MMP2 and chronic kidney disease: To explore the possible mechanisms of aging in renal function, the FL-MMP-2 and NTT-MMP-2 were examined in two mouse models of chronic kidney disease, the streptozotocin-induced model of type 1 diabetes mellitus, and the 5/6 nephrectomy model of chronic kidney disease in mice aged 8 weeks (young mice) or 14 months (old mice).