The study will assess the serum expression of MMP-9 in normal people, type 2 diabetic patients and type 2 diabetic patients with atherosclerosis.

Inclusion Criteria:

• volunteer to participate and be able to sign informed consent prior to the trial.
• patients with type 2 diabetes, aged 18-60 years old, meeting WHO1999 diagnostic criteria, have not used any drugs.
• The patients have completed carotid ultrasound during hospitalization.

Exclusion Criteria:

• patients with any antidiabetic drugs.
• impaired liver and kidney function with ALT 2.5 times higher than the upper limit of normal value; Serum creatinine was 1.3 times higher than the upper limit of normal.
• drug abuse and alcohol dependence in the past 5 years.
• systemic hormone therapy was used in the last three months.
• patients with infection and stress within 4 weeks.
• any other obvious conditions or associated diseases determined by the researcher: such as severe cardiopulmonary diseases, endocrine diseases, neurological diseases, tumors and other diseases, other pancreatic diseases, history of mental diseases.

Normal control group, newly diagnosis of type 2 diabetes mellitus with atherosclerosis, newly diagnosis of type 2 diabetes mellitus without atherosclerosis