Thermosensitive Chitosan/Gelatin Hydrogels in Traditional Chinese Veterinary Medicine: A Prospective Review on Modernizing Acupoint Embedding

Thermosensitive hydrogels have emerged as promising intelligent biomaterials for minimally invasive delivery and targeted therapy. Chitosan/gelatin thermosensitive hydrogels, integrating the biocompatibility, biodegradability, and antibacterial activity of chitosan with the excellent adhesive properties of gelatin, exhibit unique injectability, temperature-responsive gelation, and tunable physicochemical properties. This review systematically summarizes the key performance parameters of chitosan/gelatin thermosensitive hydrogels, including injectability, gelation characteristics (with sol-gel transition tunable between 37 and 42 °C to match diverse species' body temperatures), mechanical properties, biocompatibility, degradation behavior (tunable from 1 to 8 weeks), drug-loading/release capabilities, and multi-stimuli responsiveness (pH/ROS/enzyme). It focuses on exploring their feasibility and suitability as acupoint embedding materials in Traditional Chinese Veterinary Medicine (TCVM), addressing the technical bottlenecks of traditional acupoint catgut embedding (e.g., unstable degradation, insufficient biocompatibility, and lack of drug-loading capacity). While recent studies have demonstrated the utility of such hydrogels in human disease models (e.g., rheumatoid arthritis and Parkinson's disease), their translation to veterinary acupoint therapy remains largely unexplored. The prospective application of these hydrogels in treating common animal diseases (e.g., piglet diarrhea, canine degenerative joint disease, and equine laminitis) is, therefore, proposed and analyzed as an illustrative paradigm, emphasizing its integrated "stimulation-drug delivery" function and cross-species adaptability. Additionally, the current challenges (e.g., animal-specific formulation optimization, unclear mechanism of action, and insufficient long-term safety data) and future research directions (e.g., veterinary-specific formulation development, mechanistic exploration, and clinical translation) are highlighted. This review aims to promote the interdisciplinary integration of TCVM and smart biomaterials, provide precision strategies for animal disease treatment, and ultimately contribute to the modernization and standardization of TCVM technologies.