Cornification of Vaginal Epithelium of Ovariectomized Rat Produced by Smearing

Abstract

The histological examination of the vaginae of a number of spayed rats showing an unexpected response to the examination of the vagina by the smear method revealed that smearing alone, without the injection of an estrogenic hormone, may produce, under certain conditions, full cornification of the vaginal epithelium. The results of some of our experiments are summarized in Table I.

The spayed rats which were neither smeared nor injected presented a thin, smooth vaginal epithelium usually 2 cell layers in thickness with leucocytes migrating into the lumen. When the animals were smeared once, twice, and 3 times daily the typical section from the vagina showed a progressive thickening of the epithelium up to 12 or more layers with the usual desquamation of the surface cells, thus presenting a picture very similar to that obtained after the administration of estrogenic material. 1 , 2

The vaginal smear picture 3 likewise underwent a progressive change when the animals were examined once, twice, and 3 times daily. The usual — smear observed when the animals were examined once daily changed to a ± or occasionally a ± ± on and after the third day if the animals were examined twice daily. When the vaginal smears were made 3 times daily about 25% of the animals showed full + smears on the third or fourth day of treatment.∗

In order to observe whether smearing 3 times daily would change the typical picture observed after the administration of theelin, 3 animals injected daily with one rat unit of theelin and smeared 3 times each day were compared with 3 other animals injected with the same amount of theelin but smeared once daily.