Nano-selenium Alleviates Cadmium-Induced Mouse Leydig Cell Injury, via the Inhibition of Reactive Oxygen Species and the Restoration of Autophagic Flux.

Cadmium (Cd) is a well-known environmental pollutant that can contribute to male reproductive toxicity through oxidative stress. Nano-selenium (Nano-se) is an active single body of selenium with strong antioxidant properties and low toxicity. Some studies have addressed the potential ameliorative effect of Nano-se against Cd-induced testicular toxicity; however, the underlying mechanisms remain to be investigated. This study aimed to explore the protective effect of Nano-se on Cd-induced mouse testicular TM3 cell toxicity by regulating autophagy process. We showed that cadmium exposure to TM3 cells inhibited cell viability and elevated the level of reactive oxygen species (ROS) generation. Morphology observation by transmission electron microscope and the presence of mRFP-GFP-LC3 fluorescence puncta demonstrated that cadmium increased autophagosome formation and accumulation in TM3 cells, resulting in blocking the autophagic flux of TM3 cells. Meanwhile, cadmium remarkably increased the ratio of LC3-II to LC3-I protein expression (2.07 ± 0.31) and the Beclin-1 protein expression (1.97 ± 0.40) in TM3 cells (P < 0.01). Pretreatment with Nano-se significantly reduced Cd-induced TM3 cell toxicity (P < 0.01). Furthermore, Nano-se treatment reversed Cd-induced ROS production and autophagosome accumulation, and autophagy as evidenced by the ratio of LC3-II to LC3-I and Beclin-1 expression. In addition, ROS scavenger, N-acetyl-L-cysteine (NAC) or autophagy inhibitor, 3-methyladenine (3-MA) reversed cadmium-induced ROS generation, autophagosome accumulation, and autophagy-related protein expression levels, which confirmed that cadmium induced TM3 cell injury via ROS signal pathway and blockage of autophagic flux. Collectively, our results reveal that Nano-se attenuates Cd-induced TM3 cell toxicity through the inhibition of ROS production and the amelioration of autophagy disruption.

Selenium ameliorates cadmium-induced mouse leydig TM3 cell apoptosis via inhibiting the ROS/JNK /c-jun signaling pathway.

Despite the well-known acknowledgement of both the toxicity of cadmium (Cd) and the ameliorative effect of selenium (Se), the mechanism of the protective effect of selenium on cadmium-induced Mouse Leydig (TM3) cell apoptosis remains unknown. In this study, we hypothesized that the reactive oxygen species (ROS)-mediated c-jun N-terminal kinase (JNK) signaling pathway is involved in anti-apoptosis of selenium against cadmium in TM3 cells. We found that exposure to cadmium caused evident cytotoxicity, in which cell viability was inhibited, followed by inducement of apoptosis. Moreover, the level of ROS generation was elevated, leading to the phosphorylation of JNK. In addition, following cadmium exposure, the nuclear transcription factor c-jun was significantly activated, which led to increased expression of downstream gene c-jun, resulting in downstream activation of the apoptosis-related protein Caspase3 and upregulation of Cleaved-PARP, as well as inhibition of the anti-apoptosis protein Bcl-2. However, pretreatment with selenium remarkably suppressed cadmium-induced TM3 cell apoptosis. Furthermore, the level of ROS declined, and the JNK signaling pathway was blocked. Following this, the gene expression of c-jun decreased while Bcl-2 increased, which was consistent with the effects on proteins, that Caspase3 activity and Cleaved-PARP were inhibited while Bcl-2 level was restored. In order to explain the relationship between molecules of the signaling pathway, N-acetyl-L-cysteine (NAC), the ROS inhibitor, and JNK1/2 siRNA were administered, which further indicated the mediatory role of the ROS/JNK/c-jun signaling pathway in regulating anti-apoptosis of selenium against cadmium-induced TM3 cell apoptosis.

