The Study Of Mobility Parameters Assessed By Computer Assisted Sperm Analysis On IVF

According to the definition of World Health Organization (WHO), that if the childbearing couples cohabit for one year without any measures of contraception and the wife is sterility for the reason of the husband is called male infertility. It can be divided into primary infertility and secondary infertility according to the disease process. Primary infertility refers to the woman has never been pregnant after marriage; And secondary infertility refers to the woman has been pregnant after marriage, but after that the wife had no pregnancy for over three years without any measures of contraception. About10%～20%of the couples at reproductive age suffer from infertility at present, and male infertility is about50%, the incidence rate is rising year by year. Factors leading to male infertility such as disease, malnutrition, endocrine disorders, genetic,environment and so on. The above reasons affect semen quality through different mechanism, cause a decline in sperm motility, decrease the normal morphology sperm rate, and destroy the sperm DNA integrity, affect sperm function, stop the combination of oocytes and sperm. Even appeared necrospermia and azoospermia, severely reduced male fertility.Semen analysis plays an important role in judging male fertility in the management of male infertility. Conventional semen analysis, as the basic examination of judging male fertility, is widely applied in clinical practice. At present, the results of sperm concentration, motility and normal sperm morphology can not fully reflect the insemination potential of sperm. It is not accurate to determine male fertility only by sperm density and motility. Studies have found that in some patients undergoing in vitro fertilization embryo transfer(IVF-ET), the fertilization rates is low(fertilization rates≤30%) or even fertilization failure, but the sperm density, activity are normal. Clinically, this kind of patients is defined as idiopahic male infertility. This shows the sperm density, activity can not fully reflect the male fertility during diagnosis of male infertility. However, with the development and application of computer, in the80’s of the20century there appeared computer assisted sperm analysis system(CASA). Besides sperm density and activity, this system can also be used to analyze the mobility parameters which reflect motion characteristics of sperm fast, accurately and objectively. These parameters reflect sperm function, and provide a new foreground for diagnosis and treatment of male infertility. These parameters include:curvilinear velocity(VCL), straight line velocity(VSL), average path velocity(VAP), linearity (LIN), straightness(STR), wobble(WOB), amplitude of lateral head displacement (ALH), beat/cross frequency(BCF). The principle of computer assisted sperm analysis system(CAS A) is inputing sperm motion tracks microscopically to computer through the image acquisition device. Then get the mobility parameters, sperm density and activity after the analysis by picture processing software. Compared with traditional manual semen analysis,computer assisted sperm analysis is fast,ccurate and objective.In vitro fertilization embryo transfer is also called the test-tube baby. In1978, the world’s first test-tube baby was born in Britain. It is the symbol of maturation of the technique and success of clinical application. The first test-tube baby in China was born in1988. In vitro fertilization embryo transfer is what getting mature oocytes from female ovarian through endoscope or ansvaginal ultrasound, then the oocytes are fertilized with sperm in vitro, when the zygotes develop into embryos, they are transplanted into woman’s uterus and continue pregnancy, the embryo develops into fetus in the uterus. The birth and development of test-tube baby technology allow tens of thousands of infertile couples realize their desire for breeding. Since the birth of the world’s first test-tube baby in the last century70’s, after30years development, the assistive technology has got constant development, and is being widely used. Today there are more than4000000newborns are born with the help of test-tube baby technology, and the population increases year by year. In addition, IVF technology has promoted the studies of male infertility. with in vitro fertilization technology, scholars at home and abroad began to search for the reasons of in vitro fertilization failure from the male perspective, and make it possible to research the relationship between semen parameters and outcomes of in vitro fertilization. IVF can also provide platform for some tests which reflect sperm function, such as Sperm-zona pellucida binding assay.Normal fertilization rate, cleavage rate and excellent embryos rate are three