Fig. 7

Apelin-13@ROS-hydrogel administration improves rats’ function recovery after SCI Rats were randomly allocated into four groups: Sham, SCI modeling, SCI plus ROS- responsive hydrogel (ROS-hydrogel), and SCI plus Apelin-13@ROS-hydrogel. After modeling, rats in the ROS-hydrogel and SCI plus Apelin-13@ROS-hydrogel groups were immediately injected with ROS-hydrogel or Apelin-13@ROS-hydrogel into the lesion space. (A) After 28 days of modeling and treatment, spinal cord tissues were collected from model rats sacrificed under anesthesia and examined for histopathological characteristics using H&E staining. (B-C) The BBB Locomotor Rating Scale and inclined-plane test were used to evaluate the behavioral outcomes and motor ability of rats from different groups at days 0 (pre-surgery), 1, 5, 7, 10, 14, 21, and 28. (D) The apelin-13-loaded hydrogel was synthesized using apelin-13 labeled by FITC and used for in vivo degradation experiments. (E) After 28 days of modeling and treatment, the protein levels of Apelin-13 and APJ in spinal cord tissues were determined using Immunoblotting. n = 6 or 3, ** p < 0.01, vs. sham group; ## p < 0.01, vs. SCI group; && p < 0.01, vs. SCI + ROS-hydrogel group