Effects of Estrogen Administration on Eosinophil Infiltration into the Uterus of Mast Cell Deficient (W/W<SUP>v</SUP>) 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/Wv) mice were used. The ovariectomized W/Wv 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/Wv 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/Wv mice.