Muscle atrophy and cachexia are associated with sepsis and several inflammatory diseases and increase risk of morbidity and mortality. Ghrelin is an anorexigenic hormone that has an anti-inflammatory effect, it decreases mortality in sepsis and is able to improve skeletal muscle wasting induced by cancer and chronic arthritis.

Aim: 

To study the role of ghrelin in proliferation and differentiation of skeletal muscle cells and to elucidate whether ghrelin could modify the endotoxin effect in skeletal muscle cells.

Methods: 

Ghrelin and endotoxin responses were tested in two different culture types of L6 cells: myoblasts and differentiated myotubes. Myogenin, myosin heavy chain and interleukin-6 gene expression were measured by real time PCR.

Results: 

Ghrelin increased myoblast proliferation after 72 and 96 hours (P<0.05). In myotubes, ghrelin increased the myogenic factor myogenin and myosin heavy chain mRNA (P<0.05). By contrast endotoxin increased interleukin-6 mRNA (P<0.01) and decreased myogenin (P<0.05) and myosin heavy chain mRNA (P<0.01). When added together, ghrelin was not able to prevent endotoxin effects on myotube cultures.

Conclusion: 

Ghrelin stimulates skeletal muscle cells proliferation and differentiation, but it is not able to prevent endotoxin-induced decrease of myogenin and myosin heavy chain gene expression in myotubes.

This work has been supported by a grant from Proyectos de investigación Santander/UCM (PR34/07-15880), a grant from Fundación de Investigación Médica Mutua Madrileña, by a fellowship from Gobierno Vasco to E Castillero (BFI06.31), and from Ministerio de Educación y Ciencia to M López-Menduiña (BES-2007-16001).