Effects of sericin on oxidative stress and PI3K/AKT/mTOR signal pathway in cryopreserved mice ovarian tissue.

Ovarian tissue cryopreservation is an effective fertility protective strategy for preadolescent female cancer patients, whose tumor treatment cannot be delayed. In the present study, the effects of sericin, as an antioxidant, on mice ovarian tissue freezing and thawing were investigated. Mice ovarian tissues were cryopreserved and thawed in medium containing 0.5% or 1%sericin (w/v), and 0.1 mM melatonin. Then, the follicular morphology was observed. The levels of antioxidant enzymes were determined, including glutathione (GSH), glutathione peroxidase (GSH-Px), total superoxide dismutase (T-SOD), total antioxidant capacity (T-AOC) and catalase (CAT). Moreover, the levels of nitric oxide (NO), malondialdehyde (MDA) and lactate dehydrogenase (LDH) were also tested. Besides, apoptosis-related proteins Bcl-2 and Bax were determined. Our results showed that 1% sericin maintained follicular morphology, inhibited apoptosis, decreased MDA and NO levels, and boosted endogenous antioxidant enzyme levels, while had no significant effect on LDH levels. Furthermore, these effects may be related with the activation of the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of Rapamycin (mTOR) signaling pathway, as demonstrated by increased PI3K, p-AKT and mTOR levels. These findings demonstrate that 1% sericin may reduce oxidative stress and protect ovarian tissues during freezing and thawing via PI3K/AKT/mTOR signaling pathway.

Melatonin Inhibits Oxidative Stress and Apoptosis in Cryopreserved Ovarian Tissues via Nrf2/HO-1 Signaling Pathway.

In the field of assisted reproductive technology, female fertility preservation, particularly ovarian tissue cryopreservation in adolescent cancer patients, has attracted much attention. Melatonin (MLT) is well known for its antioxidative and anti-apoptotic properties; however, whether it can ameliorate the cryoinjury and inhibit the generation of reactive oxygen species (ROS) in cryopreserved ovarian tissues (OTs) has not yet been reported. Here, we demonstrated that MLT could protect follicular integrity; prevent cell apoptosis; decrease ROS, malondialdehyde (MDA), and nitric oxide (NO) levels; and increase activities of glutathione peroxidases (GSH-Px), glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) in cryopreserved OTs. Furthermore, these effects may be related with the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, as evidenced by increased mRNA levels of Nrf2 downstream genes, including heme oxygenase-1 (HO-1), glutathione S-transferase M1 (GSTM1), SOD, and CAT. In summary, MLT can not only directly scavenge ROS but also significantly induce the activation of antioxidative enzymes via the Nrf2 signaling pathway, which is a new mechanism underlying the protection effects of MLT on cryopreserved OTs.

Antioxidative effect of melatonin on cryopreserved ovarian tissue in mice.

Cryopreservation of ovarian tissues (OTs) has become the most effective way to preserve the fertility of female cancer patients. However, cryopreservation of OTs is still relatively at an experimental stage. The aim of study is to examine the effect of melatonin (MTL) on cryopreserved-thawed OTs. Fragments of OTs were cryopreserved in medium containing different concentrations (0 mM, 0.001 mM, 0.01 mM, 0.1 mM and 1 mM) of MLT. The endogenous enzymes (GSH-PX, GSH, SOD, CAT and T-AOC), MDA and ROS levels were all evaluated after cryopreservation. Our results showed that the 0.1 mM of MLT significantly improved the survival and diameter of follicles (P < 0.001). Meanwhile, the antioxidant enzymes activities (including GSH-PX, GSH, SOD, CAT and T-AOC) were enhanced and MDA content were significantly decreased in 0.1 mM of MLT group compared to other groups (P < 0.001). Additionally, compared to the control group, MTL of 0.1 mM resulted in a significantly lower ROS level. In conclusion, MLT protects the quality of cryopreserved OTs by decreasing oxidative stress level and the optimal concentration is 0.1 mM.

[LC-MS/MS Analysis on the Components of Excretory-secretory Protein of Trichinella spiralis Muscle Larvae].

Objective: To analyze the components of excretory-secretory protein（ESP） of Trichinella spiralis muscle larvae, and search for the anti-tumor protein components. Methods: The Trichinella spiralis muscle larvae were collected, and ESP was prepared. The ESP was separated in 15% SDS-PAGE. Proteins extracted from the protein bands were lysed with trypsin, and analyzed by LC-MS/MS. The identified proteins were classified by Gene Ontology（GO） according to cell component, molecular function, and biological processes. Results: SDS-PAGE revealed clear protein bands at Mr 10 000-142 000. A total of 162 proteins were analyzed with LC-MS/MS, of which 63 were identified, 34 were putative proteins, and 65 were unidentified proteins. Six anti-tumor relevant proteins were revealed, which were tropomyosin, histone H2A, cleavage and polyadenylation specificity factor subunit 2, serine proteinase inhibitor Kazal-type 4, Armadillo segment polarity protein and eukaryotic initiation factor 4A. The GO enrichment analysis showed that the identified proteins possessed 54 different types of molecular functions, and participated in cell structure and 382 biological processes. Conclusion: The ESP of Trichinella spiralis muscle larvae has complex protein components, many with unknown identities. Six anti-tumor relevant proteins were determined from the 63 identified proteins.

Rosiglitazone protects neuroblastoma cells against advanced glycation end products-induced injury.

AIM: To investigate the protective effects of rosiglitazone (RGZ) against the neuronal toxicity induced by advanced glycation end products (AGEs) and the underlying mechanisms. METHODS: Neuroblastoma cell line SH-SY5Y was used. Cell viability and apoptosis were assessed using MTT assay and flow cytometry, respectively. Superoxide dismutase (SOD) and catalase activities were measured using biochemical methods. Intracellular reactive oxygen species (ROS) were monitored using 2',7'-dichlorodihydro-fluorescein diacetate (DCFH-DA). Secreted ß-amyloid(1-42) (Aß(1-42)) level was assessed by ELISA. The expression of mRNA of Bcl2, Bax, Caspase3, Aß precursor protein (APP), ß-site APP-cleaving enzyme 1 (BACE1), and insulin degrading enzyme (IDE) were measured using quantitative real-time PCR (Q-PCR), and their protein levels were examined using Western blot. RESULTS: RGZ (0.1-10 µmol/L) significantly increased the cell viability that was reduced by AGEs (1000 µg/mL). RGZ (10 µmol/L) significantly ameliorated AGEs-triggered downregulation of SOD and catalase, and production of ROS. It also reversed Bcl2 downregulation, Bax upregulation and Caspase3 expression caused by AGEs. Moreover, it significantly attenuated AGEs-induced Aß secretion and APP protein upregulation. RGZ did not affect BACE1 expression, but induced IDE expression, which promoted degradation of Aß. All the effects were blocked by the specific PPARγ antagonist GW9662 (10 µmol/L). CONCLUSION: RGZ protects the euroblastoma cells against AGEs-induced injury via its anti-oxidative, anti-apoptotic and anti-inflammatory properties that seems to be mediated by PPARγ activation. The results suggest a beneficial role for RGZ in the treatment of Alzheimer's disease.