro culture media were supplemented with different concentrations of PTS. Treatment of zygotes with 0.25 μM PTS improved the development of day 4 blastocysts (P < 0.05). Moreover, H₂O₂ treatment significantly increased the reactive oxygen species level and reduced the glutathione level in mouse blastocyst, whereas PTS treatment counteracted these effects. The fluorescence intensity of apoptotic positive cell was higher in the H₂O₂ group than in the PTS group. Furthermore, PTS-treated embryos significantly increased the protein expression of NFE2L2 in the nucleus and decreased Kelch-like ECH-associated protein1 (KEAP1). PTS treatment significantly increased the expression of downstream target genes involved in the NFE2L2 pathway, such as catalase (CAT), heme oxygenase1 (HMOX1), glutathione peroxidase (GPX), and superoxide dismutase (SOD); these genes confer cellular protection. In addition, PTS treatment significantly increased the expression of anti-apoptotic B-cell lymphoma 2 (BCL2), with a concomitant reduction in the apoptotic Bcl-2-associated X protein (BAX) and Caspase-3 genes in the embryo. PTS treatment also increased the protein expression of BCL2 and reduced the protein expression of BAX in the mouse embryo. In conclusion, PTS activated NFE2L2 signaling pathway in the development of mouse embryos by altering downstream expression of genes involved in the antioxidant mechanisms and apoptosis.

Ferroptosis is associated with oxygen-glucose deprivation/reoxygenation-induced Sertoli cell death

Sertoli cell death contributes to spermatogenesis impairment, which is associated with male infertility. Testicular ischemia‑reperfusion (I/R) injury induces the cell death of germ cells and Sertoli cells, whereas inhibition of cell death ameliorates acute testicular I/R damage. The aim of the present study was to investigate the mechanism of I/R stress-induced cell death in TM4 cells. Oxygen‑glucose deprivation and reoxygenation (OGD/R) was demonstrated to induce I/R injury and cell death in TM4 cells. Cell death was blocked by the reactive oxygen species (ROS) inhibitor N‑acetylcysteine, as well as lipid peroxidation inhibitors Liproxstatin‑1 and iron chelator deferoxamine; however, inhibitors of apoptosis, necrosis or autophagy had no effect. It was also demonstrated that iron and lipid ROS levels were elevated in I/R injury and that mitochondria decreased in size and increased in membrane density, which is indicative of ferroptosis. Furthermore, the generation of lipid ROS suggests iron accumulation and glutathione (GSH) depletion. The expression of ferroportin (Fpn) protein and mRNA was decreased in TM4 cells. Notably, overexpression of Fpn inhibited ferroptosis, lipid ROS generation and iron accumulation. In addition, GSH‑dependent peroxidase 4 (GPX4) was inactivated via GSH depletion following I/R injury, whereas GPX4 activation blocked I/R‑induced ferroptosis by reducing lipid ROS levels. The mitogen‑activated protein kinase (MAPK) pathway was also investigated in the present study; it was observed that I/R‑induced ferroptosis was blocked by inhibiting p38 MAPK activation. The results of the present study demonstrate that ferroptosis is a pervasive and dynamic type of cell death induced by OGD/R injury in Sertoli cells. This may provide a novel insight into the application of cytoprotection in testicular I/R damage‑induced cell loss.

Protective influence of rosiglitazone against testicular ischaemia-reperfusion injury in rats

Testicular torsion is a urology urgent disease which causes testicular injury and potential sterility. In this study, we explored the protective influence of rosiglitazone on testicular ischaemia-reperfusion damage. There were 28 male Sprague Dawley rats in total, which were assigned randomly to four groups. Group A was blank control one; group B was testicular injury one; group C was rosiglitazone one; group D was rosiglitazone antagonist one. The testicles were counter-rotated after 2 hr and then underwent orchiectomy 24 hr later. We found that testicular tissue structure of rats was seriously damaged in groups B and D. However, group C had better testicular architecture. Similar findings were also shown for lipid peroxidation by evaluating the MDA activity (p < .05). Unlike group B or group D, the levels of inflammation by evaluating the MPO activity, the levels of TNF-a, IL-1 and IL-6 and the expressions of ICAM-1 were prominently lower in group C (p < .05) as well. So our researches demonstrated that rosiglitazone significantly decreased the amount of responsive oxygen radical and regulated inflammatory responses. Rosiglitazone had a protective influence against testicular ischaemia-reperfusion injury in rats and possibly depended on its anti-inflammatory and antioxidant traits.

MiR-29a Suppresses Spermatogenic Cell Apoptosis in Testicular Ischemia-Reperfusion Injury by Targeting TRPV4 Channels

Background: MicroRNAs (miRNAs) have emerged as gene expression regulators in the progression of ischemia-reperfusion injury (IRI). Accumulating evidences have indicated miR-29a play roles in myocardial and cerebral IRI. However, the role of miR-29a in testicular IRI has not been elucidated.

Methods: Changes in expression of miR-29a and Transient Receptor Potential Vanilloid 4 (TRPV4) in animal samples and GC-1 spermatogenic cells were examined. The effects of miR-29a on spermatogenic cell apoptosis in testicular IRI were analyzed both in vitro and in vivo.

