Table 1.
Signalment of all horses participating in each section of the study, showing no significant differences between matched groups.
Figure 1.
The effect of GYS1 genotype on skeletal muscle histopathology.
a–d: Boxplots illustrating the percentage of muscle fibres containing (a) internalised nuclei, (b) subsarcolemmal vacuoles, (c) cytoplasmic inclusions and (d) diastase resistant inclusions in horses homozygous (HH) and heterozygous (HR) for GYS1 mutation and controls (RR). * Denotes significant differences between individual groups (p<0.05), ** (p<0.01), following post- hoc analysis. e–h: Representative images of the pathology (arrows) identified (e) internalized nuclei, (f) subsarcolemmal vacuoles, (g) cytoplasmic inclusions and (h) diastase resistant inclusions (e–g: haematoxylin and eosin; h: Periodic acid Schiff following diastase digestion). Bar = 50 µm.
Figure 2.
Representative images of dystrophin immunohistochemistry (brown staining) in skeletal muscle counterstained with haematoxylin and eosin from (A) a control horse and (B) a horse heterozygous for the GYS1 mutation. Note the normal dystrophin expression and localisation in the region of the subsarcolemmal vacuoles (arrows). Bar = 50 µm.
Figure 3.
Muscle fibre type distributions.
Boxplots illustrating the muscle fibre type composition of horses homozygous (HH) (n = 4), heterozygous (HR) (n = 8) and control horses (RR) (n = 6). * Denotes significant differences between individual groups (p<0.05) following post- hoc analysis.
Figure 4.
Resting muscle enzyme activities.
Box plots illustrating the resting (a) CK activity and (b) AST activity for each GYS1 genotype (n = 8) (HH = homozygotes, HR = heterozygote, RR = control) * Denotes significant differences between individual groups (p<0.05) following post- hoc analysis.
Figure 5.
Pre- and post exercise muscle enzyme activites.
Graph illustrating the pre and post exercise (a) CK activity and (b) AST activity for each GYS1 genotype (n = 4) (HH = homozygotes, HR = heterozygote, RR = control).
Figure 6.
The correlation between muscle enzyme activity and muscle histopathology.
Scattergraphs illustrating the correlation between the Log10 resting CK activity (A) and Log10 AST activity (B) and the percentage of fibres containing subsarcolemmal vacuoles. (HH = triangles, HR = stars, RR = circles) (n = 18).