TNF and diabetes mellitus: Furthermore, spinal cord immunostaining confirmed that the immunostaining density of TNF-α and CXCR4 in the diabetic group did not significantly differ from that in the control group at 2 weeks of diabetes (Figures 4(a) and 4(b)), while the spinal cord immunostaining density of TNF-α and CXCR4 at 5 weeks of diabetes was significantly higher than that in the control group (Figures 5(a) and 5(b), P < 0.05).