The Research Of The Anatomic Structure Of Pelvic Floor Muscle In Rat Embryos

The function of pelvic floor muscle is blocking the pelvic floor and sustaining the organs of cavitas pelvis to exercise their function respectively. However,presently,there was still numerous debate to the structure,the boundary and the embryonal source of pelvic floor muscle. A great deal of reports have preferred that if we made the embryonal development process of pelvic floor muscle more clear , which multiplicity structure and function would be understood more explicitly.In this paper, the Wistar rat was used. The embryogenesis of the pelvic floor muscle was studied continuously and dynamicly by H&E staining and immunolabeling to Myogenin andα-Smooth Muscle Actin. The Myogenin immunohistochemistry were used to detected the expression during the development of pelvic skeletal muscle in rat embryos.α-Smooth Muscle Actin(α-SMA), a specific antibody to smooth muscle, was involved to explore the development of the internal anal sphincter of the termination of digestive tract in rat embryos. We discoveryed that :(1)On the originated area of the striated muscle complex on pelvic ploor,there was no Myogenin positive cell before E15. On E15,sporadic Myogenin positive cells was observed on the precursor of bulbospongiosus and the ventro-oralis arterior of tail furrow. On E16,we detected the fibroid structure of the striated muscle complex encircled the dorsal bulbospongiosus and terminational rectum. On E18,the muscle fibroid structure became thickness. The striated muscle complex developed continuely till E21.(2) On the originated area of external anal sphincter on Pelvic Floor,there was no Myogenin positive cells On E16. On E17,on coronal plane,scattered Myogenin positive cells was observed below the striated muscle complex, which was the precurosor of external anal sphincter. On E18, the area of positive cells to Myogenin was moving cephaladly and increasing slightly. On E21,external anal sphincter presented radialized surround the terminatio of internal anal sphincter, the muscle of external anal sphincter was separated by connective tissue.(3) On E13, E14, on the originated area of internal anal sphincter on pelvic floor,there was noα-SMA positive cells in anorectum. On E15,α-SMA positive cells appearanced in anorectum. A ring-shaped musale was observed, the terminatio of which was intumescent lightly. The intumescent mucsle was the precurosor of internal anal sphincter. On E16,E17, E18 to E21, positive cell of internal anal sphincter became clearly and intumescently gradually.