Abstract
Bearing in mind that cancer cachexia is associated with chronic systemic inflammation
and that endurance training has been adopted as a nonpharmacological anti-inflammatory
strategy, we examined the effect of 8 weeks of moderate intensity exercise upon the
balance of anti- and pro-inflammatory cytokines in 2 different depots of white adipose
tissue in cachectic tumour-bearing (Walker-256 carcinosarcoma) rats. Animals were
assigned to a sedentary control (SC), sedentary tumour-bearing (ST), sedentary pair-fed
(SPF) or exercise control (EC), exercise tumour-bearing (ET), and exercise pair-fed
(EPF) group. Trained rats ran on a treadmill (60% VO2max) 60 min/day, 5 days/week, for 8 weeks. The retroperitoneal (RPAT) and mesenteric
(MEAT) adipose pads were excised and the mRNA (RT-PCR) and protein (ELISA) expression
of IL-1β, IL-6, TNF-α, and IL-10 were evaluated. The number of infiltrating monocytes
in the adipose tissue was increased in cachectic rats. TNF-α mRNA in MEAT was increased
in the cachectic animals (p<0.05) in relation to SC. RPAT protein expression of all
studied cytokines was increased in cachectic animals in relation to SC and SPF (p<0.05).
In this pad, IL-10/TNF-α ratio was reduced in the cachectic animals in comparison
with SC (p<0.05) indicating inflammation. Exercise training improved IL-10/TNF-α ratio
and induced a reduction of the infiltrating monocytes both in MEAT and RPAT (p<0.05),
when compared with ST. We conclude that cachexia is associated with inflammation of
white adipose tissue and that exercise training prevents this effect in the MEAT,
and partially in RPAT.
Key words
cancer-cachexia - adipose tissue - cytokines - exercise training - inflammation
