The Protective Effect of Adiponectin and other Inflammatory Cytokines Induced by Early Obesity in Rat Heart

Abstract

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.