Background: Duchenne muscular dystrophy (DMD) is an X chromosome recessive hereditary disease and mainly characterized by progressive muscle weakness and atrophy. Glucocorticoid is the only proven effective medicine,while side effects limit its use. Recent studies have shown that the vascular density in the DMD patients' muscle is decreased,so muscle are in ischemic and anoxic. Remote ischemic preconditioning(RIPC) can improve the capable of resistanting ischemia and hypoxia and maybe a potential therapy for DMD patients.

Methods: 100 patients (aged 2 to 6 years)will be divided into two groups(treatment and control groups) randomly. Treatment group will receive an RIPC stimulus (inflation of a blood pressure cuff on the bilateral thighs to 150 mm Hg for four 5-minute intervals) while control group will receive a similar stimulus (inflation of a blood pressure cuff on the bilateral thighs to 40 mm Hg for four 5-minute intervals). Serum kinase level ,Blood levels of myoglobin, Evaluation of motor function(Four steps test;6-minute walking test) and MRI of lower limbs）at 0 days, 3 days, 3months ,6months.

Purpose：

1. To evaluate the safety and tolerability of remote ischemic preconditioning for DMD patients
2. To identify the effectiveness of remote ischemic preconditioning for DMD patients.

Inclusion Criteria:Genetic analysis of DMD; from 2 to 6 years old ;without other diseases .

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Exclusion Criteria: other congenital diseases;upper respiratory infection, gastroenteritis, vaccination, trauma.

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