title: A method for ovarian follicle encapsulation and culture in a proteolytically degradable 3 dimensional system.
abstract: The ovarian follicle is the functional unit of the ovary that secretes sex hormones and supports oocyte maturation. In vitro follicle techniques provide a tool to model follicle development in order to investigate basic biology, and are further being developed as a technique to preserve fertility in the clinic. Our in vitro culture system employs hydrogels in order to mimic the native ovarian environment by maintaining the 3D follicular architecture, cell-cell interactions and paracrine signaling that direct follicle development. Previously, follicles were successfully cultured in alginate, an inert algae-derived polysaccharide that undergoes gelation with calcium ions. Alginate hydrogels formed at a concentration of 0.25% w/v were the most permissive for follicle culture, and retained the highest developmental competence. Alginate hydrogels are not degradable, thus an increase in the follicle diameter results in a compressive force on the follicle that can impact follicle growth. We subsequently developed a culture system based on a fibrin-alginate interpenetrating network (FA-IPN), in which a mixture of fibrin and alginate are gelled simultaneously. This combination provides a dynamic mechanical environment because both components contribute to matrix rigidity initially; however, proteases secreted by the growing follicle degrade fibrin in the matrix leaving only alginate to provide support. With the IPN, the alginate content can be reduced below 0.25%, which is not possible with alginate alone. Thus, as the follicle expands, it will experience a reduced compressive force due to the reduced solids content. Herein, we describe an encapsulation method and an in vitro culture system for ovarian follicles within a FA-IPN. The dynamic mechanical environment mimics the natural ovarian environment in which small follicles reside in a rigid cortex and move to a more permissive medulla as they increase in size. The degradable component may be particularly critical for clinical translation in order to support the greater than 10(6)-fold increase in volume that human follicles normally undergo in vivo .
authors: Institute for BioNanotechnology in Advanced Medicine, Northwestern University, USA.
authors: Ariella
authors: A
authors: Shikanov
authors: Min
authors: M
authors: Xu
authors: Teresa K
authors: TK
authors: Woodruff
authors: Lonnie D
authors: LD
authors: Shea
mesh_terms: D000464:Alginates / Q000737:chemistry; D000818:Animals; D005260:Female; D005337:Fibrin / Q000737:chemistry; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006801:Humans; D020100:Hydrogels / Q000737:chemistry; D051379:Mice; D009924:Organ Culture Techniques / Q000379:methods*; D006080:Ovarian Follicle / Q000254:growth & development*
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020100:Hydrogels; D020723:Glucuronic Acid; D005337:Fibrin