Effects of microembolization on the skeletal muscle blood flow. A critique of the microvascular occlusion model of Duchenne dystrophy.

Muscle blood flow (MBF) during exercise was determined in both anterior tibial muscles of 12 rabbits by the local 133-Xe method before and after embolization of 20 to 80 mum dextran particles into the right femoral artery. With a relatively low dose of particles (dry weight: 8.7 mg), MBF was significantly decreased up to 4 days after each embolization, and mild histologic abnormalities were observed in the embolized muscles. A four-fold higher dose resulted in a marked and permanent decrease of the MBF, ischemic necrosis of the distal leg muscles and toe gangrene. In the light of these findings and the previously demonstrated normal MBF in Duchenne dystrophy, the validity of the assumption that Duchenne dystrophy is caused by small vessel occlusions is questioned.