Pressure and Diabetic Foot

Inclusion Criteria: * Age \>18 years * Type 2 diabetic subject * Absence of active diabetic foot ulcer * Patients "Grade 0", "Grade 1", "Grade 2" or "Grade 3" of the International Working Group on Diabetic Foot Risk Classification defined by: * absence of alteration of perception of Monofilament 10g at the level of the plantar arch for the "grade 0" * alteration of perception of Monofilament 10g at the level of the plantar arch for the "grade 1" * alteration of perception of Monofilament 10g at the level of the plantar arch associated with foot deformity and / or an arteriopathy defined by the absence of perception of one of the two peripheral pulses for the "grade 2" * History of diabetic foot ulcer for the "grade 3" * Signature of consent to participate in the study Exclusion Criteria: * Chronic alcoholism with usual consumption of at least 5 alcoholic drinks per day * Pregnancy * Congenital methemoglobinemia. * Porphyria * Skin injured on the tibia, whatever the lesion * Recent major cardiovascular history (less than 3 months) * Severe renal disease (serum creatinine\> 300 μmol.l-1)