Systemic administration of AAV9 and AAVB1 reduced glycogen storage in Gaa–/– mice. Periodic acid–Schiff staining of 1.5 μm sections of (A) the heart, (B) the diaphragm, (C) the tongue, and (D) the gastrocnemius muscle of Gaa–/– animals injected with PBS, AAV9, or AAVB1 and WT animals. Dark staining corresponds to glycogen accumulation in cells. Note the robust accumulation of glycogen in the heart, diaphragm, tongue, and gastrocnemius muscle of the PBS-treated Gaa–/– mice. In contrast, the cardiac muscle was almost completely cleared in animals treated with either AAV9 or AAVB1. The Gaa−/− animals treated with AAVB1 had almost complete clearance of glycogen in the tongue, unlike the AAV9 group where considerable amounts of glycogen remained. The diaphragm and gastrocnemius muscle had partial clearance, with complete clearance seen in many muscle fibers. Scale bar = 100 μm. Biochemical assessment of glycogen accumulation in (E) the heart, (F) the diaphragm, (G) the tongue, and (H) the gastrocnemius muscle of Gaa–/– animals injected with PBS, AAV9, or AAVB1 and WT animals. Data are represented as mean ± SEM. *p < 0.05.