Study On The Developmental Pattern And Regulation Mechanism Of The Ovary In Mongolian Horses

Equine is a seasonal singleton animal with a long reproductive cycle.Its unique reproductive physiological structure is one of the main factors affecting the reproductive efficiency of equine and the development and application of related reproductive technology.As the core organ in the reproductive system of female animals,the ovary has the function of periodically producing ovum and secreting reproductive hormones under the action and regulation of the nervous system and endocrine system.However,due to the existence of the unique structure of the ovulatory fossa,the ovary structure,development,ovulation and regulation of equines are significantly different from other livestock animals.So far,there are few reports at home and abroad on the research on the regulation of horse ovary development and the molecular mechanism of regulation.Therefore,this study took Mongolian horses(fetal period,adult period)as the experimental object,based on previous studies on the ovary tissue structure and hormone regulation of horses,and carried out histological morphological observation research,and through transcriptomics,Quantitative PCR,immunohistochemistry and other methods were used to screen and identify candidate genes that may be related to ovarian development.The differences in Mongolian horse ovary active genes and the resulting functional differences in different developmental stages were analyzed,in order to promote the development of equine reproduction.Peers in mechanism and technology research provide basic data and theoretical help.The main results we obtained from this study are as follows:1.Having an efficient histological research system in Mongolian horses is one of the indispensable conditions for the follow-up research on molecular regulatory mechanisms.However,the morphological studies of Mongolian horse ovaries show that the equine ovary has a special structure,and its medulla and cortex are reversed,which leads to equine ovaries.The production of paraffin sections cannot directly borrow the production system of other mammals.Moreover,our extensive preliminary experiments indicated that it is necessary to optimize the tissue section preparation system for Mongolian horse ovary first.In this study,a 2-year-old Mongolian horse was used as the research object.By comparing the effects of different fixation methods,tissue dehydration methods,wax immersion methods,and Hematoxylin and Eosin(HE)staining system on the production of paraffin sections,we explored the effect of Optimal system for equine ovary production.After comparison,it was determined that the tissue fragments smaller than0.5 cm were soaked in 75% alcohol for 24 h in Bouin fixative → 85% alcohol for 1 h→ 95% alcohol for 2 h → 100% alcohol for 2 h for dehydration;placed in xylene clear agent for 10 min ×2 times;pure wax and xylene were mixed at a ratio of 1:1 and soaked in wax for 40 min→pure wax I for 40 min→pure wax II 0.05 Mpa vacuum soaking in wax for 40 min was the best system for making paraffin sections of horse ovary tissue.2.In this study,Mongolian horses were used as the research object.By using transcriptome sequencing of fetal and adult mare ovaries,the obtained data were screened for differentially expressed genes,and then GO function analysis and KEGG database enrichment were performed.The results show that we have successfully constructed 6high-quality RNA sequencing libraries of Mongolian horses during fetal and adult periods.Based on the analysis of the Equ Cab 3.0 genome on the public platform,6334 differentially expressed genes were screened.These genes are mainly involved in lipid metabolic process,lipid biosynthetic process,steroid metabolic process and other processes,Cushing syndrome,Cortisol synthesis and secretion,Aldosterone synthesis and secretion,Steroid biosynthesis and other signaling pathways.3.From the above results,we noticed that many important genes related to steroid hormone synthesis,such as CYP11A1,CYP17A1,HSD17B7,LDLR,SCARB1 and STAR,were highly expressed in Mongolian horse fetal ovaries,and the difference was significant,which was different from that reported in other animals.very different.Therefore,we further detected the m RNA expression and protein expression of some Mongolian horse ovarian steroid synthesis-related genes by RT-q PCR and immunohistochemical methods.Closely related to mare pregnancy and fetal ovarian development.