Expression And Significance Of IL-15 And PDGF In The Serum And Peritoneal Fluid Of Women With Endometriosis

Objective:In recent years, more and more researchers have thought that immunology is an essential feature during the occurrence and development of endometriosis. So the stimuli and trigger mechanism become the field that many reseachers focus on. Cytokines are believed to play a major role in the pathogenesis of endometriosis. As endogenous Thl cytokine, interleukin-15(IL-15) has many functions and participate in regulating many histiocytic functions. In addition, it has been demonstrated that IL-15 receptors express at the surface of activated T cell,B cell,natural killer cell and macrophage,binding IL-15 with high affinity,promote the activation and proliferation of T and B cell;stimulate the differentiation and proliferation of NK cell,enhance natural killer cell toxic action. IL-15 can influence mononuclear macrophage proinflammatory cytokine production through autocrine way. Researches showed that these immunologic cells play an important role in the pathogenesis of endometriosis. These findings prompted us to hypothesize that IL-15 may be involved in the pathogenesis of endometriosis. The investigation on the expression and effect of IL-15 in endometriosis had the different results. In the present study, therefore, we examined the levels of IL-15 in the serum and peritoneal fluid of women with endometriosis in different stages, aimed to research the effect of IL-15 in endometriosis. Platelet-derived growth factor (PDGF) is a very important growth factor that can stimulate cell growth. It's main physiological function is to promote cell DNA synthesis and induce cell caryocinesia. Recent studies have implicated that PDGF can promote vascular proliferation and have cross-talk with VEGF and FGF. In addition, it has been demonstrated that PDGF stimulates the production of estradiol and induces the expression of matrix metalloproteinase. Angiogenesis, estrogen and matrix metalloproteinase play important role in endometriosis. It is reasonable to speculate that PDGF may play important roles in the development of endometriosis. This study aim to investigate the role of PDGF in endometriosis through detecting the levels of PDGF in the serum and peritoneal fluid of women with endometriosis in different stages and the relationship between PDGF and IL-15.Methods:Forty-two patients undergoing surgery were recruited for this study. The endometriosis group consisted of 23 patients diagnosed with different stages of endometriosis by histological examinations. The endometriosis group was divided into two groups according to Revised American Fertility Society Classification of endometriosis(R-AFS,1985). There were 4 cases inⅠ~Ⅱgroups and 19 cases inⅢ~Ⅳgroups. The control group consisted of 19 patients who were healthy, fertile women with normal pelvic anatomy. Peritoneal fluid was aspirated from the pelvic cavity during the initial period of the surgery. Concentrations of IL-15 and PDGF in the serum and peritoneal fluid of women with and without endometriosis were measured by enzyme-linked immunosorbent assay (ELISA).Results: 1. The median of IL-15 in the serum was 13.95pg/ml in the endometriosis group, the median of IL-15 in the serum was 15.59pg/ml in the control group, there were no statistically significant differences between the endometriosis and control groups(P>0.05). 2. The median of IL-15 in the peritoneal fluid was 10.51pg/ml in the endometriosis group, the median of IL-15 in the peritoneal fluid was 13.09pg/ml in the control group, there were statistically significant differences between the endometriosis and control groups(P<0.05). The median of IL-15 in the peritoneal fluid was 17.62pg/ml in the endometriosisⅠ～Ⅱstage group, the median of IL-15 in the peritoneal fluid was 8.63pg/ml in the endometriosisⅢ～Ⅳstage group. there were statistically significant differences between theⅠ～Ⅱstage groups andⅢ～Ⅳstage groups(P<0.05). 3. The median of PDGF in the serum was 20.87ng/ml in the endometriosis group, the median of PDGF in the serum was 15.75ng/ml in the control group, there were no statistically significant differences between the endometriosis and control groups(P>0.05). 4. The median of PDGF in the peritoneal fluid was 25.78ng/ml in the endometriosis group, the median of PDGF in the peritoneal fluid was 20.60ng/ml in the control group, there were statistically significant differences between the endometriosis and control groups(P<0.05). The median of PDGF in the peritoneal fluid was 16.22ng/ml in the endometriosisⅠ～Ⅱstage group, the median of PDGF in the peritoneal fluid was 28.50ng/ml in the endometriosisⅢ～Ⅳstage group, there were statistically significant differences between theⅠ～Ⅱstage groups andⅢ～Ⅳstage groups(P<0.05). 5. The concentrations of IL-15 and PDGF in the peritoneal fluid in patients with endometriosis did not show any correlation (r=0.267,P>0.05).Conclusion:1. The concentrations of interleukin-15 in the peritoneal fluid was decreased in women with endometriosis, low-level IL-15 may suppress the activity of natural killer cell and cytotoxicity T lymphocyte cell, induce the development and progression of endometriosis. 2. The concentrations of PDGF in the peritoneal fluid was increased in women with endometriosis, increased PDGF may stimulate vascular proliferation, promote the production of estradiol, induce the expression of matrix metalloproteinase, induce the development and progression of endometriosis. 3. IL-15,PDGF have effect through paracrine or autocrine secretion way in peritoneal fluid, independencely with the concentration of serum.