MORPHOMETRIC ANALYSIS OF ENDOMETRIAL PERIGLANDULAR FIBROSIS IN MARES

Objectives-To develop an objective, quantifiable assay for endometrial periglandular fibrosis (EPF) and correlate assay results with histolo gic and ultrastructural changes in equine endometrial biopsy specimens . Sample Population-Endometrial biopsy specimens from 70 mares from 3 to 27 years old in estrus. Procedure-In a double-blinded study design. endometrial biopsy specimens were graded histologically (modified Ken ney classification) for EPF and inflammation. Endometrial periglandula r collagen volume fraction (%EPCVF) was determined by light microscopi c image analysis of picrosirius red-stained sections. Specimens from s elected mares were examined by transmission electron microscopy. Resul ts-%EPCVF values varied significantly among the 4 modified Kenney EPF categories (I. IIA, IIB, end III) and increased with increasing age of mares. Morphologically, EPF consisted of concentric layers of transfo rmed fibroblasts with myofibroblastic features and deposition of fibri llar collagen around unaltered glandular basal laminae. Conclusions an d Clinical Relevance-%EPCVF correlates well with morphologic changes i n endometrial biopsy specimens. Determination of %EPCVF could be usefu l in evaluation and clinical management of subfertile mares and in inv estigations of the pathogenesis of EPF.