Standardization of a Sex-Sorting Protocol for Stallion Spermatozoa by Means of Absolute RT-qPCR

Expression of TLR7/8 in canine sperm and evaluation of the effect of ligand R848 on the sorting of canine X/Y sperm

The aim of this study was to analyze the expression pattern of Toll receptor 7/8 (TLR7/8) in canine sperm, and explore the feasibility of using TLR7/8 ligand resiquimod(R848)to separate canine X and Y sperm. In this study, cellular immunofluorescence was used to analyze the expression of TLR7/8 in canine sperm, real-time fluorescence quantitative PCR was used to calculate the proportion of X sperm in the lower layer of the incubation solution with R848 to evaluate the sorting effect of R848 on canine X/Y sperm, and sperm quality detection system was used to analyze the effect of R848 on the motility of canine sperm. The mechanism of effect of R848 on canine sperm motility was analyzed by Western blot. The results showed that TLR8 was not expressed in all canine sperm, while TLR7 was expressed in all canine sperm and was localized in the head and tail of sperm. When 0.4 μM R848 was incubated with canine sperm for 1 h, the total motility, average path velocity (VAP), average straight-line velocity (VSL), and average curved-line velocity (VCL) of canine sperm were significantly decreased(P < 0.05). There was no significant difference between the lower and upper layers of the R848 treatment group and the control group(P > 0.05), and the proportion of X sperm was nearly half. The levels of NF-κB and GSK3α/β phosphorylation of sperm in R848 treatment group were significantly increased compared with control group(P < 0.05). The above results showed that TLR7/8 was not differentially expressed in canine X and Y sperm. R848 could decrease the motility of canine spermatozoa and inhibit sperm motility by the GSK3α/β-hexokinase pathway through the phosphorylation of NFκB and GSK3α/β, while could not separate X and Y spermatozoa. The method of sorting X/Y sperm based on TLR7/8 is not feasible for dogs.

The impact of induced pluripotent stem cells in animal conservation

It is widely acknowledged that we are currently facing a critical tipping point with regards to global extinction, with human activities driving us perilously close to the brink of a devastating sixth mass extinction. As a promising option for safeguarding endangered species, induced pluripotent stem cells (iPSCs) hold great potential to aid in the preservation of threatened animal populations. For endangered species, such as the northern white rhinoceros (Ceratotherium simum cottoni), supply of embryos is often limited. After the death of the last male in 2019, only two females remained in the world. IPSC technology offers novel approaches and techniques for obtaining pluripotent stem cells (PSCs) from rare and endangered animal species. Successful generation of iPSCs circumvents several bottlenecks that impede the development of PSCs, including the challenges associated with establishing embryonic stem cells, limited embryo sources and immune rejection following embryo transfer. To provide more opportunities and room for growth in our work on animal welfare, in this paper we will focus on the progress made with iPSC lines derived from endangered and extinct species, exploring their potential applications and limitations in animal welfare research.