Figure 6. Lack of inflammation and neuronal sensitization in the colon of DIO mice fed for 4 weeks.

DIO mice fed for 4 weeks had normal mucosal thickness (A), normal expression of epithelial proinflammatory cytokines (B) and normal macrophage density (C). The expression levels of leptin, interleukin-6 (IL-6) and monocyte chemoattractant protein 1 (MCP1) in different fat tissues were increased (D, E); however, the fold increase was less than after 12 weeks of feeding (compare with Fig. 1F and G). The number of myenteric neurones responding to nicotine (F) or 2-methyl-5-hydroxytryptamine (2-methyl-5-HT) (G), as well as the spike discharge, did not differ between ND and DIO mice fed for 4 weeks (nicotine: eight DIO mice, 28 ganglia, 80 neurones and eight ND mice, 27 ganglia, 78 neurones; 2-methyl-5-HT: seven DIO mice, 29 ganglia, 63 neurones and seven ND mice, 19 ganglia, 53 neurones). Numbers in parentheses indicate number of animals. Asterisks mark significant changes, see text for P values. AP, action potential; DIO, diet-induced obese mice; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; IEC, isolated epithelial cell; IP-10. interferon-inducible protein-10; ND, mice receiving normal diet; SAA3, serum amyloid A 3; TNF, tumour necrosis factor.