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Equine Reproductive Procedures. Группа авторов
Читать онлайн.Название Equine Reproductive Procedures
Год выпуска 0
isbn 9781119555933
Автор произведения Группа авторов
Жанр Биология
Издательство John Wiley & Sons Limited
Evaluate slide quality (i.e., the presence of normal uterine epithelial cells as well as the presence and relative number of inflammatory cells (neutrophils, macrophages, lymphocytes, etc.) and any bacteria/fungi). If a low number of cells are present on the slide, the cytology should be repeated to obtain a diagnostic quality slide.
The greater the ratio of neutrophils: uterine epithelial cells, the greater the degree of inflammation or endometritis.
Neutrophils are primarily associated with acute inflammation, whereas macrophages, lymphocytes, and plasma cells are more common with chronic inflammation.
The presence of inflammatory cells does not necessarily indicate infectious endometritis. Inflammatory cells may be present in cases of pneumo‐uterus, reflux of urine into the uterus, or after normal procedures such as breeding, uterine lavage, or infusion. The case history and results of other diagnostic procedures should be considered in mares with a positive uterine cytology to differentiate infectious from non‐infectious endometritis.
The absence of inflammatory cells in a sample with an adequate number of normal endometrial cells generally indicates the absence of active inflammation. However, some bacteria, such as Escherichia coli, do not stimulate a large inflammatory response, whereas other bacteria, such as Streptococcus equi subspecies zooepidemicus are associated with a significant inflammatory response.
Uterine Epithelial Cells
Uterine epithelial cells (UECs) can range from cuboidal in anestrus to tall columnar during the estrous cycle. A majority of UECs are not ciliated, but ciliated cells are often observed in cytology preparations (Figure 17.1). A range of UECs may be noted, including large rafts of cells, intact individual cells, or disrupted UECs (Figure 17.2). A large number of disrupted or degenerate UECs may indicate improper sample preparation, handling, or storage prior to staining or may be associated with a chronic uterine infection.
Figure 17.1 Ciliated tall columnar epithelial cells normally found in non‐inflammatory uterine cytology.
Debris
Debris may be classified as none/minimal (<25% of the slide), mild (25–50% of the slide), or moderate/severe (>75% of the slide). The presence of moderate to severe debris has been associated with bacterial endometritis.
Figure 17.2 A raft of normal endometrial epithelial cells in an equine uterine cytology sample.
White Blood Cells
Neutrophils are the predominant white blood cells (WBCs) identified on uterine cytology preparations (Figure 17.3). Neutrophils are 10–12 μm in diameter (about twice as large as a red blood cell (RBC)), with a single nucleus that may be indented or divided into 3–5 lobes or segments.
A cytology sample collected from a normal mare in estrus should have very few or no neutrophils; however, a rare neutrophil may be noted in association with blood contamination that occurred during the collection process. Neutrophils may be present in the uterine lumen following breeding, after uterine lavage or infusion, during the postpartum period, or in cases of endometritis.
Other WBCs such as macrophages, lymphocytes, or eosinophils are not commonly found on equine uterine cytology preparations.
Lymphocytes are approximately 7 μm in diameter (the same size as RBCs), are round to oval, and have only a small amount of cytoplasm (Figure 17.4).
Macrophages are approximately 20 μm in diameter with abundant blue‐staining cytoplasm filled with various‐sized vacuoles (Figure 17.5). Lymphocytes and macrophages are found in in the postpartum mare and in chronic uterine infections.
Eosinophils are 12–15 μm in diameter, with blue‐staining cytoplasm that contains multiple pink or red granules (Figure 17.6). Eosinophils are found in cases of pneumovagina, fungal infections, or reflux of urine into the uterus.
The average number of WBCs per high power field (hpf) is determined after evaluating at least 10 hpf in multiple areas of the slide, and is used to categorize the degree of inflammation (Table 17.1).
Another method used to categorize the inflammatory response is the number of WBCs per UEC. A ratio of 1 WBC to 20–40 epithelial cells has been used as a gauge of the degree of inflammation.Figure 17.3 Inflammatory uterine cytology with quiescent macrophage (large arrow) and many neutrophils (small arrow).Figure 17.4 A lymphocyte (arrow) in a uterine cytology sample.Figure 17.5 A pair of macrophages (solid arrows) in a uterine cytology sample along with neutrophils (open arrow) and red blood cells (arrow head).Figure 17.6 An eosinophil (arrow) in a uterine cytology sample along with neutrophils and a red blood cell.Table 17.1 Description of the number of neutrophils per hpf with corresponding inflammation classification for samples collected from a brush/swab.Number of Neutrophils per hpfClassification0 to rareNormal1–2Mild inflammation3–5Moderate inflammation>5Severe inflammation
Categorizing the degree of inflammation represented in a cytologic sample from a low volume lavage can be difficult. Centrifugation of the uterine effluent concentrates UECs, WBCs, microbial organisms, and debris into a pellet. The pellet is subsequently smeared onto a glass slide, stained and evaluated. A normal mare should have very few or no WBCs noted in the cytology from a low volume lavage. Mares with mild uterine inflammation often have >5–10 neutrophils per hpf, whereas mares with more severe inflammation usually have >10 neutrophils per hpf. The presence of microbial organisms should be interpreted with caution, as there is a higher risk potential for contamination during sample collection with a low volume lavage procedure versus the use of a double‐guarded uterine swab or brush.
Red Blood Cells
Red blood cells are 6 μm in diameter with a central pallor. These cells are commonly found in low numbers (i.e., <4/hpf) on routine cytologic evaluation.
Excessive numbers of RBCs may indicate irritation to the endometrium from infection, infused compounds, or aggressive sampling technique.
Bacteria
Bacteria can