Relationship between extent of cytoskeleton damage of oocytes incubated in PF of endometriosis and the stage of the disease and duration of infertility

Abstract

OBJECTIVE: Our previous studies demonstrated that endometriosis may induce alterations in the cytoskeleton (microtubules and chromosomes). Our objective was to evaluate the relation between the degrees of damage of the cytoskeleton of oocytes incubated in PF of patients with endometriosis and the stage of the disease as well as the duration of infertility. DESIGN: Experimental prospective controlled study. MATERIALS AND METHODS: PF was collected from patients with endometriosis and divided into: Group I = mild (stage 1 and 2) and group II = severe (stages 3 and 4). 400 mature metaphase II mouse oocytes were divided into three groups. Group I: 165 incubated in the PF of patients with endometriosis both mild and severe disease. Group II: 135 incubated in the PF of patients with tubal ligation (controls) Group III: 100 Oocytes incubated in plain human tubal fluid media (HTF). Oocytes were fixed in Formaldehyde 3 % followed by incubation with anti α-tubulin monoclonal antibody for microtubule staining and FITC labeled anti-mouse Ig G antibody. Propidium iodide was used for chromosomal staining. Microtubules and chromosomes were examined by confocal microscopy. Both microtubules and chromosomes were scored as: 1-2 = normal and 3-4 = abnormal. RESULTS: Oocytes that were incubated in PF of patients with endometriosis showed high grade of microtubules and chromosome damage compared to control. Percentage of abnormal microtubules/chromossome score were seen in endometriosis (68/64) vs. tubal ligation PF (24/19) and HTF) (18/18) (p< 0.001 for all groups compared with control. The degree of damage for microtubules correlated with stage of the disease (r = 0.42; P<0.029) and duration of infertility (r = 0.46, p<0.001) and for chromosomes scores, for stage (r = 0.17; p<0.029) and duration (r = 0.20; P< 0.014, respectively).Table 1Microtubules and chromosomes damage in patients and controlScoresControl (Tubal ligation)Control (HTF)EndometriosisP-valueMicrotubules (mean ± SD) % abnormal2.07 ± 0.85 24%1.95 ± 0.72 18%2.81 ± 0.86 68%<0.001Chromosomes (mean ± SD) % abnormal1.89 ± 0.82 19%1.84 ± 0.75 18%2.72 ± 0.72 64%<0.001P<0.05 was significant between control and endometriosis group. Open table in a new tab P<0.05 was significant between control and endometriosis group. CONCLUSIONS: Endometriosis damages microtubules as well as the chromosomes of metaphase II mouse oocytes, which may lead to poor oocyte quality. The degree of damage is correlated to the stage of the disease and the duration of infertility.