Study On The Relationships Between Tumor Necrosis Factor-alpha, Inhibin B, Androgen Receptor And Polycystic Ovarian Syndrome

Polycystic ovarian syndrome (PCOS) is a common endocrinic disease in Gynecology, it is characterized by chronic anovulation, hyperandrogenemia and, in most cases, also by metabolic alterations related to insulin resistance(IR), such as hyperinsulinemia and obesity. In women with PCOS, a high occurrence of infertility and recurrent miscarriage has been described. Considerable attentions have been paid to PCOS, but to date, the cause and the underlying pathogenic mechanism is not clear, which affects the effective treatment to the disease. So, it is important to find the pathogenesis of PCOS.IR has been generally considered as an important pathogenesis of PCOS for the past 10 years, while the search for the pathogenic factors for IR is still on. According to some studies, white adipose tissue is a significant source of tumor necrosis factor-alpha (TNF-α) production. TNF-α can result in IR through many means. Since obese women with PCOS make up over 50 percent of the total women with PCOS, we should study on whether there is an excessively high level of TNF-a in women with PCOS, which promotes PCOS by IR. Inhibin B(INHB) is produced mainly by preantral and antral follicles. INHB regulates follicle stimulating hormone(FSH) secretion by negative feedback and is regarded as an important factor to regulate gonadotropin secretion besides estrogen and progesterone. The composition and secretion of INHB are from granulose cells and regulatedby luteinizing hormone(LH) and FSH, especially by LH, PCOS is characterized by an increasing number of small antral follicles and a high serum LH level which engenders the mass production of INHB. It has been hardly reported and agreed that patients with PCOS must have a high serum INHB level, which further disorders the composition and secretion of FSH and promotes PCOS. After treatment by clomifene, high ovulation rate, low pregnancy rate and high miscarriage rate are observed in PCOS. PCOS is characterized by hyperandrogenemia and high serum estrogen. Androgen and estrogen may up-regulate the expression of androgen receptor (AR) in endometrium. Nevertheless it is not certain whether women with PCOS show elevated endometrial AR expression, which leads to defects in uterine receptivity.Objective:This study was designed to observe the changes of TNF-a and INHB levels, the change of immunohistochemical localization of AR in endometria in women with PCOS, and to evaluate the relationships between TNF-a , INHB , AR and PCOS in order to seek a new way to prevent and cure PCOS.Materials and methods1.Study on serum (1) Patients:40 women with PCOS ( mean age, 20. 92 ±3. 72years ) .(2) Controls: included 20 infertility patients ( tubal or male infertility ) and 20 healthy volunteers ( mean age, 21.18 + 3. 66years ) with regular menstrual cycles. (3) Subgroups: ?All subjects were classified by body mass index ( BMI ) into obese group ( BMI-^25 ) and normal-weight group ( BMK25 ) .?All subjects were classified by age into puberal group ( age^l9 years old ) and reproductive-aged group ( age >19 years old ) . All these women had not taken oral contraceptives or other medications for at least 3 months before starting the study. Hyperprolacti- nemia, androgen secreting neoplasm, Cushing's syndrome,thyroid disease, and so on, were excluded by appropriate test. Venous blood was collected at 8:00 am after an overnight fast on day 3 of menstrual cycle, serum was immediately separated and stored at - 20°C or -80°C until the time for radioimmuno- assay ( RIA ) or enzyme-linked immunosorbentassay ( ELISA ) .Measurement of TNF-a was carried out with RIA, and INHB was carried out with ELISA.2. Study on endometrium 20 married women were selected from the patients by randomized allocation and 20 married women were selected from the controls by randomized allocation. Endometria were obtained on day 5 of a menstrual cycle, HE stain, to determine whether the endometrium had the changes of early proliferative phase. Measurement of AR was carried out with immunohistochemistry.3. All experimental data were analyzed by means of Student's t-test, analysis of variance, Newman-Keuls test or linear correlation and processed by SPSS 10. 0. There was a statistical significance when P<0. 05.Results1. There was no significant difference between the patients and the controls in age and BMI. 2. Serum concentrations of LH were higher than those of the controls.( 17.16+2. 07 vs. 5. 02+1.65 U/L; ￡=28.988, P<0. 01 ), testosterone were higher than the controls (2.46 + 0.41 vs. 0.90 + 0. 32nmol/L; ￡=19. 080, P<0. 01 ) and insulin were higher than the controls ( 15.60 + 2.77 vs. 8. 42 + 3.00 mU/L; ￡=11.132, P<0. 01 ) .Women with PCOS exhibited a little lower mean serum FSH concentration compared with the controls ( 5. 05+0. 95 vs. 6.86±0. 94 U/L; t=~8. 578, P<0. 01 ) . There was no significant difference between the patients and the controls in estradiol and glucose. 3. Serum TNF- a levels were higher in patients with PCOS than controls ( 1. 16+0. 20 vs. 0. 76 + 0. 20 ug/L; t=8. 968, P<0. 01 ) . Serum TNF-a levels were highest in obese patients. There was no difference in TNF-a concentrations between puberal women and reproductive-aged women. 4.TNF- a concentrations were inversely correlated with insulin sensitivity index ( r=-0. 626, P<0. 05 ) in patients with PCOS. 5. Serum concentrations of INHB in patients were higher than those of the controls ( 91. 38+15. 85 vs. 73. 18 + 14.11 pg/ml; 1=5. 424, P<0. 01 ) . There was no difference in INHB concentrations between obese women and normal-weight women, between puberal women and reproductive-aged women. 6. The serum INHB and LH were directly correlated in women with PCOS ( r=0.405, P< 0.05 ) .11. The patients with PCOS exhibited elevated endometrial AR expression compared to controls, this increase was most apparent in glandular epithelium(2. 48 ±0.30 vs. 0.90 + 0. 35; ￡=15. 289, P<0. 05 ) , and there was no significant difference between the patients and the controls in stromal cells. Conclusions:1. Serum TNF- a is increased in women with PCOS. Increased circulating TNF-a mediates IR, and in turn promotes PCOS. TNF-a can predict the presence or absence of IR in patients with PCOS. This discovery is also helpful of the treatment for IR in PCOS patients.2. The high levels of INHB in serum of patients with PCOS influence the reproductive axis, it is disadvantageous to follicle maturation. INHB is a key factor for normal ovulation. INHB levels can be used to predict the ovulatory response in women with PCOS undergoing ovulation induction.3. The high expression of AR in endometrial glandular cells can influence the degree of endometrial maturation and can be harmful to embryo implantation or growth. It may be correlated with the low clinical pregnancy rate and high miscarriage rate observed in patients with PCOS after ovulation induction.