The current study was performed to investigate mitochondrial protection and anti-aging activity of Astragalus polysaccharides (APS) and the potential underlying mechanism. Lipid peroxidation of liver and brain mitochondria was induced by Fe2+–Vit C in vitro. Thiobarbituric acid (TBA) colorimetry was used to measure the content of thiobarbituric acid reactive substances (TBARS). Mouse liver mitochondrial permeability transition (PT) was induced by calcium overload in vitro and spectrophotometry was used to measure it. The scavenging activities of APS on superoxide anion (O2•−) and hydroxyl radical (•OH), which were produced by reduced nicotinamide adenine dinucleotide (NADH)—N-Methylphenazonium methyl sulfate (PMS) and hydrogen peroxide (H2O2)–Fe2+ system respectively, were measured by 4-nitrobluetetrazolium chloride (NBT) reduction and Fenton reaction colorimetry respectively. The Na2S2O3 titration method was used to measure the scavenging activities of APS on H2O2. APS could inhibit TBARS production, protect mitochondria from PT, and scavenge O2•−, •OH and H2O2 significantly in a concentration-dependent manner respectively. The back of the neck of mice was injected subcutaneously with D-galactose to induce aging at a dose of 100 mg/kg/d for seven weeks. Moreover, the activities of catalase (CAT), surperoxide dismutase (SOD) and glutathione peroxidase (GPx) and anti-hydroxyl radical which were assayed by using commercial monitoring kits were increased significantly in vivo by APS. According to this research, APS protects mitochondria by scavenging reactive oxygen species (ROS), inhibiting mitochondrial PT and increasing the activities of antioxidases. Therefore, APS has the effect of promoting health.
MicroRNA-195 (miR-195) is a tumor suppressor that plays an important role in tumorigenesis. There are few studies on miR-195 expression in breast cancer patients and the results have been inconsistent; therefore, this study examined miR-195 expression in the serum of BC patients. Samples from 102 normal subjects and 210 subjects with BC who had detailed clinical follow-up information available were selected. An internal reference (miR-16) and serum miR-195 were amplified and quantitatively detected by SYBR green-based real-time RT-PCR. We analyzed the differences in miR-195 levels between BC and healthy cases and the relationships between the miR-195 level and TNM stage and other clinicopathological parameters. In addition, changes in miR-195 levels were examined for 21 BC cases using paired samples before and after neoadjuvant chemotherapy. miR-195 was downregulated in BC compared with control samples (P = 0.000, Mann-Whitney U test). The sensitivity and specificity of miR-195 in the diagnosis of BC were 69.0 and 89.2 %, respectively; whereas, the sensitivities of carcinoembryonic antigen (CEA) and carbohydrate antigen 153 (CA153) were only 15.08 and 21.1 %, respectively. Remarkably, serum miR-195 had higher sensitivity, 73.97 % (108/146), as a tumor marker in the diagnosis of early stage BC [ductal carcinoma in situ, tumor-node-metastasis (TNM) I, II] compared with the conventional tumor markers CA153 and CEA (12.41 and 7.59 %). Moreover, compared with CEA and CA153, miR-195 had a higher sensitivity for detecting the response to neoadjuvant chemotherapy and significantly increased, more than twofold, after neoadjuvant chemotherapy (P = 0.025, paired t test) in 52.381 % (11/21) of BC cases. However, there were no significant relationships between miR-195 expression and other clinicopathological parameters (TNM stage/pathotype/ER/PR/lymph node status). Our data indicate serum miR-195 is a promising tumor marker for BC diagnosis and general screening, especially for early stage BC. The high sensitivity of miR-195 to neoadjuvant chemotherapy may lay the foundation for future studies on the use of miRNA-based methods for monitoring BC treatment and therapy.
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