Morphologic characteristics of equine endometrium classified as Kenney categories I, II, and III, using light and scanning electron microscopy.

The research article investigates the pathological changes in the endometrium of mares, categorizing these changes into three segments according to Kenney’s method. It uses both light and scanning electron microscopy to identify, describe, and compare these changes in tissue samples collected from 16 mares at different stages of their estrous cycle.

Methodology

• The research involved the aseptic collection of uterine biopsy specimens from 16 mares. These mares were at different stages of their estrous cycle; some were in the estrous stage (active period) while others were in the diestrous stage (resting period).
• The pathological changes in the endometrium were evaluated using light microscopy. These endometrial tissue samples were then categorized according to Kenney’s categories; I, II, or III.
• The respective endometrial tissues from the different categories were further processed for investigations using scanning electron microscopy.
• All specimens were immediately fixed after biopsy to avoid the formation of bleb-like projections, which were noted to form when fixation was delayed.

Findings

• Category I endometrium exhibited healthy tissue with normal glands and no signs of fibrotic tissue. Scanning electron microscopy revealed hexagonal cells covered in microvilli. This category also contained ciliated cells with long healthy cilia.
• Category II endometrium contained 2 to 4 nests surrounded by collagen fibers. Three out of four specimens showed moderate infiltration of leukocytes. Its cellular characteristics included some inflammatory changes, slight swelling of the cell surface, and a lack of microvilli in some cells. However, healthy hexagonal cells interdispersed these cells.
• Category III endometrium displayed many nests, with two of its specimens showing severe infiltration of white blood cells. More pathological changes were noted in this category.

Conclusion

• The study reveals distinct morphological differences in the equine endometrium across different categories of Kenney’s classification, aiding in the understanding of pathological endometrial changes in mares.
• The utilization of both light and scanning electron microscopy offered detailed insights into the cellular changes associated with each category, informing both broad and granular changes.