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Acta Physiologica 2012; Volume 206, Supplement 693
Joint FEPS and Spanish Physiological Society Scientific Congress 2012
9/8/2012-9/11/2012
Santiago de Compostela, Spain
MSH TREATMENT HAS AN ANTI-INFLAMMATORY EFFECT AND AMELIORATES ARTHRITIS-INDUCED MUSCLE ATROPHY
Abstract number: P143
Gomez-San Miguel1 A, Martin-Velasco1 A, Gomez-Moreira1 C, Nieto-Bona2 P, Fernandez-Galaz3 C, Gros4 A, Lopez-Menduina4 M, Villanua-Bernues4 M, Lopez-Calderon4 A
1Department of Physiology, Faculty of Medicine, Complutense University of Madrid. 28040 Madrid, Spain,
2Department of Histology, Faculty of Health Sciences, Rey Juan Carlos University. Av. de Atenas s/n, 28922 Alcorcn, Madrid, Spain,
3Department of Physiology, Faculty of Medicine, Complutense University of Madrid. 28040 Madrid, Spain.,
4Department of Physiology, Faculty of Medicine, Complutense University of Madrid. 28040 Madrid, Spain
Objectives:
Adjuvant-induced arthritis is an inflammatory illness that induces muscle wasting due to an increased expression of the ubiquitin ligases atrogin-1 and MuRF-1.Melanocyte stimulating hormone(MSH) regulates a variety of physiological functions including inflammation.The aim of this work was to elucidate whether MSH is able to prevent arthritis-induced muscle atrophy.
Materials:
Arthritis was induced in rats by an intradermal injection of Freund's adjuvant.Eight days after adjuvant injection,control and arthritic rats were treated with 50 ug MSH sc twice a day(at 9:00 h and 17:00 h) or with 250 ul of saline.A pair-fed group injected with saline was also included.Rats were sacrificed 16 days after adjuvant injection.Gastrocnemius COX-2 and Murf-1 proteins were measured by western-blotting; atrogin-1 and MuRF1 mRNA were measured by RT-PCR.Mean cross-sectional area of gastrocnemius fast fibers was determined by immunohistochemistry.
Results:
MSH treatment decreased the external signs of arthritis (P<0.05). Arthritis increased COX-2 expression in the gastrocnemius (P<0.01),whereas MSH administration reverted the effect of arthritis on COX-2 levels.MuRF1 and atrogin-1 expression in the gastrocnemius were higher in arthritic rats than in controls rats (P<0.01).MSH administration prevented the stimulatory effect of arthritis on MuRF1 expression in muscle.In arthritic rats, MSH treatment decreased atrogin-1 mRNA (P<0.01),but to higher levels than those of control or pair-fed rats (P<0.05).Pair feed rats had similar gastrocnemius COX-2, MuRF1 and atrogin-1 levels than control rats.Arthritis decreased mean fiber area of the gastrocnemius (P<0.01).Pair-fed rats had lower mean fiber area than control rats (P<0.05), but higher than arthritic rats (P<0.01).MSH treatment to arthritic rats increased gastrocnemius mean fiber area (P<0.05).
Conclusions:
These results suggest that peripheral MSH treatment to arthritic rats,in addition to its anti-inflammatory effect,attenuates muscle wasting by decreasing atrogin-1 and MuRF1 expression.
To cite this abstract, please use the following information:
Acta Physiologica 2012; Volume 206, Supplement 693 :P143