Toxic Effects of Lipopolysaccharide From Bacteroides Intermedius and Escherichia Coli Assessed in the Pre‐implantation Mouse Embryo Culture System

A comparative study on the toxic effects of endotoxin (lipopolysaccharide, LPS) from the strictly anaerobic Bacteroides intermedius BM1 and from Escherichia coli 055 was performed. Pre-implantation mouse embryos at the 2-cell stage from LPS responder (C57BL/6J) and low responder (C3H/Hej) mouse strains were exposed to the endotoxins, and development was observed during 72 h in vitro. Toxic effects of both endotoxins on embryos from both mouse strains were demonstrated. B. intermedius LPS was less toxic than E. coli LPS. The C3H/Hej embryos were more susceptible to endotoxins than the C57BL/6J embryos. A biphasic dose-response relationship was observed, as 100 micrograms/ml LPS was less embryotoxic than 1, 10 or 500 micrograms/ml, suggesting more complex mechanisms of effect than non-specific cell toxicity.