Gross pathology of heart and plantaris muscles from HIV-1 transgenic rats. (A) Relative heart masses from HIV-1 transgenic rats were increased compared to controls. In addition to this cardiac tissue defect, several skeletal muscles from HIV-1 transgenic rats were atrophied, including gastrocnemius (gastroc), soleus, and plantaris. (B) Specifically, the cross-sectional areas (CSA) of total and myosin heavy chain (MHC) isoform type-specific (i.e., slow, hybrid or fast MHC isoforms) from plantaris fibers were reduced in HIV-1 transgenic rats. Data in panel A represented as milligram of tissue weight divided by body mass in grams. Bar in panel B = 100 μm. *, p ≤ 0.05 vs. control.