Oxidative stress plays an important role in the pathogenesis of endothelial dysfunction, which is found to precede the development of diverse cardiovascular diseases (CVDs). The aim of this study was to observe the protective effects of PD against H2O2-induced oxidative stress injury (OSI) in human umbilical vein endothelial cells (HUVECs) and the possible mechanism of PD in OSI treatment. HUVECs were subjected to H2O2 in the absence or presence of PD. It turned out that PD improved cell viability and adhesive and migratory abilities, inhibited the release of lactate dehydrogenase (LDH) and reactive oxygen species (ROS), and elevated the content of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). TUNEL, fluorometric assays, and Western blotting showed that OSI upregulated the apoptosis ratio, the activity of caspase-3 and the level of proapoptotic protein Bax and decreased the level of antiapoptotic protein Bcl-2. However, PD treatment partially reversed these damage effects and Protein Kinase C (PKC) activation by thymeleatoxin (THX) in turn eliminated the antiapoptotic effect of PD. Furthermore, PD attenuated the H2O2-induced phosphorylation of PKCs α and δ and increased the phosphorylation of PKC ε. Our results indicated that PD might exert protective effects against OSI through various interactions with PKC pathway.

Leydig cells (LCs) in the adult testis have been identified as the major sites of oestrogen production, which is crucial for mammalian germ cell differentiation. Our previous work showed that transforming growth factor beta 1 (TGFB1) inhibits estradiol (E) secretion via down-regulating gene expression in mature rat LCs. However, the mechanism remains unclear. In the present study, the effects of TGFB1 on the expression levels of steroidogenic factor 1 (SF1), liver receptor homolog 1 (LRH1), cAMP response element-binding protein (CREB) and cAMP responsive element modulator (CREM) were evaluated both in primary cultured LCs and in rat testis. The involvement of TGFB1 signalling in the regulation of SF1 and LRH1 expression was then validated by applying the inhibitor of the TGFB type 1 receptor (TGFBR1) SB431542. Moreover, the expression of CYP19 in testicular LCs was investigated and the production of E in testicular interstitial fluid (TIF) was measured. The results showed that TGFB1 especially down-regulated the expression levels of SF1 and LRH1 both in primary cultured LCs and in rat testis. The down-regulations of TGFB1 in the production of E in TIF and the expression of CYP19 in testicular LCs were also observed These inhibitory effects could be reversed by TGFBR1 inhibitor SB431542. Our findings suggest that TGFB1 may act through the canonical signalling pathway involving ALK5 to restrain SF1 and LRH1 accumulation and eventually attenuate transcription and oestrogen production in LCs.

No abstract

Oxidative stress plays a critical role in the process of testicular torsion and detorsion (T/D). The purpose of the present study was to investigate the protective effect of polydatin (PD) on testicular T/D injury. Rats were randomly divided into three groups, a sham group, a group subjected to 2h torsion followed by 24h detorsion and a group subjected to T/D and injected i.p. with 20mgkg PD 30min before detorsion. Unilateral orchiectomy was performed after 24h of reperfusion. Half the testes were prepared for histological examination by haematoxylin-eosin staining and the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) technique. In the remaining tissues, levels of malondialdehyde (MDA), catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) were determined, as was the expression of several apoptosis-related proteins. Compared with the T/D group, PD pretreatment significantly ameliorated the morphological damage, lowered the Cosentino histological score and increased the mean number of germ cell layers and Johnsen's testicular biopsy score. In addition, PD treatment markedly decreased MDA levels and upregulated CAT, GPx and SOD activity. Furthermore, PD decreased T/D-induced germ cell-specific apoptosis, attenuated the activation of caspase-3, caspase-8, caspase-9 and poly(ADP-ribose) polymerase and increased the Bcl-2/Bax ratio. The findings indicate that PD has a protective effect against testicular T/D injuries, especially at the histological, antioxidative stress and antiapoptotic levels.

No abstract