Effects of Estrogen Administration on Eosinophil Infiltration into the Uterus of Mast Cell Deficient (W/W^v) Mice

Abstract

The effect of estrogen administration on eosinophil infiltration into the uterus was examined. To investigate the role of mast cells in eosinophil infiltration, genetically mast cell-deficient (W/W^v) mice were used. The ovariectomized W/W^v mice were injected subcutaneously with 7 doses (0.001-0.25μg/g BW) of estradiol-17β (E₂) once a day for 2 days. The treatment resulted in significant increases in the uter-ine weight and the number of uterine eosinophils compared to the vehicle-injected control W/W^v mice 24 hrs after the second injection. Although the increases were dependent on the dose of E₂ administered, the magnitude of the responses was maximal in the uterus treated with the doses over 0.05μg/g BW. Fur-thermore the uterine weight in the treated mice was not increased between 24 and 48 hrs after the second injection of E₂ (0.15 μg/g BW). On the other hand, the number of eosinophils was increased until 48 hrs after the injection. The E₂ treatment at a dose of 0.15 μg/g BW resulted in a significant increase in histamine content of the uterus than that of the vehicle-injected control. However, there was no difference in the con-centration of the uterine histamine between the treated and control groups. These data suggest that the E₂ induced uterine eosinophilia is not mediated by mast cells in the W/W^v mice.