ABSTRACT
Slow freezing is the most commonly used technique for the cryopreservation of spermatozoa in clinical practice. However, it has been shown to have a negative impact on sperm function and structure. Vitrification as a successful alternative method has been proved to have better protective effects on human embryos, but vitrification of spermatozoa is still subject to low recovery rates. In this study, a modified vitrification method for native spermatozoa was developed. A total of 28 semen samples were included; each sample was divided into three equal parts and assigned to fresh, slow freezing, and vitrification groups. Sperm vitality, motility, morphology, DNA integrity, and acrosome reaction were assessed for each of the groups. The results showed that vitrification achieves better results for several sperm protection parameters than slow freezing; vitrification achieves a higher recovery rate (P < 0.05), motility (P <0.05), morphology (P <0.05), and curve line velocity (P <0.05) than slow freezing. Furthermore, DNA fragmentation was decreased (P <0.05) and better acrosome protection (P <0.05) was exhibited in the spermatozoa after vitrification. Principal component analysis of all sperm parameters revealed that the vitrification cluster was closer to the fresh cluster, indicating that spermatozoa are better preserved through vitrification. In conclusion, while both slow freezing and vitrification have negative effects on sperm function and structure, the vitrification protocol described here had a relatively better recovery rate (65.8%) and showed improved preservation of several sperm quality parameters compared with slow freezing.
ABSTRACT
<p><b>OBJECTIVE</b>To study the effect of inhibiting the expression of endothelial-overexpressed lipopolysaccharide-associated factor 1 (EOLA1) on proliferation of human umbilical vein endothelial cell line ECV304.</p><p><b>METHODS</b>After constructing and transfecting EGFP-EOLA1 fusion protein expressive vector into ECV304 cells, the transfected cells was cultured in M199 containing G418 for 5 weeks to screen the cell line stable expression EGFP-EOLA1 fusion protein. Oligonucleotides targeting EOLA1 at different sites were synthesized and inserted into pSinencer3.1/H1 vector. Then, the recombinant vector was transfected into the cultured ECV304 cells and the inhibiting effect to target gene EOLA1 was investigated by observing the green fluorescence in transfected cells under inverted fluorescent microscope and by Western blot assay. The proliferation of ECV304 cells was numbered when the expression of EOLA1 in ECV304 cells was inhibited by RNA interference.</p><p><b>RESULTS</b>The ECV304 cell line stably expressing EGFP-EOLA1 fusion protein was constructed and the siEOLA1 interfere vectors can knock down EOLA1 gene expression specially. When blocking the expression of EOLA1 in ECV304 cells,the proliferation of cells slowed down.</p><p><b>CONCLUSION</b>EOLA1 maybe has a role on the proliferation of cells.</p>