Astaxanthin improves preserved semen quality at 17 degrees C by enhancing sperm antioxidant and motility properties

Porcine sperm is rich in polyunsaturated fatty acids; therefore, it is highly susceptible to oxidative damage during storage. Inhibition of oxidative stress during preservation is essential for maintaining sperm motility. Astaxanthin is a potent antioxidant used in the cosmetic and pharmaceutical industries. This study aimed to explore the effect of supplementing astaxanthin as an extender of porcine semen preservation dilutions at 17 degrees C. Various concentrations of astaxanthin were added to diluted porcine semen at 17 degrees C. We performed computer-assisted semen analysis, evaluation of plasma membrane integrity and acrosome integrity, and measurement of total antioxidant activity, malondialdehyde (MDA) content, reactive oxygen species levels, superoxide dismutase (SOD) activity, catalase (CAT) activity, glutathione peroxidase (GSH-PX) activity and sperm motility parameters. Compared with the control group, the addition of 0.25 mu g/ml astaxanthin group significantly improved sperm motility parameters stored on the fifth day; these were increased levels of sperm SOD, GSH-PX and CAT (p < .05), increased sperm adenosine trisphosphate and lactate dehydrogenase levels and decreased sperm MDA levels (p < .05). These findings suggest that adding 0.25 mu g/ml of astaxanthin improves the quality of porcine semen stored at 17 degrees C. Our findings provide theoretical support for developing new protective agents critical for preserving pig semen at 17 degrees C

miR-24-3p promotes proliferation and inhibits apoptosis of porcine granulosa cells by targeting P27

Ovarian follicle development is associated with the physiological functions of granulosa cells (GCs), including proliferation and apoptosis. The level of miR-24-3p in ovarian tissue of high-yielding Yorkshire×Landrace sows was significantly higher than that of low-yielding sows. However, the functions of miR-24-3p on GCs are unclear. In this study, using flow cytometry, 5-ethynyl-2´-de-oxyuridine (EdU) staining, and cell count, we showed that miR-24-3p promoted the proliferation of GCs increasing the proportion of cells in the S phase and upregulating the expression of cell cycle genes, moreover, miR-24-3p inhibited GC apoptosis. Mechanistically, on-line prediction, bioinformatics analysis, a luciferase reporter assay, RT-qPCR, and Western blot results showed that the target gene of miR-24-3p in proliferation and apoptosis is cyclin-dependent kinase inhibitor 1B (P27/CDKN1B). Furthermore, the effect of miR-24-3p on GC proliferation and apoptosis was attenuated by P27 overexpression. These findings suggest that miR-24-3p regulates the physiological functions of GCs

Total Synthesis and Determination of the Absolute Configuration of Rakicidin A

Rakicidin A is a cyclic depsipeptide that has exhibited unique growth inhibitory activity against chronic myelogenous leukemia stem cells. Furthermore, rakicidin A has five chiral centers with unknown stereochemical assignment, and thus, can be represented by one of 32 possible stereoisomers. To predict the most probable stereochemistry of rakicidin A, calculations and structural comparison with natural cyclic depsipeptides were applied. A total synthesis of the proposed structure was subsequently completed and highlighted by the creation of a sterically hindered ester bond (C1–C15) through trans-acylation from an easily established isomer (C1–C13). The analytic data of the synthetic target were consistent with that of natural rakicidin A, and then the absolute configuration of rakicidin A was assigned as 2<i>S</i>, 3<i>S</i>, 14<i>S</i>, 15<i>S</i>, 16<i>R</i>. This work suggests strategies for the determination of unknown chiral centers in other cyclic depsipeptides, such as rakicidin B, C, D, BE-43547, and vinylamycin, and facilitates the investigations of rakicidin A as an anticancer stem cell agent