On the interpretation of second harmonic generation intensity profiles of striated muscle

摘要: Recently, a supramolecular model was developed for predicting striated skeletal muscle intensity profiles obtained by label-free second harmonic generation (SHG) microscopy. This allows quanti- tative determination of the length thick filament antiparallel range or M-band (M), and results in M ¼ 0.12 μm single-band when fixing A-band (A )t oA 1.6 μm, value origi- nating from electron microscopy (EM) observations. Using simulations experimental data sets, we showed that objective numerical aperture (NA) refractive index (RI) mismatch (Δn n2ω − nω) between illumination wave (ω) (2ω) severely affect simulated sarcomere profiles. Therefore, our recovered lengths did not match with those observed EM. For an RI Δn 0.02 moderate NA 0.8, analysis SHG freely adjustable A- sizes yielded A 1.40 � 0.04 0.07 0.05 muscle. These lower than expected values were rationalized terms myosin density distribution along axis. Our provided new practical insights application to study © 2015 Society Photo-Optical Instrumentation Engineers (SPIE)