important indexes reflecting the outcome of in vitro fertilization. fertilization is observed after IVF, no pronucleus is defined as unfertilized, double pronuclei and double polar bodies are defined as normal fertilization, one pronucleus or multiple pronuclei is abnormal fertilization. After continuous and rapid cell division of the zygote, many small cells are formed, the process is called cleavage. The embryo is divided into six levels according to the numbers, size of blastomere and embryo fragmentation:grade Ⅰ, equal sized blastomeres, no fragmentation; grade Ⅱ, equal sized blastomeres,<20%fragmentation; grade Ⅲ, unequal sized blastomeres,<20%fragmentation; grade Ⅳ, equal or unequal sized blastomeres,20-50% fragmentation; grade V, equal or unequal sized blastomeres,>50%fragmentation, grade VI, all fragmentation.7-8cells for grade I and II are called excellent embryos. Normal fertilization rate, cleavage rate and excellent embryos rate are associated with embryo transfer, the pregnancy rate and normal development of fetus, and it is necessary for healthy child.In recent years, the development of assisted reproductive technology(ART)make some infertile couples get the chance of fertility. With the increase of patients undergoing ART, low fertilization rate (≤30%)and fertilization failure Because of male infertility become more and more. At present, studies on the impact of the outcome of IVF mainly focus on female factors, such as the woman’s age, pelvis, oviduct and ovum quality. Studies on the male factor are focusing on the sperm density, motility and morphology. However, the density, vitality and morphology of sperm only reflect the quality of semen, but can not fully reflect the function of sperm. Currently, the parameters reflecting the function of sperm(VCL, VSL, VAP, LIN, STR, WOB, ALH, BCF)assessed by computer assisted semen analysis have not been paid more attention to, its effect on the outcome of in vitro fertilization more rarely reported. It is becoming more and more important to study the association between these parameters and normal fertilization rate, cleavage rate and excellent embryos rate, in order to provide new direction and new ideas for looking for index which influence the outcome of IVF.Objective:To test the differences of mobility parameters(VCL, VSL, VAP, LIN, STR, WOB, ALH, BCF) assessed by computer assisted sperm analysis(CASA) system between high normal fertilization rate group and low normal fertilization rate group, test the differences of these mobility parameters between high cleavage rate group and low cleavage rate group, test the differences of these mobility parameters between high excellent embryos rate group and low excellent embryos rate group; To evaluate the relationships between mobility parameters assessed by computer assisted sperm analysis and the rate of normal fertilization,cleavage and excellent embryos after IVF.Methods:Collected288cases who visited in Center for Reproductive Medicine of our hospital for the first time because of infertility from January2011to January2012, the age ranged from25to45years old, the reasons included salpingemphraxis, endometriosis and ovulation failure and so on.288cycles were included.288patients were divided into two groups according to the normal fertilization rate of≥50%and <50%; two groups according to the cleavage rate of≥90%and<90%; two groups according to the excellent embryos rates of≥50%and<50%. The means of the sperm motility parameters analyzed by CASA two times before oocyte retrieval were recorded and calculated with t-test to assess the mobility parameters related to the rates of normal fertilization,cleavage and excellent embryos of in vitro fertilization (IVF).Results:3539oocytes were retrieved in288cycles,12.29±6.51oocytes for each cycle, total normal fertilization rate68.44%±18.19%, total cleavage rate96.98%±10.14%, total excellent embryos rate50.21%±27.01%.248cases in normal fertilization rate≥50%group,40cases in normal fertilization rate<50%group;257cases in cleavage≥90%group,31cases in cleavage<90%group;161cases in excellent embryos≥50%group,127cases in excellent embryos<50%group.values of VCL, VAP, ALH in the group with normal fertilization rates≥50% were significantly higher than that in the<50%group, the differences had statistical significance (P<0.05), values of VCL and VAP in group with cleavage rate^90%were significantly higher than that in the<90%group,the differences had statistical significance (P<0.05);However, there were no differences in VCL,VSL,VAP,LIN, STR,WOB,ALH,BCF for excellent embryos rate between^50%group and<50%group (P>0.05)Conclusions:①The results show that the normal fertilization and cleavage rates are associated with sperm motility.②There is no association between the excellent embryos rate of IVF and the sperm motility parameters.