Different from high-dose STZ injection, which completely induces beta-cell impairment, low-dose STZ injection modestly injures beta-cells, in which the serum insulin is maintained at a medium level (Figure 1L), and T2DM is stable without an insulin intake requirement (46), that is suitable for studies on diabetic complications including neuropathy (29). This evidence concerns the gene INS and type 2 diabetes mellitus.