A Comparison Of Sperm Ultrastructures And Proteome Reveals Relationships Between Sperm Morphology,ATP Content And Motility

Objective: Asthenozoospermia is one of male infertility diseases,which is characterized by poor progressive motility.The etiology of the disease is still unclear.The sperm motility mainly depends on the integrity of the sperm morphology.To date,there is still a lack of clear understanding of how sperm morphology and their metabolism status adapt to flagellar beating.Therefore,in-depth study of sperm morphology and their metabolism is of great significance in elucidating the pathogenesis of asthenozoospermia.Enhance,this study is involved with sperm morphology,biochemistry,molecular biology and other aspects,and deeply analyze the relationship among the ultrastructure,sperm movement speed and ATP content among species.This thesis attempts to explore the key proteins regulating the sperm flagellar structures and motor properties,and to find new targets to prevent diseases,so as to provide scientific basis for the treatment of asthenozoospermia.Methods:1.Transmission electron microscopy(TEM)was used to quantify and compare the sizes and regression slopes of the axonemes,outer dense fibers(Odfs),mitochondrial sheath(MS)and fibrous sheath(FS)from the base to the tip of the sperm flagella in ten mammalian species.2.Scanning electron microscopy(SEM)was used to quantify and compare the longitudinal characteristics of sperm in 10 mammalian species,and to establish the relationship between sperm characteristic structure and sperm ultrastructure slope.3.Based on the results of TEM and SEM,the correlation between sperm flagella length and the ultrastructural cross-sectional area of sperm was analyzed by principal component analysis(PCA).4.The ATP content of sperm among 10 species was detected by luciferase assay,and the relationships between the ultrastructure,sperm motility and ATP content were established,combining with previous data.5.The key components that regulate mammalian sperm length,especially flagella length,are analyzed by label-free quantitative proteomics assays.Results:1.Cross-species studies have shown that the area of the sperm flagella axonemes not only decreases slightly from the base to the tip,but also the slope of the axonemes is related to variants in flagella length.2.The areas of the ODFs and/or MS are positively correlated with the length of midpiece,principal piece and total flagella.3.The area of ODFs and the volume of mitochondrial sheath were positively correlated with ATP content and sperm velocity.Conclusions:1.The integrity of the ultrastructure of sperm flagella and normal metabolic function are of vital importance for sperm motility.2.The spermatic flagella segment,which is characterized by the mitochondrial sheath or the longest segment of the sperm flagella,may be the main component to regulate the mammalian sperm length,especially the length of the flagella.