Search

To examine the role of the transcription factor nuclear factor-erythroid 2 (NF-E2)-related factor 2 (Nrf2) and the SAFE pathway (JAK/STAT) in the induction of germ cell apoptosis (GCA) and the protective role of epigallocatechin-3-gallate (EGCG) during testicular ischemia reperfusion injury (tIRI). Male Sprague-Dawley rats (n = 18) were divided into three groups: sham, unilateral tIRI, tIRI + epigallocatechin-3-gallate (EGCG, 50 mg/Kg). Unilateral tIRI was induced by 1-h ischemia followed by 4-h reperfusion, and EGCG was injected i.p. 30-min post ischemia. Immuno-histological analyses were used to detect spermatogenesis, oxidative DNA damage, and the immuno-expression of the JAK2, STAT3, and STAT1. Biochemical assays were used to investigate the oxidative, apoptosis proteins and enzymes, while Western blot was used to detect the expression of NOX and Nrf2. Expression of apoptosis-related genes was measured by real-time PCR. During tIRI, there was a clear damage to spermatogenesis associated with decreased activities of SOD, CAT, and GPx and increased levels of lipid peroxidation and oxidative DNA damage. In addition, GCA was indicated by the activation of caspase1, PARP, decreased gene expression of survivin and increased Bax to Bcl2 ratio. In contrast to lowered Nrf2 levels, NOX levels were augmented and phosphorylation of JAK2, STAT3, and STAT1 was increased. Pre-perfusion treatment with EGCG prevented the above modulations. The coordinated activation of the SAFE pathway and suppression of Nrf2 contribute to the tIRI-induced oxidative damages and GCA, which were modulated by EGCG.

Testicular ischemia reperfusion injury (tIRI) is considered as the underlying mechanism of testicular torsion, which can cause male infertility. tIRI-induced damage was investigated by assessing the gene expression of spermatogenesis master transcription factors (TFs) and that of major adhesion molecules of the blood-testis barrier. The effect of lutein, a hydroxyl carotenoid, in alleviating tIRI-induced damage was also studied. Male Sprague-Dawley rats were divided into three groups: sham, unilateral tIRI, and tIRI + lutein (0.2 mg/kg). tIRI was induced by occlusion of the testicular artery for 1 h, followed by 4 h of reperfusion. Lutein was injected 15 min after the start of ischemia. Histological analysis and real-time polymerase chain reaction revealed significant decreases in tissue biopsy scores, reduced seminiferous tubule diameters, and downregulated the mRNA expression of the TFs cAMP-responsive element modulator (CREM), TATA box-binding protein-related factor 2 (TRF2), and regulatory factor X 2 (RFX2) compared with the sham group. Lutein treatment reversed these effects. The mRNA expression of the adhesion molecules N-cadherin, nectin-2, claudin-11, occludin, and connexin-43 was significantly downregulated during tIRI, but this change was prevented by lutein treatment. In addition, lutein normalized the tIRI-induced increase in total antioxidant capacity, increased malondialdehyde (MDA) levels, augmented number of TdT-mediated dUTP-X nick-end labeling (TUNEL)-positive nuclei, and activated caspase-8 pathway. The components of survivor activating factor enhancement (SAFE) were also activated during tIRI. Increased tissue expression of TNF-α and its receptor, TNFR1, was accompanied by increased phosphorylation of Janus kinase (JAK) and STAT3, which was prevented by lutein treatment. Our findings suggested that tIRI-induced spermatogenic damage may involve modulation of the SAFE pathway and could benefit from lutein treatment.

Muscle degeneration and impairment following nerve injury could lead to apoptosis as a result of increased levels of reactive oxygen species. This activates the apoptotic cascade through mitochondrial dysfunction and damage to lipids, proteins, and DNA. In considering of the multifactorial protective properties of green tea polyphenols (-)-epigallocatechin-3-gallate (EGCG), this study investigates whether EGCG treatment does improve skeletal muscle function impairments, induced by crushing of the sciatic nerve. Compared to the saline-treated injured group of animals, EGCG treatment of axonotomized animals showed significant motor enhancement in the toe spread and foot positioning analysis and gain in the percentage motor deficit. The proprioceptive function expressed by the hopping response showed significant progression in the EGCG-treated group. Recovery of sensory innervation was followed by a slowly retreating neuropathic pain-like syndrome in the EGCG-treated animals. Muscle tissues from injured limb showed severe histopathological alterations that were significantly attenuated by EGCG treatment at the end of week 3 post-surgery. Semi-quantitative desmin immunohistochemistry revealed intense staining in the saline-treated injured animals, whereas EGCG treatment decreased the desmin immunoreactivity back to sham control levels. Using RT-PCR, EGCG treatment induced a significant anti-apoptotic effect in injured muscle tissues by normalizing the Bax/Bcl-2 ratio back to baseline levels and inhibiting overexpression of the p53 apoptotic gene at days 3 and 7 post-surgery. In conclusion, our results demonstrate that EGCG enhances functional recovery, protects muscle fibers from cellular death by activating anti-apoptotic signaling pathway, and improves morphological recovery in skeletal muscle after nerve injuries.