Figure 3.

Representative immunohistochemical stainings of Ca²⁺ handling proteins in DM. In DAB immunohistochemistry (a–k, m, n, p, q), the specific signal is dark brown, and the background staining (H&E) is blue. In the upper panel, in control both RYR1 (b) and DHPR (c) are slightly more intensely expressed in fast fibres, when compared to MyHC-II (a) (detecting fast fibres). Reduction of RYR1 immunoreactivity in DM2 (e), and reduction of both RYR1 and DHPR in DM1 (h, i) is evident. In the lower panel, normal SERCA1 staining, similar to control (j) is seen in both DM2 (m) and DM1 (p). Reduction of JPH1 is seen in DM1 (q), but not in DM2 (n). The last panel with immunofluorescent staining shows drastic reduction of CASQ2 (green) in DM2 (o), and a less extensive reduction in DM1 (r) compared to healthy control (l). (a–c, j, k) N_??_VL_03; (L) N_M40_G_004; (d–f, m–o) DM2_M38_VL_001; (g, h, p) DM1_M48_TA_004; (i) DM1_M55_TA_010; (q) DM1_M48_VL_005; (r) DM1_M46_TA_001