The Mechanism Research Of Uterine Contraction During Ovulatory Time

The uterus is a organ with smooth muscle components. Study of intrapartum uterine contractions for dealing with exception of delivery and postpartum hemorrhage has important significance. In the non-pregnant uterus contractions also exist in menstrual cycles and changes with steroid hormone fluctuations, which are the most active around ovulation. With the development of assisted reproductive technology, scholars have payed more and more attention on the role of uterine contractions before ovulation. The study found that the appropriate uterine contractions before and after ovulation can promote the transport of sperm and eggs as well as the transformation of the endometrium. The frequency of uterine contractions should be decreased to ensure the embryo implantation.As the pregnancy progresses, a large number of oxytocin receptors (OTRs) were synthesized companying the levels of estrogen gradually increased. Before delivery, the overtop levels of serum oxytocin (OT) bind to the OTR, which binding by the receptor-coupled calcium channels, elevating the free calcium concentration in cytoplasm. The latter combined with calmodulin (GAM) and activated the activity of myosin light chain kinase (MLCK), which phosphorylated myosin and lead to the contraction of the muscle fibers.Similar to intrapartum uterine smooth muscle, the OTRs in the uterine smooth muscle of non-pregnant were also affected by the role of steroid hormones, which expressed the most highly before ovulation. The smooth muscle contractility of the non-pregnant uterine OT can also be regulated by OT partly. But the contraction of the non-pregnant uterine involve a few subendometrial myometrial, or even just was a passive movement with the exercise of the endometrium, which was different from the involvement of the whole muscle layer of the uterine during delivery.As above, the inside and outside muscle layers around ovulation were collected to study the mechanism of the non-pregnant uterus contraction. The following components were included:Part One:The Comparison of the Contractility of the Inner and Outer Layer of the Uterine Muscle Around OvulationObjective:to compare the contractility of the muscles of the uterine between inner and outer layers. The tension of contraction of inner and outer muscle bundles was measured.Methods:We obtained6uteri in the proliferative of the cycle by abdominal hysterectomy from20-45years old women for Cervical Intraepithelial Neoplasia(CIN), excluding uterine fibroids, adenomyosis and avoiding infectious diseases, endocrine and metabolic diseases, hormone therapy nearly three months. The specimens were cut from lcm to the internal opening of the cervix, which were1cm long and1cm wide and consisting of the throughout muscle layer. Three effective muscle strips subendometrial myometrium (from the endometrium<5mm) and the myometrium near to serosa were collected from the specimens respectively. They were set into the control group (no treatment), OT group (Add OT) and OTR-anta+OT group (Add OTR-anta and OT)Results:(1) The frequency and the amplitude of the contraction of the subendometrial myometrium was significantly higher than the outer muscular layer.(2) The uterine smooth muscle contraction frequency significantly increased when the addministration of OT, and this effect of OT can be inhibited by competitive antagonist; Meanwhile, the contraction frequency of the inner muscle were higher than outside in all of the treatment groups. The contraction amplitude of the uterine smooth muscle were increased in the role of OT and were also inhibited by its antagonist. The contraction amplitude of the inner and outer smooth muscle were tending to indistinguishableness Conclusion:The contractility of the inside of the uterine smooth muscle was significantly higher than the outside, and the contraction capacity can be promoted by OT; the role of OT can be promoted by OTR-Anta antagonisticly, which made the contraction of the inner and outer consistency. Part Two:The Comparison of the Distribution of the Oxytocin Receptors of the Inner and Outer Layer of the Uterine Muscle Around OvulationObjective:To compare inner and outer muscle layer in the uterine oxytocin receptor distribution differences around ovulation.Methods:The adapted source of the specimens, the inclusion and exclusion criteria were accordancing with the first part. Each group was consisted of6experimental specimens. The experiments of OTR immunohistochemical analysis and Western blot were done between the inside and outside of the uterine smooth muscle tissue.Results:(1) The immunohistochemistry results suggested that the lateral uterine smooth muscle cells were larger than the inside of the cell. The distribution of OTRs was more than the outside of cells.(2) The Western blot experiments confirmed that OTRs distribution from the inner uterine myometrium cells more than the outside of cells at the protein level.(P<0.05).Conclusion:The OTRs of the inner uterine myometrium cells were significantly higher than outside cells. The differences of the distribution of this receptors were in keeping with with the distinguish of the muscle contractility, which prompted that the the density of OTRs may be the physiological basis of the difference of contractility between inside and outside muscle. Part There:The Role of OT on the intracellular calcium concentration in the myometrium cells around ovulationObjective:To study the intracellular calcium concentration changes in the inner and outer myometrium cells around ovulation by OT though laser confocal microscopy.Methods:The adapted source of the specimens, the inclusion and exclusion criteria were accordancing with the first part. The cells in second culture were stained by fluorochrome and were placed in a confocal microscope to observe changes in the intracellular fluorescence intensity. The changes were recorded when OT was administrated.Results:(1) The inner myometrium cells was observed5calciumion fluctuations in10minutes; There was no significant fluctuation of calciumions in the outer myometrium cells10minutes.(2) The fluorescence of intracellular calcium values are significantly increased after the administration of OT with a dose of10-6. The elevate of intracellular calcium concentration is not obvious in the outside cells.Conclusion:The calciumion fluctuations were existed in inner myometrium as same as the intrapartum myometrium, but there was no significant fluctuations in calcium in the outer cells. The calcium levels in the inner cells were significantly increased using exogenous OT, but there was no significant increase in outer cells. Such differences of intracellular calciumion oscillations maybe were closely related to the differences of the density of OTRs, which may be the evidences of distinguish of the myometrial contractility of different parts.