Dietary Glycine Prevents FOLFOX Chemotherapy-Induced Heart Injury: A Colorectal Cancer Liver Metastasis Treatment Model in Rats

Figures

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  Figure 1. Flowchart of the animal experiment. FOLFOX—chemotherapy regimen containing calcium folinate, oxaliplatin, and 5-fluorouracil; BW—body weight; CRLM—colorectal cancer liver metastasis; i.p. —intraperitoneally.

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  Figure 2. Glycine effect on HCM cell growth and proliferation by MTT (3-(4,5-dimethylthiazol-2-yl)5-diphenyltetrazolium bromide) assay. HCM cells viability after incubation with various concentrations of glycine measured by MTT assay and presented as the percentage of the controls.

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  Figure 3. Serum levels of heart fatty acid binding protein (h-FABP) on the last experimental day. h-FABP level measured on the last experimental day was different between the study groups. * p < 0.05. The Casein–FOLFOX group had a significantly higher h-FABP level compared to groups that had not received chemotherapy (Glycine–Control; Casein–Control; Glycine–Sham; Casein–Sham). Although, the difference between Casein–FOLFOX and Glycine–FOLFOX groups was not significant.

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  Figure 4. Left ventricle ejection fraction (LVEF) before and after chemotherapy in different diet groups. (A) Left ventricle ejection fraction (LVEF) before and after chemotherapy in the study groups; * p < 0.05. (B) Representative view from heart ultrasound. Left: Heart in parasternal short-axis view; Right: M-mode, left ventricular internal diameters.

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  Figure 5. Fibrosis index measured by chromotrope aniline blue staining. Representative pictures at 100× magnification of chromotrope aniline blue stain for fibrous tissue in the myocardium of animals treated with FOLFOX and glycine (A) and FOLFOX alone (B). The amount of fibrosis between the study groups was different (C). * The fibrosis index in the group treated with FOLFOX alone was significantly higher compared to that of all other study groups, p < 0.05.

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  Figure 6. The apoptotic index measured by immunohistochemistry with anti-Caspase 3 antibody. Representative pictures at 100× magnification of anti-Caspase 3 staining for fibrous tissue in the myocardium of animals treated with FOLFOX and glycine (A) and FOLFOX alone (B). The apoptotic cell rate was significantly higher in the FOLFOX-alone group compared to that in the group treated with FOLFOX with glycine, * p < 0.05 (C).

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  Figure 7. Transmission electron microscopy scans of heart samples. Representative pictures of hearts scanned by electron microscopy in (A) groups without FOLFOX (Casein–Sham, Glycine–Sham, Casein–Control, Glycine–Control) at magnification 7000×; (B) Casein–FOLFOX; and (C) Glycine–FOLFOX groups at magnification 12,000×. FOLFOX induced a significant increase of the collagen fibers in the heart muscle, and lysosomes within the endothelial cells were observed in the Casein–FOLFOX group. Glycine prevented FOLFOX-induced ultrastructural changes. MF—myofibrils; M—mitochondria; N—nucleus, L—lysosomes; Lec—lysosomes within endothelial cells; asterisk—lysosomes containing dark granules and other lipids; v—vessels; CF—collagen fibers.

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  Figure 8. Type I and II collagen and brain natriuretic peptide (BNP) gene expression in the heart muscle by qPCR. Type I collagen gene expression was significantly increased in FOLFOX groups (Casein–FOLFOX; Glycine–FOLFOX) compared to that in corresponding controls (Casein–Control; Glycine–Control), * p < 0.05. Although, there was no difference between Casein–FOLFOX and Glycine–FOLFOX groups (A). Type II collagen (B) and BNP (C) expression was not different between the study groups.