tannins and Spinal-Cord-Injuries

Mimicking soft tissue mechanical properties and the high conductivity required for electrical transmission in the native spinal cord is critical in nerve tissue regeneration scaffold designs. However, fabricating scaffolds of high conductivity, tissue-like mechanical properties, and excellent biocompatibility simultaneously remains a great challenge. Here, a soft, highly conductive, biocompatible conducting polymer hydrogel (CPH) based on a plant-derived polyphenol, tannic acid (TA), cross-linking and doping conducting polypyrrole (PPy) chains is developed to explore its therapeutic efficacy after a spinal cord injury (SCI). The developed hydrogels exhibit an excellent electronic conductivity (0.05-0.18 S/cm) and appropriate mechanical properties (0.3-2.2 kPa), which can be achieved by controlling TA concentration. In vitro, a CPH with a higher conductivity accelerated the differentiation of neural stem cells (NSCs) into neurons while suppressing the development of astrocytes. In vivo, with relatively high conductivity, the CPH can activate endogenous NSC neurogenesis in the lesion area, resulting in significant recovery of locomotor function. Overall, our findings evidence that the CPHs without being combined with any other therapeutic agents have stimulated tissue repair following an SCI and thus have important implications for future biomaterial designs for SCI therapy.

Topics: Animals; Cell Survival; Cells, Cultured; Cross-Linking Reagents; Hydrogels; Mice; Polymers; Spinal Cord Injuries; Tannins

To develop a method for the study of spinal cord injury (SCI) that can visualize the blood vessels and is compatible with hematoxylin and eosin (HE) staining and immunohistochemical techniques.. Visualization of the vascular changes is important for the study of SCI. The original ferric tannate method can stain the spinal cord vasculature to its terminals, but the diffuse tannate precipitates spoil the delicacy of the picture. More importantly, it is incompatible with HE staining and immunohistochemical techniques, which is crucial for the study of SCI. We thus aimed to develop a modified ferric tannate method that could meet the requirement for the study of SCI.. This study was carried out in China.. The original ferric tannate method involves a two-step procedure: intravascular perfusion of tannic acid, followed by soaking the tissue sections in a solution of ferric chloride. In the modified method both chemicals were delivered through perfusion.. In the original method, diffuse ferric tannate precipitates blurred the profile of the vessels. More importantly, it was incompatible with either HE or immunostaining methods. Our modified method stained the blood vessels with clean background and was compatible with both HE staining and immunohistochemical techniques.. The modified method is far superior to the original method and meets the requirement for the study of SCI.

Topics: Animals; Biomarkers; Blood Vessels; Chlorides; Coloring Agents; Disease Models, Animal; Ferric Compounds; Histocytochemistry; Immunohistochemistry; Male; Nerve Tissue Proteins; Perfusion; Rats; Rats, Sprague-Dawley; Spinal Cord; Spinal Cord Injuries; Staining and Labeling; Tannins