Effects of exogenous sex hormones on mouse estrous cycle, vaginal microbiota and immune cells

DE GREGORIO PRISCILLA ROMINA; SALVA SUSANA; JUÁREZ TOMÁS MARÍA SILVINA; NADER-MACÍAS MARÍA ELENA FÁTIMA

SCANDINAVIAN JOURNAL OF LABORATORY ANIMAL SCIENCE

SCANDINAVIAN FEDERATION LABORATORY ANIMAL SCIENCE

Año: 2018 vol. 44

0901-3393

Sex hormones are often administered to mice in vaginal microbial studies in order to synchronize estrous. Our objective was to evaluate the effect of estradiol-hemisuccinate (EH) or medroxyprogesterone-acetate (MPA) administration on estrous cycle, vaginal microbiota, and immune cell populations of various organs in a murine model. Two-month-old female BALB/c mice were intramuscularly injected with EH (day -2) or MPA (day -5) to induce estrous (E) or diestrous (DE), respectively. On sampling days (Sd) 0, 2, 6 and 8, vaginal washings (v.w.), vagina, blood, spleen and bone marrow (BM) samples were taken. Most of the animals remained in E or DE states until Sd 6 after EH or MPA administration, respectively. The number of cultivable vaginal bacteria was not modified by hormonal treatments; higher quantities were detected in mice in E. Only EH administration modified serum sex hormone levels, increasing serum estradiol on Sd 0. In v.w., myeloid population was dominant while lymphoid populations were not detected. Only MPA administration induced a reduction in myeloid cells on Sd 0. Hormonal treatments did not affect myeloid populations in BM but caused a slight decrease in T and B cells. In spleen, hormonal administration did not affect B or T population size while an increase in mature B cells and a decrease in immature B cells were observed in MPA-treated mice compared with EH-treated mice. Thus, although both hormonal treatments induced slight changes in some of the parameters evaluated compared to control animals, adequately standardized and consistent experimental protocols were established for further studies.