Chemical composition and antioxidant activity of phenolic compounds from Dioscorea (Yam) leaves.

This study was aimed to assess the potential of Dioscorea (yam) leaves as a source of antioxidants. Microwave-assisted extraction (MAE) process was used to prepare the extracts. The phenolic compounds in Dioscorea leaves extracts were analyzed by HPLC-DAD-ESI-MS/MS method and the contents of major compounds were determined. Results indicated that a total of 17 phenolic compounds were separated identified by means of UV and mass spectra compared with authentic reference substances and/or reported values in the literature. The main phenolic compound was rosmarinic acid and its highest amount was found in Dioscorea glabra Roxb. leaves (22.31±1.33 mg/g DW). Rutin was the dominant flavonoid followed by quercetin which highest amount was found in Dioscorea alata leaves (8.66±0.29 mg/g DW). Antioxidant activity of the extracts was estimated by the use of DPPH and ABTS assays. Both kinds of leaves exhibited satisfied antioxidant capacity which was correlated with phenolic contents. In the cytoprotective effect on HUVECs viability assay, Dioscorea glabra Roxb. leaves extract was found to be more active than that of Dioscorea alata against H2O2-induced oxidative stress. Our findings support the promising role of Dioscorea leaves that can be used as an interesting source of phenolic antioxidants.

The protection of selenium on cadmium-induced inhibition of spermatogenesis via activating testosterone synthesis in mice.

Selenium (Se) is an essential trance element in testis. However, the potential protective effects of Se against cadmium (Cd)-induced reproductive toxicity remained to be elucidated. Male ICR mice were orally administered by gavage with Na2SeO3 (0.1, 0.2, 0.4 mg/kg BW) for 1h prior to CdCl2 (5 mg/kg BW) alone or in combination for 15, 25 or 35 days. Cd exposure caused a significant decrease in body weight, sperm concentration and motility as well as plasma testosterone level which was accompanied by decreased antioxidant enzymatic activity of SOD and GSH-Px and by increased lipid peroxidation (as malondialdehyde, MDA). Se pretreatment compensated deficits in the sperm parameters (concentration, motility and morphology) induced by Cd. Se (0.4 mg/kg BW) treatment significantly increased serum testosterone level that was reduced by Cd (on 15th, 25th and 35th day) (P<0.01). Se treatment ameliorated Cd-induced reduction in testicular steroidogenic acute regulatory (StAR) and 17ß-hydroxysteroid dehydrogenase (17ß-HSD) activities. The present study suggest that the protective potential of Se against Cd-induced reprotoxicity might be due to up-regulation StAR and testosterone synthetic enzyme activity, which could be useful for increasing testosterone synthesis for achieving optimum protection in sperm quality and spermatogenesis.

Liquiritigenin induces mitochondria-mediated apoptosis via cytochrome c release and caspases activation in HeLa Cells.

It has been demonstrated that many flavonoids possess a potent and broad spectrum of antitumor activity. Liquiritigenin is a flavanone extracted from Glycyrrhizae. This study investigated the effects of liquiritigenin on cell viability and apoptosis induction in human cervical carcinoma (HeLa) cells. The results show that liquiritigenin significantly suppressed cell proliferation in a dose- and time-dependent manner in HeLa cells. In addition, liquiritigenin promoted apoptosis in HeLa cells, evidenced by apoptotic morphological changes and Annexin-V binding. The apoptosis induction with liquiritigenin is associated with the up-regulation of p53 and Bax, along with down-regulation of Bcl-2 and survivin. Finally, examination of the mitochondrial pathway of apoptosis revealed that cytochrome c is released from mitochondria to cytosol, associated with the activation of caspase-9 and -3, and the cleavage of poly (ADP-ribose) polymerase (PARP). Overall, the results indicate that liquiritigenin induces apoptosis in part via the mitochondrial pathway, which is associated with p53 up-regulation, release of cytochrome c and elevated activity of caspase-9 and -3 in HeLa cells.