Utility of Optical Density of Picrosirius Red Birefringence for Analysis of Cross-Linked Collagen in Remodeling of the Peripartum Cervix for Parturition.

We report on development of a rapid, quantitative analysis technique of collagen fibers in cross-linked structures to assess remodeling of the cervix during the transition from soft to ripening in preparation for birth. Optical density analysis of picrosirius red stain tissue using circular polarized birefringence light from fixed paraffin-embedded or frozen cervix from pregnant mice during phases of remodeling prior to birth. Data were analyzed using NIH Image J and extended recently to include studies of prepartum cervix in peripartum women. Our results, developed a rapid, consistent, technique to quantify cervical organization. This approach assesses the structure of collagen organization (the principle component of the cervix) and is essential for analysis of experimental outcomes that disrupt cervical morphology in rodent models of preterm birth. The technique, in this report has, for the first time permitted rapid, accurate assessment of the stages that define cervical ripening with large numbers of slides from individual animals. The approach integrates analysis of collagen organization, with distensability and inflammation, processes associated with cervical change before birth. This analysis further holds promise to evaluate other tissues, but also fibrolytic and fibrogenic changes in collagen associated with physiological or pathophysiological conditions.