Figure 4. SOCE inhibitor reduces calpain activation in dystrophic fibers.

(A) Confocal images of FDB fibers from DMSO-injected mdx mice and BTP2 injected mdx mice at T₀ (addition of 50 µM fluorogenic, membrane-permeable peptide, Suc-LLVY-AMC) and T₁ (25 min later to allow for penetration of Suc-LLVY-AMC into FDB fiber and cleavage by cytosolic calpain) at excitation wavelength of 360 nm and emission wavelength of 460 nm. The lower transmission panel is to show that only healthy muscle fibers with clear striation pattern were chosen for the experiment; (B) Statistical analysis of changes in the fluorescence signals (ΔF) generated by Suc-LLVY-AMC cleavage in control mdx fiber (open bar) and BTP2-treated mdx fiber (hatched bar), n = 8 (BTP2) and 14 (DMSO), ^* P<0.05.