| Background:At present, more and more people in the world have the trouble of infertility, IVF-ET treatment has become an important means of infertility. Recently, with the outstanding improvement of assisted reproductive technology (ART), The clinical Pregnancy rate following one cycle of IVF-ET can be as high as40-60%. But even in the very successful units, some couples fail repeatedly. The causes for repeated implantation failure may be poor oocyte quality, low fertilization rate and poor embryo development.Follicular fluid provides a very important microenvironment for the development of oocytes. It is reasonable to think that some biochemical characteristics of follicular fluid surrounding the oocyte may play a critical regulated role in determining oocyte quality and the subsequent potential to achieve fertilization and embryo development.Human chorionic gonadotropin(hCG) is produced by placental syneytiotrophoblast. hCG is a glycoprotein hormone with the typical heterodimeric structure also exhibited by LH, FSH, and TSH.These hormones share a common-subunit but have distinctly different subunits. hCG and LH have85%of the amino acid sequence of their subunit in common. The main differences between them, however, lie within the N-linked oligosaccharides and the C-terminal sequence. The latter are responsible for the longer half-life of hCG compared with LH.HCG has been used to mimic the endogenous LH surge to trigger final follicle and oocyte maturation and ovulation at the end of ovulation induction regimens. At present, hCG appears to be the most reliable way to trigger final oocyte maturation both in antagonist and in agonist cycles.Cytokines have been proposed to regulate monthly ovarian processes, including promotion of ovarian follicular growth, leukocyte infiltration and activation necessary for ovulation, and tissue remodeling during luteinization and luteolysis. Cytokines such as interleukin-1(IL-1), IL-2, IL-6, TNF-a, IFN-y, and GM-CSF have been shown to play important roles in ovulation. In humans, it has also been shown that follicular fluid exerts chemotactic activity toward neutrophilic granulocytes and that the concentration of this activity is related to the outcome of IVF treatment.Interleukin-8(IL-8), an angiogenic, proinflammatory, growth-promoting cytokine, is thought to be important in the developing follicle for the inflammatory events that occur at the time of ovulation and luteolysis.Objective:The study focuses on hCG and IL-8levels in serum and follicular fluid of women who underwent IVF/intracytoplasmic sperm injection (ICSI) treatment and their role in ovarian follicles, fertilization, embryo development, and implantation and to find out whether they could be a useful predictive parameter of IVF/ICSI outcome.Materials and methods: Totally70patients undergoing IVF/ICSI cycles were recruited from May2010to Aug2011in the Assisted Reproductive Unit, Women’s Hospital, School of Medicine, Zhejiang University, including35IVF cycles and35ICSI cycles.All patients signed an informed consent form upon entering the study. Ovarian stimulation was facilitated by the standard long protocol(61cycles) and short protocol (9cycles). Ovulation was induced using250ug r-hCG (Ovidrel;Merck Serono Geneva,Switzerland) if the leading follicle was18mm in diameter or larger and there were at least three follicles more than16mm in diameter or at least two follicles more than17mm diameter,.Serum and follicular fluid samples were collected from women undergoing IVF/ICSI with controlled ovarian hyperstimulation (COH) on the day of transvaginal oocyte retrieval. The hCG concentration was measured by chemiluminescent immunoassay. The IL-8concentration was measured using an enzyme-linked immunosorbent assay (ELISA). The oocytes corresponding to the study follicles were cultured individually in separate dishes. Information on oocyte maturity (ICSI group) and fertilization and daily embryo morphology was recorded.The hCG and IL-8concentrations were correlated to BMI, fertilization, embryo quality and IVF outcome.All statistical analyses were performed using the SPSS13.0statistical package (SPSS Inc., Chicago, IL). The data were presented as as means±SD. The t test were used to compare numerical variables for normal distribution between groups. Mann-Whitney U test was used to compare independent numerical variables because of abnormal distribution.Correlation was assessed with Spearman’s correlation coefficients. Two-sided P values <0.05were considered to be statistically significant.Results:1. The mean concentration of IL-8in follicular fluid increased to165.60±115.01pg/mL, whereas the IL-8concentration in serum decreased to153.81±242.43pg/mL (P<0.01). The mean concentration of hCG in follicular fluid decreased to46.98± 30.76IU/L, whereas the hCG concentration in serum increased to95.65±35.67IU/L(P<0.01).2. The hCG levels in follicular fluids of fertilized ovum(50.8±33.0IU/L) were significantly higher than that of unfertilized ovum (34.1±16.5IU/L)(P<0.05). The hCG levels in serum of fertilized ovum(98.5±39.0IU/L) were higher than that of unfertilized ovum (86.2±19.2IU/L)(P>0.05).There were no significantly difference in IL-8levels between fertilized group and unfertilized group(P>0.05).3. The hCG and IL-8levels of embryos in grade I and II were similar to those grade III and IV (P>0.05).4. In total70patients,64patients underwent fresh embryo transfer.The pregnancies were occurred in37cycles and the pregnancy rate per ET was57.8%. The IL-8levels were similar in pregnancy group and non-pregnancy group of patients. The hCG levels in follicular fluids that obtained from the women with clinical pregnancy (54.2±36.8IU/L) were significantly higher than those that with nonpregnancy (37.5±17.8IU/L)(P<0.05). The hCG levels in serum that obtained from the women with clinical pregnancy (102.0±40.9IU/L) were higher than those that with nonpregnancy (87.4±25.3IU/L)(P>0.05).5. The hCG levels in follicular fluids of normal weight group (52.0±33.1IU/L) were significantly higher than that of overweight group (31.4±13.0IU/L)(P<0.01). The hCG levels in serum of normal weight group (103.2±36.9IU/L) were significantly higher than that of overweight group (72.0±16.6IU/L)(P<0.01). The IL-8levels in follicular fluids or serum were similar in overweight group and normal weight groups of patients (P>0.05).Conclusions:1. We found Interleukin-8is present in the follicular fluid in all cases.No correlation between the follicular fluid concentrations of IL-8and the treatment outcomes.2. The study showed the follicular fluid hCG levels can promote development of oocytes, and raise the potentiality of fertilized ovums, may be associated with pregncancy rates of IVF-ET.3. The hCG levels in follicular fluids of normal weight group were significantly higher than that of overweight group (P<0.01). The hCG levels in serum of normal weight group were higher than that of overweight group (P<0.01). The study showed it is recommened to increase rHCG dose for trigger ovulation for overweight patient without high OHSS risk. |
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