Abstract
The influence of the diabetic state on the number and activity of intraperitoneal macrophages was investigated in the GK rat. This rat is a model of non-insulin-dependent diabetes mellitus and was established from the normal Wistar rat. The cell number of a macrophages preparation in diabetic GK rats (10-15 weeks of age) did not differ from that in normal Wistar rats (9-10 weeks of age). The co-cultured macrophages in diabetic GK rats (9-12 weeks of age) significantly increased the tube formation of aortic endothelial cells (EC) compared with that in age-matched Wistar rats. The conditioned medium obtained from a culture of macrophages from GK rats also increased tube formation more than that from a culture of macrophages from Wistar rats. The effect of macrophages in the GK rat was not influenced by interferon-γ (160 and 460pM), but macrophages in normal rats were activated by these concentrations of interferon-γ. In conclusion, the diabetic state increased the activity but not the number of macrophages in the GK rat, to stimulate tube formation of EC. The tube-forming effect of macrophages in the diabetic state may depend on released factors which differ from that of normal macrophages.
