Short- and long-term effects of lipopolysaccharide-induced endotoxemia on mice ovarian tissue: histomorphometrical evaluation

Abstract

Endotoxemia is an acute systemic reaction of the body caused by the presence of endotoxins such as bacterial lipopolysaccharide in the blood, which is associated with clinical signs. Lipopolysaccharide is a part of the outer membrane of the cell wall of gram-negative bacteria. The aim of the present study was to determine the effect of E-coli lipopolysaccharide administration on histomorphometric changes in mice ovarian tissue. Adult female mice were randomly divided into the control and treatment groups, with ten mice in each. The treatment group received 6750 μg/kg of lipopolysaccharide intraperitoneally and in the control group, normal saline was injected at the same dosage. Five mice from each experimental group were euthanized on days 3 & 30 after the beginning of the treatment, then the right ovary was removed, fixed and serially sectioned for histomorphometric evaluation. The results obtained showed that 3 days after lipopolysaccharide injection the estimated ovarian parameters, including primary follicles, secondary follicles and corpora lutea, had decreased significantly (P≤0.05). The mean number of antral follicles was not influenced by lipopolysaccharide injection on days 3 and 30. The mean number of primary follicles on day 30 (53.4 ± 4.6) showed a significant increase in comparison with the treatment group on day 3 (42.1 ± 4.1) which was close to its values in the control group. The mean number of secondary follicles and corpora lutea on day 30 (36 ± 4.8 and 34.2 ± 10.8, respectively) showed a relative improvement, however it was still lower than the control group counterparts (49.5 ± 5.0 and 39.2 ± 3.9, respectively). According to our results, endotoxemia induced by lipopolysaccharide has short-time deleterious effects on ovarian follicles but they recovered somewhat after a short time equal to a folliculogenesis cycle, from primordial follicle to preovulatory antral follicle.