Author(s): SIMON, E., RUVIRA, S., MORTIER, A., VAN DOORSELAER DE TEN RYEN, S., MAHY, T., DELDICQUE, L., Institution: UCLOUVAIN, Country: BELGIUM, Abstract-ID: 1925

INTRODUCTION:
Oxidative stress is defined as a state of imbalance between the production of oxidants and reductants. In obese individuals, this redox imbalance is prevalent in adipose tissue, causing damage to biomolecules and contributing to the development of chronic diseases. On the contrary, physical exercise improves antioxidant defences, by increasing the activity of antioxidant enzymes. Developing a cellular model to better understand the mechanisms of intercellular communication between adipocytes and skeletal muscle tissue is therefore crucial. Our main aim is to test the feasibility of a protocol incubating a conditioned medium (CM) produced by electrical pulsatile stimulation (EPS) of myotubes in cultured adipocytes.
METHODS:
Two cell lines were used: C2C12 myotubes and 3T3-F442A matured adipocytes. Differentiated C2C12 myotubes were electrically stimulated for 4 consecutive days for 3 hours/day at 1Hz and 14V using the C‐Pace EP cell culture stimulator, with C‐dish and carbon electrodes (IonOptix, Milton, MA, United States) to simulate chronic endurance exercise. We then investigated the effect of the conditioned medium coming from stimulated or unstimulated C2C12 myotubes on 3T3-F442A matured adipocytes. For this purpose, we created several groups and ratios between the C2C12 differentiation medium (CM) and the 3T3-F442A basal medium (BM2): CTRL-CM ratio 1:1 (50% BM2 and 50% non-stimulated CM from myotubes), CTRL-CM 1:0 (100% CM from non-stimulated myotubes), EPS-CM 1:1 (50% BM2 and 50% CM from stimulated C2C12) and EPS-CM 1:0 (100% CM from stimulated C2C12). All the media were collected after treatment, centrifuged and stored at -80°C. The expression of the antioxidant enzymes superoxide dismutase 2 (SOD2) and catalase (CAT) was determined by Western Blot. Statistical analyses were performed using a t-test for C2C12 data and a Kruskal-Wallis test for 3T3-F442A data.
RESULTS:
EPS increased CAT expression (p<0.001) and tended to increase SOD2 expression (p=0.097) in C2C12 cells. When applying conditioned media from stimulated and unstimulated C2C12 myotubes to 3T3-F442A adipocytes, no differences were found for SOD2 and for CAT expression, whatever the ratio used between the media.
CONCLUSION:
Despite the increase in CAT and the trend to increase in SOD2 expression by EPS in C2C12 myotubes, conditioned media from stimulated myotubes did not modify the expression of those enzymes in 3T3-F442A adipocytes.