Butyric acid induces spontaneous adipocytic differentiation of porcine bone marrow–derived mesenchymal stem cells

Butyric acid (BA) affects the differentiation of mesenchymal stem cells (MSC) through the activation of different transcriptional pathways. The aim of this study was to determine the effects of BA on proliferation and spontaneous differentiation of porcine bone marrow–derived MSC. Second passage MSC (n = 6) were cultured in either a basal medium (BM, DMEM + 10% FBS), or BM + 2.5 mmol/L BA (BA-2.5) or BM + 5 mmol/L BA (BA-5). Cell proliferation was significantly decreased by both BA-2.5 and BA-5 after 48 h and 72 h (− 55% and − 63%, respectively). To assess the impact of BA on spontaneous differentiation, MSC were cultured for 27 d, with complete media changes every 3 d. At day 27, cells were stained for osteocytic, chondrocytic, and adipocytic differentiation. No terminal differentiation was detected in control MSC, while accumulated small drops of lipids were stained by Oil-Red-O in BA-treated cells. The phenotypic changes were associated with changes in gene expression, determined by qPCR. Treatment with BA modulated the expression of adipocytic differentiation markers: peroxisome proliferator-activated receptor γ and CCAAT/enhancer binding protein α were significantly increased by both BA-2.5 and BA-5 throughout the study, while lipoprotein lipase and fatty acid-binding protein 4 were increased by BA-5 at day 3, and decreased by both BA-5 and BA-2.5 later throughout the study. Osteocalcin and aggrecan mRNA was reduced throughout the experiment by both doses of BA (P < 0.05). In conclusion, our data support that BA promotes the spontaneous differentiation of porcine bone marrow–derived MSC toward an adipocytic lineage in the absence of inducing cocktail media.