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This Article Full Text Full Text (PDF) All Versions of this Article: 297/5/R1322    most recent 00388.2009v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Castillero, E. Articles by López-Calderón, A. PubMed PubMed Citation Articles by Castillero, E. Articles by López-Calderón, A.

Articles

Eicosapentaenoic acid attenuates arthritis-induced muscle wasting acting on atrogin-1 and on myogenic regulatory factors

Department of Physiology, Faculty of Medicine, Complutense University of Madrid, Madrid, Spain

Submitted July 6, 2009 ; accepted in final form August 27, 2009

Eicosapentaenoic acid (EPA) is an omega-3 polyunsaturated fatty acid that has anti-inflammatory and anticachectic actions. The aim of this work was to elucidate whether EPA administration is able to prevent an arthritis-induced decrease in body weight and muscle wasting in rats. Arthritis was induced by intradermal injection of Freund's adjuvant; 3 days later, nine rats received 1 g/kg EPA or coconut oil daily. All rats were killed 15 days after adjuvant injection. EPA administration decreased the external signs of arthritis and paw volume as well as liver TNF- mRNA. EPA did not modify arthritis-induced decrease in food intake or body weight gain. However, EPA treatment prevented arthritis-induced increase in muscle TNF- and atrogin-1, whereas it attenuated the decrease in gastrocnemius weight and the increase in MuRF1 mRNA. Arthritis not only decreased myogenic regulatory factors but also increased PCNA, MyoD, and myogenin mRNA in the gastrocnemius. Western blot analysis showed that changes in protein content followed the pattern seen with mRNA. In the control rats, EPA administration increased PCNA and MyoD mRNA and protein. In arthritic rats, EPA did not modify the stimulatory effect of arthritis on these myogenic regulatory factors. The results suggest that in experimental arthritis, in addition to its anti-inflammatory effect, EPA treatment attenuates muscle wasting by decreasing atrogin-1 and MuRF1 gene expression and increasing the transcription factors that regulate myogenesis.

adjuvant-induced arthritis; ubiquitin-proteasome system; MyoD; myogenin; proliferating cell nuclear antigen