Human Umbilical Cord Mesenchymal Stem Cell Infusion for Type 2 Diabetic Nephropathy

Inclusion Criteria: * Aged 18 to 80 years, with no gender and ethnicity restrictions. * Patients who meet the diagnostic criteria for type 2 diabetes mellitus (T2DM) as defined by the Chinese Guideline for the Prevention and Treatment of Type 2 Diabetes Mellitus (2020 Edition), with: 1. Baseline serum C-peptide concentrations ranging from 0.3 to 3.0 ng/mL; 2. Stable antihyperglycemic and antihypertensive medication regimen for at least 3 months prior to screening, defined as dosage adjustment less than 25%. * Urinary albumin-to-creatinine ratio (UACR) ≥ 30 and ≤ 5000 mg/g together with estimated glomerular filtration rate (eGFR) ≥ 30 and \< 90 mL/min/1.73 m². * Patients are required to have renal biopsy-proven DN glomerulopathy with Tervaert Class IIa to Class III glomerular lesions. * Patients voluntarily agree to participate and provide written informed consent after full disclosure of the study's purpose, procedures, nature, and potential adverse reactions. Exclusion Criteria: * Other non-T2DM, such as type 1 diabetes. * Individuals allergic to MSCs or their preservation solution. * Individuals with any of the following conditions during screening: 1. History of acute diabetic complications within the past 6 months, including diabetic ketoacidosis, hyperglycemic hyperosmolar state, or lactic acidosis; 2. Unstable disease status or severe diabetic complications within the past 6 months, such as proliferative diabetic retinopathy or macular edema, severe diabetic neuropathy, intermittent claudication, active diabetic foot lesions; 3. History of three or more Level 3 hypoglycemic events within the past 6 months, as defined by the Guidelines for the Management of Type 2 Diabetes in China (2020 Edition); 4. History of any of the following cardiac conditions within the past 6 months: decompensated heart failure (New York Heart Association Class III-IV); unstable angina, myocardial infarction, coronary artery bypass grafting, or coronary stent implantation; severe arrhythmias requiring treatment, including second-degree or third-degree atrioventricular block, long QT syndrome, or QTc interval prolongation ≥ 500 ms, and deemed by the investigator to render the subject unsuitable for study participation; 5. History of hemorrhagic or ischemic stroke within the past 6 months deemed by the investigator to render the subject unsuitable for study participation; 6. History of other severe endocrine disorders affecting glucose metabolism, such as multiple endocrine neoplasia, acromegaly, and Cushing's syndrome, deemed by the investigator to render the subject unsuitable for study participation; 7. History of severe digestive system diseases, nutritional and metabolic disorders, or rheumatologic diseases, deemed by the investigator to render the subject unsuitable for study participation; 8. Concurrent malignancy or history of malignancy (except malignancies with at least 5 years of disease-free survival); 9. Severe psychiatric disorder or speech impairment, or the subject is unwilling or unable to fully understand and comply with study requirements; 10. Severe infection or major surgery within the past 6 months, deemed by the investigator to render the subject unsuitable for study participation; 11. Acquired Immunodeficiency Syndrome, active hepatitis B, hepatitis C infection, or other acute or chronic infectious diseases; 12. Poorly controlled blood pressure, defined as a systolic blood pressure \> 180mmHg and/or diastolic blood pressure \> 110mmHg. * Laboratory test results meet the following criteria: 1. Alanine aminotransferase or aspartate aminotransferase ≥ 2.5 times the upper limit of normal (ULN); 2. Total bilirubin ≥ 2.0 times ULN; 3. Currently suffering from severe renal disease, or eGFR (CKD-EPI2012Scr-CysC) \< 30 mL/min/1.73 m²; 4. Fasting triglycerides \> 5.6 mmol/L; 5. Serum amylase or serum lipase ≥ 1.5 times ULN; 6. Hemoglobin \< 10.0 g/dL (100 g/L), serum albumin \< 30 g/L; 7. Glycosylated hemoglobin ≥ 10%. * History of long-term systemic corticosteroid administration (consecutive or cumulative ≥ 7 days) within 1 month prior to screening (including but not limited to intravenous administration, oral administration, or intramuscular injection). * Renal replacement therapy within 3 months prior to screening, current ongoing, or planned initiation within the next 3 months (including hemodialysis, peritoneal dialysis, continuous renal replacement therapy). * Participation in other drug or device clinical trials within 3 months prior to screening. * Previous use of other stem cell treatments. * Use of immunosuppressants, tripterygium glycosides, eplerenone, spironolactone, or similar agents within 3 months prior to screening. * Pregnancy, lactation, or intention to become pregnant during the study period. * Any other condition that, in the investigator's judgment, would make the subject unsuitable for the study. * Renal biopsy revealing DN with coexisting non-DN pathology.