Figure 1. The representative histopathological images of heart from control and db/db mice at the age of 16 weeks.

The image of ventricular cross-sections from control (A) and db/db mice (A′) and graph bars (A″) illustrating quantitatively the surface of ventricular cavities (1) and total ventricular surface (2). Sirius red staining shows low collagen deposit (red colour) in the sections of heart of control mice (B and C) and abundant collagen in the sections from heart of db/db (B′ and C′). Quantitative analysis of collagen deposits calculated under double refraction allowing specific separation of collagen fluorescence in black background indicates significant elevation of cardiac collagen deposits in db/db vs. control mice (B″). HE (haematoxylin–eosin) staining shows that in comparison to control mice (D), the cardiomyocyte (CM) surface is elevated in db/db mice (D′). Caspase−3 immunocytochemistry (E) and Tunel analysis (F) of apoptotic nuclei in cardiac sections revealed low number or the absence of positive nuclei in sections from control mice, and the presence of apoptotic nuclei in cardiac sections from db/db mice (E′ and F′, respectively). *P < 0.05; scale bars, 50 μm.