Figure 1.
Muscle membrane integrity improvement in TO-2 skeletal and cardiac muscles via systemic delivery of AAV8-MG53.(a) Immunofluorescent (IF) staining of myc-tagged-MG53 expression in muscles of neonatally treated TO-2 hamsters at vector dose of 1 × 1013 vg/kg. Samples were collected 2 months later. Age-matched untreated TO-2 served as controls (n = 5 per group; bar = 100 µm). (b) The same as in (a) except that a vector dose of 2 × 1013 vg/kg was delivered in 2-month-old TO-2 hamsters. Samples were collected at 2 months after injection (n = 5 per group; bar = 100 µm). (c) Western analysis of myc-tagged-MG53 in muscle and nonmuscle tissues in both neonate-treated and adult-treated TO-2 hamsters. Samples collected were same as described in (a) and (b). Muscles included tibialis anterior (TA), gastrocnemius (GAS), triceps (TRI), quadriceps (QD), heart, diaphragm (DIA), abdominal muscle (ABD), masseter (MA), and intercostal muscle (ITM). Nonmuscle tissues included liver, pancreas (PAN), kidney, and lung. (d) Improvement in muscle membrane integrity as revealed by exclusion of Evan blue dye (red fluorescence) in muscle and heart at 2 month after neonatal injection (1 × 1013 vg/kg). (e) Reduction of serum CK levels after delivery of AAV8-MG53 in newborn hamsters. Low dose: 1 × 1013 vg/kg; high dose: 1 × 1014 vg/kg. *P < 0.05 versus the untreated TO-2. (f) Reduction of serum CK level after delivery of AAV8-MG53 (2 × 1013 vg/kg) in adult hamsters. *P < 0.05 versus the untreated TO-2. (g) Time-course of FM1-43 accumulation at injury sites of the isolated single myofibers following UV-laser induced membrane damage in the presence of 2 mmol/l Ca2+ in solution. Values represent mean ± SD. P < 0.01 when AAV-MG53 treated (1 × 1013 vg/kg) versus the untreated TO-2 myofibers. (h) The same as in (g) except the absence of extracellular Ca2+ (plus 0.5 mmol/l EGTA). Values represent mean ± SD. AAV, adeno-associated virus.