A Practical Approach, Second Edition=Ronald D. Ho.pdf

464 DEVELOPMENTAL REPRODUCTIVE TOXICOLOGY: A PRACTICAL APPROACH, SECOND EDITIONDiestrusFull DiestrusLeukocytesLeukocytesProestrusProestrusCornifiedepithelial cellsLeukocyteNucleatedepithelial cellsClumped nucleatedepithelial cellsEstrusCornified epithelialcellsIrregularly shapedcellsProlonged EstrusFigure 10.10Estrous cycle evaluation.leukocytes, few or no polynucleated epithelial cells, and many flat cornified cells. The changes invaginal cytology are shown in Figure 10.10.2. Vaginal Lavage MethodologyVaginal lavage for the determination of the stage of estrous can be performed at any time of theday; however, it is important that the samples be collected at approximately the same time eachday over the course of a study. A pre- and postcheck of the saline should be made. (Note: If glasspipettes are used, the rubber bulbs can be saved and washed for future use, while the glass stemsshould be discarded after each sampling. If plastic pipettes are used, the pipette should be discardedfollowing each sampling. Dropping pipettes should be held with the tip pointing down whenever© 2006 by Taylor & Francis Group, LLC