31/01/2020
🔬 VAGINAL CYTOLOGY🔬
-Vaginal cytology refers to as the microscopic examination of the cells residing in the vaginal wall in particular importance to the vaginal epithelium.
- It helps to differentiate the various stages of an estrous cycle as a result of the effects of s*x hormones.
-This differentiation helps in determining:
> when the animal is in heat(Estrus) for a natural mate or Artificial insemination
> Helps in determining when to administer exogenous hormonal therapy like P4 or LH..
> Helps to determine the correct time to perform a cesarean if neceassary..
> Helps to determine if the animal is under the influence of estrogen..
🔆VAGINAL EPITHELIUM:
Vaginal epithelium is formed of stratified squamous epithelium with a little degree of keratinisation depending upon the species..
However its squamous layers are divided into 3 layers:(From bottom to Top)
1)The Basal layers
2)The Intermediate layers
3)The Superficial layers
During a normal reproductive cycle, the vaginal epithelium undergoes changes due to the effects of estrogen: With increased estrogen- Increased proliferation of epithelial cells takes place and an increase in epithelial cell layers take place. The cells proliferate and mature and ultimately undergo complete cornification.
-Hormone induced changes also occur in different parts ofvthe female reproductive system but the vaginal epithelium is extremely sensitive to it and therfore its structures are an indicative of estrogen levels and thus indicate the stages of estrous.
The cells of the vaginal epithelium seen in the vaginal smears include:
•BASAL CELLS: Small cells with round nuclei and high nucleus:cytoplasm (N:C) ratio. Gives rise to all epithelial cells from the base of the vaginal epithelium and are rarely seen in vaginal smears
•PARABASAL CELLS: Small round cells with a high N:C ratio
•INTERMEDIATE CELLS: 2-3 times larger than parabasal cells but nuclei similar in size to parabasal cell nuclei. Sizes vary depending on the amount of cytoplasm: They may be large intermediate cells or small intermediate cells.
•SUPERFICIAL CELLS: These are the largest type of epi cells in the smears. These are dead cells whose nuclei become pyknotic and then faded often progressing towards the anucleated forms..
OTHER CELL TYPES IN VAGINAL SMEARS:
⭐️METESTRUM: Vaginal epi cells with Neutrophils in the cytoplasma
⭐️BACTERIA: From Normal vaginal flora or from contaminated slides
⭐️SPERMATIZOA: From mated bi***es
⭐️TROPHOBLAST CELLS: Trophoblast like synctia may also be observed in vaginal smears particularly after parturation
⭐️NAVICULAR CELLS: Boat shaped benign epi cells seen in the pap (papanicolaou) test in order to detect any cancerous or precancerous processes in the cervix or in the colon as well.. maybe due to the effect of medroxyprogesterone acetate or maybe seen in second trimester of the pregnancy.
⭐️Endometrial cells,endocervical cells and leucocytes may also be seen.
🦠OBSERVABLE CELLS IN DIFFERENT STAGES OF OESTROUS CYCLES:
🩸EARLY PROESTRUS: A Shift from parabasal cells to intermediate and superficial cells
Increased no. Of neutrophils and RBCs. Presence of vaginal mucosa
🩸LATE PROESTRUS: Decrease in Neutrophils and cytology mostly consists of Large intermediate and superficial cells. RBCs and bacteria may be present.
🩸ESTRUS: Presence of a superficial cells with mostly being Anucleated and the rest having small pyknotic fading nucleus. RBCs and bacteria maybe present aswell. No leukocytes.
🩸DIESTRUS: Superficial cells replaced with parabasal and intermediate cells within 1-2 days. Increased no. Of neutrophils
RBCs may be present or absent. Bacteria normally present as normal flora.
🩸ANESTRUS: comprised of intermediate and parabasal cells. Smaller cells with large nuclei. Little number Of neutrophils. No RBCs. Overall Lesser no. of cells.