LPS-Induced Implantation Failure: One of the Causes of Female Infertility

A fundamental feature of implantation is synchronized development of the embryo to the blastocyst stage and differentiation of the uterus to the receptive state. Lipopolysaccharide (LPS), a bacterial endotoxin, is a component of the outer membrane of Gram-negative bacteria and its detection in biologic fluids is an evidence of microbial invasion of a sterile compartment, such as the amniotic cavity. A gramnegative bacterial infection model has been established in the mice. LPS alters the expression of tumor necrosis factor-a, interleukin-1, and colony-stimulating factor. LPS treatment disturbs serum P4, E2 and their receptors. Expression of Hsp90, Hsp70, Hsp60, and Hsp25 also altered due to LPS treatment. LPS disturbs the level of FSH and LH and, FSHR in embryos and ovaries, LHR in embryos and uterus. Disturbance in the embryonic and uterine expression of cytokines, growth factors, steroid hormones and its receptors, gonadotropins and its receptors and heat shock proteins in response to LPS probably trigger the multiple factors in the embryonic and uterine cells, which are responsible for implantation failure. The present review will contribute to our understanding of the mechanism of early pregnancy loss during gram-negative bacterial infection in