Extracellular microparticles exacerbate oxidative damage to retinal pigment epithelial cells.

Oxidative stress-induced retinal pigment epithelial cell (RPE) dysfunction is a primary contributing factor to early dry age-related macular degeneration (AMD). Oxidative injury to the retina may promote extracellular vesicles (EVs) released from RPE. In this study, we investigated the effects of oxidative-induced RPE cell-derived microparticles (RMPs) on RPE cell functions. The oxidative stress induced more RMPs released from RPE cells in vitro and in vivo, and significant more RMPs were released from aged RPE cells than that from younger RPE cells. RMPs were taken up by RPE cells in a time-dependent manner; however, blockage of CD36 attenuated the uptake process. Furthermore, the decrease of RPE cell viability by RMPs treatment was associated with an increased expression of cyclin-dependent kinase inhibitors p15 and p21. RMPs enhanced senescence and interrupted phagocytic activity of RPE cells as well. The present study demonstrated that RMPs produce a strong effect of inducing RPE cell degeneration. This finding further supports the postulate that RMPs exacerbate oxidative stress damage to RPE cells, which may uncover a potentially relevant process in the genesis of dry AMD.

Upstream or swim up processing technique: which one is more effective to select human sperm with high chromatin integrity.

BACKGROUND: Sperm processing methods separate motile sperms with good morphology from dead and abnormal forms of sperms, immature germ cells, and non-sperm cells. OBJECTIVE: The propose of this study was to compare the efficacy of upstream and swim-up processing techniques to separate sperms with the high quality especially in relation to sperm chromatin integrity. MATERIALS AND METHODS: This experimental study used semen samples from 60 normozoospermic men. Specimens were divided into equal aliquots for processing by swim up (group A), and upstream (group B) methods and compare with control by raw semen (group C). Sperm concentration, morphology, motility, DNA fragmentation and chromatin maturation were measured in these three groups. RESULTS: The results revealed that sperm concentration in the swim up samples was significantly greater than upstream samples (p≤0.04). as addition, motile sperm recovery including the percentage of progressive motility and a total number of motile sperm was better in the swim-up compared to an upstream method and raw semen (p≤0.001). The cell debris and seminal fluid were equally removed by both methods and the percentage of normal forms was also similar in both procedures (p≥0.4). In addition, sperm DNA fragmentation and chromatin maturation were not significantly different between the three groups (p≥0.1). CONCLUSION: According to results, apparently the upstream method had no significant efficiency to separate good quality sperms compare to swim up. Therefore, swim up seems to be a simple, inexpensive, reliable and widely available method with an efficient yield to separate motile sperm with good morphology and better chromatin integrity for insemination in the infertility clinics.