GA alleviates axon and myelin loss and decreases lesion volume
after SCI
To examine the correlation between behavioral data and histological
outcomes such as axon loss, myelin loss, and lesion volume, we performed
histological analysis of the spinal cord tissues from the animals used
for behavioral experiments. First, we performed immunostaining with
NF200 and 5-HT antibodies to detect remaining axons and the density of
preserved axons. In the sham control, NF200-positive axons in both
ventral and dorsolateral funiculi were dense, and axonal packing was
uniform (Fig. 9A and B, Sham). However, the axon density was markedly
decreased in the injured tissue (Fig. 9A and B, Veh). The number of
NF200 positive axons in both ventral and dorsolateral funiculi was
significantly higher in the GA-treated group compared to that in the
vehicle-treated group (Fig. 9A and B). Moreover, the density of 5-HT
serotonergic axons in the ventral horn was higher in the GA-treated
group compared to that in the vehicle-treated group (Fig. 9C). These
results suggest that GA treatment alleviates axon loss after SCI. Next,
we measured the extent of myelin loss after injury by Luxol fast blue
staining. As shown in Fig. 9D, extensive myelin loss near the lesion
area was evident in the vehicle-treated group at 35 d after injury
compared with that of the sham control (Fig. 9D, Veh), whereas GA
treatment apparently alleviated myelin loss (Fig. 9D, GA).
To evaluate tissue loss after SCI, serial longitudinal sections were
stained with Cresyl violet, and the lesion volume was measured. As shown
in Fig. 9E, the total lesion volume was significantly reduced in the
GA-treated group at 35 d after injury compared to that of the
vehicle-treated group (Fig. 9E).