Table 5.
Cardiac ultrastructure metabolic-induced cardiac perturbations.
| Models of diabetes and responses to high fat diet (HFD) | Ultrastructural changes | Quantitative TEM | References |
|---|---|---|---|
| Rats 4 and 8 months after STZ (60 mg/kg)-induced diabetes | No changes noted for sarcomere lengths, basal laminar membrane thickness, papillary muscle and ventricular muscle for myofibrils, z-lines, and mitochondrial appearances | Sarcomere lengths quantified to be ~2 μm for both ventricle and papillary muscle at 4 or 8 months after STZ | Howarth et al., 2000 |
| Rats 7 weeks after STZ (65 mg/kg)-induced diabetes (7 weeks) and the effect of exercise (starts 2 weeks before STZ until end of study) examined | ↑ Damaged mitochondria, myofibrillar dysregulation, nuclear envelope changes, and lipid deposition 7 weeks after STZ | Grading: 1, fully intact; 2, <50% disruption of inner mito membranes; 3, >50% disruption of inner membranes; 4, disruption of the outer membrane only; 5, disruption of both inner and outer membranes ↓ %Mito/intracellular area from 45% to 38%, ↑ collagen fiber cross-section area 35–42 × 10−4 mm2, by sedentary diabetic but not exercised diabetic. ↑ % cytoplasmic area (14%−20% or 18%), ↑ Area of lipid droplets (LD)/μm2 2%−9% by both sedentary diabetic and exercised diabetic |
Searls et al., 2004 |
| Rabbit (24 prepubertal New Zealand white) with HFD 3 months | ↑ LD, the presence of swollen, cristae damaged mitochondria, disorganized myofibril and sarcomeric structure, and damaged gap junctional regions, in both sexes | No | Sibouakaz et al., 2018 |
| Wild-type (WT), atg7f/f:αMHC-cre, or Parkin KO mice | HFD for 2 months produced bigger LD in the heart of Atg7f/f:αMHC-cre, or Parkin KO mice, compared to WT | 0.3 μm in WT, 1.0 μm in Atg7f/f:αMHC-cre, and 0.7 μm in Parkin KO mice | Tong et al., 2019 |
| Rat late exercise preconditioning (LEP), exhaustive exercise (EE), and the use of wortmannin i.p. (W) | Changes in cardiac mitochondrial morphology and myofibrillar structure, and cardiac ischemia and troponin I in plasma, have been shown with different exercise groups and with wortmannin | No | Yuan and Pan, 2018 |
Highlighted in bold are the subcellular structures observed by TEM.