Objective: Obesity is linked to inflammatory processes and an imbalance in proand anti-inflammatory cytokines. A previous study revealed that early obesity causes increased cellular turnover and compensatory up-regulation of AT2 receptors in the rat heart. We surveyed the effect of early obesity on the imbalance of inflammatory cytokines according to changes in cellular components.
Material and Methods: Early obesity was induced by overfeeding rat pups for 28 days. The normal litter (NL) had 10 male pups and the small litter (SL) had 3 male pups per dam. We measured body weight, serum glucose, and Masson trichrome (MT) stain. Western blotting to detect inflammatory cytokines was performed using antibodies against metalloproteinase 9 (MMP-9), tissue inhibitor of MMPs type 1 (TIMP-1) and adipokines, including adiponectin, plasminogen activator inhibitor 1 (PAI-1), and tissue necrosis factor-α (TNF-α), and monocyte chemotactic protein 1 (MCP-1) and an anti-CD68 antibody of tissue macrophages (ED-1).
Results: Body weight and heart weight were significantly increased, but relative heart weight (heart weight / body weight) was significantly decreased in the SL (P < 0.001*). Both collagen and glucose in the SL were increased, but these increases were not statistically significant. Protein expression of MMP-9 (P < 0.001*), PAI-1 (P < 0.001*), and adiponectin (P = 0.009) was increased, but changes in TIMP-1, TNF-α, ED-1, and MCP-1 were not significant in the SL. (all data are 95% confidence interval)
Conclusions: Early obesity induces increases in collagen and inflammatory cytokines. However, the anti-inflammatory effects of adiponectin protect the heart in early obesity and those effects of adiponectin should be investigated.
Kee Hwan Yoo, Jo Won Jung, Hyung Eun Yim, Gi Young Jang, In Sun Bae, Jung Hwa Lee, Kee Soo Ha, Young Sook Hong and Joo Won Lee