Pyruvate reduces in vitro the embryotoxic effect of peritoneal fluid from infertile women with endometriosis

OBJECTIVES: To ascertain the embryotoxicity of peritoneal fluid from infertile women with endometriosis (PF-E), on mouse embryos in culture and to examine the effect of pyruvate in the culture medium on PF-E induced embryotoxicity. STUDY DESIGN: Blood-free peritoneal fluid samples were obtained during laparoscopic investigation for infertility from 21 infertile women with endometriosis. The severity of endometriosis ranged from minimal or mild (PF-min to mild-E; n=7), moderate (PF-mod-E; n=7), to severe (PF-sev-E; n=7). Peritoneal fluid samples were centrifuged at 600 x g for 10 min and 4 degrees C, and the supernatant was incubated at 56 degrees C for 30 min in a water bath to inactivate the complement protein. Mice were super ovulated with intraperitoneal injection (IP) of 5IU of pregnant mare serum gonadotrophin and human chorion gonadotrophin. Twenty-four hours after confirmation of mating two-cell mouse embryos were obtained. They were then cultured in modified Whitten's medium (mWM) with peritoneal fluid from patients with endometriosis, and either in the absence or presence of excess pyruvate (0.062 mmol(-1)). Embryos were cultured for 72 h. RESULTS AND CONCLUSION: Addition of 5% PF-E significantly (p<0.001) suppressed embryo growth at 24, 48, and 72 h of culture and the degree of suppression correlated with the severity of the disease. The presence of 0.062 mmol(-1) pyruvate in the culture medium significantly (p<0.001) reduced the embryotoxicity of PF-min to mild-E and PF-mod-E at each stage of development, but was only seen at 24h of culture (p<0.001) in cultures with PF-sev-E even when the concentration of pyruvate in the medium was increased to 0.31 mmol(-1). This study confirms the embryotoxicity of PF-E in vitro, which was reduced by the presence pyruvate in the culture medium, particularly in cultures containing fluid from women with endometriosis of minimum or mild to moderate severity.