Date Published: May 28, 2019
Publisher: Public Library of Science
Author(s): Morgan Dundon, Odile Madden, Pierre Comizzoli, Ilja Kusters.
Plastic polymers can be combined with additives that modify physical properties and stability of the material. However, the biocompatibility of those additives is not well known. The objective of the study was to characterize the impact of zinc stearate–a common additive–through the development of a novel three-dimensional (3-D) in vitro platform with endometrial cells from domestic cats. Epithelial and stromal cells from adult uteri were isolated and cultured in medium supplemented with 3% Matrigel for two weeks in plastic tissue culture dishes that had been identified as polystyrene with and without zinc stearate by Raman, FTIR, and X-ray fluorescence spectroscopies. Three-dimensional cell structures that were obtained were measured and categorized by shape. Cell viability, proliferation, differentiation, organization, and apoptosis then were assessed by immuno-staining. Results indicated that zinc stearate did not affect 3-D endometrial cell structure morphology, viability, or cellular composition. This first study of a new in vitro platform will be useful for studies testing the influence of other additives, drugs, or exogenous hormones.
In recent decades, biomedical research has shifted from glassware to convenient, sterile, disposable plasticware. Plastic supplies are now standard from molecular biology to in vitro culture of cells and embryos. The defining components of plastics are polymers, long or net-like organic molecules made of thousands of repeating segments. The vast expanse of these connected, identical segments results in a moldable substance, the properties of which can be tailored to impart flexibility, strength, transparency, or affinity for water or oils, for example . Polymers often are combined with additives that modify the plastic’s working properties during manufacturing or the properties of the finished object. Additives are incorporated at various points in the manufacturing process (i.e., by the compounder, additive manufacturer, or molder) or as contamination, and documentation of their presence often does not reach consumers. Plastics destined for biomedical use also can undergo surface treatments with chemicals, gas plasmas, or electrical discharges to favor certain interactions with biological specimens, like cell attachment or repulsion .
After a thorough plastic and additive characterization, we developed a preliminary 3-D in vitro culture platform for studying the effects of plastic on the endometrial cells. 3-D endometrial cell structures grown from epithelial and stromal cells were viable and proliferating. Structural properties of these structures were similar to endometrial organizations found in cat uterine horns. Although no significant effects from zinc stearate were observed during the two-week culture, this platform could be used, with further study and validation, for future studies investigating the influence of other plastic additives, drugs, or exogenous hormones.