Attenuated Phagocytic Activity of Monocytes in Type 2 Diabetic Goto-Kakizaki Rats

The aim of this study was to determine whether phagocytic activity of leukocytes is altered in type 2 diabetes. Goto-Kakizaki (G-K) rats, a genetic model for type 2 diabetes, and Wistar rats (control) were used to analyze the immunological status of phagocytes. Direct analysis of phagocytes was performed using peripheral whole blood. Phagocytic activity of monocytes induced by Escherichia coli BioParticles was significantly lower in G-K rats than in the control rats, whereas no significant differences in phagocytic activity of granulocytes and lymphocytes were found between G-K and control rats. Monocytes of G-K rats showed significantly lower CD11b/c expression compared with that in monocytes of control rats. However, lipopolysaccharide-stimulated activation of extracellular signal-regulated kinase and nuclear factor-κB in monocytes was not significantly different between G-K and control rats. Restriction of diet in G-K rats greatly improved their hyperglycemic status, but did not restore the levels of phagocytic activity and CD11b/c expression in monocytes of G-K rats to the levels observed in control rats. The results suggest that the phagocytic activity of monocytes is attenuated in G-K rats and that this attenuation is independent of blood glucose levels and is partly explained by a decrease in CD11b/c expression in G-K rats.