A Comparison of the Effects of Pentoxifylline on Quality of Fresh and Frozen-thawed Bull Spermatozoa

[Object]This study aimed to examine the effects of 3,7-dimethyl-1-（5-oxo-hexyl）-xanthine（pentoxifylline,PF）on the motility,mitochondrial activity,acrosome integrity and fertilization rate of spermatozoa in both fresh and frozen-thawed bull semen.[Method]Fresh and frozen-thawed bull spermatozoa were exposed to 5 mmol/L PF with untreated samples as controls.[Result]Fresh spermatozoa showed reduced（P〈0.05）motility after 2 h incubation with PF whereas,surprisingly,frozen-thawed samples exhibited increased sperm motility（P〈0.05）after 2 h incubation with PF and they also showed enhanced longevity compared to controls.Mitochondrial activity in both fresh and frozen-thawed bull spermatozoa increased（P〈0.05）during 4 h incubation with PF whereas acrosome integrity remained unchanged in both types of semen.However,treatment with 5 mmol/L PF did not influence the in vitro fertilization efficiency of fresh spermatozoa but improved significantly（P〈0.05）that of frozen-thawed spermatozoa.[Conclusion]These results indicate that PF can improve sperm quality of frozenthawed bull semen,and may improve pregnancy rates in bovine artificial insemination programmes employing frozen semen.

Oocyte Transfer as an Analytical Tool:Vintage Experiments in Domestic Farm Animals

Four transplant studies are described that focus on fertilisation and early development or the progression of unfertilised oocytes （eggs） in the oviduct. （1） Pig eggs transplanted from ovulations induced during the luteal phase of the estrous cycle were fertilised in the oviducts of inseminated recipient animals in estrus. By contrast, pig eggs from donors in estrus became highly polyspermic when transplanted to the oviducts of animals force-mated during the luteal phase. （2） Pig embryos at the stage of hatched blastocysts （ days 7 and 8） could be transplanted successfuUy to synchronous recipients and full embryonic development demonstrated to between days 19 and 23 of pregnancy. Thus, the exposed trophectoderm of developing embryos could withstand the physical ma- nipulation of recovery and transplantation, and the li-fespan of corpora lutea in the unmated recipients could be prolonged by transfer of day 7 and 8 blastocysts. （3） Bovine oocytes aspirated from 2 to 6 mm diameter Graafian follicles and matured in vitro were fertilized normally in the oviducts of inseminated recipient heifers, demonstrating the potential of slaughterhouse ovaries for the generation of embryos. （4） Transplanting equine eggs to a pig oviduct, in which egg descent to the uterus requires only 46 to 48 h, did not reveal a retarded progress of degenerating unferfil- ised horse eggs, suggesting the involvement of nonphysical factors in equine embryo progression to the uterus. Prostaglandins of embryonic origin are now known to be a key. A final section examines the postovulatory role of ovarian follicular cells on the secretory activity of the oviductal epithelium.

Cloning,Sequencing and Analysis of DDX3Y Gene in Five Male Equus Animals

[ Objective] This study analyzed the differences in DDX3 Y gene sequences among male horse, male donkey, male mule, male hinny and male foal to investigate the relationship between DDX3Y gene structure and the mechanism of infertility in male Equus fetus × asirms. [ Method] Partial sequences of DDX3Y gene in male horse, male donkey, male mule, male hinny and male foal were obtained by genome comparison, sequencing and cloning, and compared by bioinformatics methods. [ Result] The CDS regions varied in 5 base pairs and two amino acids. DDX3Y protein was predicted to be an unstable protein. In addition, the results also showed that DDX3 Y gene in male horse displayed a closer phylogenetic relationship to male mule and male foal; DDX3Y gene in male donkey displayed a closer phylogenetic relationship to male hinny. [ Conclusion] This study provided scientific basis for further exploring the function of DDX3 Y gene and the mecha- nism of reproductive regulation in male Equus ferus × asinus.

Blastoids generated purely from embryonic stem cells both in mice and humans

Dear Editor,Embryonic stem cells(ESCs)and trophoblast stem cells(TSCs)are derived from blastocysts(Lu et al.,2001).Blastocyst-like structures(blastoids)are self-assembled structures formed by a combination of ESCs and TSCs(Rivron et al.,2018).To increase the success rate of blastoid formation and its similarity with the features of blastocysts,some reports showed that blastoid could also be derived from a combination of three cell lines,ESCs,TSCs,and extraembryonic endoderm cells(XENs),or novel type of stem cells(Sozen et al.,2018;Weatherbee et al.,2023:Wu et al.,2023;Zhang et al.,2023;Zhang et al.,2019).