| Lipid droplets are organelles that store lipids in cells and distributed in various tissues and organs.Lipid droplets affect various functions of the body through their metabolites.As the important reproductive organ in the reproductive system of female animals,the cervix has different functions and states in different reproductive stages.Our group has already found numerous of lipid droplets in the cervical epithelium through the Electron Microscope Observation of the cervix and Oil Red O staining.In this study,various methods were used to demonstrate the expression of proteins related to lipid droplet metabolism in cervical tissues,in order to understand the metabolic status of lipid droplets in different reproductive stages,and to provide a theoretical basis for studying the role of cervical lipid droplets in reproduction..In order to ensure the accuracy of the mouse cervix,the experiment firstly cut the transverse and longitudinal section of the genital tract of the empty mouse and HE staining to understand the histological characteristics of the uterus,cervix and vagina.The results showed that the uterine epithelium was a single-layered columnar epithelium,and had glandular tubes in the subepithelial tissue.The cervical epithelium is similar to the uterus,but there is no glandular duct in the subepithelial tissue,and the squamous epithelium is located at the outer os of cervix.Unlike the vaginal stratified squamous epithelium,there is no glandular duct in the subepithelial tissue.Secondly,the ultrastructure of cervical tissues of adult mice with nonpregnancy,pregnancy,and parturition were observed by electron microscopy.The results showed that there were a large number of lipid droplets in the cervical tissue in three periods,especially in epithelial cells.The uniform density of lipid droplets mainly underlying the nucleus and fewer autophagosomes are in cervical epithelial cells at nonpregnancy.However,the density of lipid droplets in cervical epithelial cells during pregnancy and parturition is not uniform,some lipiddroplets are vacuolated,and the number of autophagosomes in the cells is incresed.It indicates that during the pregnancy and parturition,lipid droplets are metabolized and autophagy is enhanced in the cells.Finally,several important proteins related to lipid droplet metabolism were localized and quantified by immunohistochemistry and western blotting.The results suggested that the proteins associated with lipid droplets metabolism are differently expressed in several layers of cervical tissues.The nuclear receptor protein PPARγ involved in lipid droplet synthesis is highly expressed at nonpregnancy,whereas the expression level at pregnancy and parturition is relatively low.The expression of HSL and ATGL related to lipid droplet catabolism is highest at pregnancy,followed by delivery,and the lowest expression level at nonpregnancy.cAMPK promotes lipid droplet metabolism by phosphorylating HSL.Its expression pattern is similar to HSL.AMPK plays an important role in energy metabolism,but it is hardly expressed in cervical epithelium,but higher expression in subepithelial tissue.The expression level was the highest at delivery,followed at pregnancy,and the lowest at nonpregnancy.CPLA 2 is an enzyme that breaks down intracellular phospholipids.Its expression is hogher during pregnancy and parturitionn than nonpregnancy.PGE2 was localized by immunohistochemistry.The results showed that the cervical epithelium contained numerous PGE2;LC3 was in the cervix.The expression of LC3 in pregnancy and delivery was higher than that in nonpregnancy.The above results proved that the lipid droplets in the cervical epithelial cells during pregnancy and delivery are obviously catabolized,and the metabolite may be the raw materials of PGE2 synthesis.The autophagy occurs in the cervical epithelial cells during pregnancy and delivery.It is related to lipid droplet metabolism. |
