1. Study population:It is applicable to male participants with genetically confirmed and clinically confirmed Duchenne muscular dystrophy (DMD), aged between 6 and 10 years. 2. Research period:The main research period of this clinical study is one year. Participants were tested during the baseline period and were followed up on days 0, 7, 14, 21, 60, 120, 200, and 360. 3. Exploratory indicators：MR Of both thighs, quantitatively calculating the muscle fat replacement indicators of the buttocks and proximal thighs；Patient Self-Rating Scale, Caregiver Self-Rating Scale. 4. Safety assessment：The safety assessment population will include all participants who have received the drug dose and have at least one post-drug safety assessment. Adverse events (AE) collected from the participants signed informed consent, all the way to the main study period at the end of the last follow-up. Safety laboratory evaluation, laboratory safety monitoring, including hematology, blood biochemistry, urine analysis (including troponin I, CK and CK - MB) and blood coagulation function, as well as complement. All common medication will be recorded. All adverse events, including abnormal complete blood cell count results, will be continuously tracked until they are resolved or stabilized. Only treatment-related adverse events (TEAE) will be summarized. AEs will be based on MedDRA and organ systems are recorded and archived. The classification and terminology related to AEs will be described according to the version of CTCAE v6.0.
Participant age: 6-10 years old (including 10 years old).
Gender: male.
Gene diagnosis of DMD gene type, conform to the DMD phenotypes and clinical manifestations.
There has been a muscle weakness, symptoms of motor function decline.
The participants are in active virus infection or other pathogen infection, including but not limited to, the TORCH virus, Epstein - Barr virus, the new crown virus, bacteria, fungi, etc.
Having received a live attenuated vaccine or systemic antiviral, anti-infective and/or interferon therapy within 3 months prior to the treatment with investigational product.
Serological tests revealed infections of HIV, HBV, HCV and syphilis.
Severe infections (such as pneumonia, pyelonephritis or meningitis) occurred within 8 weeks before the start of treatment with investigational product.