Resistin overexpression exacerbates TAC-induced hypertrophy, cardiac dysfunction, and cardiac fibrosis in RKO mice. (A) Study protocol for Retn overexpression via AAV9 in TAC-induced RKO mice. (B) Analysis of heart weights (HW)/body weight (BW) and HW/tibia length ratios in AAV9-empty or AAV9-mRetn RKO mice subjected to TAC for 7 weeks (n = 6–11). (C) Western blot quantification and mRNA heart expression of Retn in AAV9-mRetn vs. AAV9-empty controls (n = 4–5). Protein levels were normalized to GAPDH, a loading control; mRNA levels were normalized to 18S. (D) Real-time PCR analysis of the expression levels of Anf, Myh7, Myh6, and Acta1 (n = 5). (E) Representative echocardiographic images and quantification of fractional shortening (FS%) and the left ventricular internal diameters in systole (LVIDs) of AAV9-empty or AAV9-mRetn RKO mice subjected to TAC for 7 weeks (n = 5). (F) Assessment of the load-independent parameter end-systolic pressure–volume relationship (ESPVR) by pressure–volume conductance catheters (n = 5). (G) Survival curve of AAV9-empty or AAV9-mRetn RKO mice subjected to TAC for 7 weeks (n = 6–22). (H) Representative images of Masson’s trichrome-stained hearts sections and myocardial fibrosis quantification as percentage of blue-stained area (fibrotic) vs. control (scale bar, 100 µm, n = 3). (I) Real-time PCR analysis of the expression levels of fibrosis-related factors: Col1a1, FN, CCN2, and LOX (n = 5). N, each animal is shown as an individual point whereas horizontal lines represent median values. Values are shown as mean ± S.E.M. with each experiment performed in biological and technical replicates as indicated. Significance was evaluated by Student’s t-test. P values <0.05 were considered significant.