Characterization of HSPB7 CKO mouse.

(A) Immunoblot analysis for HSPB7 protein expression levels in control (Flox/Flox) and CKO animals 4 days (d4) and 7 days (d7) after tamoxifen administration. The GAPDH signal shows the loading of samples between lanes. (B) Quantitative analysis for immunoblot analysis of HSPB7 expression protein levels in cardiac tissue from control and CKO mice. Seven days after the first tamoxifen administration, HSPB7 protein expression dropped to less than 10% in CKO animals, as determined by immunoblot blot (HSPB7 compared with GAPDH). Data are presented as means ± SD. (C) Double staining of the left ventricle section with HSPB7 and Hoechst 33342 in the control and CKO hearts at d7 after tamoxifen administration. HSPB7 was no longer present at the intercalated disc and sarcomere. Scale bar: 20 μm (D) Significant increase in heart weight in HSPB7 CKO mice (n = 8; *p = 0.00027). (E) Kaplan–Meier survival curve of HSPB7 CKO and control mice. (F) Representative whole mounts (left), Masson’s trichrome (middle left and right), and hematoxylin-eosin–stained (right) transverse sections of control and CKO mouse hearts. Histological analysis showed inflammatory infiltration in the myocardium, identified as mostly lymphocytes and plasma cells, in HSPB7 CKO hearts at d7 after tamoxifen administration. In addition, Masson’s trichrome staining showed no significant collagen deposition in HSPB7 CKO hearts, as compared to control mice.