Abnormal skeletal muscle and myocardial vasoreactivity manifests prior to heart failure in a diabetic cardiomyopathy rat model

Figures

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  Fig. 1. Representative cardiac T1 maps during different intervals of normoxia-hypercapnia-recovery normoxia gas stimuli in control and diabetic rats of both sexes. Young male (A) and female (B) control and diabetic rats at 1 month post-diabetes induction are shown. Black arrows highlight signal changes in the septum

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  Fig. 2. T1 measurements (ms) during different intervals of normoxia-hypercapnia-recovery normoxia gas stimuli in the myocardium of all male control and diabetic rats. T1 measurements were averaged over the septum, anterior wall, and posterior wall for each animal at each time point [n = 3–5 male control (top) and n = 4–5 male diabetic (bottom)]

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  Fig. 3. T1 measurements (ms) during different intervals of normoxia-hypercapnia-recovery normoxia gas stimuli in the myocardium of all female control and diabetic rats. T1 measurements were averaged over the septum, anterior wall, and posterior wall for each animal at each time point [n = 5 female control (top) and n = 5 female diabetic (bottom)]. Significance is indicated relative to the start of each 10-min challenge (** p < 0.01)

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  Fig. 4. Cardiac gas challenge and corresponding percent change (%) in T1 relaxation time (ms) for all rats. Percent T1 changes are calculated relative to the previous gas challenge, with significance indicated (* p < 0.05, ** p < 0.01). Data represented as mean ± SEM

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  Fig. 5. Representative skeletal muscle T1-weighted spoiled-gradient echo images during different intervals of normoxia-hypercapnia-recovery normoxia gas stimuli in a young male control rat. Images depict the leg muscle pre-contrast injection (A), post-contrast injection after 10 min on normocapnic-normoxia (B), after 10 min on 5% CO2 (C), and after 6 min on recovery normocapnic-normoxia (D). Dotted red line represents the region of interest where measurements were collected

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  Fig. 6. MRI analysis in skeletal leg muscle for the partial derivative of T1 with respect to time in male control (n = 3–4) and diabetic (n = 4–5) rats during different intervals of normoxia-hypercapnia-recovery normoxia gas stimuli for all timepoints. Color coded segments correspond to different microvascular vasoreactive responses

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  Fig. 7. MRI analysis in skeletal leg muscle for the partial derivative of T1 with respect to time in female control (n = 4–5) and diabetic (n = 4–5) rats during different intervals of normoxia-hypercapnia-recovery normoxia gas stimuli for all timepoints. Color coded segments correspond to different microvascular vasoreactive response

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  Fig. 8. Laser Doppler perfusion measurements compared to MRI measures of partial derivative of T1 during different intervals of normoxia-hypercapnia-recovery normoxia gas stimuli in leg skeletal muscle of a representative male control (A) and a male diabetic rat (B). Measurements were collected at 6-month post-diabetes induction for each animal at a frequency of 10 Hz. Doppler perfusion is represented by black dashed lines with units in relative blood perfusion units (BPU)