(A) Schematic representation of the BDA injection site (contralateral to
stroke side) and corticospinal tract (CST).
(B–M) ISP enhances contralateral cross-callosal projections to
the stroke side (B–D, vehicle (Veh)-treated stroke mice; E–G,
ISP-treated stroke mice). Quantification in (H) and (I). ISP-treated mice show
more callosal projecting neuronal cell bodies retrogradely labeled by BDA
directly adjacent to the lesion. (C and F and higher magnification shown in
C′ and F′). ISP also enhances the corticospinal tract (CST)
sprouting from the non-stroke cortex to the contralateral side across the
midline of the cervical spinal cord (J and K and J′ and K′ showing
higher magnification). Quantification for CST cross-midline sprouting in (L).
Note that BDA injection volume at the non-stroke cortex is similar in Veh or
ISP-treated mice (representative images in B and E and quantification in M).
(N and O) ISP treatment enhances the density of 5-HT+ axons
that are in the peri-infarct area and crossing the glial scar region
(quantification shown in P and Q). Scale bar: 100 μm (n = 3 mice for each
group; multiple brain and spinal cord sections were analyzed for each mouse, and
average was used as a single data point for statistical analysis). **p <
0.01 and ***p < 0.001, Student’s t test.