Results: The expression of MiR-29a was negatively correlated with the expression of TRPV4 and significantly downregulated in animal samples and GC-1 cells as testicular IRI progressed. Further studies revealed TRPV4 as a downstream target of miR-29a. Inhibition of miR-29a expression increased the expression of TRPV4 and promoted spermatogenic cell apoptosis, whereas overexpression of miR-29a downregulated TRPV4 expression and suppressed spermatogenic cell apoptosis caused by testicular IRI in vitro and in vivo.

Conclusion: Our results suggest that miR-29a suppresses apoptosis induced by testicular IRI by directly targeting TRPV4.

Effects of pomegranate peel extract on histopathology, testosterone levels and sperm of testicular torsion–detorsion induced in adult Wistar rats

Background

In the present study, effects of pomegranate peel extract have been evaluated on decreasing the damage induced by testis torsion.

Methods

In this study, 30 adult Wistar rats were randomly divided into three groups of control, experimental (1) and experimental (2). Control: no ischemia, received vehicle alone, exposed to sham operation. Experimental (1): Received the vehicle alone during ischemia followed by 60 days’ reperfusion. Experimental (2): After performing ischemia reperfusion, 500 mg/kg of pomegranate peel extract has been used for 60 days. Blood samples and sperm samples were collected. Testes were harvested and stained with haematoxylin and eosin to study the structure of seminiferous tubules.

Results

The statistical comparison between sperm count and their viability and testosterone hormone amount showed a significant difference between control and experimental (1) groups and control and experimental (2) groups. The results showed an improvement of morphological condition of seminiferous tubules.

Conclusions

Pomegranate peel extract has revealed desirable changes on the effective parameters in infertility.

Effects of platelet-rich plasma against experimental ischemia/reperfusion injury in rat testis

BACKGROUND

Testicular torsion is a common problem and, to date, there is no agent to preserve testicular function following detorsion. Platelet-rich plasma (PRP), with its rich growth factor composition, has proven beneficial in regenerative therapy. It is believed that PRP has not been studied in testis for ischemia/reperfusion (I/R) injury.

OBJECTIVE

This study investigated the effect of PRP in an I/R rat model 1 month after detorsion.

STUDY DESIGN

Of 24 adult male Sprague-Dawley rats, 18 were randomly assigned into three groups, with six in each: control, I/R and I/R + PRP. The PRP was prepared from the remaining six. Each group underwent right orchiectomy. Ischemia was performed by rotating the left testis 720° and fixing with a nylon suture for 4 h. Reperfusion occurred 4 h later by removing the suture, and PRP was administered at a dose of 10 μl (2000 × 10⁹/l) into the left testis via the intraparenchymal route. Animals were sacrificed at the fourth week, and testes were taken for malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), myeloperoxidase (MPO), transforming growth factor β (TGF-β), and caspase-3 measurements.

RESULTS

Ischemia/reperfusion caused a significant increase in MDA, MPO and caspase-3 activity, and significant decrease in GSH levels and SOD activity. The PRP treatment helped correct the alterations in SOD, caspase-3, and MPO activities and MDA levels. However, the mean MDA level and MPO activity were not totally restored compared with the controls. Serum testosterone levels of the I/R group were significantly lower compared with the control and I/R + PRP groups. TGF-β and caspase-3 protein expressions were significantly higher in the I/R group compared with the control group and were low with PRP administration compared with I/R groups (summary Table).

DISCUSSION

The findings of the present study suggest that PRP, by inhibiting neutrophil infiltration and oxidative stress and increasing antioxidant defense, exerts protective effects on testicular tissues against I/R. This study had some limitations: a scoring system was not used in the assessment of spermatogenesis in the histopathological findings and specific testis cell types were not histologically assessed.

CONCLUSIONS

In light of the biochemical, histological and, especially, hormonal findings, intraparenchymal PRP injection may have a protective effect in testicular tissue against I/R injury.

Testicular compartment syndrome: an overview of pathophysiology, etiology, evaluation, and management

Testicular compartment syndrome (TCS) refers to the impairment of microcirculation in the testicle due to either increased venous resistance or extraluminal compression, which leads to hypoxia. TCS releases oxidants through hypoxia and ischemia/reperfusion injury (IRI). The pathophysiology, etiology, evaluation, and management of TCS are reviewed. Based on the properties of TCS, specific causes, e.g., varicocele, hydrocele, orchitis, cryptorchidism, and scrotal hernia, are suggested and categorized. The oxidant-induced stress from TCS may explain the correlations between these causes and infertility. A chief shortcoming of current imaging modalities is that they detect TCS late after it has progressed to impair the macrocirculation of the testicle. We propose frequent sequential periodic power Doppler ultrasonography to monitoring for earlier detection. Intraoperatively, TCS can be diagnosed by the dull purple appearance of a hypoxic testicle and by tissue pressures above 30 mmHg. When compartment pressure is low, the underlying etiology must be promptly treated. During acute presentation, an incision of the resilient tunica albuginea may be necessary. A great challenge of treating TCS is restoring microcirculation while minimizing IRI; concomitant antioxidant therapy secondary to treatment may be effective and harmless at the least. Because testicular oxidant stress is common in infertility and since TCS can cause such a stress, TCS may be a larger factor in infertility than currently suspected.