Background: Obesity is associated with low-grade and chronic inflammatory state that contributes to the metabolic disruption. This condition increases the production of several
inflammatory cytokines and impairs the insulin pathway. In the liver, insulin resistance increases glucose production in postprandial situations and decreases the synthesis of glycogen. On the other
hand, omega-3 fatty acids can act reducing the inflammation through its receptor, GPR120, which interrupt the inflammatory process from Toll-like and cytokines receptors. However, the mechanisms
responsible for regulating GPR120 expression are still not completely elucidated. Additionally, physical exercise is also able to reduce the progression of the inflammatory signaling. In the present
study, we investigated the role of acute physical exercise in the gene expression and protein content of GPR120 in the hepatic tissue of lean mice. In addtion, we analyzed the protein content of
GPR120 in obese mice submitted to a physical exercise training protocol and a flax seed oil treatment, as well as their impact on the insulin signaling pathway and in the propagation of the
Methods: Swiss mice (4 weeks old) were submitted to an acute physical exercise session. After that, fragments of hepatic tissue were removed at time 0, 8, 16, 24 and 48 hours after
the session for analysis of gene expression and protein content of GPR120. On another study, the mice were feed by 8 weeks with standard or high fat diet. Subsequent to the development of obesity, a
part of these animals were submitted to an exercise training protocol or a treatment with flax seed oil for more four weeks. At the end of the experimental period, fragments of the hepatic tissue were
extracted to measure the activity and concentration of the proteins involved in pathways of omega-3, insulin, inflammation and, glycogen synthesis.
Results: The animals exposed to the acute physical exercise did not show increase in gene expression and protein content of GPR120 compared with the sedentary animals. Nevertheless,
mice exposed to the exercise training showed increase in protein expression of GPR120 compared with sedentary obese group. Moreover, the animals subjected to the exercise training presented increase
on insulin sensitivity when they were compared with HF group and decrease levels of some inflammatory proteins (IkB-a, JNK, TNF-a and IL-1B). Furthermore, the flax seed oil treatment was also able to
increase protein content of GPR120 and reduce the inflammatory process (JNK and TNF-a).
Conclusions: These results indicate that acute physical exercise is not able to modulate the gene expression and protein content of GPR120 in lean mice. However, the exercise training
and the flax seed oil treatment seem to be able to increase the protein content of GPR120 in obese animals. Moreover, the trained mice showed reduced the activity of proteins involved in the
inflammatory signal. Therefore, the possible role of physical exercise on the modulation of GPR120 can contribute to the development of new strategies against obesity.