MMP9 and diabetes mellitus: The aims of this study were (1) to compare the expression of MMP-2, MMP-9 and TIMP-1/2 in the peripheral nerve of control rats and rats with streptozotocin (STZ)-induced diabetes; (2) to assess the effects of minocycline on indices of experimental diabetic neuropathy and regulation of MMPs in the peripheral nerve; and (3) to investigate the effect of MMP-2 and minocycline on in vitro sensory neuron growth.