Studies On The Ultrastructure Of Postpartum Uterus In The Ewes

The ultrastructural changes of the uterine endometrium and myometrium in the period of involution were studied in 9 normal postpartum ewes by using scanning electron microscope and transmission electron microscope. The objectives of the study were to reveal degradation changes of the uterine tissue during the period of involution from cell and subcell levels.The results from the examination of scanning electron microscope revealed that within the days I to 7 postpartum the endometrium epithelium was badly damaged and the epithelium cells loose connected. There were many tissue debris on the surface of the endometrium .The damaged area of the endometrium reduced, and some new epithelium cell appeared in the damaged area by the 13th day postpartum; Newly growed cells and glands increased in their numbers on the surface of the endometrium .By the day 25 the endometrium were almost covered by the epithelium cells and until the day 31 postpartum, the surface of the endometrium was restored entirely, and the uterine gland increased in their numbers and possessed the secretary function.The results from the examination of the transmission electron microscope revealed that within the 1 to 7 days postpartum the collagen fibers were disordered, broken into sections, dissolved and formed various cavity; The size of the smooth muscle cell was small and the cytoplasma of the smooth muscle cell was filled with myofilament; Macrophage was in a large number. Within the days 7 to 13 postpartum, macrophage obviously increased in number, the cellular organs, such as, mitochondria and rough endoplasmic reticulum(R.ER) and first and/or second lysosome were in a large number in the cytoplasm ; At the same time, there was a small number of the plasmocyte in the muscle tissue of the uterus and pericyte with increased cellular organs around capillary . After the 13th day postpartum, the newly growed epithelium cells appeared on the endometrium; The collagen sections reduced in number and its fibers were in a regular arrangement; The number of macrophage and the cellular organs decreased; Plasmocyte increased in number, RER and mitochondria and Golgi complex increased their number in its cytoplasma; Fibroblast and its organs increased in number and volume. From the 19th day postpartum, the size of smooth muscle cells and the number of its cellular organs increased; Plasmocyte and fibroblast and as well as their cellular organs deceased in number. By the 25th day postpartum, glandular epithelium cells were surrounded by the basic membrance, the microvilli appeared in the cavity; Collagen fiber bunch arranged in a crisscross way, cross striation was clear, and no collagen sections were seen; pericyte around capillary obviously decreased. During the periods of uterine involution, the inflitration of lymphocytes was common.The above results indicated that parturation causes the partly endometrial damage of the ewes, epithelium cell growth was complete basicly by the 25th day postpartum, and by the 31 th day postpartum the repair of the epithelium tissue was completed; The degradation of the uterine collagen is one of the major factors leading to reduce the uterine size; The macrophage, plasmocyte, fibroblast, lymphocyte and pericyte around capillary in the connective tissue of the uterus take part in and help the involution.Postgraduate:Zhao KaiM a j o r: Clinical Veterinary ScienceSupervisor:Professor han Wenru...