Polyvinyl alcohol can replace the fetal bovine serum during cryopreservation of canine adipose mesenchymal stromal cells

Abstract

Mesenchymal stromal cells (MSCs) are cells with multipotent characteristics present in various tissues and used as a promising alternative in cell therapy protocols in animals and humans. Creating stem cell banks for various purposes through cryopreservation is a common practice with MSCs. In this regard, the association between 10% dimethyl sulfoxide (Me2SO) and 90% fetal bovine serum (FBS) is widely used as a cryoprotective protocol for MSCs. However, these components have disadvantages, with possible risks to therapy receivers, contamination, and cytotoxic effects on MSCs. To replacing and reducing the use of FBS in the MSCs cryopreservation protocols, four agents were selected, being FBS at 10%, methylcellulose (MC) at 0.1%, polyvinyl alcohol (PVA) at 1%, and bovine albumin (BSA) at 1%, all associated with 10% Me2SO and 80% DMEM high glucose media. In the cell viability test with flow cytometry, the group with MC at 0.1% performed significantly worse than other treatments, except for BSA, which had a similar performance to MC. The expression of membrane proteins evaluation with flow cytometry showed that the cells treated with PVA and 10% FBS performed better at expressing lower values of CD34 and MHC-II. There were no differences regarding the osteogenic and adipogenic differentiation induction between the groups. We concluded that low concentrations of FBS (10% in DMEM) associated with BSA or PVA have a similar protective effect on cell viability during cryopreservation with Me2SO as 90% FBS. PVA showed an additional effect since the MSCs expressed lower concentrations of MHC-II and CD34.