Isolation and culture of adult and fetal rabbit bladder smooth muscle cells and their interaction with biopolymers

Purpose: The aim of this study was to test the feasibility of isolation and culture of adult and fetal rabbit bladder smooth muscle cells (SMCs) and comparison of their interactions with different types of biodegradable biopolymers in cell culture. Methods: Bladder SMCs isolated from adult and fetus rabbits were identified by immunostaining for smooth muscle α-actin and myosin. Growth kinetics of SMCs were estimated using population doubling time (PDT) and thymidine labeling index (TLI). Poly (D, L-lactide-co-glycolide; PLGA) copolymers were synthesized at 85:15 and 75:25 monomer ratios. The porous scaffolds prepared from these polymers were seeded with SMCs. The study compared the effectiveness of adsorbing fibronectin and fetal calf serum (FCS) on these biopolymers. The cells grown on these polymers were quantified using a neutral red uptake assay. Results: Over 90% of the 2 cell populations stained positive for SMC marker proteins, Fetal SMCs were seen to emerge from the tissue after 3 to 4 days, whereas adult SMCs were seen after 5 to 6 days. However, estimated PDT of fetal and adult SMCs was 85.2 and 54.5 hours, respectively, and TLI of adult SMCs was also higher than with fetal SMCs. Proliferation on 75:25 PLGA was better than for 85:15 and for both biopolymers; adsorption of FCS significantly affected cell attachment relative to fibronectin. Conclusions: Although fetal SMCs were shown to emerge from explants early after seeding onto dishes, doubling time and S-phase fraction of adult bladder SMCs were markedly higher than of fetal derived cells. Adsorption of serum proteins significantly enhances the attachment of both fetal and adult SMCs to biopolymers.