(a) Representative spinal cord sections from AR121Q mice treated
with vehicle (1% DMSO in corn oil) or high-dose MEPB (100 mg/kg, three
times per week) from one independent experiment. Sections were stained with
H&E and toluidine blue to assess spinal cord morphology. Sections were
also stained with AR (N20), polyQ (5TF1-1C2), and ubiquitin antibodies. White
arrowheads indicate ubiquitin-positive nuclear inclusions. Scale bars represent
200 μm. (b) Quantification of the mean relative number of
cells in the spinal cord ventral horn containing positive polyQ (blue) or
ubiquitin (red) staining in AR121Q mice. Quantification was performed from total
8 fields for polyQ staining, 8 (vehicle), 10 (50 mg/kg MEPB), and 4 (100 mg/kg
MEPB) fields for ubiquitin staining, 2-4 mice per treatment group,
**P =0.0022,
***P =0.0005 by two-way
ANOVA followed by Dunnett’s posthoc analysis for pairwise comparisons
between each MEPB treatment group and vehicle. (c) Representative
skeletal muscle (gastrocnemius/soleus) sections from AR121Q mice treated with
either vehicle or high-dose MEPB from one independent experiment. Sections were
stained with H&E and Gomori trichrome to evaluate morphology, in
addition to AR, polyQ, and ubiquitin antibodies. Dotted lines trace around
representative myofibers, demonstrating differences in myofiber size. Arrows
indicate atrophied myofibers. Arrowhead indicates myofibers containing
centralized nuclei. Scale bars represent 200 μm. (d)
Quantification of the mean muscle fiber diameter of gastrocnemius/soleus
myofibers of NTG (gray) and AR121Q mice (black). Quantification was performed
from 20 muscle fibers per mouse, 2 (NTG) and 3 (AR121Q) mice per treatment
group, ****P ≤ 0.0001
by two-way ANOVA followed by Dunnett’s posthoc analysis for pairwise
comparisons between each MEPB treatment group and vehicle. Quantification was
performed from 2–4 fields/mouse, 3 mice/treatment group.
(e) Representative images of skeletal muscle stained with
antibodies against NCAM and PSA-NCAM in AR121Q mice treated with vehicle
(1% DMSO in corn oil), low-dose MEPB (50 mg/kg, three times per week),
or high-dose MEPB (100 mg/kg, three times per week). Scale bars represent 50
μm. (f) Quantification of PSA-NCAM/NCAM colocalized
regions. n = 6 fields for all NTG groups, 6, 9, and 10 fields for
vehicle, 50 mg/kg, and 100 mg/kg MEPB treated AR121Q group, 2 mice for all NTG
and vehicle treated AR121Q groups, 3 mice for 50 mg/kg and 100 mg/kg MEPB
treated AR121Q groups, ****P
≤ 0.0001 by two-way ANOVA followed by Dunnett’s posthoc analysis
for pairwise comparisons between each MEPB treatment group and vehicle.
(g) The area of testis were measured in n = 7, 6, 9,
and 9 sections from n=2, 2, 3, and 3 mice for vehicle treated NTG,
vehicle, 50 mg/kg, and 100 mg/kg MEPB treated AR121Q group, respectively. Data
were evaluated by one-way ANOVA followed by Dunnett’s posthoc analysis
for comparison between each AR121Q treatment group and NTG vehicle.
*P
=0.0342. All graphs represent mean ±
s.e.m.