The Effects of Triclosan on Ovarian Reserve and Fecundity in a Mouse Model.

OBJECTIVE To investigate the acute and chronic effects of triclosan exposure on ovarian reserve dynamics and reproductive potential in a mouse model.

DESIGN Female C57BL/6 mice were given a diet containing triclosan (TCS) 10mg/kg per day or a control diet starting on postnatal day (PND) 30. Ovaries were collected at PND 37, 60, 90, 210, 300, and 360 reflecting 1 week, 1 month, 2 month, 6 month, 9 month, and 12 month periods of exposure. Ovarian follicular compositions were analyzed in both groups at all exposure time points. Animals from both groups at the same exposure time groups were bred with age-matched control C57BL/6 male mice and number of litters, pups per litter, inter-litter interval, and number of deceased pups were recorded.

SETTINGS Laboratory study.

SUBJECTS C57BL/6 mice.

EXPOSURE Triclosan 10mg/kg per day diet or control diet.

MAIN OUTCOME MEASURE(S) Ovarian follicular compositions were analyzed in triclosan-treated mice compared to controls for both acute and chronic exposure time points. Animals from both exposure groups were bred and number of litters, pups per litter, inter-litter time interval, and number of deceased pups were analyzed.

RESULT(S) Primordial follicle density decreases with age in control and TCS-exposed mice with a trend towards an accelerated decline in the PND90, 300, and 360 TCS-exposed group. TCS-exposed mice at PND37 and PND60 both exhibit a trend towards decreased growing follicle (primary and secondary) densities. At PND300 and 360, there are decreased follicular densities across all follicle types in the TCS-exposed compared to control groups with lower antral follicle densities (0.27 vs. 0.04, p=0.050 at PND300 and 0.22 vs. 0.06, p=0.104 at PND360). Litter sizes were similar between groups across all time points. The length of time between first and fifth litters is increased in the TCS-exposed group at PND37 (116 days vs. 135.2 days, p=0.04) with similar trends seen in the PND60 (114.7 days vs. 122.8 days, p=0.31) and PND90 (140.8 vs. 158.8 days, p=0.30) groups, which may suggest longer cycles and reduced rates of ovulation in mid-reproductive life. No increase in stillbirth was seen in the TCS-exposure groups compared to controls.

CONCLUSION(S) Our study demonstrates that triclosan exposure may accelerate normal age-related ovarian follicular loss with decreased antral follicle density at chronic exposure timepoints. Triclosan exposure may also impact estrous cycles at mid-reproductive age.