Abstract: Abstract Objective: To explore the dependability of matrix metalloproteinase-9 (MMP-9) gene -1562C/T and diabetic nephropathy (DN), and the relationship with different stage of DN. Methods: 150 type 2 diabetes (T2DM) patients were divided into DN group and diabetes without DN (NDN) group. DN group included microamount albuminuria, clinical alubuminuria and renal inadequacy stage. 52 healthy people were selected as normal control (NC) group. The genotypes were assessed by restriction fragment length polymorphism．Results: The average HbA1c、SBP、Cr、BUN、UAER of DN group were significantly higher than that of NDN or NC group (P<0.01).There was significant difference in frequencies of allele or genotype of polymorphismC/T between three groups (P<0.01). DN incidence rate in type 2 diabetics containing with genotype of CC, CT or TT respectively were decreased gradually. DN incidence rate containing with allele C and T were 59.2% and 40.5% respectively. The T allele carriers had 0.47 times risk for increased incidence of DN compared with that of C allele carriers (P<0.01，95%CI 0.29～0.75). The frequencies of TT genotype and T allele in three stages of DN decrease with renal hypofunction. Conclusion: The polymorphism of MMP-9 -1562C/T is associated with the development of DN, T allele is the protective gene of DN.

Key words: matrix metalloproteinase-9, gene polymorphism, diabetic nephropathy