脊髓损伤
-
Figure 2｜Argatroban improves the functional nerve outcome of SCI rats.
We performed locomotor and electrophysiology tests to evaluate the functional outcome of animals with contusive SCI treated by argatroban. Hind limb movement was completely normal before SCI and the BBB score was 21 (Figure 2A). On the first day after surgery, the BBB scores of the SCI and Argatroban groups were 0, indicating successful modeling and complete loss of hind limb motor function. SCI rats had a slight motor function recovery after SCI over time, with a score of approximately 7 at 6 wpi, indicating that functional recovery was limited to large joint movement. After argatroban administration, the motor function recovery of rats showed improvement starting from 1 wpi and increased until the endpoint, with a final score of approximately 13 (6 weeks, F(2, 15) = 182.2, P = 0.00006), indicating that gait and motor coordination of the hind limb had been restored. We also conducted gait analysis of rats at 6 wpi (Figure 2B). The regularity index of the Argatroban group was increased compared with that of the SCI group (F(2, 15) = 141.1, P = 0.00005; Figure 2C), indicating that argatroban effectively improved the gait coordination of rats with SCI. These findings were consistent with the BBB score results.
Figure 7｜Argatroban inhibits astrogliosis at the acute phase of SCI.
JAK2/STAT3 is a key signaling pathway that regulates glial scar formation (Radulovic et al., 2016). We further examined the expression of the naive astrocyte marker Vimentin after SCI (Figure 7A and B). Vimentin expression was dramatically increased in the epicenter of spinal cord at 3 dpi and was decreased by argatroban administration (F(2, 6) = 132.4, P = 0.00032). The expression of PAR1 in Vimentin+ astrocytes was increased after SCI, and argatroban administration downregulated its expression (F(2, 6) = 59.91, P = 0.00085; Figure 7A and C). The observation site in the spinal cord is shown in Figure 7D.
Figure 8｜Argatroban decreases GFAP expression and astrocyte activation for repairing SCI.
We have proved that argatroban inhibited Vimentin expression in acute SCI. To explore the long-term effects of argatroban administration on chronic SCI, the degree of glial scar formation in rats at 6 wpi was assessed by immunofluorescence staining (Figure 8A). At 6 wpi, glial scars formed in the injury center in the SCI group, and an astrocyte-activated area also formed in the epicenter; GFAP expression was significantly increased (P < 0.001; Figure 8B and C). After administration of argatroban, the expression of GFAP in the damage-related spinal cord segmented was significantly down-regulated (F(2, 6) = 43.51, P = 0.03961; Figure 8A and B), especially in the epicenter (F(2, 6) = 45.87, P = 0.00729; Figure 8A and C).