P054 Effects of leucine-rich diet on inflammatory response induced by tumour growth in young, adults and senile rats

Abstract

Introduction The anorexia–cachexia syndrome is caused by metabolic changes; in particular, induced by cytokines released by tumour cells or in response to the host’s immune system. These cytokines also promote lipolysis and proteolysis. Methods We examined the effect of leucine-rich diet on the inflammatory response in young (21 days old), adults (90 days old) and senile (400 days old) Walker 256 tumour-bearing rats. Wistar rats were submitted to eutrophic diet or leucine-rich diet and distributed into 7 groups: C – control rats; YW – young tumour-bearing; AW – adult tumour-bearing; SW – senile tumour-bearing; YWL – young tumour-bearing fed leucine diet; AWL – adult tumour-bearing fed leucine diet; SWL – senile tumour-bearing fed leucine diet. Results The tumour development induced an increase in proinflammatory cytokines. The serum tumour necrosis factor (TNF-α) content was higher in the young tumour-bearing fed leucine diet (YWL) compared to control group C and to the other groups. Another proinflammatory cytokine, interferon-γ (INF-γ) increased in the young tumour-bearing fed a leucine-rich diet group YWL vs control group C; the other groups showed similar values as the control group. The interleukin 4 (IL-4), cytokine related to defence host response showed an increase in young and senile groups compared to group C. The serum concentration of interleukin-6 (IL-6), a pro-inflammatory cytokine, increased in group YW, YWL, AWL; and SWL in relation to control group. The concentration of interleukin-1α (IL-1α), another pro-inflammatory cytokine, increased in group YW in comparison to control and the other tumour-bearing groups. The anti-inflammatory cytokine, IL-10, increased in all groups with tumour YW (728 + 122 pg/mL); YWL (1684 + 339); AW (1016 + 61); AWL (775 + 140), SW (1414 + 178) and SWL (1445 + 642) vs C (313 + 91). The tumour/body weight ratio was lower in the young tumour-bearing groups versus senile tumour-bearing groups. The serum glucose and protein content reduced in young tumour-bearing groups compared senile tumour-bearing groups. Conclusion Although the tumour growth in young rats induced chronic inflammation increasing the proinflammatory cytokines release, which occur in the development of cachexia; in senile tumour-bearing groups these effects are decreased possibly due to a reduced metabolism. Supported by PIBIC/CNPq and FAPESP #2010/11328-9; # 2010/00260-4.