Received December 26, 2022
Accepted July 01, 2023

Objective: To assess whether follicular fluid (FF) from infertile women with endometriosis in advanced stages [moderate/severe (EIII/IV) without or with endometrioma (Endometrioma)] induce more oocyte damages than in early stages (minimal/mild: EI/II); and whether supplementation with L-carnitine (LC) and omega 3 (n3) can prevent these oocyte damages. Methods: Experimental study using bovine oocytes (obtained of ovaries from slaughterhouse), and human FF (samples were obtained during oocyte recovery for ICSI). Bovine oocytes were submitted to in vitro maturation (IVM) divided into 9 groups: no FF(No-FF), with 1% FF from infertile women without endometriosis (FFC), with EI/II, EIII/IV and Endometrioma, and with (or not) LC+n3 addition. After IVM, oocytes were fluorescently labelled and visualized by confocal microscopy to analyze chromosomes and spindle. Results: FF from endometriosis decreased rate of normal MII (spindle assembly and chromosome alignment) compared to No-FF (87.2%) and FFC(87.2%). FFEIII/IV (80.7%) and FFEndometrioma (69.3%) decreased total MII rate compared to No-FF(91.9%) and FFC (89.2%), and FFEndometrioma had lower total MII rate compared to other groups. LC+n3 increased MII rate in the FFEIII/IV (80.7% vs 90.8%) and the Endometrioma (69.3% vs 86.4%), and it prevented damages in spindle and chromosomes in MII oocytes in the FFEI/II group (62.2% vs 84.5%) and the FFEIII/IV group (70.2% vs 84.1%). Conclusions: FF of endometriosis damaged the meiotic spindle of bovine MII oocytes. EIII/IV led to impaired nuclear maturation; FF from women with endometrioma had further negative impact in oocyte maturation. LC+n3 completely prevented the effects of FF from women with endometriosis on oocyte.