Objective: To compare the histological changes of the vaginal wall during different stages of pregnancy and estrus cycle. Design: Sample collection from vaginal wall through biopsy or after slaughter.
Animals: 58 samples from dorsal part of the vaginal wall of the ewes. were collected randommly for further histological atudy.
Procedure: In this study, samples were collected either from slaughter house or through biopsy from live animals. After preparation and staining by the method of haematoxylin- eosine , histological and histmorphometrical studies were carried out .
Statistical analysis: Using Dancan’s multiple range test to find the statistical difference in the number of cell layers and epithelial thickness.
Results: During oestrus the epithelium consisted of a single layer of columnar mucus secreting cells which somewhere it followed by 1-3 layers of polyhedral cells with a large activites of vascular and fibroblastes and small number of plasma cells in mucosa and sub mucosa. During di-oestrus 4-8 layers of epithelial cells were present. Vascular and fibroblastic activities were lower than during ocstrus and large number of plasma cells were present in sub mucosa and lamina propria. The results from pregnant cows showed that, there is not a significant difference in thickness between different months of gestation whereas there was a remarkable difference between month 9 and other months. In the number of epithelial cell layers, a significant difference has been seen between months 1 , 2, 3, 4 with 5 , 6,7,8 specially between months 8 and 9. The most important finding in morphometric study was the remarkable difference of months 8 with 9 in thickness and epithelial cell layers. There was not a difference in cell type of epithelium until 7 months of pregnancy. There were small cells with a pyknotic arid dark nuclis. Surface layers of cells were squamous and/or cuboidal types. From month 8, secretory columnar cells have been seen in epithelium and increased in month 9. In conclusion until 7 month of gestation, a large number of plasma cells were present in sub mucosa and epithelium but there was a relative decrease in month 8 and a significant decrease in month 9. Vascular and fibroblastic activitis was less until month 7, but in months 8 and 9, there was a significant increase in vascular and fibroblastic activities and sub mucosa was oedematous. All the changes were seen in different stages of pregnancy and oestrus cycle, can be described by hormonal changes.
Clinical implications: The most important finding was the remarkable difference between months 8 & 9 in thickness and epithelial cell layers. Also active secretory cells remarkably appeared in surface from layer seventh month of gestation.