193 Creatine Monohydrate on In Vitro Cultivated Bovine Cells Leading to Guanidinoacetic Acid Supplementation In Vivo

Abstract

Abstract Guanidinoacetic acid (GAA) is an amino acid-like compound that acts as a precursor to creatine (CRE) when either made in the body or digested. Creatine is directly used by skeletal muscle tissue as an energy source with the potential to act as a growth-promoting agent. The study objectives were to evaluate the effects of various CRE concentrations on bovine satellite cells for the rate of proliferation and myogenic differentiation. Satellite cells (SC) were isolated from the Longissimus muscle of 3-month-old Holstein bulls (n = 5). Cells were seeded at a density of 1 × 104 cells/mL on 96-well plates and incubated with 0 (CON), 2.5, 5, 7.5, and 10 mM of CRE. The absorbance rate was measured at 0, 24, 48, 72, and 96 h of incubation. Cells for gene expression were plated on 6-well plates at a density of 1 × 105 in 10% FBS/DMEM. Following 24 h of adhesion, SC were incubated with 5 and 7.5mM CRE for 48 h. After which, cells were harvested after 48 h for Pax3, Pax7, and Myf5 mRNA gene expression analysis. To identify the effects of CRE during myogenic differentiation, SCs were induced myogenic differentiation. Upon reaching approximately 90% confluency, the growth medium was replaced by differentiation media (2% horse serum/ DMEM) containing 0 (CON), 5, and 7.5 mM CRE. A two-way ANOVA and Tukey's HSD test were conducted regarding cell proliferation. A one-way ANOVA and Tukey's HSD test were performed for gene expression. Interaction of treatment against time was noted (P < 0.01) in Con, 2.5, 5, 7.5, and 10 mM CRE. Cell proliferation rate was influenced by CRE treatment (P < 0.01). At 72 h of incubation, all CRE treatments increased cell proliferation rate compared with Con (P < 0.05). At 96 h of incubation, cells treated with 2.5, 5, and 7.5 mM of CRE increased proliferation compared with Con (P < 0.05). At 96 h, CRE treatment 2.5, 5, and 7.5 mM increased proliferation rate compared with 10mM CRE treated cells (P < 0.05). No treatment effect was found in the mRNA gene expression of Pax7, Pax3, and Myf5 (P > 0.05). Cells incubated with CRE showed no change in mRNA gene expression of IGF-1 and Myogenin (P > 0.05), and a tendency was noted for S6KB1 increase expression under treatment (P = 0.0643). S6KB1 is a protein kinase that, through mTOR pathway expression, leads to an increase in cell growth, protein synthesis, and cell proliferation. Results suggest that the treatment of BSCs with CRE impacted proliferation, CRE at 5mM vs. 7.5 mM concentrations treatment of differentiated muscle cells led to a trend in altering S6KB1 gene expression.